Enhancing of anthracnose disease resistance indicates a potential role of antimicrobial peptide genes in cassava

摘要

Cassava (Manihot esculentaCrantz.) is an important economic crop in tropical countries. Demands for using cassava in food, feed and biofuel industries have been increasing worldwide. Cassava anthracnose disease, caused byColletotrichum gloeosporioidesf.sp.manihotis(CAD), is considered a major problem in cassava production. To minimize the effects of such disease, this study investigated the response of cassava to attack by CAD and how the plants defend themselves against this threat. Genome-wide identification of antimicrobial peptide genes (AMPs) and their expression in response to fungal infection was performed in the resistant cassava cultivar (Huay Bong 60; HB60) in comparison with the highly susceptible cultivar (Hanatee; HN). A total of 114 gene members ofAMPwere identified in the cassava genome database. Fifty-six gene members were selected for phylogenetic tree construction and analysis of putativecis-acting elements in their promoter regions. Differential expression profiles of six candidate genes were observed in response to CAD infection of both cassava cultivars. Upregulation ofsnakins,MeSN1andMeSN2was found in HB60, whereasMeHEL,Me-AMP-D2andMeLTP2were highly induced in HN. TheMeLTP1gene was not expressed in either cultivar. HB60 showed a reduced severity rating in comparison to HN after CAD infection. The biomembrane permeability test of fungal CAD was strongly affected after treatment with protein extract derived from CAD-infected HB60. Altogether, these findings suggest that snakins have a potential function in the CAD defense response in cassava. These results could be useful for cassava improvement programs to fight fungal pathogen.