Molecular marker-based genetic variability among Yellow Leaf Disease (YLD) resistant and susceptible arecanut (Areca catechu. L.) genotypes

Abstract

Yellow Leaf Disease (YLD) is a lethal disease affecting the arecanut palms of south India causing heavy yield loss. Presently, there is no cure for this disease and breeding for resistance is the only solution. Disease-free palms identified in hotspot areas (i.e., heavily disease affected regions), may harbour special gene family. The present study aimed to differentiate YLD resistant areca palms with susceptible palms using three different marker systems, i.e., RAPD, ISSR and resistant gene based markers. Amplification of arecanut genomic DNA using these marker systems yielded a total of 248 fragments, that could be scored, of which 130 were polymorphic between YLD resistant and susceptible individuals. Among these markers, RAPD generated greater polymorphic fragments (61.6%) than ISSR (34.9%) and resistant gene specific markers (40.7%). The primers, UBC 321, OPAF 15, and OPE13 produced distinct banding patterns for resistant and susceptible palms. The average genetic similarity coefficient for pair-wise comparison of individuals ranged from 0.73 to 0.88. The average similarity between the YLD resistant palms was found to be 0.79 and that of susceptible was 0.80. The highest similarity coefficient, 0.88 was observed between the YLD resistant individuals (R1 and R2). It has been found that the resistant and susceptible areca palms show relatively less genetic diversity and are skewed towards their phenotype. The results of this molecular characterization may provide starting points for map-based cloning of the YLD resistant genes.