Banana bunchy top virus movement protein induces resistance in banana against Fusarium wilt

Abstract

Banana Fusarium wilt, which is known as Panama disease and caused by Fusarium oxysporum f. sp. cubense (Foc), is a destructive disease that can lead to plant death and complete loss of banana plantations. For obtaining resistant varieties against Fusarium wilt, research is required to elucidate the mechanisms of genetic resistance to Foc. In this research, the banana plants infected with banana bunchy top virus (BBTV) showed resistance to Foc. RNA-seq results showed that the infection with Foc upregulated many resistance-related genes in BBTV-positive plants, especially genes related to ROS production. It was also found that more H2O2 in BBTV-positive plants was induced during Foc infection. The movement protein (MP) of BBTV could increase H2O2 levels by promoting the accumulation of MaSGT1a (suppressor of the G-two allele of SKP1) via direct interaction. Thus, the resistance to Foc induced by BBTV may attribute to MP increasing MaSGT1a protein levels to induce ROS production. MaSGT1a could promote the accumulation of R proteins MaRPM1 and MaRPP8, and increase H2O2 levels in Nicotiana benthamiana. The expression of R proteins in Nicotiana benthamiana caused an increase in H2O2 levels and promoted resistance to Foc. Thus, the MP of BBTV could induce plant defense through interaction with MaSGT1a. We speculate that MaSGT1a is likely involved in R gene-mediated resistance and thereby promotes the resistance of banana against Foc.