Molecular cloning, characterization and expression analysis of putative resistance gene analogs from betelvine (Piper betle L.) against anthracnose disease

Betelvine (Piper betle L.) is a cash crop whose cultivation generates healthy earnings, significantly impacting the livelihood security of India and other Asian countries. However, betelvine plant encounters various fungal dis-eases, out of which anthracnose disease is a serious concern in India caused by Colletotrichum capsici. It causes crop loss up to 60% subsequently decreasing the overall production and market price. Several chemicals and fungicides are used against anthracnose disease. However, all of these are not fully effective in eradicating the disease as well as have an adverse effect on the environment. The development of resistant clones would be an alternative and effective approach. In this study, degenerate primers were used for cloning and characterization of NBS-LRR type resistant gene from betelvine against anthracnose disease. A strong amino acid identity ranging from 90.38 to 97.75% and the presence of internal conserved motifs, provided evidence that the identified resistance gene analogs (RGAs) belong to the non-TIR NBS-LRR class of R genes. The multiple sequence align-ment and phylogenetic relationship study identified three non-TIR NBS-LRR class of RGAs from betelvine. Further, the gene expression pattern of identified RGAs were studied against resistant and susceptible lines of betelvine. A differential gene expression pattern after C. capsici inoculation was observed using qRT-PCR. The identification of betelvine RGAs specific to C. capsici would have enough significance for the in depth charac-terization of potential C. capsici resistance gene and the development of resistant lines.