Genetic mapping of seed dormancy as a key domestication trait in pea (Pisum sativum L.)

Bc. Glory OKOJIE, B.A.

Master's thesis

Genetic mapping of seed dormancy trait in pea ( Pisum sativum L.)

Abstract:

In this research, I focused on the analysis of candidate gene(s) encoding calcineurin and testing its association with seed dormancy in pea. To identify the gene locus conditioning seed dormancy in wild pea (Pisum elatius L.), I selected two genetically divergent parents of wild (JI64) and cultivated (JI92) pea which show clear difference in the dormancy for genetic mapping based on genome - wide association mapping on RIL population (Hradilová et al. 2017). This analysis resulted in identification of two loci, one of them placed at chromosome 2. Searched at current pea genome (Cameor version 1.0) indicated 49 gene of which two were homologues genes encoding calcineurin-like protein. The rate of recombination of these two genes (Psat2g013240 and Psat2g024960) was compared between RILs of JI64xJI92 and its reciprocal JI92xJI64 using PCR and restriction analysis. Also comparison of the testa thickness measurement, anatomic and phenotypic analysis between cultivated (JI92) and wild (JI64) pea as well as their RILs. Furthermore, statistical analysis was used to evaluate the dormancy status between parental alleles in the recombinant inbred lines and also to test the relationship between the seed coat thickness and level of imbibition. Based on genetic diversity analysis panel, it has shown a strong support for Psat2g013240 gene of wild genotype (JI64) being related to dormancy. However, sequence variability detected in set of domesticated, non-dormant pea genotypes excluded domestication based selection as expected for key genes. Thus respective gene might be associated but not causative with dormancy status in pea.

Abstract:

In this research, I focused on the analysis of candidate gene(s) encoding calcineurin and testing its association with seed dormancy in pea. To identify the gene locus conditioning seed dormancy in wild pea (Pisum elatius L.), I selected two genetically divergent parents of wild (JI64) and cultivated (JI92) pea which show clear difference in the dormancy for genetic mapping based on genome - wide association mapping on RIL population (Hradilová et al. 2017). This analysis resulted in identification of two loci, one of them placed at chromosome 2. Searched at current pea genome (Cameor version 1.0) indicated 49 gene of which two were homologues genes encoding calcineurin-like protein. The rate of recombination of these two genes (Psat2g013240 and Psat2g024960) was compared between RILs of JI64xJI92 and its reciprocal JI92xJI64 using PCR and restriction analysis. Also comparison of the testa thickness measurement, anatomic and phenotypic analysis between cultivated (JI92) and wild (JI64) pea as well as their RILs. Furthermore, statistical analysis was used to evaluate the dormancy status between parental alleles in the recombinant inbred lines and also to test the relationship between the seed coat thickness and level of imbibition. Based on genetic diversity analysis panel, it has shown a strong support for Psat2g013240 gene of wild genotype (JI64) being related to dormancy. However, sequence variability detected in set of domesticated, non-dormant pea genotypes excluded domestication based selection as expected for key genes. Thus respective gene might be associated but not causative with dormancy status in pea.

Keywords

Pea (Pisum elatius L), Dormancy, Domestication, Genetic mapping, Anatomic and Phenotypic analysis, Seed coat, RILs population, genotype, genetically divergent, Allele, Calcineurin, Homologues gene

Language used: English

Date on which the thesis was submitted / produced: 9. 5. 2023

Thesis defence

• Supervisor: prof. Ing. Petr Smýkal, Ph.D.

Palacký University Olomouc

Faculty of Science

Master programme / field:
Plant Biology / Plant Biology