Boufleur Thaís R, Massola Júnior Nelson S, Becerra Sioly, Baraldi Elena, Bibiano Líllian B J, Sukno Serenella A, Thon Michael R, Baroncelli Riccardo
Department of Plant Pathology and Nematology, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba, Brazil.
Department of Microbiology and Genetics, Institute for Agribiotechnology Research (CIALE), University of Salamanca (USAL), Villamayor, Spain.
Front Plant Sci. 2022 Nov 25;13:1046418. doi: 10.3389/fpls.2022.1046418. eCollection 2022.
Soybean () is among the most important crops in the world, and its production can be threatened by biotic diseases, such as anthracnose. Soybean anthracnose is a seed-borne disease mainly caused by the hemibiotrophic fungus . Typical symptoms are pre- and post-emergence damping off and necrotic lesions on cotyledons, petioles, leaves, and pods. Anthracnose symptoms can appear early in the field, causing major losses to soybean production.
In preliminary experiments, we observed that the same soybean cultivar can have a range of susceptibility towards different strains of , while the same strain can cause varying levels of disease severity in different soybean cultivars. To gain a better understanding of the molecular mechanisms regulating the early response of different soybean cultivars to different strains, we performed pathogenicity assays to select two soybean cultivars with significantly different susceptibility to two different strains and analyzed their transcriptome profiles at different time points of interaction (0, 12, 48, and 120 h post-inoculation, hpi).
The pathogenicity assays showed that the soybean cultivar 1 is more resistant to strain 1080, and it is highly susceptible to strain 1059, while cultivar 2 shows the opposite behavior. However, if only trivial anthracnose symptoms appeared in the more resistant phenotype (MRP; 1-1080; 2-1059) upon 120 hpi, in the more susceptible phenotype (MSP; -1059; 2- 1080) plants show mild symptoms already at 72 hpi, after which the disease evolved rapidly to severe necrosis and plant death. Interestingly, several genes related to different cellular responses of the plant immune system (pathogen recognition, signaling events, transcriptional reprogramming, and defense-related genes) were commonly modulated at the same time points only in both MRP. The list of differentially expressed genes (DEGs) specific to the more resistant combinations and related to different cellular responses of the plant immune system may shed light on the important host defense pathways against soybean anthracnose.
大豆是世界上最重要的作物之一，其产量会受到诸如炭疽病等生物病害的威胁。大豆炭疽病是一种主要由半活体营养型真菌引起的种传病害。典型症状是出苗前和出苗后猝倒以及子叶、叶柄、叶片和豆荚上的坏死斑。炭疽病症状在田间可能早期出现，给大豆生产造成重大损失。
在初步实验中，我们观察到同一大豆品种对不同菌株的易感性存在差异，而同一菌株在不同大豆品种中可导致不同程度的病害严重程度。为了更好地理解调控不同大豆品种对不同菌株早期反应的分子机制，我们进行了致病性测定，以选择对两种不同菌株易感性显著不同的两个大豆品种，并分析它们在相互作用的不同时间点（接种后0、12、48和120小时，hpi）的转录组谱。
致病性测定表明，大豆品种1对菌株1080更具抗性，对菌株1059高度敏感，而品种2表现出相反的情况。然而，如果在接种后120小时，抗性较强的表型（MRP；1 - 1080；2 - 1059）仅出现轻微的炭疽病症状，那么在较敏感的表型（MSP；1 - 1059；2 - 1080）中，植株在接种后72小时就已出现轻微症状，之后病害迅速发展为严重坏死并导致植株死亡。有趣的是，仅在两种MRP中，与植物免疫系统不同细胞反应（病原体识别、信号事件、转录重编程和防御相关基因）相关的几个基因在相同时间点被共同调控。特定于抗性较强组合且与植物免疫系统不同细胞反应相关的差异表达基因（DEGs）列表可能有助于揭示对抗大豆炭疽病的重要宿主防御途径。
