The sporophytic type of fertility restoration in the A3 CMS-inducing cytoplasm of sorghum and its modification by plant water availability conditions

The A3 type of CMS in sorghum is one of the most difficult to restore fertility because of the low frequency of fertilityrestoring genes among sorghum accessions, the complex mechanism of fertility restoration that occurs with the complementary interaction of two gametophytic genes Rf3 and Rf4, and the sensitivity of their expression to air and soil drought. In order to test the hypothesis of the sporophytic type of fertility restoration in CMS lines with A3 type cytoplasm developed in our laboratory, we analyzed segregation in the self-pollinated progeny of fertile F1hybrids grown under different water availability conditions (in a dryland plot, in plots with additional irrigation, in a growth chamber, and in an experimental field with a natural precipitation regime) and in their backcrosses to the maternal CMS-line. The presence of sterile plants in the F2 and BC1 families with the maternal CMS line grown in all tested water availability conditions argues for the sporophytic mechanism of fertility restoration. Cytological analysis of fertile F1 hybrids revealed a significant amount of degenerating pollen grains (PGs) with impaired starch accumulation and detachment of the PG contents from the cell wall. It is assumed that the expression of the fertility-restoring genes Rf3 and Rf4 in the hybrids with studied CMS lines starts already in the sporophyte tissues, normalizing the development of a certain part of the PGs carrying the recessive alleles of these genes (rf3 and rf4), which are involved in fertilization and give rise to sterile genotypes found in F2 and BC1 families. For the first time, the transgenerational effect of water availability conditions of growing a fertility-restoring line on male fertility of the F2 generation was detected: a pollinator grown in a plot with additional irrigation produced more fertile and less sterile individuals compared to the same pollinator grown under a rainfall shelter (p < 0.01), and the segregation pattern changed from digenic to monogenic, indicating heritable inhibition of the expression of one of the fertility-restoring genes (kind of “grandfather effect”). The possibility of selection for the stability of the fertility restoration system of the A3 cytoplasm to functioning under conditions of high vapor pressure deficit during the flowering period was shown. These data may contribute to the creation of effective fertility restoring lines for this type of CMS in sorghum.

1. Alsdurf J., Anderson C., Siemens D.H. Epigenetics of drought-induced trans-generational plasticity: consequences for range limit development. AoB Plants. 2016;8: plv146. DOI 10.1093/aobpla/plv146.

2. Atkin O.K., Macherel D. The crucial role of plant mitochondria in orchestrating drought tolerance. Ann. Bot. 2009;103:581-597. DOI 10.1093/aob/mcn094.

3. Bohra A., Jha U.C., Adhimoolam P., Bisht D., Singh N.P. Cytoplasmic male sterility (CMS) in hybrid breeding in field crops. Plant Cell Rep. 2016;35:967-993. DOI 10.1007/s00299-016-1949-3.

4. Chase C.D., Gabay-Laughnan S. Cytoplasmic male sterility and fertility restoration by nuclear genes. Eds. H. Daniell, C.D. Chase. Molecular Biology and Biotechnology of Plant Organelles. New York: Springer, 2004;593-621.

5. Dahlberg J.A., Madera-Torres P. Restorer reaction in A1 (AT×623), A2 (A2T×632), and A3 (A3SC 103) cytoplasms to selected accessions from the Sudan sorghum collection. Int. Sorghum Millet Newsl. 1997;38:43-58.

6. Dolferus R., Powell N., Xuemei J.I., Ravash R., Edlington J., Oliver S., Van Dongen J., Shiran B. The physiology of reproductive-stage abiotic stress tolerance in cereals. Eds. G.R. Rout, A.B. Das. Molecular Stress Physiology of Plants. Dordrecht; Heidelberg; New York; London: Springer Science & Business Media, 2013;193-216. DOI 10.1007/978-81-322-0807-5_8.

7. Duvick D.N. Cytoplasmic pollen sterility in corn. Adv. Genet. 1965;13:1-56. DOI 10.1016/S0065-2660(08)60046-2.

8. Elkonin L.A., Gerashchenkov G.A., Tsvetova M.I., Sarsenova S. Kh., Rozhnova N.A. Environmental effects on expression of A3 type CMS of sorghum. Intern. J. Plant Reprod. Biol. 2019;11(2).Accepted for publication.

9. Hauser M.T., Aufsatz W., Jonak C., Luschnig C. Transgenerational epigenetic inheritance in plants. Biochim. Biophys. Acta. 2011;1809(8): 459-468. DOI 10.1016/j.bbagrm.2011.03.007.

10. Horn R., Gupta K.J., Colombo N. Mitochondrion role in molecular basis of cytoplasmic male sterility. Mitochondrion. 2014;19:198205. DOI 10.1016/j.mito.2014.04.004.

11. Jacoby R.P., Li L., Huang S., Lee С.P., Millar A.H., Taylor N.L. Mitochondrial composition, function and stress response in plants. J. Integr. Plant Biol. 2012;54:887-906. DOI 10.1111/j.17447909.2012. 01177.x.

12. Kaul M.L.H. Male Sterility in Higher Plants (Monographs on Theoretical and Applied Genetics, Vol. 10). London: Springer-Verlag, 1988.

13. Kozhemyakin V.V., Elkonin L.A., Dahlberg J.A. Effect of drought stress on male fertility restoration in A3 CMS-inducing cytoplasm of sorghum. Crop J. 2017;5(4):282-289. DOI 10.1016/j.cj.2017.02.003.

14. Kuhlman L.C., Pring D.R., Rooney W.L., Tang H.V. Allelic frequency at the Rf3 and Rf4 loci and the genetics of A3 cytoplasmic fertility restoration in converted Sorghum lines. Crop Sci. 2006;46:1576-1580. DOI 10.2135/cropsci2005.10-0380.

15. Kumar S., Kumari R., Sharma V. Transgenerational inheritance in plants of acquired defense against biotic and abiotic stresses: implications and applications. Agric. Res. 2015;4(2):109-120. DOI 10.1007/s40003-015-0170-x.

16. Li S., Wan C., Hu C., Gao F., Huang Q., Wang K., Wang T., Zhu Y. Mitochondrial mutation impairs cytoplasmic male sterility rice in response to H2O2 stress. Plant Sci. 2012;195:143-150. DOI 10.1016/j.plantsci.2012.05.014.

17. Liberatorе K.L., Dukowic-Schulze S., Miller M.E., Chen C., Kianian S.F. The role of mitochondria in plant development and stress tolerance. Free Rad. Biol. Med. 2016;100:238-256. DOI 10.1016/j.freeradbiomed.2016.03.033.

18. Lukens L.N., Zhan S.H. The plant genome’s methylation status and response to stress, implications for plant improvement. Curr. Opin. Plant Biol. 2007;10:317-322. DOI 10.1016/j.pbi.2007.04.012.

19. McDonald J.H. Handbook of Biological Statistics (3rd ed.). Baltimore, Maryland: Sparky House Publ., 2014. (http://udel. edu/~mcdonald/statexactbin.html).

20. Ng S., De Clercq I., Van Aken O., Law S.R., Ivanova A., Willems P., Giraud E., Van Breusegem F., Whelan J. Anterograde and retrograde regulation of nuclear genes encoding mitochondrial proteins during growth, development, and stress. Mol. Plant. 2014;7:1075-1093. DOI 10.1093/mp/ssu037.

21. Paszkowski J., Grossniklaus U. Selected aspects of transgenerational epigenetic inheritance and resetting in plants. Curr. Opin. Plant Biol. 2011;14:195-203. DOI 10.1016/j.pbi.2011.01.002.

22. Pring D.R., Tang H.V., Howad W., Kempken F. A unique two-gene gametophytic male sterility system in sorghum involving a possible role of RNA editing in fertility restoration. J. Hered. 1999;90: 386-393.

23. Reddy B.V.S., Ramesh S., Ortiz R. Genetic and cytoplasmic-nuclear male sterility in Sorghum. Ed. J. Janik. Plant Breeding Reviews. Hoboken; New Jersey: Willey & Sons, Inc., 2005;Vol. 25: 139-169.

24. Reddy S.P., Rao M.D., Reddy B.V.S., Kumar A.A. Inheritance of male-fertility restoration in A1, A2, A3 and A4(M) cytoplasmic male-sterility systems of sorghum [Sorghum bicolor (L.) Moench]. Indian J. Genet. 2010;70(3):240-246.

25. Tang H.V., Chang R., Pring D.R. Co-segregation of single genes associated with fertility restoration and transcript processing of sorghum mitochondrial orf107 and urf 209. Genetics. 1998;150:383-391.

26. Tang H.V., Pedersen J.F., Chase C.D., Pring D.R. Fertility restoration of the sorghum A3 male-sterile cytoplasm through a sporophytic mechanism derived from sudangrass. Crop Sci. 2007;47:943-950. DOI 10.2135/cropsci2006.08.0542.

27. Torres-Cardona S., Sotomayor-Rios A., Quiles Belen A., Schertz K.F. Fertility restoration to A1, A2, and A3 cytoplasm systems of converted sorghum lines. MP-1721. Texas Agric. Exp. Stn., Texas A&M Univ., College Station, 1990;1-11.

28. Tricker P.J. Transgenerational inheritance or resetting of stressinduced epigenetic modifications: two sides of the same coin. Front. Plant Sci. 2015;6:699. DOI 10.3389/fpls.2015.00699.

29. Tricker P.J., Gibbings J.G., Lopez C.M.R., Hadley P., Wilkinson M.J. Low relative humidity triggers RNA-directed de novo DNA methylation and suppression of genes controlling stomatal development. J. Exp. Bot. 2012;63(10):3799-3814. DOI 10.1093/jxb/ers076.

30. Wang W.-S., Pan Y.J., Zhao X.-Q., Dwivedi D., Zhu L.-H., Ali J., Fu B.Y., Li Z.-K. Drought-induced site-specific DNA methylation and its association with drought tolerance in rice (Oryza sativa L.). J. Exp. Bot. 2011;62:1951-1960. DOI 10.1093/jxb/erq391.

31. Wilson Z.A., Song J., Taylor B., Yang C. The final split: the regulation of anther dehiscence. J. Exp. Bot. 2011;62:1633-1649. DOI 10.1093/jxb/err014.

32. Worstell J.V., Kidd H.J., Schertz K.F. Relationships among malesterility inducing cytoplasms of sorghum. Crop Sci.1984;24(1): 186-189.

33. Zaitsev G.N. Mathematical Statistics in Experimental Botany. Мoscow: Nauka Publ., 1984. (in Russian)

34. Zheng X., Chen L., Li M., Lou Q., Xia H., Wang P., Li T., Liu H., Luo L. Transgenerational variations in DNA methylation in-duced by drought stress in two rice varieties with distinguished difference to drought resistance. PLoS One. 2013;8(11):e80253. DOI 10.1371/journal.pone.0080253.