Genetic diversity of kaffir sorghum accessions from the VIR collection in kafirin-encoding loci

Background. Sorghum is a universal, highly drought-resistant crop, widely cultivated throughout the world. Sorghum grain has a valuable biochemical composition and is utilized in both food and feed production. Due to the unique structure of endosperm storage proteins, kafirins, adding sorghum flour to dough is promising for producing dietetic nutrition components. Employing polymorphic DNA markers to study the diversity of kaffir sorghum accessions from the VIR collection as potential donors of biological and morphological traits in their grain is relevant for the development of sterile lines and sterility maintainers.

Materials and methods. Sixteen kaffir sorghum accessions were phenotyped according to morphological features and kafirin electrophoretic banding patterns in their grain, and genotyped using PCR markers specific for kafirin-encoding genes. The phenotype of mature grains was assessed by seed coat color as well as by the thickness ratio between the vitreous and farinaceous endosperm layers on grain cuts. Proteins were fractionated by polyacrylamide gel electrophoresis. The SSR markers linked to the genes for β- and γ-kafirins, and the STS marker of the coding region of the δ-kafirin gene were used in the PCR analysis.

Results and conclusions. The studied accessions differed in grain color and endosperm structure. Three accessions demonstrated a significant thickness of the vitreous layer, while the others had a farinaceous or partially vitreous endosperm. No differences were found among the accessions in the kafirin electrophoretic banding patterns. Meanwhile, the accessions manifested highly polymorphic fragments amplified with primers flanking microsatellite sequences linked to the β- and γ-kafirin genes. Two different versions of the STS marker were detected after amplification with the primers specific to the δ-kafirincoding gene region. The studied accessions were differentiated using the principal coordinates analysis (PCoA).

1. Anisimova I.N., Alpatieva N.V., Abdullaev R.A., Karabitsina Yu.I., Kuznetsova E.B. Screening of plant genetic resources with the use of DNA markers: basic principles, DNA isolation, PCR setup, agarose gel electrophoresis: (guidelines). E.E. Radchenko (ed.). St. Petersburg: VIR; 2018. [in Russian] DOI: 10.30901/978-5-905954-81-8

2. Aniskina Yu.V., Malinovskaya E.V., Mitsurova V.S., Velishaeva N.S., Kolobova O.S., Shilov I.A. The study of the sorghum genetic diversity using the multiplex microsatellite analysis. Plant Biotechnology and Breeding. 2019;2(3):20-29. [in Russian] DOI: 10.30901/2658-6266-2019-3-o1

3. Antimonov A.K., Syrkina L.F., Antimonova O.N. Breeding of food grain sorghum. Zemledelie = Crop Farming. 2021;(8):28-32. [in Russian] DOI: 10.24412/0044-3913-2021-8-28-32

4. Belton P.S., Delgadillo I., Halford N.G., Shewry P.R. Kafirin structure and functionality. Journal of Cereal Science. 2006;44(3):272-286. DOI: 10.1016/j.jcs.2006.05.004

5. Chamba E.B., Halford N.G., Forsyth J., Wilkinson M.D., Shewry P.R. Molecular cloning of β-kafirin, a methioninerich protein of sorghum grain. Journal of Cereal Science. 2005;41(3):381-383. DOI: 10.1016/j.jcs.2004.09.004

6. De Morais Cardoso L., Pinheiro S.S., Martino H.S.D., Pinheiro-Sant’Ana H.M. Sorghum (Sorghum bicolor L.): Nutrients, bioactive compounds, and potential impact on human health. Critical Reviews in Food Science and Nutrition. 2016;57(2):372-390. DOI: 10.1080/10408398.2014.887057

7. Dorokhov D.B., Klocke E. A rapid and economic technique for RAPD analysis of plant genomes. Russian Journal of Genetics. 1997;33(4):358-365. [in Russian]

8. El’konin L.A., Domanina I.V., Ital’yanskaya Yu.V. Genetic engineering as a tool for modification of seed storage proteins and improvement of nutritional value of cereal grain (review). Agricultural Biology. 2016;51(1):17-30. [in Russian] DOI: 10.15389/agrobiology.2016.1.17rus

9. Elkonin L.A., Panin V.M., Kenzhegulov O.A., Gerashchenkov G.A. Improvement of grain sorghum nutritive properties using modern genetic and biotechnological methods. Plant Biotechnology and Breeding. 2019;2(3):41-48. [in Russian] DOI: 10.30901/2658-6266-2019-3-o6

10. FAOSTAT. Food and Agriculture Organization of the United Nations. Statistics: [website]. Available from: https://www.fao.org/statistics/en [accessed Aug. 01, 2024].

11. Holding D.R. Recent advances in the study of prolamin storage protein organization and function. Frontiers in Plant Science. 2014;5:276-284. DOI: 10.3389/fpls.2014.00276

12. Ivanyukovich L.K., Doronina Yu.A. Review of the classification of sorghum – Sorghum Moench. Proceedings on Applied Botany, Genetics and Breeding. 1980;69(1):18-27. [in Russian]

13. Jakushevsky E.S. Varietal composition of sorghum and its use in breeding. Proceedings on Applied Botany, Genetics and Breeding. 1969;41(2):148-178. [in Russian]

14. Khomutnikova L.A. Study of grain sorghum polymorphism by electrophoretic banding patterns of storage proteins (Issledovaniye polimorfizma zernovogo sorgo po elektroforeticheskim spektram zapasnykh belkov). Scientific and Technical Bulletin of the N.I. Vavilov All-Union Research Institute of Plant Industry. 1992;223:37-38. [in Russian]

15. Konarev V.G. (ed.). Identification of varieties and registration of crop genetic diversity according to seed proteins (Identifikatsiya sortov i registratsiya genofonda kulturnykh rasteniy po belkam semyan). St. Petersburg: VIR; 2000. [in Russian]

16. Kurbonov M., Khaitov R. Sorghum as a substitute for corn in poultry feed. E3S Web of Conferences. 2023;390:02025. DOI: 10.1051/e3sconf/202339002025

17. Laidlaw H.K.C., Mace E.S., Williams S.B., Sakrewski K., Mudge A.M., Prentis P.J. et al. Allelic variation of the β-, γand δ-kafirin genes in diverse Sorghum genotypes. Theoretical and Applied Genetics. 2010;121(7):1227-1237. DOI: 10.1007/s00122-010-1383-9

18. Li A., Jia S., Yobi A., Ge Z., Sato S.J., Zhang C. et al. Editing of an alpha-kafirin gene family increases, digestibility and protein quality in sorghum. Plant Physiology. 2018;177(4):1425-1438. DOI: 10.1104/pp.18.00200

19. Mawouma S., Condurache N.N., Turturică M., Constantin O.E., Croitoru C., Rapeanu G. Chemical composition and antioxidant profile of sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R. Br.) grains cultivated in the Far-North region of Cameroon. Foods. 2022;11(14):2026. DOI: 10.3390/foods11142026

20. NCBI. National Center for Biotechnology Information: [website]. Available from: https://www.ncbi.nlm.nih.gov [accessed Aug. 08, 2024].

21. Osborne T.B. The vegetable proteins. London: Longmans, Green & Co; 1919. DOI: https://doi.org/10.5962/bhl.title.18912

22. Osterman L.A. Methods of protein and nucleic acid research. Vol. 3. Electrophoresis – Isoelectric Focusing Ultracentrifugation. Berlin; Heidelberg: Springer-Verlag; 1984.

23. Peakall R., Smouse P.E. GenALEx 6.5: Genetic analysis in Excel. Population genetic software for teaching and research – an update. Bioinformatics. 2012;28(19):2537-2539. DOI: 10.1093/bioinformatics/bts460

24. Price A.L ., Pat terson N.J., Plenge R.M., Weinblat t M.E., Shadick N.A., Reich D. Principal components analysis corrects for stratification in genome-wide association studies. Nature Genetics. 2006;38(8):904-909. DOI: 10.1038/ng1847

25. Reddy B.V.S., Ramesh S., Reddy P.S., Ramaiah B. Combining ability and heterosis as influenced by male-sterility inducing cytoplasms in sorghum [Sorghum bicolor (L.) Moench]. Euphytica. 2007;154(1-2):153-164.

26. Righetti P.G., Chillemi F. Isoelectric focusing of peptides. Journal of Chromatography A. 1978;157:243-251. DOI: 10.1016/S0021-9673(00)92339-2

27. Shewry P.R., Halford N.G. Cereal seed storage proteins: structures, properties and role in grain utilization. Journal of Experimental Botany. 2002;53(370):947-958. DOI: 10.1093/jexbot/53.370.947

28. Shull J.M., Watterson J.J., Kirleis A.W. Proposed nomenclature for the alcohol-soluble proteins (kafirins) of Sorghum bicolor (L.) Moench based on molecular weight, solubility, and structure. Journal of Agricultural and Food Chemistry. 1991;39(1):83-87. DOI: 10.1021/jf00001a015

29. Snowden J.D. A classification of the cultivated sorghums. Bulletin of Miscellaneous Information (Royal Botanic Gardens, Kew). 1935;5(1935):221-255. DOI: 10.2307/4107126

30. Universiteit Gent: [website]. Available from: ugent.be [accessed Aug. 08, 2024].

31. Wong J.H., Lau T., Cai N., Singh J., Pedersen J.F., Vensel W.H. et al. Digestibility of protein and starch from sorghum (Sorghum bicolor) is linked to biochemical and structural features of grain endosperm. Journal of Cereal Science. 2009;49(1):73-82. DOI: 10.1016/j.jcs.2008.07.013

32. Wu Y.R., Messing J. RNA interference-mediated change in protein body morphology and seed opacity through loss of different zein proteins. Plant Physiology. 2010;153(1):337-347. DOI: 10.1104/pp.110.154690

33. Xu J.H., Messing J. Organization of the prolamin gene family provides insight into the evolution of the maize genome and gene duplications in grass species. Proceedings of the National Academy of Sciences of the United States of America. 2008;105(38):14330-14335. DOI: 10.1073/pnas.0807026105