Pathogenic fungi represent one of the major biotic stresses for soybean production across the world. Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating fungal pathogen that is responsible for significant yield losses in soybean. In this study, the chitinase gene CmCH1, from the mycoparasitic fungus Coniothyrium minitans, which infects a range of ascomycetous sclerotia, including S. sclerotiorum and S. minor, was introduced into soybean. Transgenic plants expressing CmCH1 showed higher resistance to S. sclerotiorum infection, with significantly reduced lesion sizes in both detached stem and leaf assays, compared to the non-transformed control. Increased hydrogen peroxide content and activities of defense-responsive enzymes, such as peroxidase, superoxide dismutase, phenylalanine ammonia lyase, and polyphenoloxidase were also observed at the infection sites in the transgenic plants inoculated with S. sclerotiorum. Consistent with the role of chitinases in inducing downstream defense responses by the release of elicitors, several defense-related genes, such as GmNPR2, GmSGT-1, GmRAR1, GmPR1, GmPR3, GmPR12, GmPAL, GmAOS, GmPPO, were also significantly upregulated in the CmCH1-expressing soybean after inoculation. Collectively, our results demonstrate that overexpression of CmCH1 led to increased accumulation of H2O2 and up-regulation of defense-related genes and enzymes, and thus enhanced resistance to S. sclerotiorum infection while showing no detrimental effects on growth and development of soybean plants.

中文翻译：

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Coniothyrium minitans 的几丁质酶基因 CmCH1 的过度表达增强了大豆对核盘菌的抗性。


病原真菌是全世界大豆生产的主要生物胁迫之一。核盘菌（Sclerotinia sclerotiorum）是核盘菌茎腐病的致病菌，是一种毁灭性的真菌病原体，导致大豆产量严重损失。在这项研究中，来自菌寄生真菌 Coniothyrium minitans 的几丁质酶基因 CmCH1 被引入大豆中，该真菌感染一系列子囊菌核，包括 S. sclerotiorum 和 S.minor。与未转化的对照相比，表达 CmCH1 的转基因植物对核盘菌感染表现出更高的抗性，在分离茎和叶测定中病灶尺寸显着减小。在接种核盘菌的转基因植物的感染位点还观察到​​过氧化氢含量和防御响应酶（例如过氧化物酶、超氧化物歧化酶、苯丙氨酸解氨酶和多酚氧化酶）活性增加。与几丁质酶通过释放激发子诱导下游防御反应的作用一致，一些防御相关基因，如 GmNPR2、GmSGT-1、GmRAR1、GmPR1、GmPR3、GmPR12、GmPAL、GmAOS、GmPPO，在接种后表达CmCH1的大豆。总的来说，我们的结果表明，CmCH1 的过度表达导致 H2O2 积累增加以及防御相关基因和酶的上调，从而增强对核盘菌感染的抵抗力，同时对大豆植物的生长和发育没有不利影响。