Differential gene expression in common bean during interaction with race 65 of Colletotrichum lindemuthianum

Abstract

Anthracnose, caused by the hemibiotrophic fungus Colletotrichum lindemuthianum, is a damaging disease of common bean that can drastically reduce crop yield. The pathogen co-evolves with the host, allowing the selection of different genetic combinations and high virulence diversity. The race 65 of C. lindemuthianum stands out as an important and widespread race in several countries, including Brazil. Considering the great relevance of elucidating the molecular basis of anthracnose resistant in common bean, the differential expression of candidate genes has been one of the most explored strategies. The present study aimed to investigate the expression levels of candidate genes for anthracnose resistance in common bean genotypes with contrasting reaction to race 65 of C. lindemuthianum. To do so, leaves of the common bean lines BRS Esplendor (resistant) and BRS Valente (susceptible) were collected after 72 h from inoculation with race 65 of C. lindemuthianum. The RNA of both lines was isolated from inoculated and non-inoculated leaves, and an RT-qPCR assay was performed to measure the expression of the CBP, MAPKK, PGIA, CNGC-2, PvPOD, PAL2, PvPR1, FLS2, NPR1, and β-GLUC genes. In phenotypic evaluation, 10 days after inoculation, the common bean line BRS Esplendor was completely resistant, and BRS Valente was completely susceptible. Among the tested genes, PvPR1, FLS2, NPR1, and β-GLUC were responsive to inoculation with the pathogen, with relative higher expression levels in the inoculated resistant common bean line, suggesting that these genes may be involved in the common bean defense system against race 65 of C. lindemuthianum.