Luan Hexiang, Shine M B, Cui Xiaoyan, Chen Xin, Ma Na, Kachroo Pradeep, Zhi Haijan, Kachroo Aardra
National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China (H.L., N.M., H.Z.);Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546 (H.L., M.B.S., P.K., A.K.); andJiangsu Academy of Agricultural Sciences, Nanjing 210014, China (X.Cu., X.Ch.).
National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China (H.L., N.M., H.Z.);Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546 (H.L., M.B.S., P.K., A.K.); andJiangsu Academy of Agricultural Sciences, Nanjing 210014, China (X.Cu., X.Ch.)
Plant Physiol. 2016 Sep;172(1):221-34. doi: 10.1104/pp.16.00505. Epub 2016 Jun 29.
The biochemical function of the potyviral P3 protein is not known, although it is known to regulate virus replication, movement, and pathogenesis. We show that P3, the putative virulence determinant of soybean mosaic virus (SMV), targets a component of the translation elongation complex in soybean. Eukaryotic elongation factor 1A (eEF1A), a well-known host factor in viral pathogenesis, is essential for SMV virulence and the associated unfolded protein response (UPR). Silencing GmEF1A inhibits accumulation of SMV and another ER-associated virus in soybean. Conversely, endoplasmic reticulum (ER) stress-inducing chemicals promote SMV accumulation in wild-type, but not GmEF1A-knockdown, plants. Knockdown of genes encoding the eEF1B isoform, which is important for eEF1A function in translation elongation, has similar effects on UPR and SMV resistance, suggesting a link to translation elongation. P3 and GmEF1A promote each other's nuclear localization, similar to the nuclear-cytoplasmic transport of eEF1A by the Human immunodeficiency virus 1 Nef protein. Our results suggest that P3 targets host elongation factors resulting in UPR, which in turn facilitates SMV replication and place eEF1A upstream of BiP in the ER stress response during pathogen infection.
虽然已知马铃薯Y病毒属病毒的P3蛋白可调节病毒复制、移动和发病机制，但其生化功能尚不清楚。我们发现，大豆花叶病毒（SMV）的假定毒力决定因子P3作用于大豆翻译延伸复合体的一个组分。真核延伸因子1A（eEF1A）是病毒发病机制中一种著名的宿主因子，对SMV毒力及相关的未折叠蛋白反应（UPR）至关重要。沉默GmEF1A可抑制SMV及另一种内质网相关病毒在大豆中的积累。相反，内质网（ER）应激诱导化学物质可促进野生型植株而非GmEF1A基因敲除植株中SMV的积累。对编码eEF1B同工型的基因进行敲除，该同工型对eEF1A在翻译延伸中的功能很重要，对UPR和SMV抗性有类似影响，表明其与翻译延伸存在联系。P3和GmEF1A相互促进对方的核定位，类似于人类免疫缺陷病毒1 Nef蛋白对eEF1A的核质运输。我们的结果表明，P3作用于宿主延伸因子导致UPR，进而促进SMV复制，并将eEF1A置于病原体感染期间内质网应激反应中BiP的上游。
