Analysis of genetic diversity and population structure of peanut cultivars and breeding lines from China,India and the US using simple sequence repeat markers

Cultivated peanut is grown worldwide as rich- source of oil and protein. A broad genetic base is needed for cultivar improvement. The objectives of this study were to develop highly informative simple sequence repeat （SSR） markers and to assess the genetic diversity and popuJation structure of peanut cultivars and breeding lines from different breeding programs in China, India and the US. A total of 111 SSR markers were selected for this study, resulting in a total of 472 alleles. The mean values of gene diversity and polymorphic information content （PIC） were 0.480 and o.429, respectively. Country-wise analysis revealed that alleles per locus in three countries were similar. The mean gene diversity in the US, China and India was 0.363, o.489 and 0.47 with an average PIC of 0.323, 0.43 and o.412, respectively. Genetic analysis using the STRUCTURE divided these peanut lines into two populations （P1, P2）, which was consistent with the dendro- gram based on genetic distance （G1, G2） and the clustering of principal component analysis. The groupings were related to peanut market types and the geographic origin with a few admixtures. The results could be used by breeding programs to assess the genetic diversity of breeding materials to broaden the genetic base and for molecular genetics studies.

Cleavage of the Babuvirus Movement Protein B4 into Functional Peptides Capable of Host Factor Conjugation is Required for Virulence

Banana bunchy top virus(BBTV)poses a serious danger to banana crops worldwide.BBTV-encoded protein B4 is a determinant of pathogenicity.However,the relevant molecular mechanisms underlying its effects remain unknown.In this study,we found that a functional peptide could be liberated from protein B4,likely via proteolytic processing.Site-directed mutagenesis indicated that the functional processing of protein B4 is required for its pathogenic effects,including dwarfism and sterility,in plants.The released protein fragment targets host proteins,such as the large subunit of RuBisCO(RbcL)and elongation factor 2(EF2),involved in protein synthesis.Therefore,the peptide released from B4(also a precursor)may act as a non-canonical modifier to influence host-pathogen interactions involving BBTV and plants.