CHEMICALLY INDUCED MUTAGENESIS IN THE KING OYSTER MUSHROOM Pleurotus eryngii TO GENERATE HIGH-TEMPERATURE TOLERANT STRAIN

In this study, a high-temperature-tolerant strain of the king oyster mushroom (Pleurotus eryngii) was generated by chemical mutagenesis. Cultivation of P. eryngii generally involves incubating the mycelia at 25°C and then moving the spawns for further incubation at 18°C for fruitification. However, in tropical countries, the temperature is a major concern in the production of oyster mushroom where the average temperature is 32°C. In the current study, the mycelia were treated with ethyl methane sulphonate (EMS) or methyl methane sulphonate (MMS) for chemical-induced mutation. Seven mutants (EMS 1, 2, 6, 26, 35, 36, and 38) from EMS mutagenesis exhibited higher growth rates than the wild-type strain at 32°C. However, mutant strains from MMS mutagenesis showed a low growth rate when compared with wild-type. On sawdust substrate, the spawn running conditions for these strains were performed at 32°C, and fruitification occurred at 18°C. The yield and biological efficiency of EMS 36 and 38 mutants were higher than those of the wild-type strain. The activities of cellulase and xylanase of EMS 36 and 38 mutants showed that both these mutants had higher activities than the wild-type strain which may influence mushroom production. Therefore, these EMS 36 and 38 mutants can be cultivated in tropical countries, which could provide a high yield and reduce the cost during spawn running step.

A comparison of mutagenic potential of Aji-no-Moto with a traditional chemical mutagen on microsporogenesis in barley (Hordeum vulagre L.)

Aji-no-Moto or Mono Sodium Glutamate (MSG) is a flavour enhancer being used extensively in South East Asian cuisine. The Federation of American Societies for Experimental Biology for the United States Food and Drug Administration (FDA) has concluded that MSG is safe when "eaten at customary levels" but there is still great confusion regarding its toxicity at higher concentrations. Therefore, it was decided to assess the mutagenic efficacy of MSG on a plant system and present the findings as a model for probably similar effects in the animal model. For this, a traditionally popular genus for genetic studies, Hordeum vulgare L. or winter barley, was used as the model system. The studies of microsporogenesis were done in order to see the long term effect. The sets were compared with experimental sets of plants grown from seeds treated with a traditional chemical mutagen Ethyl Methane Sulphonate (EMS). The study revealed that MSG does not induce much genotoxic effects at lower doses and the chromosomal damages induced were very few. However, at higher doses, it almost equals the effects of EMS in terms of heritable genetic damage. The work is significant as MSG continues to be one of the most popular flavouring agents and does not face any challenge to its biosafe status. However, the clastogenic and chromotoxic effects of higher doses of MSG as observed in the study are in total contradiction to the popular belief.

Studies on Effect of Mutagens on Quantitative Characters in M2 and M3 Generation of Horsegram [Macrotyloma uniflorum (Lam.) Verdc]

Background: Induction of mutation plays an important role in the breeding programme among modern methods of plant breeding. Genetic variability is prerequisite for crop improvement and through induced mutation it was found to be very effective for creating variability in the quantitative and qualitative characters. Hence, the present study was aimed to induce genetic variability within short time. In the present investigation positive as well as negative impact on quantitative traits were recorded. Methods: The experiment material comprised of seeds of horsegram [Macrotyloma uniflorum (Lam.) Verdc] variety Paiyur 2 which was subjected to ethyl methane sulphonate (02, 0.3, 0.4 and 0.5%), gamma radiation (100, 200, 300 and 400 Gy) and combination treatments. The mutations affecting gross morphological changes in growth and yield characters such as plant habit, flowering, pod morphology, maturity and seed yield were scored as quantitative characters. The micro mutations at population level can be easily detected in the form of increased variations for quantitative traits in the segregation of mutagen treated populations. Micro mutations can alter morpho-physiological characters hence they are of a particular interest to the plant breeders. ANOVA test was performed to determine the significant differences and duncan’s multiple range test (p=0.05) to compare the differences among treatment means. Result: Among the twenty-five treatments studied both the mutagens, gamma radiations and Ethyl Methane Sulphonate proved to be very effective to induce variability in quantitative traits in M2 and M3 generations. The results of Duncan’s multiple range test analysis revealed that the treatment of mutagens in combinations induced more positive effects as compared to that of using alone. The combined treatments were found positive for improvement of primary branches per plant, no. of pods per plant, pod length, no. of seeds/pod and seed yield per plant in M2 and M3 generations whereas the treatment of gamma irradiation imparted its significant role for improvement of plant height, days required for 50% flowering, days to maturity and 1000 seed weight in both M2 and M3 generations whereas the treatment with Ethyl Methane Sulphonate is useful for improving no. of pods per plant and no. of seeds/pod in M2 generation alone.

Identification and Characterization of Escherichia coli from Bronchial Plug of Broiler Chicken with Respiratory Distress

A Twenty-five bronchial plug samples from dead broiler chicken with signs of respiratory distress collected for identification of avian pathogenic E. coli (APEC). Samples comprised of one pooled sample each from 25 poultry farms located in and around Junagadh city. Isolation, culture and colony characteristics used for primary detection followed by PCR assay targeting four virulence genes (iss, papC, tsh and vat)for confirmatory diagnosis. All bronchial plugs were found to be positive for E. coli infection by isolation. Out of 25 flock sampled, the highest number of E. coli isolates were found positive for the presence of iss gene (22) followed by tsh gene (15), vat gene (13) and papC gene (8)by PCR. On antibiogram, overall E. coli was highly sensitive to colistin (Methane sulphonate) and meropenem(100%) followed by levofloxacin (76%), ceftriaxone (64%), gentamicin (60%), amikacin (60%), co-trimoxazole (40%), amoxycilin-clavunic acid (8%) and imepenem (8%). These results indicated the high prevalence of the E. coli with variable antibiotic resistance in broiler chicken.

Impact of Ethyl Methane Sulphonate Mutagenesis in Artemisia vulgaris L. under NaCl Stress

The present investigation aimed to obtain salt-tolerant Artemisia vulgaris L. to develop a constant form through in vitro mutagenesis with ethyl methane sulphonate (EMS) as the chemical mutagen. NaCl tolerance was evaluated by the ability of the callus to maintain its growth under different concentrations, ranges from (0 mM to 500 mM). However, NaCl salinity concentration at (500 mM) did not show any development of callus, slight shrinking, and brown discoloration taking place over a week. Thus, all the biochemical and antioxidant assays were limited to (0–400 mM) NaCl. On the other hand, selected calluses were treated with 0.5% EMS for 30, 60, and 90 min and further subcultured on basal media fortified with different concentrations of 0–400 mM NaCl separately. Thus, the callus was treated for 60 min and was found to induce the mutation on the callus. The maximum salt-tolerant callus from 400 mM NaCl was regenerated in MS medium fortified with suitable hormones. Biochemical parameters such as chlorophyll, carotenoids, starch, amino acids, and phenol contents decreased under NaCl stress, whereas sugar and proline increased. Peroxidase (POD) and superoxide dismutase (SOD) activities peaked at 200 mM NaCl, whereas catalase (CAT) was maximum at 100 mM NaCl. Enhanced tolerance of 0.5% the EMS-treated callus, attributed to the increased biochemical and antioxidant activity over the control and NaCl stress. As a result, the mutants were more tolerant of salinity than the control plants.

Genetic Variability through Induced Mutation

The success of plant breeding is based on the accessibility of genetic variation, information about desired traits with well-organized approach that make it likely to develop existing genetic resources. Food security demands to break the yield barrier through increasing new cultivars which can adapt to wide range of environment. It is especially important to observe the character association for yield along with its components before recognizing novel technique to break the yield barrier. There are numerous methods for improved exploiting of the inherent genetic makeup of crops with heritable variations. It is recommended that recognized parental resources can also be induced to mutate for unmasking novel alleles of genes that organize the traits suitable for the crop varieties of the 21st century world. Chemical mutagens have extensively been applied to make genetic changes in crop plants for breeding investigation as well as genetic studies. Ethyl methane sulphonate (EMS) is the most frequently applied as chemical agents in plants. EMS normally induces GC → AT transitions in the genome causing mutated protein that performed different functions rather than normal. It is exposed that the utilization of EMS is an efficient approach for developing novel gene pool.

EFFECT OF PHYSICAL AND CHEMICAL MUTAGENESIS IN LITTLE MILLET (PANICUM SUMATRENSE ROTH EX ROEMER AND SCHULTZ) ON SEED GERMINATION, SEEDLING SURVIVAL THROUGH INDUCED MUTATION

Little millet (Panicum sumatrense Roth ex Roemer & Schultz) belongs to Poaeceae family and it is Indian in origin. Milletsare mostly rain fed crops and used as food and fodder. Mutations can be induced in a variety of ways, such as by exposure to electromagnetic or ionizing radiation or chemical mutagens. The seed of little millet variety of Co (samai) 4 seeds were treated with different dose/concentration of physical mutagens (5,10,15,20,25,30,35,40,45 and 50KR) and chemical mutagens like EMS (Ethyl Methane Sulphonate) (5,10,15,20,25,30,35,40,45 and 50 mM). After that the treated seeds are sown in Petri dish under the laboratory conditions. It was found that the M1 generation is effected in seed germination, seedling survival and morphology mutation.