Cytological analysis of EMS (Ethyl methane sulphonate) treated population of Fagopyrum esculentum revealed an abnormal behaviour of microsporogenesis that affected the meiotic events resulting in the formation of abnormal meiotic products that prevent the gamete formation and impair pollen fertility. The two desynaptic mutants were recorded, showing distinctive variations in the morphology as compared to the control plants. The seeds of Fagopyrum esculentum were treated with EMS solution in different concentrations such as 0.1%, 0.3% and 0.5% using potassium phosphate buffer (pH-7) for 5 hrs. During cytological investigation, 0.5% concentration of EMS enhanced the univalent frequency per cell at diakinesis/Metaphase I, respectively along with unequal segregation at anaphase I which is pronounced to be higher in contrast to bivalents. Because of higher frequency of univalents desynapsis has been categorized as medium- strong type. EMS induced desynaptic plants showed abnormal meiotic behaviour leading to pollen sterility and no seed setting was recorded. The chemical mutagen has acted on recombination genes system which is accountable for synapsis and chiasma formation and further disrupted the complete chiasma assembly. The desynaptic mutant is a potential tool that provides genetic information on the maintenance of chiasma and the study offers the possibility for formation of aneuploids production which may be exploited successfully through chemical mutagenesis in breeding programmes.
Keywords: Meiosis, EMS, Univalents, medium strong type, pollen sterility, Fagopyrum esculentum
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References
1. Pagliarini, M.S., Calisto, V., Fuzinatto, V.A., Message, H.J., Mendes-Bonato, A.B., Boldrini, K.R., and Valle, C.B.D., Desynapsis and precocious cytokinesis in Brachiaria humidicola (Poaceae) compromise meiotic division, Indian Acad. Sci., 2008, vol. 87, no. 1, pp. 27–31.
2. Tsubouchi, H. and Roeder, G.S., The importance of genetic recombination for fidelity of chromosome pairing in meiosis, Dev. Cell, 2003, vol. 5, no. 6, pp. 915–925.
3. Sharma, S.K., Kumaria, S., Tandon, P., and Rao, S.R., Synaptic variation derived plausible cytogenetical basis of rarity and endangeredness of endemic Mantisia spathulata Schult, Nucleus, 2011, vol. 54, no. 2, pp. 85–93.
4. Franklin, A.E., McElver, J., Sunjevaric, I., Rothstein, R., and Borwen, B., Three dimensional microscopy of the Rad 51 recombination protein during meiotic prophase, Plant Cell, 1999, vol. 11, pp. 809–824.
5. Pazy, B. and Plitmann, U., Asynapsis in Cistanche tubulosa (Orobanchceae), Plant Syst. Evol., 1996, vol. 3, pp. 201–271.
6. Sosnikhina, S.P., Mikhailova, E.I., Tikholiz, O.A., and Priyatkina, S.N., Smirnov VG., Voilkov AV., et al., Genetic collection of meiotic mutants of rye Secale cereal L., Russ. J. Genet., 2005, vol. 41, no. 10, pp. 1071–1080.
7. Jenkins, G. and Okomus, A., Indiscriminate synapsis in achiasmate Allium fistulosum L.(Liliaceae), J. Cell Sci., 1992, vol. 103, pp. 414–422.
8. Maguire, M.P. and Riess, ParedesA.M., Evidence from a maize desynaptic mutant points to a probable role of synaptinemal complex central region components in provision for subsequent chiasma maintenance, Genome, 1993, vol. 36, no. 5, pp. 797–807.
9. Pagliarini, M.S., Souza, V.F., Silva, N., Scapim, C.A., Rodovalho, M., and Faria, M.V., Ms 17: a meiotic mutation causing partial male sterility in a corn silage hybrid, Genet. Mol. Res., 2011, vol. 10, no. 3, pp. 1958–1962.
10. Cai, X. and Xu, S.S., Meiosis-driven genome variation in plants, Curr. Genom., 2007, vol. 8, no. 3, pp. 151–161.
11. Chedda, H.R. and De Wet, J.M.J., Desynapsis in the Bathriochloa hybrids, Proc. Okla. Acad. Sci., 1960, pp. 14–18.
12. Soost, R.K., Comparative cytology and genetics of asynaptic mutants in Lycopersicon esculentum L., Genetics, 1951, vol. 36, no. 4, pp. 410–434.
13. Burnham, C.R., Discussion in Cytogenetics, Minneapolis Minn.: Burgess Publ. Co., 1962.
14. Ratan, P. and Kothiyal, P., Fagopyrum esculentum Moench (common buckwheat) edible plant of Himalayas: a review, Asian J. Pharm. Life Sci., 2011, vol. 1, no. 4, pp. 426–442.
15. Joshi, B.D., Status of buckwheat in India, Fagopyrum, 1999, vol. 16, pp. 7–11.
16. Kreft, I., Fabjan, N., and Yasumoto, K., Rutin content in buckwheat (Fagopyrum esculentum Moench) food materials and products, Food Chem., 2006, vol. 98, no. 3, pp. 508–512.
17. Liu, C.L., Chen, Y.S., Yang, J.H., and Chiang, B.H., Antioxidant activity of tartary (Fagopyrum tartaricum (L.) Gaertn.) and common (Fagopyrum esculentum Moench) buckwheat sprouts, J. Agric. Food Chem., 2008, vol. 56, no. 1, pp. 173–178.
18. Pullaiah, T., Encyclopaedia of World Medicinal Plants, Regency Publications, New Delhi, 2006, vol. 2, pp. 936–937.
19. Tang, C., Peng, J., Zhen, D., and Chen, Z., Physicochemical and antioxidant properties of buckwheat (Fagopyrum esculentum Moench) protein hydrolysates, Food Chem., 2009, vol. 115, pp. 672–678.
20. Kaul, M.L.H., Male Sterility in Higher Plants, Monographs on Theoretical and Applied Genetics 10, Berlin: Springer Verlag.
21. Naseem, S. and Kumar, G., Induced desynaptic variation in poppy (Papaver somniferum L.), Crop Breed. Appl. Biotechnol., 2013, vol. 13, no. 4, pp. 363–366.
22. Prakken, R., Studies of asynapsis in rye, Hereditas, 1943, vol. 71, pp. 475–495.
23. Bowling, S.E. and Makaroff, C.A., A defect in synapsis causes male sterility in a T-DNA-tagged Arabidopsis thaliana mutant, Plant J., 1997, vol. 11, no. 4, pp. 659–669.
24. Kitada, K. and Omura, T., Genetic control of meiosis in rice Oryza sativa L. Cytogenetical analyses of desynaptic mutants, Jpn. J. Genet., 1983, vol. 58, pp. 567–577.
25. John, B., Meiosis, Cambridge: Cambridge Univ. Press, 1990.
26. Maguire, M.P., Is the synaptinemal complex a disjunction machine?, J. Hered., 1995, vol. 86, pp. 330–340.
27. Miyazaki, W.Y.Orr. and Weaver, T.L., Sister chromatid cohesiveness in mitosis and meiosis, Ann. Rev. Genet., 1994, vol. 28, pp. 167–187.
28. Maguire, M.P., Evidence for separate genetic control of crossing over and chiasma maintenance in maize, Chromosoma, 1978, vol. 65, no. 2, pp. 173–183.
29. Koduru, P.R.K. and Rao, M.K., Cytogenetic of synaptic mutants in higher plants, Theor. Appl. Genet., 1981, vol. 59, pp. 197–214.
30. Dawe, R.K., Meiotic chromosome organization and segregation in plants, Ann. Rev. Plant Physiol. Plant. Mol. Biol., 1998, vol. 49, pp. 371–95.
31. Ji, Y.E., Stelly, D.M., Donato, M.D., Goodman, M.M., and Williams, C.G., A candidate recombination modifier gene for Zea mays L., Genetics, 1999, vol. 151, no. 2, pp. 821–830.
32. Simchen, G. and Stamberg, J., Fine and coarse controls of genetic recombination, Nature, 1969, vol. 222, pp. 329–332.
33. Kumar, P., Singhal, V.K., Kaur, M., and Gupta, R.C., High pollen sterility and 2n pollen grains in an asynaptic 4x cytotype (2n = 48) of Solanum nigrum L., Cytologia, 2012, vol. 77, no. 3, pp. 333–342.