Ohki Shinya, Takahara Hiroyuki, Imamura Tomohiro, Sakane Kosei, Bai Asihan, Sasaki Kazunori, Nishiuchi Takumi, Mori Masashi
Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), Nomi 923-1292, Ishikawa, Japan.
Department of Bioproduction Science, Ishikawa Prefectural University, Nonoichi 921-8836, Ishikawa, Japan.
Plants (Basel). 2025 Aug 18;14(16):2562. doi: 10.3390/plants14162562.
Phytopathogenic fungi secrete numerous effector proteins to disrupt plant defenses. At present, their sequence-structure-function relationships remain poorly understood owing to their diversity. Comprehensive understanding of conserved effectors is necessary to elucidate the molecular relationship between fungi and plants. To fill this research gap, we investigated the effector candidate (ChEC)-88 specifically expressed during infection. Notably, similar to the biotrophy-associated secreted protein 3 (BAS3) from , ChEC88 inhibited plant cell death caused by necrosis- and ethylene-inducing peptide 1-like protein (NLP1). Nuclear magnetic resonance analysis results revealed that ChEC88 adopted a novel pseudo two-fold symmetrical three-dimensional structure. Homology modeling suggested that BAS3 exhibited a ChEC88-like conformation despite sharing less than 50% sequence identity. Through PSI-BLAST searches, we found that ChEC88 homologs were conserved in various hemibiotrophic phytopathogenic fungi, including , , and species. Functional assays demonstrated that all of the representative homologs suppressed NLP1-induced plant cell death. Mutation experiments identified the residues critical for ChEC88 function. Overall, our findings suggest that hemibiotrophic phytopathogenic fungi share a conserved immune-suppression strategy mediated by ChEC88-like proteins and that such effectors possibly originated from a common ancestral lineage of phytopathogenic fungi.
植物病原真菌分泌多种效应蛋白来破坏植物防御。目前，由于其多样性，它们的序列 - 结构 - 功能关系仍知之甚少。全面了解保守效应蛋白对于阐明真菌与植物之间的分子关系至关重要。为了填补这一研究空白，我们研究了在感染过程中特异性表达的效应蛋白候选物（ChEC）-88。值得注意的是，与来自[具体来源未提及]的生物营养相关分泌蛋白3（BAS3）类似，ChEC88抑制了由坏死和乙烯诱导肽1样蛋白（NLP1）引起的植物细胞死亡。核磁共振分析结果表明，ChEC88呈现出一种新颖的伪二重对称三维结构。同源建模表明，尽管BAS3的序列同一性低于50%，但其呈现出与ChEC88相似的构象。通过PSI-BLAST搜索，我们发现ChEC88同源物在各种半活体营养型植物病原真菌中保守，包括[具体真菌种类未提及]、[具体真菌种类未提及]和[具体真菌种类未提及]物种。功能分析表明，所有代表性同源物均抑制NLP1诱导的植物细胞死亡。突变实验确定了ChEC88功能的关键残基。总体而言，我们的研究结果表明，半活体营养型植物病原真菌共享一种由ChEC88样蛋白介导的保守免疫抑制策略，并且此类效应蛋白可能起源于植物病原真菌的一个共同祖先谱系。
