Comparative proteomics combined with analyses of transgenic plants reveal ZmREM1.3 mediates maize resistance to southern corn rust.

Shunxi Wang,Lei Tian,Jinlong Zhou,Liuji Wu,Ping Liu,Zan Chen,Yezhang Ding,Yanhui Chen,Jun Zhang

doi:10.1111/pbi.13129

Abstract

SummarySouthern corn rust (SCR), which is a destructive disease caused by Puccinia polysora Underw. (P. polysora), commonly occurs in warm‐temperate and tropical regions. To identify candidate proteins related to SCR resistance and characterize the molecular mechanisms underlying the maize–P. polysora interaction, a comparative proteomic analysis of susceptible and resistant maize lines was performed. Statistical analyses revealed 1489 differentially abundant proteins in the resistant line, as well as 1035 differentially abundant proteins in the susceptible line. After the P. polysora infection, the abundance of one remorin protein (ZmREM1.3) increased in the resistant genotype, but decreased in the susceptible genotype. Plant‐specific remorins are important for responses to microbial infections as well as plant signalling processes. In this study, transgenic maize plants overexpressing ZmREM1.3 exhibited enhanced resistance to the biotrophic P. polysora. In contrast, homozygous ZmREM1.3 UniformMu mutant plants were significantly more susceptible to P. polysora than wild‐type plants. Additionally, the ZmREM1.3‐overexpressing plants accumulated more salicylic acid (SA) and jasmonic acid (JA). Moreover, the expression levels of defence‐related genes were higher in ZmREM1.3‐overexpressing maize plants than in non‐transgenic control plants in response to the P. polysora infection. Overall, our results provide evidence that ZmREM1.3 positively regulates maize defences against P. polysora likely via SA/JA‐mediated defence signalling pathways. This study represents the first large‐scale proteomic analysis of the molecular mechanisms underlying the maize–P. polysora interaction. This is also the first report confirming the remorin protein family affects plant resistance to SCR.

Highlights

Rust fungi constitute the largest group of fungal plant pathogens, with more than 7000 species described, some of which are responsible for three rusts diseases of corn [i.e. common rust, southern corn rust (SCR) and tropical rust] (Rochi et al, 2016)
The results showed that P178 is highly resistant to SCR and Lx9801 is highly susceptible to SCR
In combination with the expression data from qTeller (Figure S3), these results suggested that ZmREM1.3 is constitutively and ubiquitously expressed in maize plants

Summary

Introduction

Rust fungi constitute the largest group of fungal plant pathogens, with more than 7000 species described, some of which are responsible for three rusts diseases of corn [i.e. common rust, southern corn rust (SCR) and tropical rust] (Rochi et al, 2016). (P. polysora), commonly occurs in warmtemperate and tropical regions and has become one of the most destructive plant diseases in the United States of America (Raid et al, 1988), Asia (Liu et al, 2003) and Africa (Agarwal et al, 2001). Disease symptoms induced by P. polysora first appear on leaves, resulting in necrotic lesions, which spread to the rest of the plant, damaging the photosynthetic activities and resulting in death (Cammack, 1958). Southern corn rust was detected in 1949 in West Africa, where it decreased corn yield by about 50% (Nattrass, 1953; Stanton and Cammack, 1953). SCR has gradually spread to highlatitude areas and has recently become a serious threat to crop production worldwide

Results

Discussion

Conclusion