| Genus Lathyrus is an important cool-season legume family, of which grasspea(Lathyrus sativus L.) is the major cultivated species primarily used for human consumption. Due to its high potential for grain yield and protein content, nitrogen fixation, resistance to abiotic and biotic stresses, grasspea becomes the most hopeful legume crop supplying human consumption in the arid and impoverished areas of Aisa and Africa. It is no doubt that grasspea can be a model crop in sustainable development of agriculture with significant advantages for improving soil fertility and decreasing famine. However, the concentration of β-ODAP in grasspea raised the risk of poisoning and limited its popularization as a food legume crop. In this study, a large set of SSR markers were developed by high-throughput sequencing method and magnetic beads enrichment. 768 SSR markers were selected randomly from the large set to validate the polymorphism. The polymorphic primers were applied to analyze genetic diversity of Lathyrus collected throughout the world. In order to offer theoretical foundation for further research of worldwide Lathyrus germplasm, the population structure, genetic variation and genetic evolution relationship were analyzed based on SSR-PCR results. The primary results were as following.1. A total of 62342 SSR primers were successfully developed by high-throughput sequencing and magnetic beads enrichment. 50144 non-redundant primers were achieved by further selection, including 24331 perfect SSR markers and 25181 compound SSR markers. Among the perfect SSR markers, 466 were mononucleotide type, 15127 were dinucleotide type, 7650 were trinucleotide type, 833 were tetranucleotide type, 155 were pentanucleotide type and 100 were hexanuccleotide type. Among the compound SSR primers, 25181 were ‘c’ type and 632 were ‘c*’ type.2. 768 SSR primers were randomly selected to validate the polymorphism using 8 Lathyrus accessions(6 Lathyrus sativus accessions and 2 wild relatives). Finally, 30 SSR markers were verified effective amplification with clear bands and polymorphism, which including 18 trinucleotide type, 7 dinucleotide type and 5 compound type. The 30 testified SSR markers will be used to analyze the genetic diversity of targeted 283 Lathyrus accessions.3. The targeted 283 Lathyrus accessions of 17 grasspea related accessions and 266 grasspea accessions were collected all over the world. Of which, 33 accessions came from Africa, 100 collected from Europe and 133 originated from Asia. The above mentioned 30 polymorphic primers were applied for SSR-PCR to analyze the population structure, genetic evolution relationship, principal component and genetic variation of 283 accessions. Manifest differences were identified between grasspea and its relatives based on the structure analysis and cluster analysis. Lathyrus cicera L. and Lathyrus sativus L. were verified to be the closest phylogeny relationship, which indicated that the L. cicera has a high genetic similarity to L. sativus and it is the most probable progenitor of grasspea. Lathyrus latifolius L. and Lathyrus sylvestris L. shared close association due to their similar phenotype and close genetic distance. Historic seeds exchanges may resulted in gene flow, and grasspea accessions originated from different geographic areas would be grouped together. In addition, grasspea from Africa has closer genetic relationship with Europern accessions than that with Asian accessions. In this study, the genetic diversity of Asian Lathyrus is richer than that from Africa and Europe, which seems to support the hypothesis of Indian-subcontinent origin of grasspea. |
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