Identification and functional analysis of LysM effectors from Marssonina brunnea

Abstract

Popular is not only an important tree species economically, but is also a model system for plant biology. Marssonina leaf spot is a serious leaf disease caused by Marssonina brunnea, which can result in significant economic losses. M. brunnea is considered to be a hemibiotrophic pathogen but its pathogenesis remains unclear. Full length cDNA of 24 LysM effector genes were obtained based on the sequencing of the M. brunnea genome. All of these genes belonged to a single gene family for which the characteristics of the amino acid sequences and protein domains were analyzed. Further detailed analysis was carried out on two representative gene family members. These two genes were up-regulated during the infection process and, when transformed into Arabidopsis thaliana, reduced the plant’s sensitivity to chitin thus might compromised its immune system. LysM effectors appear to show a specific affinity for chitin since the expressed proteins co-precipitated with insoluble chitin. We performed a series of studies into the molecular mechanism of LysM effectors from M. brunnea and carried out a preliminary analysis into the interaction between the pathogen and its host. This research lays a foundation for further investigation into forest tree resistance breeding.