美國維吉尼亞理工學院生物信息研究所（VBI）的研究者及其同事的一項最新研究，證實了某家族毒性蛋白在植物病原體Phytophthora sojae的傳染過程中起到了重要作用,。相關(guān)論文發(fā)表在《植物細胞》（The Plant Cell）上,。

VBI的教授Brett Tyler及其同事、中國南京農(nóng)業(yè)大學以及荷蘭Wageningen大學的研究者,，共同檢測了這種名為Avr1b的蛋白在P. sojae中的功能,，結(jié)果發(fā)現(xiàn)Avr1b可以抑制植物免疫中所謂的“程序性細胞凋亡”這一重要過程。細胞凋亡是細胞一種內(nèi)在的自毀機理,，可以殺掉被感染的植物組織并使毒素充斥其中,，從而使病原體不能再吞噬植物組織。

P. sojae是一種霉菌植物病原體,，可以嚴重損害大豆植物,。在美國，每年農(nóng)場主都會因P. sojae受到100萬到200萬美元的損失,，世界范圍內(nèi)則更多,。通過改變該效應蛋白的關(guān)鍵性氨基酸殘基，研究者發(fā)現(xiàn),，Avr1b是通過C端蛋白的兩個氨基酸序列（W和Y）來抑制細胞凋亡,。Tyler教授的研究組最近在其它卵菌病原體的毒性蛋白中也發(fā)現(xiàn)了這些氨基酸序列。

Tyler認為,，如同人類HIV病毒一樣,，卵菌植物病原體病癥是通過攻擊植物的免疫系統(tǒng)來達到感染它們的目的。（科學網(wǎng) 劉巍 任霄鵬/編譯）

生物谷推薦原始出處：

（The Plant Cell）,，10.1105/tpc.107.057067,，Daolong Dou, Brett M. Tyler

Conserved C-Terminal Motifs Required for Avirulence and Suppression of Cell Death by Phytophthora sojae effector Avr1b
Daolong Dou 1, Shiv D. Kale 1, Xinle Wang 2, Yubo Chen 2, Qunqing Wang 2, Xia Wang 1, Rays H.Y. Jiang 3, Felipe D. Arredondo 1, Ryan G. Anderson 4, Poulami B. Thakur 4, John M. McDowell 4, Yuanchao Wang 2, and Brett M. Tyler

1 Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
2 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
3 Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061; Laboratory of Phytopathology, Wageningen University, NL-6709 PD Wageningen, The Netherlands
4 Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
5 Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061; Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061

The sequenced genomes of oomycete plant pathogens contain large superfamilies of effector proteins containing the protein translocation motif RXLR-dEER. However, the contributions of these effectors to pathogenicity remain poorly understood. Here, we show that the Phytophthora sojae effector protein Avr1b can contribute positively to virulence and can suppress programmed cell death (PCD) triggered by the mouse BAX protein in yeast, soybean (Glycine max), and Nicotiana benthamiana cells. We identify three conserved motifs (K, W, and Y) in the C terminus of the Avr1b protein and show that mutations in the conserved residues of the W and Y motifs reduce or abolish the ability of Avr1b to suppress PCD and also abolish the avirulence interaction of Avr1b with the Rps1b resistance gene in soybean. W and Y motifs are present in at least half of the identified oomycete RXLR-dEER effector candidates, and we show that three of these candidates also suppress PCD in soybean. Together, these results indicate that the W and Y motifs are critical for the interaction of Avr1b with host plant target proteins and support the hypothesis that these motifs are critical for the functions of the very large number of predicted oomycete effectors that contain them.