Development of simple sequence repeat markers based on whole-genome sequencing to reveal the genetic diversity of Glomerella cingulata in China.

Glomerella leaf spot (GLS) has been found on apple trees in China since 2011 and severely affects apple production (Malus domestica Borkh.). The fungus that causes GLS, Glomerella cingulata (Stoneman) Spauld. & H.Schrenk, is epidemic in regions with humid climates each year. It can spread more than 200 km per year, and within the last several years has been found in most apple-producing areas in China. To investigate the origin, evolution and diversity of G. cingulata for better GLS management, we sequenced the whole genome of G. cingulata isolate 030206 and scanned simple sequence repeat (SSR) motifs in the genome. Then we constructed an SSR marker library containing 844 markers and their primers for amplifying the makers. We selected 25 prime pairs to test 96 G. cingulata isolates gathered from eight areas in Shandong Province, China, where GLS is prevalent and proved that the SSR markers were polymorphic among the tested isolates and were informative for analyzing genetic diversity. Developing SSR markers for G. cingulata using the whole-genome sequence is an efficient strategy for genetic diversity analysis, and the library of SSR marker constructed in this study should aid the identification of G. cingulata. [ABSTRACT FROM AUTHOR]