FvLcp1, a type-D fungal LysM protein with Chitin-binding domains, is a secreted protein involved in host recognition and fumonisin production in Fusarium verticillioides - maize kernel interaction

Abstract

O_LIFusarium verticillioides is one of the key maize ear rot pathogens and produces fumonisins, a group of mycotoxins detrimental to humans and animals. Unfortunately, our understanding on how this fungus interacts with maize kernels to trigger mycotoxin biosynthesis is very limited.\nC_LIO_LIWe performed a systematic computational network-based analysis of large-scale F. verticillioides RNA-seq datasets to identify potential gene subnetwork modules that are associated with virulence and fumonisin regulation.\nC_LIO_LIAmong the highly discriminative subnetwork modules, we identified a putative hub gene FvLCP1, which encodes a putative a type-D fungal LysM protein with a signal peptide, three LysM domains, and two chitin binding domains. FvLcp1 is a unique protein that harbors these domains amongst five representative Fusarium species.\nC_LIO_LIFvLcp1 is a secreted protein important for fumonisin production with LysM domain playing acritical role. Chitin-binding domain was essential for in vitro chitin binding.\nC_LIO_LIUsing rice blast fungus, we learned that FvLcp1 accumulates in appressoria, a key infection structure, suggesting that FvLcp1 could be involved in host recognition and infection. Also, full length FvLcp1 was able to suppress the BAX triggered plant cell death in Nicotiana benthamiana.\nC_LIO_LIThis is the first report where a unique type-D LysM secreted protein with chitin-binding domain in mycotoxigenic fungus F. verticillioides was shown to be potentially involved in suppressing host cell death and promoting fumonisins biosynthesis while the pathogen colonizes maize kernels.\nC_LI