The key iron assimilation genes ClFTR1, ClNPS6 were crucial for virulence of Curvularia lunata via initiating its appressorium formation and virulence factors

Iron is virtually an essential nutrient for all organisms, to understand how iron contributes to virulence of plant pathogenic fungi, we identified ClFTR1 and ClNPS6 in maize pathogen Curvulaira lunata (Cochliobolus luntus) in this study. Disruption of ClNPS6 significant impaired siderophore biosynthesis. ClFTR1 and ClNPS6 did mediate oxidative stress, but had no significant impact on vegetative growth, conidiation, cell wall integrity (CWI) and sexual reproduction. Conidial germination delayed and appressoria formation reduced in ΔClftr1 comparing with wild type (WT) CX-3. Genes responsible for conidial germination, appressoria formation, non-host selective toxin biosynthesis and cell wall degrading enzymes were also down-regulated in transcriptome of ΔClftr1 and ΔClnps6 compared with WT. The conidial development, toxin biosynthesis, and polygalacturonase (PG) activity were impaired in the mutant strains with ClFTR1 and ClNPS6 deletion during their infection to maize. ClFTR1 and ClNPS6 were up-regulated expression at 12-24 hpi and 48-120 hpi in WT, respectively. ClFTR1 positively regulated conidial germination, appressoria formation in the biotrophy-specific phase. ClNPS6 positively regulates non-host selective toxin biosynthesis, and cell wall degrading enzyme activity in the necrotrophy-specific phase. Our results indicated that ClFTR1 and ClNPS6 were key genes of pathogen known to conidia development and virulence factors. This article is protected by copyright. All rights reserved.