中文摘要：黄瓜花叶病毒（CMV）可通过CMV2b蛋白与寄主中过氧化氢酶间的交互作用引起拟南芥特异性坏死，其中可能会涉及到泛素-蛋白酶体途径。先前已有研究报道，CMV2b蛋白是病毒RNA沉默抑制因子，可与H2O2清除剂过氧化氢酶（CAT3）交互作用，引起接种CMV的拟南芥叶片坏死。本研究发现，在CAT3淘汰的突变体（cat3）中CMV 的积累更多，CAT3可使寄主植物对CMV更耐受。本研究结果表明，寄主中至少有部分蛋白酶体途径是负责CAT3的降解的，这表现在感染了CMV的组织上。
外文摘要：Cucumber mosaic virus (CMV) can induce a specific necrosis on Arabidopsis through the interaction between the CMV 2b protein and host catalase, in which the ubiquitin-proteasome pathway may be involved. We previously reported that the CMV 2b protein, the viral RNA silencing suppressor, interacted with the H2O2 scavenger catalase (CAT3), leading to necrosis on CMV-inoculated Arabidopsis leaves. We here confirmed that CMV could more abundantly accumulate in the CAT3-knockout mutant (cat3), and that CAT3 makes host plants a little more tolerant to CMV. We also found that the necrosis severity is not simply explained by a high level of H2O2 given by the lack of CAT3, because the recombinant CMV, CMV-N, induced much milder necrosis in cat3 than in the wild type, suggesting some specific mechanism for the necrosis induction. To further characterize the 2b-inducing necrosis in relation to its binding to CAT3, we conducted the agroinfiltration experiments to overexpress CAT3 and 2b in N. benthamiana leaves. The accumulation levels of CAT3 were higher when co-expressed with the CMV-N 2b (N2b) than with CMV-Y 2b (Y2b). We infer that N2b made a more stable complex with CAT3 than Y2b did, and the longevity of the 2b-CAT3 complex seemed to be important to induce necrosis. By immunoprecipitation (IP) with an anti-ubiquitin antibody followed by the detection with anti-CAT3 antibodies, we detected a higher molecular-weight smear and several breakdown products of CAT3 among the IP-proteins. In addition, the proteasome inhibitor MG132 treatment could actually increase the accumulation levels of CAT3. This study suggests that the host proteasome pathway is, at least partially, responsible for the degradation of CAT3, which is manifested in CMV-infected tissues.
外文关键词：Cucumber mosaic virus; Catalase; Ubiquitinproteasome; 2b Protein Arabidopsis thaliana; Necrosis
作者：urota, Katsunori; Shimura, Hanako; Takeshita, Minoru; 等
作者单位：日本北海道大学
期刊名称：PLANT CELL REPORTS
期刊影响因子：3.088
出版年份：2017
出版刊次：1
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