Kang Baoshan, Liu Lifeng, Liu Liming, Liu Mei, Wu Huijie, Peng Bin, Liang Zhiling, Liu Fengnan, Zang Yaoxing, Gu Qinsheng
Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Zhengzhou 450009, China.
Zhongyuan Research Center, Chinese Academy of Agricultural Sciences (CAAS), Xinxiang 453500, China.
Plants (Basel). 2024 Dec 6;13(23):3431. doi: 10.3390/plants13233431.
Potyviral P3 is involved in viral replication, movement, and pathogenicity; however, its biochemical function is unknown. In this study, the P3 of the zucchini yellow mosaic virus (ZYMV) interacted with ClBBD, a protein with high ortholog bifunctional nuclease activity, in watermelon. The binding site was shown via yeast two-hybrid screening and BiFC assay to be located at the N-terminus of P3 rather than P3N-PIPO. ClBBD localized predominantly to the chloroplast and plasma membrane. ZYMV P3 was also present in the nucleus and cytoplasm as aggregates. When co-expressed with P3 in tobacco, ClBBD formed aggregates with P3 in the cytoplasm. The knockdown of using the VIGS vector pV190 and challenge with ZYMV revealed a positive correlation between viral accumulation and ClBBD expression, indicating that ClBBD reduces the resistance of watermelon to ZYMV. Furtherly, we found that when P3 and ClBBD were transiently co-expressed in tobacco, the level of P3 was significantly higher than that when it was expressed alone or co-expressed with GUS. It inferred that ClBBD may be able to stabilize the expression of P3. Overall, the results suggest that the interaction of P3 with ClBBD promotes virus infection, and ClBBD may be involved in stabilizing the expression level of P3.
马铃薯Y病毒属病毒的P3蛋白参与病毒复制、移动和致病性；然而，其生化功能尚不清楚。在本研究中，西葫芦黄花叶病毒（ZYMV）的P3蛋白与西瓜中具有高度直系同源双功能核酸酶活性的蛋白ClBBD相互作用。通过酵母双杂交筛选和双分子荧光互补分析表明，结合位点位于P3的N端，而非P3N-PIPO。ClBBD主要定位于叶绿体和质膜。ZYMV P3也以聚集体形式存在于细胞核和细胞质中。当与P3在烟草中共同表达时，ClBBD在细胞质中与P3形成聚集体。利用病毒诱导的基因沉默载体pV190敲低并接种ZYMV，结果表明病毒积累与ClBBD表达呈正相关，这表明ClBBD降低了西瓜对ZYMV的抗性。此外，我们发现当P3和ClBBD在烟草中瞬时共表达时，P3的水平显著高于其单独表达或与GUS共表达时的水平。由此推断，ClBBD可能能够稳定P3的表达。总体而言，结果表明P3与ClBBD的相互作用促进病毒感染，且ClBBD可能参与稳定P3的表达水平。
