AUTHOR=Wang Limin , Xie Shunpei , Zhang Yinshan , Kang Ruijiao , Zhang Mengjuan , Wang Min , Li Haiyang , Chen Linlin , Yuan Hongxia , Ding Shengli , Liang Shen , Li Honglian 

TITLE=The FpPPR1 Gene Encodes a Pentatricopeptide Repeat Protein That Is Essential for Asexual Development, Sporulation, and Pathogenesis in Fusarium pseudograminearum

JOURNAL=Frontiers in Genetics

VOLUME=Volume 11 - 2020

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.535622

DOI=10.3389/fgene.2020.535622

ISSN=1664-8021

ABSTRACT=Fusarium crown rot (FCR) and Fusarium head blast (FHB) are caused by Fusarium pseudograminearum and are newly emerging diseases of wheat in China. In this study, we characterized FpPPR1, a gene that encodes a protein with 12 pentatricopeptide repeat (PPR) motifs. The radial growth rate of the Fpppr1 deletion mutant was significantly slower than the wild type strain WZ-8A on potato dextrose agar and exhibited significantly smaller colonies with sector mutations. The aerial mycelium of the mutant was almost absent in culture tubes. The Fpppr1 mutant was able to produce spores, but spores of abnormal size and altered conidium septum shape were produced with a 30-fold reduction in sporulation compared to wild type. Fpppr1 failed to cause disease on wheat coleoptiles and barley leaves using mycelia plugs or spore suspensions. The mutant phenotypes were successfully restored to the wild type levels in complemented strains. FpPPR1-GFP signals in spores and mycelia predominantly overlapped with Mito-tracker signals, which substantiated the mitochondria targeting signal prediction of FpPpr1. RNAseq revealed significant transcriptional changes in the Fpppr1 mutant with 1159 genes down-regulated and 2714 genes up-regulated. NAD-binding proteins, thioredoxin, 2Fe-2S iron-sulfur cluster binding domain proteins, and cytochrome P450 genes were significantly down-regulated in Fpppr1, implying the dysfunction of mitochondria-mediated reductase redox stress in the mutant. The mating type idiomorphic alleles MAT1-1-1, MAT1-1-2, and MAT1-1-3 in F. pseudograminearum were also down-regulated after deletion of FpPPR1 and validated by real-time quantitative PCR. Additionally, 21 genes encoding putative heterokaryon incompatibility proteins were down-regulated. The yellow pigmentation of the mutant was correlated with reduced expression of PKS12 cluster genes. Taken together, our findings on FpPPR1 indicate that this PPR protein has multiple functions in the fungal asexual development, regulation of heterokaryon formation, mating-type, and pathogenesis in F. pseudograminearum.