Development of microsatellite markers for anthracnose resistance in greater yam (Dioscorea alata L.) from expressed sequence tags of heterologous crop species

Greater yam (Dioscorea alata L.), belonging to the family Dioscoreaceae, is a staple food crop of the tropics. It is cultivated for its edible, nutritious, underground tubers. Its productivity declined due to anthracnose disease. There was no sequence information for yam in the public database. Therefore, the current study was designed with an objective to generate simple sequence repeat (SSR) markers for yam from publicly available expressed sequence tag (EST) sequences of crops related to yam. A total of 415801 ESTs collected from 15 different species were used to design 600 SSR primer pairs. Out of 600, only 308 SSR primer pairs were included in the study. Among the 308 screened, 39 (13%) pairs were identified polymorphic for greater yam. The PCR-based polymorphic microsatellites in greater yam revealed 24 markers with distinct gene expression. Out of the 24, five markers (VSU 146, VSU 155, VSU 161, VSU 172 and VSU 182) were informative for use in greater yam anthracnose resistance. These five informative markers indicated resistance to fast-growing salmon (FGS) or slowgrowing grey (SGG) strains of Colletotrichum gloeosporioides (C.g.) that cause anthracnose disease in greater yam. The 24 polymorphic markers could be tried for screening other strains of Colletotrichum gloeosporioides.