Convergent Evolution of Effector Protease Recognition by Arabidopsis and Barley
Convergent Evolution of Effector Protease Recognition by Arabidopsis and Barley
复制标题
DOI：
10.1094/mpmi-07-18-0202-fi
复制
发表时间：
2019-05-01
影响因子：
3.5
通讯作者：
Wise, Roger P.
中科院分区：
文献类型：
--
作者：
Carter, Morgan E.;Helm, Matthew;Wise, Roger P.
假单胞菌半胱氨酸蛋白酶AvrPphB通过切割第二宿主蛋白PBS 1来激活拟南芥抗性蛋白RPS5。AvrPphB在其他植物物种中诱导防御反应，但在这些物种中介导AvrPphB识别的基因和机制尚未确定。在这里，我们表明，AvrPphB诱导防御反应，在不同的大麦品种。我们还表明，大麦含有两个PBS1直系同源物，其产品被AvrPphB裂解，大麦AvrPphB反应映射到一个单一的位点，含有一个核苷酸结合的富含亮氨酸的重复序列（NLR）基因，我们称之为AvrPphB反应1（Pbr 1）。PBR1与野生型AvrPphB的瞬时共表达，但不与蛋白酶失活突变体触发防御反应，表明PBR1检测AvrPphB蛋白酶活性。此外，PBR1与大麦和本氏烟草PBS1蛋白共免疫沉淀，表明与RPS5检测的机制相似。最后，我们确定，小麦品种也承认AvrPphB蛋白酶活性，并含有两个推定的Pbr 1直系同源。然而，系统发育分析表明，Pbr 1是不是orthopathic到RPS5。我们的研究结果表明，识别AvrPphB的能力进化收敛，并意味着选择保护PBS1样蛋白发生在不同物种。此外，这些结果表明，PBS1为基础的诱饵可用于工程蛋白酶效应器的抑制大麦和小麦的抗性。
The Pseudomonas syringae cysteine protease AvrPphB activates the Arabidopsis resistance protein RPS5 by cleaving a second host protein, PBS1. AvrPphB induces defense responses in other plant species, but the genes and mechanisms mediating AvrPphB recognition in those species have not been defined. Here, we show that AvrPphB induces defense responses in diverse barley cultivars. We also show that barley contains two PBS1 orthologs, that their products are cleaved by AvrPphB, and that the barley AvrPphB response maps to a single locus containing a nucleotide-binding leucine-rich repeat (NLR) gene, which we termed AvrPphB Response 1 (Pbr1). Transient coexpression of PBR1 with wild-type AvrPphB but not with a protease inactive mutant triggered defense responses, indicating that PBR1 detects AvrPphB protease activity. Additionally, PBR1 coimmunoprecipitated with barley and Nicotiana benthamiana PBS1 proteins, suggesting mechanistic similarity to detection by RPS5. Lastly, we determined that wheat cultivars also recognize AvrPphB protease activity and contain two putative Pbr1 orthologs. Phylogenetic analyses showed, however, that Pbr1 is not orthologous to RPS5. Our results indicate that the ability to recognize AvrPphB evolved convergently and imply that selection to guard PBS1-like proteins occurs across species. Also, these results suggest that PBS1-based decoys may be used to engineer protease effector recognition-based resistance in barley and wheat.