Asghar Raheel, Cheng Yu, Wu Nan, Akkaya Mahinur S
School of Bioengineering, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, China.
Plants (Basel). 2025 Feb 2;14(3):435. doi: 10.3390/plants14030435.
Wheat ( L.) is a primary crop globally. Among the numerous pathogens affecting wheat production, f. sp. () is a significant biotic stress agent and poses a major threat to world food security by causing stripe rust or yellow rust disease. Understanding the molecular basis of plant-pathogen interactions is crucial for developing new means of disease management. It is well established that the effector proteins play a pivotal role in pathogenesis. Therefore, studying effector proteins has become an important area of research in plant biology. Our previous work identified differentially expressed candidate secretory effector proteins of stripe rust based on transcriptome sequencing data from susceptible wheat () and resistant wheat () infected with . Among the secreted effector proteins, contained an ancient double-psi beta-barrel (DPBB) fold, which is conserved in the rare lipoprotein A (RlpA) superfamily. This study investigated the role of in plant immune responses, which encodes a protein, here referred to as Pst-DPBB, having 131 amino acids with a predicted signal peptide (SP) of 19 amino acids at the N-terminal end, and the DNA sequence of this effector is highly conserved among different stripe rust races. analysis indicated that expression levels are upregulated during the early stages of infection. Subcellular localization studies in leaves and wheat protoplasts revealed that it is distributed in the cytoplasm, nucleus, and apoplast. We demonstrated that negatively regulates the immune response by functioning in various compartments of the plant cells. Based on Co-IP and structural predictions and putative interaction analyses by AlphaFold 3, we propose the probable biological function(s). Pst-DPBB behaves as a papain inhibitor of wheat cysteine protease; Pst-DPBB has high structural homology to kiwellin, which is known to interact with chorismate mutase, suggesting that Pst-DPBB inhibits the native function of the host chorismate mutase involved in salicylic acid synthesis. The DPBB fold is also known to interact with DNA and RNA, which may suggest its possible role in regulating the host gene expression.
小麦（L.）是全球主要作物。在众多影响小麦生产的病原体中，条锈菌（f. sp. ()）是一种重要的生物胁迫因子，通过引发条锈病或黄锈病对世界粮食安全构成重大威胁。了解植物 - 病原体相互作用的分子基础对于开发新的病害管理方法至关重要。众所周知，效应蛋白在发病机制中起关键作用。因此，研究效应蛋白已成为植物生物学的一个重要研究领域。我们之前的工作基于感病小麦（）和感染条锈菌的抗病小麦（）的转录组测序数据，鉴定了条锈病差异表达的候选分泌效应蛋白。在分泌的效应蛋白中，含有一个古老的双ψβ - 桶（DPBB）折叠，该折叠在罕见脂蛋白A（RlpA）超家族中保守。本研究调查了在植物免疫反应中的作用，其编码一种蛋白质，在此称为Pst - DPBB，具有131个氨基酸，在N末端有一个预测的19个氨基酸的信号肽（SP），并且该效应蛋白的DNA序列在不同条锈菌生理小种中高度保守。分析表明，在感染早期表达水平上调。在烟草叶片和小麦原生质体中的亚细胞定位研究表明，它分布在细胞质、细胞核和质外体中。我们证明通过在植物细胞的各个区室中发挥作用来负向调节免疫反应。基于免疫共沉淀（Co - IP）以及结构预测和AlphaFold 3的推定相互作用分析，我们提出了可能的生物学功能。Pst - DPBB表现为小麦半胱氨酸蛋白酶的木瓜蛋白酶抑制剂；Pst - DPBB与已知与分支酸变位酶相互作用的基维林具有高度的结构同源性，这表明Pst - DPBB抑制参与水杨酸合成的宿主分支酸变位酶的天然功能。还已知DPBB折叠与DNA和RNA相互作用，这可能表明其在调节宿主基因表达中的可能作用。
