eChapters

1. Introduction

Mushrooms represent a highly specialized group of fungi, mostly basidiomycetes, with production of fruiting bodies bearing the spores for continued propogation. The fruiting bodies vary greatly in shape, size, color, texture, structure and aroma (Rajarathnam et al., 1998). They are endowed with the unique ability to biodegrade cellulosic wastes, including lignin, and biotransform into edible fruiting bodies (Rajarathnam et al., 1992, 1998, Rajarathnam and Zakia Bano, 1990). Their chemistry is also varied comprising characteristic polysaccharides, phenolics, proteins, amino acids, peptides, lectins, fatty acids, minerals, and so on (Rajarathnam et al., 1998). The wide spectrum of compounds have endowed the mushroom species with a spectrum of biofunctional activities of medicinal importance and accordingly their role in human health are implicated through studies on chemical, cell culture and animal feeding experiments. Vast literature available on this subject is condensed for presentation here.
Fifty nine medicinal species are reported from Diaoluoshan Nature Reserve in Hainan Province, China (Li et al., 2003). A health food made from luminescent mushrooms (Mycena chlorophos) is described. The luminescent parts that emit light in the carpophore of the mushrooms are dried without thermal decomposition and pulverized (Sugimoto, 2006). Consideration is given to the health promoting properties of 3 types of Asian fungi, namely, shiitake (Lentinus edodes), reishi (Ganoderma lucidum) and maitake (Grifola frondosa). Properties considered include beneficial components (e.g polysaccharides, vitamins, amino acids) and effects on the immune system (Anon, 1997). Auricularia auricula (kikurage or tree-ear) and Tremella fuciformis (shirokikurage or white jelly-leaf) are widely used in Chinese cuisine. Chemical structures of some of the polysaccharides from A. auricula and T. fuciformis, in relation to their medicinal and nutritional effects are described (Misaki and Kakuta, 1995).

1. INTRODUCTION

Mushrooms are edible fungi of commercial importance and their cultivation has emerged as a promising agro-based land-independent enterprise. There are about 20 varieties of mushrooms being cultivated throughout the world for food. In India, only white button mushroom (Agaricus bisporus J.E. Lange Imbach), oyster mushroom (Pleurotus spp. [Fr.] P. Kumm) and paddy straw mushroom (Volvariella volvacea [Bul.] Singer) are grown commercially. Of these, white button mushroom contributes ~90% of the total production. Mushrooms have been recognized as an alternate source of good quality protein and produce the highest quantity of protein per unit area from agro-wastes. Besides, they provide potentiality for generating employment, improving economic status of growers, help in checking pollution and earn foreign exchange.

Out of the total production about 45% of mushrooms produced are consumed in the fresh form while the other 55% are processed, with 5% in dehydrated form and 50% in canned form. This is because their shelf-life in the fresh form is very short and hence mushrooms are traded in the world market mostly in the processed form. Fruiting bodies (reproductive phase) of Agaricus are appreciated not only for texture and flavour but also for their chemical and nutritional characteristics.

Sciarid(mushroom flies): Bradysia paupera, Lycoriella auripila: Sciaridae

The larvae feed on the mycelial attachments and restrict the growth of the spawn. The maggots also feed on the developing mushrooms or pinheads and thus cause loss in yield. They also bore the developing mushrooms and render them hollow.

1.1. Mushroom

Fruiting body of fungus appears above ground and contains spores.

Fungi are network of fine microscopic threads collectively known as mycelium.

Fungi are the part of the plant kingdom and don’t contain chlorophyll and root system.

Mushroom comes under sub division Basidiomycotina, order – Agaricales.

Melons (Cucumis melo) are annuals with climbing, creeping or trailing vines of length up to three meters. The desert types quench thirst and add to the nutrient content of main diet. The non-desert types are used as vegetables. Muskmelon (Cucumis melo., 2n=2x=24) encompasses the netted, salmon -flesh cantaloupe, the smooth – skinned green fleshed ‘Honey Dew’, the wrinkled, white – fleshed, ‘Golden Beauty’ and several other dessert melons in USA.

Origin: Not known with certainty but, 40 or more wild species of Cucumis are found to occur in the tropics and subtropics of Africa. Wild species of Cucumis occur in Africa and it is likely that it originated in African continent. It does not appear to have been known to the ancient Egyptians, not to the Greeks and seemed to have reached Europe towards the decline of Roman Empire. Although melon was introduced into Asia at a comparatively later date there are undoubtedly well developed secondary centers of origin of C. melo in India, China and then Southern USSR. In India Oriental pickling melon (C. melo var conomon) and snap melon (C. melo var momordica) are unique and have considerable variability in Western Ghats of India. They are popular desert and preserving melons cultivated in Warm humid tropical condition of South India. It is also considered that China as primary center of origin and Indo-Burma as secondary center of origin. It has been introduced to Europe and from Europe to the USA by the early travelers. At present muskmelon is being cultivated throughout the world under tropical and subtropical climatic conditions. Polymorphism in leaf, flower, fruit shape and colour (Kirkbride, 1993), allowed the classification of horticulturally important melons into seven groups.

Scientific name: Abelmoschus moschatus Medik.
Family: Malvaceae
Abelmoschus moschatusMedik., commonly known as ambrette, annual hibiscus, or musk mallow, is a tropical plant species belonging to the Malvaceae family. Native to India, Southeast Asia, and Africa, this herbaceous plant has been cultivated for centuries for its medicinal, culinary, and fragrant properties. It is an annual or biennial plant that grows up to 2 meters in height, with hairy, palmate leaves and showy, yellow flowers with a purple center. The plant's seeds, leaves, and flowers emit a strong, musky fragrance used in perfumery and traditional medicine. Abelmoschus moschatus is a warm-season crop that thrives in tropical and subtropical regions, requiring well-drained soil and full sun to partial shade. The plant has been used in traditional medicine for its anti-inflammatory, antibacterial, and antifungal properties, and its leaves and flowers are used as a vegetable and in salads. In contrast, the seeds are used as a spice. The plant's essential oil is also used in perfumes, cosmetics, and aromatherapy products, making it a valuable crop for small-scale farmers, providing income through the sale of seeds, leaves, and essential oil.
Origin and distribution
Abelmoschus moschatus, a tropical plant species, is native to India and widely cultivated in Southern China, Vietnam, Nepal, Tropical Asia, South East Asia, and parts of the Pacific. It is also found in the tropical regions of Africa, Australia, and the Americas.

Melon or muskmelon (Cucumis melo L., 2n = 2x = 24, family Cucurbitaceae, mostly andromonoecious, cross-pollinated as well as self-pollinated) has latest global production close to 30 million tons where top ten producing countries are China (16.0 million tons), Turkey (1.8 million tons), Iran (1.6 million tons), Egypt (1.1 million tons), India (1.0 million tons), Kazakhstan (0.9 million tons), USA (0.8 million tons), Spain (0.7 million tons), Italy (0.6 million tons), Guatemala (0.6 million tons). India produced 1.2 million tons melons from 54000 ha acreage during 2017-18 giving a productivity of 22 tons/ha (MAFW, 2018).

US melons encompass the netted, salmon-flesh cantaloupe; the smooth-skinned green fleshed ‘Honey Dew’, the wrinkled-skinned, white-fleshed ‘Golden Beauty’ and several other dessert melons. Other forms with different fruit characters (white-fleshed, green-fleshed, having striped thin skin and juicy) are commonly found in India and in Orient as indigenous land-race cultivars. These are getting displaced by the cultivar types as cantaloupe, Madhuras and Galia due to their long shelf life.

Melon is mainly cultivated for the consumption of the fruits which can be harvested immature; in this case, the fruit is not sweet and can be eaten raw, cooked or pickled. In most cases, the fruit is harvested at maturity with high sugar content (mainly sucrose). Fruit is mainly eaten raw; marginal uses are cubes canned in syrup, in “fruits confits”, candies, ice-creams, biscuits and also in cosmetics. Locally, seeds can also be consumed (Pitrat, 2008).

Melons are annual plants that have up to three meters of climbing, creeping, or trailing vines. Several of them are consumed as dessert fruits while a few varieties/types are used for vegetable purposes. Generally, the fruits of commercial varieties are sweet, juicy, delicious with good nutritional and medicinal properties and a daily intake of 120-150 g can help in weight loss, better eye and skin health (Shivapriya et al., 2021).

Currently, muskmelon is being cultivated throughout the world, especially under tropical and subtropical climatic conditions. In India, muskmelon is grown in 54,000 ha with a production of 1.23 million tons (NHB, 2018). The estimated national seed requirement per year is about 27 tons with a value of about Rs. 27 crores. The crop is cultivated mainly in rabi season (November to February sowings), thus limiting its availability in the market during summer. Rarely, melons are cultivated for the off-season market, and those fetch a premium price. The total value of muskmelon fruits in the domestic market is estimated as Rs.1231 crores.

Muskmelon, Cucumis melo under the family Cucurbitaceae (Chromosome number: 2n = 2× = 24) is a highly relished crop because of its attractive flavour, sweet taste and refreshing effect. It is an important crop of Africa, Middle East, Asia, Southeast Asia, Japan, USA, South and Central America, France, Spain, Israel and many eastern European countries. Mature fruits are eaten fresh as a dessert fruit, canned or used for syrup or jam. Muskmelon is quite rich in ß carotene, vitamin B9, vitamin C and minerals like potassium and low in calorie content.
Origin, domestication and adaptation in India
The genus Cucumis, which includes cucumber (Cucumis sativus) and melon (Cucumis melo), has numerous wild African species, and it has therefore been assumed that melon originated in tropical Africa in eastern region, south of Sahara Desert. This proposition is supported by the presence of true wild melons which can still be found in some African countries. Some botanists consider melons native to the Levant and Egypt, while others place their origin in Iran, India, Afghanistan or Central Asia. Sebastian et al (2010) reported that the wild progenitor of C. melo occurs in India, and they confirmed that the Southeast Asian Cucumis hystrix is the closest relative of cucumber and most surprisingly, the closest relative of melon, Cucumis picrocarpus was from Australia. The wild forms of muskmelon reported from India are feral escapes derived from local cultivars.

The initial symptom of Alternaria brassiciola appears as small, dark colored spots which enlarge rapidly to form circular lesions. Under humid conditions a bluish velvety fungal growth is seen in the centre of these spots. Spots caused by Alternaria brassicae are almost similar to those produce by Alternaria brassicicola but are comparatively smaller and lighter in colour. When many spots are formed on the leaves, the leaves turn yellow and dry prematurely. Formation of pods and seeds are adversely affected.

Alternaria Blight
Diagnostic Symptoms
• Symptom first appear on the lower leaves as small circular brown necrotic spots which slowly increase in size.
• Many concentric spots coalesce to cover large patches showing blightening and defoliation in severe cases.
• Circular to linear, dark brown lesions also develop on stems and pods, which are elongated at later stage.
• Infected pods produce small, discolored and shriveled seeds( Fig.2).
Etiology
Scientific Classification
Kingdom : Fungi
Phylum : Ascomycota
Class : Dothideomycetes

Introduction

Agriculture is the foundation of India’s economy, as it provides food to people, feed to cattle, raw materials to primary and secondary industries, contributes upto 19 percent of GDP and employs 54.6 percent of the workforce (Kirti and Prasad, 2016). Due to diverse soil and climate conditions, vast varieties of crops such as cereals, pulses, spices , millets, oilseeds, flowers and fruits are being grown in India. Among these crops grown, India is among the leading producers of pulses, cereals and spices in the world (Mishra et al., 2021). India is the fourth largest oilseed economy in the world. Among oilseeds, there are nine crops that are the primary sources of oils in the country, out of which seven are edible oils (soybean, rapeseed-mustard , groundnut, sunflower, sesame, niger and safflower) and two are non-edible (linseed and castor).

To isolate a streptomycin resistant mutant of E.coli by Direct selection using Gradient Plate Method.

Introduction

Zylbalskii devised this technique.

A mutation is any change in the nucleotide sequence of DNA. These changes are heritable. Although most mutations are harmful to the organism, a small percentage is beneficial under certain environmental conditions. Mutation can occur during chromosome duplication and they may be spontaneous of they may be induced by mutagenic agent. In this experiment, we select for a mutation causing streptomycin resistance in E. coli. Resistant mutants will be detected directly using thy gradient plate method.

Principle

Microbiologist developed a highly efficient method for isolation of antibiotic resistant mutant. The gradient is said as gradient of antibiotic formed on an agar plate. A gene imparting resistant toward an antibiotic is present in plasmid or chromosome. The occurrence of mutant with different level of streptomycin resistant involves mutation of gene with unequal potential. This means that under certain cells degree of mutation is more while few shows less mutation. Some cells show intermediate resistant while others show completes resistant. The resistant in cell against streptomycin of this type, while in case of penicillin resistant increases step arise & so resistant mutant of high concentration of penicillin cannot be isolated/ obtained. While it is possible with streptomycin obtaining high resistance to penicillin stepwise & so this stepwise increase in resistance involves mutation of gene with equal potential. This theory of mutation through multi step procedure. The gene direct the organism to produce an enzyme, which inactivates an antibiotic & thus resistance to antibiotic, is observed in case of cells. Resistance of antibiotic is a plasmid-mediated resistance.

To isolate a streptomycin resistant mutant of E.coli by Indirect selection using Replica Plate Method.

Introduction

J. Lederberg & his wife E. M. Lederberg devised this technique in 1952.

U.V. light coming from the sun emits strong radiation to extent the antibacterial effect in the microbial population. However it has a very short penetration power, UV light is used as a mutagenic agent & was used by Beedle & Tatum to obtain biochemical mutation. The mutation rate is only once in 10^-9 cells per population. Then hence using mutagens like UV light by 10 to 1000 folds will increase this mutation rate.

In isolation of the mutant using UV light the dose of UV light is measured by its units/nm² organisms. The time selected for the mutation is calculated on the basis of 0.1 to 1% survival & a suitable biochemical character is used to evaluate the mutation.

A detailed treatment on the concepts of mutagenic effectiveness and efficiency was given by Konzak et al. (1965). They proposed the term “effectiveness” as a measure of gene mutations in relation to the dose and “efficiency” as an estimate of the mutation rate in relation to other biological effects induced, such as lethality, injury or sterility. To obtain high efficiency, the mutagenic effect must greatly surpass other effects in the cell, such as chromosomal aberrations, and toxic effects which generally lead to damage

Mutation
Definition: “Mutation is the change in our DNA base pair sequence due to various environmental factors such as UV light, or mistakes during DNA replication.”
What Are Mutations?
The DNA sequence is specific to each organism. It can sometimes undergo changes in its base-pairs sequence. It is termed as a mutation. A mutation may lead to changes in proteins translated by the DNA. Usually, the cells can recognize any damage caused by mutation and repair it before it becomes permanent.
A mutation is a sudden, heritable modification in an organism’s traits. The term “mutant” refers to a person who exhibits these heritable alterations. Mutations usually produce recessive genes.

Mutations are sudden heritable changes in characteristic of the organism, that is other than due to recombination (Swaminathan, 1983). Mutations occur naturally as spontaneous mutations and induced as spontaneous mutations and induced artificially by treating the biological materials with physical and chemical agents (mutagens). Experimental mutagenesis is effective method to enlarge genetically controlled variation, considerably within a short time.

Darwin’s theory of evolution explains that “variation is the mainspring of evolution”. The extent of genetic variability available in the breeding population and the selection techniques determine the efficiency of any breeding programme. In classical plant breeding programme, variation is generated by hybridization and selections are made from the resulting segregating generations. Induced mutagenesis can supplement hybridization or replace as a source of variability. Thus, mutation provides the raw material for crop evolution (Mahadeva and Randerson, 1982) and it provides the fundamental variability required for crop improvement by breeding (Konzak, 1984).

MUTATION BREEDING

Mutation refers to sudden heritable change in phenotype of an organism or permanent change in the number, kind and sequence of nucleotides in genetic material, while individuals showing these changes are known as mutants. Mutation was first discovered by Wright in 1791 in male lamb which had short legs. Hugo de vries coined the term mutation. In crop improvement the breeders are always look for wide range of variability and stabilization of desirable traits. Mutation breeding is very useful in inducing new variability, which is an essential requirement of any plant breeding programme. The modern day cultivars are the resultants of various breeding techniques like selection, hybridization, tissue culture and mutagenesis including some biotechnological tools. Novelty in commercial traits like colour, size, shape, length, post harvest life of flowers etc. are always valued and preferred by consumers. Mutation breeding by exposing planting material with irradiation has play vital role in inducing novelty in a number of flower crops.

MUTATION BREEDING

Mutation refers to sudden heritable change in phenotype of an organism or permanent change in the number, kind and sequence of nucleotides in genetic material, while individuals showing these changes are known as mutants. Mutation was first discovered by Wright in 1791 in male lamb which had short legs. Hugo de vries coined the term mutation. In crop improvement the breeders are always look for wide range of variability and stabilization of desirable traits. Mutation breeding is very useful in inducing new variability, which is an essential requirement of any plant breeding programme. The modern day cultivars are the resultants of various breeding techniques like selection, hybridization, tissue culture and mutagenesis including some biotechnological tools. Novelty in commercial traits like colour, size, shape, length, post harvest life of flowers etc. are always valued and preferred by consumers. Mutation breeding by exposing planting material with irradiation has play vital role in inducing novelty in a number of flower crops.

TYPES OF MUTATION

Based on occurrence

(1)Spontaneous mutation: Occur spontaneously in nature and not present in sufficiently high frequency and spectrum.

(2)Induced mutation: Artificially produced by the treatment of various mutagenic agents and present in sufficiently high frequency and spectrum

The discovery of mutagenic effects of X-rays on the fruit fly (Drosophila) by H. Muller in 1927 and by L. J. Stadler in barley and maize in 1928 paved the way for researchers to experiment with its effects on various organisms. In 1928, H. Stubbe showed the use of mutagenesis in producing mutants in crop plants like tomato, soybean and others. The first commercial mutant was produced in tobacco in 1934. Reports by B. Sigurbjornsson and A. Micke mentioned 77 cultivars that were developed through mutagenesis prior to 1995. In 1995, this number was 484. This number has since been significantly increased covering a large number of crops, namely, corn, wheat, pea, chrysanthemum, poinsettia, dahlia, citrus, apple, peach and the modified traits include plant maturity, winter hardiness, lodging resistance, protein and lysine content and numerous ornamental mutants. By the end of 20th century, the number of mutant varieties rose to 2252 covering a range of crops like cereals, oilseeds, pulses, vegetables, fruits, fibres, and ornamentals. Majority of these mutants were released as direct mutants and the rest as a result of cross breeding with the mutants. Most of the mutant varieties have come as a result of using physical mutagens (X-rays, gamma rays, thermal and fast neutrons) with gamma rays alone accounting for more than 60% of the mutant varieties. By 2017, nearly 3250 mutant varieties belonging to 175 plant species have been developed and released where China, Japan, India, Russia, the Netherlands, Germany and USA are the leading countries. India with 345 commercialized mutants stands third after China (810 mutants) and Japan (481 mutants). Thus mutation breeding is a significant contributor to the development and release of commercial cultivars in several crops and for several traits.

Mutations are sudden and heritable changes in the genetic material. They can result in deletion, inversion and translocation of certain portions in the chromosomes, which can result in the changed expression of a trait due to the interaction of alleles within or without the locus, sometimes the effects revert back or can be heritable.

Most of the fruit crops are highly heterozygous. However, heterozygosity is one of the advantages when it comes to mutation. In highly heterozygous crops wherein there is a need for improvement in a single trait, mutations have been of great use. One of main limitations is use of vegetative material, which due to the unlikelyhood of uniform penetration and distribution of mutagenic agent can result in chimera. Although hybridization and selection have made a fair dent in the improvement of fruit crops, mutation is one of the methods that can be relied upon to develop pre-breeding lines and to bring about change in the quantitavie traits. Another very important fact is that there are crops like grapes wherein a lot of spontaneous mutants have become established varieties viz., Sonaka and Saritha to quote a few. Some of the existing varieites wherein one or two traits need to be improved, mutation would greatly help in this in comparatively short time. In some of the crops like sapota, wherein the conventional breeding would take long time, mutation can be resorted to both for inducing variability in the germplasm as well as for trait improvement. It is also to be noted here that mutation breeding can be a good supplement for conventional breeding, more so with the emergence of tissue culture propagation, which often throws up spontaneous mutants. Mutation as a methodology can also be tried in some fruit crop spp where there is no disease resistance source within. It can also be adopted in cases where there is a need to break linkages.

Vegetables are cheaper source of carbohydrates, proteins, minerals, vitamins and dietary fibers, and hence, assume a place of very great importance in the diet of individuals. All kinds of vegetable are grown almost universally. India occupies the prime position in the production of vegetable crops and is the second largest producer of vegetables in the world. The area and production of vegetables in India have been increasing during the post-green revolution period, and the country is heading towards another revolution in the form of Golden Revolution. However, there is an utmost requirement for genetic improvement of vegetable crops in terms of productivity, qualitative characters and resistance to biotic and abiotic stresses. For any genetic improvement programme, the presence of genetic variation is pre-requisite and mutation is the ultimate source of this heritable variation.

Mutation technique that holds promise of generating a much wider desirable variability than classical breeding has been refined. Out of 2275 mutant varieties worldwide in all crops, as many as 66 mutants are in vegetables. In terms of percentage, China, India, USSR, The Netherlands, The United States of America and Japan account for 26.8, 11.5, 9.3, 7.8, 5.7 and 5.3%, respectively of mutagen varieties in all crops. Such varieties are 3% in case of vegetables. After mutation treatment by a mutagen to a specific plant, DNA alterations (deletion, duplication, inversion, translocation, or transposition of larger DNA fragments, or simple basic pair changes) occur and lead to the DNA sequence change. Hence, new characteristics of that plant are established. In fact, induced mutations supply us with many new plant lines, which may be used as primary materials for crop breeding. Hence, mutation breeding seems to be an effective and ultimate option to improve vegetable crops in the shortest possible time. A large number of new promising varieties in different crops, including vegetables, have successfully been developed worldwide using various mutagens (Chopra, 2005).

22.1 Introduction

Mutations are sudden heritable changes in the genotype of an organism. De Vries (1900) for the first time used the term mutation (mutare in Latin means ‘to change’) for the appearance of new types in evening primrose (Oenothera) plant. In 1901 he put forth the idea of producing mutations artificially for use in crop improvement. Alberto Pirovano (1922) was first to use X-rays and ultraviolet rays for inducing mutations in plants, but his work remained unknown. So, Muller (1927) became the first known to induce mutation in Drosophila fly using X-rays. Though Stadler (1928) had started working simultaneously on barley and maize and induced mutations, he was late in reporting mutation due to longer life cycle of these plants compared to Drosophila. Mutation may be gene mutation (the result of change in the nuclear gene or plasma gene) or chromosomal mutation (change in chromosome number, structure or chromosomal aberrations of various types).

Since genetic variability is essential for any crop improvement programme, the creation and management of genetic variability becomes central to crop breeding. Experimentally induced mutations provide an important source of variability. An advantage of such created variability is that the starting point can be an agronomically accepted cultivar rather than a genetic stock of no direct commercial value with many undesirable attributes. It should, however, be realized that none of the imposed treatments in a plant system has so far been able to direct a specific change. As a result, following mutagenic treatments, a mixed bag of induced variants is found and many of these may not be of any value. Also, many events take place concurrently in a treated cell to produce variation at several loci within a genome. Because of these reasons it will be unrealistic to expect miracles out of a mutation breeding programme. The desired results can be achieved only when the objectives are clearly defined and the experiments are specifically designed to achieve those objectives. When a mutant of the required type is obtained, we only reach the step of identification of a desired recombinant in a conventional breeding programme and all the succeeding steps of evaluation of the mutant are in no way different from those in the conventional breeding procedures.

Refers to entire operation of the induction and isolation of mutants.

Term mutation was introduced by Hugo de vries in 1900 in connection with sudden heritable changes observed by him in Oenothera.

Mutagenesis is the process whereby sudden heritable changes occur in the genetic information of an organism not caused by genetic segregation or genetic recombination, but induced by chemical, physical or biological agents.

Mutations were first identified by Hugo de Vries in the late nineteenth century, while experimenting on the ‘rediscovery’ of Mendel’s laws of inheritance. He coined the term ‘mutation’. Radiation-induced mutations as a tool for generating novel genetic variability in plants, advanced as a field after the discovery of the mutagenic action of X-rays demonstrated in maize, barley and wheat by Stadler. The discovery of X-rays by Rontgen in 1895 led to the application of X-rays for inducing mutations in fruit fly by Muller (1927). Mutation is of two types

A. Define/Explain the followings

1. Mutation: Sudden heritable change in the phenotype of an individual.

2. Macro-mutations: Mutations with distinct morphological changes in the phenotype are called macro-mutations. Such mutations are found in qualitative character and, therefore, are also called oligogenic mutations.

Mutation is defined as a sudden heritable change in gene or in chromosome structure. The process of hereditary change is termed mutation and the individuals affected by the change are called mutants. Besides recombinations, mutations are the cause of genetic variation from which every breeding activity proceeds. By means of mutations, the multiplicity of the types of a population is not only increased by one genotype, but also by large number of further new genotypes due to possibility of subsequent recombinations of mutant with the existing genotypes.

Mutation breeding is a method that uses physical radiation or chemical means to induce genetic variation in plants to develop new crop varieties. Mutation can be defined as a sudden heritable change in the character of an organism which is not due to either segregation or recombination. Mutation is the source of most genetic variation and the motor of evolution. It is a natural process, which occurs spontaneously and slowly over generations in plants, animals and all living beings. It involves alteration of their DNA, leading to the development of changes within the organism. Mutation may be sped up through the treatment of physical or chemical mutagens to achieve alteration in characteristics that are useful for the development of new variety of a plant species.
Spontaneous mutations
Spontaneous mutations are the net result of all that can go wrong with DNA during the life cycle of an organism (Glickman et al., 1986). Thus, the types and amounts of spontaneous mutations produced are the resultant of all the cellular processes that are mutagenic and those that are anti-mutagenic. Spontaneous mutations occur naturally without any apparent cause however, there are two possible sources of origin of these mutations.

Introduction

My journey into the heart of wildlife conservation began in the unassuming classrooms of KendriyaVidyalaya, where my curiosity for the natural world was nurtured by dedicated teachers and an enriching curriculum. My dreams took f light when I studied stories of Mahadevi Verma in my school days where she was taking care of wild animals in her home. Fuelled by my determination, I pursued my education in Veterinary College, Hebbal, Bangalore from 2006 to 2011. To increase my knowledge and help the wild animals in better way, I did master in Veterinary Microbiology from Veterinary College, Hebbal, Bangalore during 2012-2014, research was conducted in “Salmonellosis in Wild Animals” and PG diploma course in wild animal disease management from TANVAS, Chennai in 2016 research was on “Oral Microflora of Snakes”. Pursing higher studies gave direction to help wild animal, also gave me abilities to write research paper which will help the communities.

Mycobacteria are slender rods of varying lengths that sometimes show branching filamentous form resembling ‘fungal mycelium’. Hence, the name mycobacteria, meaning fungus like bacteria.
Although cytochemically gram positiive, the Mycobacteria do not take up the dyes of the gram stain because the cell walls are rich in lipids – Mycolic acid. Once a dye has been taken up by the cells they are not easily decolourised, even by acid-alcohol. Mycobacteria are therefore called as acid-fast bacilli. The genus includes animal and human pathogens as well as saprophytic members often referred to as atypical, anonymous, opportunistic, tuberculoid and MOTT (Mycobacteria other than typical tubercle) bacilli. Clasification of Mycobacteria (Tubercle Bacilli)
I. Slowly growing Mycobacteria
• Mycobacterium tuberculosis causes human tuberculosis in human and dogs.
• Mycobacterium bovis causes bovine tuberculosis in many animal species and also cause tuberculosis in human
• Mycobacterium africanum causes human tuberculosis.
• The human type (Mycobacterium tuberculosis) is primarily a pathogen for man. But can cause disease in cattle, pigs, dogs, monkeys, parrots and other species. The bovine type (Mycobacterium bovis) is a common cause of disease in domestic animal particularly cattle, pigs, cat, dogs and horse. The avian type (Mycobacterium avium) is primarily a pathogen for birds. But can cause disease in cattle, sheep, goat and pigs.

Etiology

The condition is characterized by formation of granuloma to pyogranulomatous dermatitis with paniculitis. The causative organism is normally present in the macrophage which may be Mycobacterium tuberculosis, M? bovis and M? microti.

Etiology

Genus Mycobacterium contains many pathogenic species that can cause disease in birds (M. avium, M. tuberculosis, M. genavenes, M. gordonae). Within M. avium, organisms are divided into four sub species. M. avium sp avium, M.avium sp silvaticum, M. avium sp homnissuis and M. avium sp paratuberculosis. Mycobacterium avium sp avium - has wide host spectrum; poultry, pigeons, raptors, ratites and wild birds. M. genavense- affects Psittacines and passarines. M. tuberculosis- psittacines and other cage birds, and wild birds in captivity. M.bovis- Psittacines and others.

Under natural conditions, M. avium sp avium does not cause severe disease in mammals except in rabbit and pig. Majority of mycobacteriosis in pigs is by M. avium sp avium. In cattle and other mammal infection by M. avium remain localized and is known to give positive reaction to mammalian tuberculin. The disease in caged and wild birds in captivity is common with M. tuberculosis, because of its close contact with humans. Tuberculosis is a serious problem in zoological gardens. M. avium is being isolated in increasing number of immunocompromized human patients.

In 1882, Robert Koch first isolated the organism, stained with alkaline methylene blue and vesuvin as counter stain and proved its etiologic relationship with Tuberculosis.  Ehrlich first developed acid fast stain in 1882 and used for better staining of the bacteria which was adopted by Robert Koch. Later this staining technique was modified by Ziehl-Neelsen, accordingly it is now a day known as Z-N staining. In 1890, Koch prepared a glycerine broth extract of the tubercle bacillus, known as ‘tuberculin’.

      He tried to prepare it as a curative agent; however, it was used later in diagnosis. In 1895, Johne and Frothingham described the first case of paratuberculosis in cattle, later known as ‘Johne’s disease’. Although, the causative agent was first isolated by Twort and Ingram in 1910.

            In India, bovine Tuberculosis was reported from several states since 1959 (Dhanda and Lal, 1959). Whereas bovine paratuberculosis was first reported by Nanda and Singh (1940) in Hissar, Haryana.

Introduction

Avian mycoplasmosis is caused by several pathogenic mycoplasma of which mycoplasmosis due to Mycoplasma gallisepticum (Mg), Mycoplasma synoviae (MS) and Mycoplasma meleagridis are important. The mycoplasma are group of bacteria that lack cell wall due to which the shape of bacteria is pleomorphic. Due to lack of cell wal, mycoplasma are resistant to those drug which act on cell wall and includes Penicillin and its derivatives. Mycoplasma primarily affects respiratory system and joints in birds and respiratory and urogenital system in humans. The avian mycoplasma are mainly transmitted by vertical route (egg transmission), but can also transmitted by horizontal route. Mycoplasma gallisepticum (Mg) causes chronic respiratory disease (CRD) in chicken, turkeys and game birds. Mycoplasma synoviae (Ms) causes infectious synovitis in chicken and turkeys whereas Mycoplasma meleagridis cause disease in turkey. The Mg and Ms belongs to class of Mollicutes (Molecutis: soft tissue), order Mycoplasmatales and family Mycoplasmataceae. The CRD caused by Mg affects respiratory system and air sac in presence of other respiratory pathogen/ stress or immunosuppression. Clinically, CRD affected birds show respiratory rales, gasping, nasal discharge, and rhinitis with mortality due to complication with other respiratory viral pathogens or E. coli infection. The Ms has affinity for tendon and ligaments of joint causing severe lameness due to tenosynovitis with mild lesions in respiratory system and air sac. The Ms affected birds show lameness, breast blister and increased culling of male breeder birds. The Mg and Ms causes significant losses in poultry industry due to decreased egg production, condemnation and downgrading of carcass and decreased hatchability. Mycoplasma meleagridis in turkey associated with air sacculitis and drop in egg production.

    Q.1.    How many species of Mycoplasma are responsible for causing mastitis?
    Ans.    At least seven species like Mycoplasma bovis, Mycoplasma Canadensis, Mycoplasma bovigenitalium, Mycoplasma alkalensis, Mycoplasma capricolium, Mycoplasma californicum, Mycoplasma disper and Ureaplasma sp. are responsible for causing mastitis

    Q.2.    Which herds are more prone to such type of mastitis?
    Ans.    The herds where milking hygiene is very poor and when the cows are imported from other farms or from public sale yards.

    Q.3.    Which organs act as common habitat of the Mycoplasma organisms?

The name Mycoplasma is originated from the Greek word mykes (fungus) and plasma (formed). It was first used by Albert Bernhard Frank, a German Biologist in 1889. He thought it was a fungus. An older name for Mycoplasma was Pleuropneumonia-Like Organisms (PPLO), referring to organisms similar to the causative agent of contagious bovine pleuropneumonia (CBPP). It was later found that the fungus-like growth pattern of M. mycoides is unique to that species. It was first isolated in 1898 by Edmond Nocard and E. Roux from bovine lungs. Whereas, Mycoplasma pneumoniae was considered as a virus previously. Eaton and his co-workers cultured the causative agent of human primary atypical pneumonia (PAP) or "walking pneumonia." It was known as "Eaton's agent." In the early 1960s, Leonard Hayflick, in Philadelphia, was first to isolate and cultivate the causative agent of primary atypical pneumonia and identified the agent as a Mycoplasma and named it Mycoplasma pneumoniae.

The mycoplasmas are microorganisms in the class Mollicutes. Of the nine genera in this class, five contain species of veterinary interest. The genus Mycoplasma, in which there are about 100 species, contains most of the animal pathogens. The first mycoplasma identified in 1890 was Mycoplasma mycoides subspecies mycoides, the cause of contagious bovine pleuropneumonia. Similar types of mycoplasmas which were subsequently identified were called pleuropneumonia- like organisms (PPLO).
Mycoplasmas, the smallest prokaryotic cells capable of self-replication, are pleomorphic organisms ranging from spherical (0.3 to 0.9 pm in diameter) to filamentous (up to 1.0 μm long). Because they cannot synthesize peptidoglycan or its precursors, they do not possess rigid cell walls but have flexible, triplelayged outer membranes.
Their flexibility allows them to pass through bacterial membrane filters of pore size 0.22 to 0.45 μm. Mycoplasmas are susceptible to desiccation, heat, detergents and disinfectants. However, they are resistant to antibiotics such as penicillin which interfere with the synthesis of bacterial cell walls. Based on 5s rRNA sequence analyses, the mycoplasmas have been shown to be linked phylogenetically to Gram-positive bacteria such as Clostridium species which have low guanine-cytosine content in their DNA. They require enriched media for growth, characteristically forming umbonate micro-colonies
when illuminated obliquely and microcolonies with a ‘fried egg’ dppearance in transmitted light. The dense central zone is due to extension of the microcolony into the agar. Mycoplasmas, which have relatively small genomes (approximately 800 genes) are fastidious in their growth requirements.
Most mycoplasmas are facultative anaerobes and some grow optimally in an atmosphere of 5 to 10% CO2. Nonpathogenic anaerobic mycoplasmas are found in the rumens of sheep and cattle. The genera Mycoplasma and Ureaplasma contain animal pathogens.

1. Introduction
Bioremediation is an environmentally friendly process that uses numerousdifferent microbes (e.g., fungi & bacteria), green plants, or combinations
of them to weaken and detoxify dangerous pollutants in a sequential orsuccessional manner. The pollutant composites are converted by biologicalorganisms through a response that takes place as part of their metabolicprocesses. They convert poisonous pollutants into carbon dioxide (CO2) andwater (H2O), microbial biomass, and other products that are less poisonous.The organic wastes are biologically degraded under controlled, harmless, andsafe condition into inoffensive products below the admissible limits establishedby supervisory authorities.

Mycorrhizal symbiosis is the most prevalent and important mutualistic association in plant kingdom. ‘Mycorrhiza’- the word means fungus - root, this association was reported by A.B.Frank in the year 1885. Nearly 95% of plant species form this mycorrhizal association. This serves as critical linkage between plant roots and soil and characterized by the movement of plant produced carbon to fungus and fungal acquired nutrients to plants. Through its hyphae this fungus absorbs the available P from soil and transports directly to root cortex. Mycorrhizal associations vary widely in structure and function. There are seven types of mycorrhizae (Table 1). These are endo (arbuscular), ecto, ectendo, arbutoid, monotropoid, ericoid, and orchidaceous mycorrhizae. Among them, endomycorrhizae and ectomycorrhizae are the most abundant and widespread

Mycorrhizae denote the symbiotic associations between plant roots and fungal mycelia. Literally it means fungal root. In 1840, Vittandini proposed that ‘tree rootlets are nourished by certain fungal mycelia which mantle them’. The first illustrations of mycorrhiza were published in the same year by Robert Hartig. However, in 1885 A.B. Frank coined the term “mykorrhizen” to the mutualistic symbiotic fungal association of roots (‘mykos’ fungus ‘rhizen’ roots). He characterized the sheath-forming fungi on tree as ‘ectotropisch’ (ectotrophic) and those without such compact sheath as ‘endotropisch’ (endotrophic). Fossil records reveal that mycorrhizae are as old as terrestrial plants.

The term ‘mycorrhizae’ was coined more than a century ago (Frank 1885) describing that the roots of most plants are colonized by fungi and transformed into fungus roots organ. Mycorrhizae result from a mutualistic symbiosis between plant roots and certain fungi. Roots of most flowering plants live in mutual symbiosis with mycorrhizae which bio-tropically colonise the root cortex and extra-metricial mycelia help the plant to obtain plant nutrients from soil (Barea, 1991).

These fungi are ubiquitous in soil and are found in the roots of many Angiosperms, Gymnosperms, Pteridophytes and Thallophytes (Mosse et al., 1981). The mycorrhizal fungi perform the function of root hairs. The fungus takes carbohydrates from the plant and in turn supplies the plants with nutrients, hormones and protects it from root pathogens. The dependency of fungal species on host plant ranges from obligate to facultative (Brundrett, 2002; Read and Perez-Moreno, 2003). The mycorrhizal plants have greater tolerance to toxic heavy metal, nigh soil temperature, soil salinity, unfavourable soil pH and to transplantation shocks.

They play an important role in increasing plant growth and nutrients uptake (Bagyaraj, 1992, VasanthaKrishna and Bagyaraj 1993). These fungi can be used to promote biotechnologically developed plant in soil (Varma and Schuepp 1994).

INTRODUCTION

The fine feeder roots of many vascular plants are invaded by specific nonpathogenic fungi forming a distinct morphological unit known as mycorrhiza (In Greek, Mykes mean mushroom or fungus, rhiza mean root). Physiologically mycorrhiza represents a case of symbiosis.

The term mycorrhizae were coined by a German botanist Albert Bernard Frank in 1885 which literally mean “fungus-roots”.  Mycorrhizal fungi form a symbiotic association with agricultural and horticultural crops in addition to certain tropical tree species.
Mycorrhizal fungi are broadly classified in to two groups:
1) Ectomycorrhizae  
2) Endomycorrhizae.

INTRODUCTION

Soil is known to harbour an array of micro-organisms. The soil micro-organisms play vital roles in the half-hidden portion of the plant i.e., the rhizosphere, where they are invariably present and are stimulated by organic substrates supplied by the plant. These are known to form the mutualistic, symbiosis with photosynthetic plants and play a key role in increasing availability of plant nutrients, the improvement of their uptake, the production of plant growth regulators, plant protection against root pathogens etc. in both natural and man-modified eco-systems.