Proteomic Analysis of UV-B-Induced Virulence-Mutant Strains of Puccinia striiformis f. sp. tritici Based on iTRAQ Technology.

Yaqiong Zhao,Pei Cheng,Haiguang Wang,Yuzhu Zhang

doi:10.3389/fmicb.2020.542961

Abstract

The emergence of new physiological races of Puccinia striiformis f. sp. tritici (Pst) causing wheat stripe rust can lead to the loss of resistance of wheat cultivars to stripe rust, thus resulting in severe losses in wheat yield. In this study, after the germination of urediospores of three Pst strains including the original strain (CYR32, a dominant physiological race of Pst in China) and two virulence-mutant strains (CYR32-5 and CYR32-61) acquired from CYR32 via UV-B radiation, proteomic analysis based on isobaric tags for relative and absolute quantification (iTRAQ) technology was performed on the strains. A total of 2,271 proteins were identified, and 59, 74, and 64 differentially expressed proteins (DEPs) were acquired in CYR32-5 vs. CYR32, CYR32-61 vs. CYR32, and CYR32-61 vs. CYR32-5, respectively. The acquired DEPs were mainly involved in energy metabolism, carbon metabolism, and cellular substance synthesis. Furthermore, quantitative reverse transcription PCR assays were used to determine the relative expression of the 6, 7, and 1 DEPs of CYR32-5 vs. CYR32, CYR32-61 vs. CYR32, and CYR32-61 vs. CYR32-5, respectively, at the transcriptional level. The relative expression levels of one, five, and one gene, respectively, encoding the DEPs, were consistent with the corresponding protein abundance determined by iTRAQ technology. Compared with CYR32, the DEPs associated with energy metabolism and stress—including E3JWK6, F4S0Z3, and A8N2Q4—were up-regulated in the mutant strains. The results indicated that the virulence-mutant strains CYR32-5 and CYR32-61 had more tolerance to stress than the original strain CYR32. The results obtained in this study are of great significance for exploring the virulence variation mechanisms of Pst, monitoring the changes in Pst populations, breeding new disease-resistant wheat cultivars, and managing wheat stripe rust sustainably.

Highlights

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating wheat disease in wheat producing regions worldwide (Li and Zeng, 2002; Line, 2002; Chen, 2005; Wan et al, 2007; Chen et al, 2014; Wang et al, 2014)
After germination of the urediospores of the original strain (CYR32) and the two UV-B-induced virulence-mutant strains (CYR32-5 and CYR32-61), proteins were extracted from the germinated urediospores and germ tubes, the differentially expressed proteins (DEPs) among the proteomes of the three Pst strains were screened by using the proteomics method based on isobaric tags for relative and absolute quantification (iTRAQ) technology, and the acquired DEPs were subjected to COG (Cluster of Orthologous Groups) annotations, KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses, and quantitative reverse transcription PCR assays
In this study, using the proteomics method based on iTRAQ technology, a total of 144 DEPs were obtained from the germinated urediospores with germ tubes in the CYR32-5 vs. CYR32, CYR32-61 vs. CYR32, and CYR32-61 vs. CYR32-5 conditions

Summary

Introduction

Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating wheat disease in wheat producing regions worldwide (Li and Zeng, 2002; Line, 2002; Chen, 2005; Wan et al, 2007; Chen et al, 2014; Wang et al, 2014). As the main propagules of wheat stripe rust, Pst urediospores, in high-altitude areas of northwestern China with high-intensity UV-B radiation and in processes of long-distance dispersal with upper air flows, are affected by UV-B radiation, and virulence-mutant strains may be induced (Li and Zeng, 2002; Cheng et al, 2014; Hu et al, 2014; Kang et al, 2015)

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Discussion

Conclusion