The infection of potato with Ralstonia solanacearum UW551 gives rise to bacterial wilt disease via colonization of roots. The type III secretion system (T3SS) is a determinant factor for the pathogenicity of R. solanacearum. To fully understand perturbations in potato by R. solanacearum type III effectors(T3Es), we used proteomics to measure differences in potato root protein abundance after inoculation with R. solanacearum UW551 and the T3SS mutant (UW551△HrcV). We identified 21 differentially accumulated proteins. Compared with inoculation with UW551△HrcV, 10 proteins showed significantly lower abundance in potato roots after inoculation with UW551, indicating that those proteins were significantly downregulated by T3Es during the invasion. To identify their functions in immunity, we silenced those genes in Nicotiana benthamiana and tested the resistance of the silenced plants to the pathogen. Results showed that miraculin, HBP2, and TOM20 contribute to immunity to R. solanacearum. In contrast, PP1 contributes to susceptibility. Notably, none of four downregulated proteins (HBP2, PP1, HSP22, and TOM20) were downregulated at the transcriptional level, suggesting that they were significantly downregulated at the posttranscriptional level. We further coexpressed those four proteins with 33 core T3Es. To our surprise, multiple effectors were able to significantly decrease the studied protein abundances. In conclusion, our data showed that T3Es of R. solanacearum could subvert potato root immune-related proteins in a redundant manner.

Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

马铃薯感染Ralstonia solanacearum UW551会通过根部定植而引起细菌性枯萎病。III型分泌系统（T3SS）是青枯菌致病性的决定性因素。为了充分了解茄形假单胞菌III型效应子（T3Es）对马铃薯的扰动，我们使用蛋白质组学方法测量了茄形假单胞菌UW551和T3SS突变体（UW551△ Hrc V）接种后马铃薯根部蛋白质丰度的差异。我们鉴定出21种差异积累的蛋白质。与UW551△ Hrc接种的比较V，10种蛋白质在接种UW551后在马铃薯根中显示出明显较低的丰度，表明这些蛋白质在入侵过程中被T3E显着下调。为了确定它们在免疫中的功能，我们沉默了本氏烟草中的那些基因，并测试了沉默植物对病原体的抗性。结果表明，非洲奇果蛋白，HBP2和TOM20导致免疫力青枯。相比之下，PP1易感性。值得注意的是，四种下调的蛋白（HBP2，PP1，HSP22和TOM20）均未在转录水平上被下调，这表明它们在转录后水平上被显着下调。我们进一步将这四种蛋白与33个核心T3Es共表达。令我们惊讶的是，多种效应子能够显着降低所研究的蛋白质丰度。总之，我们的数据表明青枯菌的T3E可能以多余的方式破坏马铃薯根部免疫相关蛋白。

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