Tea Research Institute, Shandong Academy of Agricultural Sciences, Jinan, China.
Tea Research Institute, Qingdao Agricultural University, Qingdao, China.
BMC Plant Biol. 2024 Nov 15;24(1):1079. doi: 10.1186/s12870-024-05806-x.
Sooty mold (SM), caused by Cladosporium species, is a pervasive threat to tea plant health, affecting both canopy structure and crop yield. Despite its significance, understanding the complex interplay between defense genes and metabolites in tea plants across various SM-infected canopy layers remains limited. Our study employed hyperspectral imaging, transcriptomic profiling, and metabolomic analysis to decipher the intricate mechanisms underlying the tea plant's response to SM infection.
Our hyperspectral imaging identified three critical wavelengths (552, 673, and 800 nm) inflection points associated with varying degrees of SM infection. This non-invasive method allows for the precise assessment of disease progression. Concurrently, transcriptome analysis revealed a wealth of differentially expressed genes (DEGs) enriched in metabolic pathways, secondary metabolite biosynthesis, and plant-pathogen interactions. Cluster analysis highlighted an intensified immune response in A2 and A3 samples. A comprehensive metabolomic profile identified 733 co-changed metabolites in SM-infected leaves, with alcohols, lipids (free fatty acids), hydrocarbons, and amino acids significantly accumulating in A1, while flavonoids were predominantly upregulated in A2 and A3. Weighted Gene Co-Expression Network Analysis (WGCNA) uncovered five hub genes (Dormancy-associated protein, Serine/threonine-protein phosphatase, ABC transporter, and some uncharacterized proteins) and two hub metabolites (D-Mannitol and 17-Hydroxylinolenic Acid) that exhibit significant relationships with DEGs and metabolites. Further co-expression analysis indicated that tea plants mainly employed genes and metabolites related to the biosynthesis of secondary metabolites, plant hormone signal transduction, and plant-pathogen interaction to combat SM.
This study establishes a foundation for understanding the immune mechanisms of tea plants across different canopy layers in response to SM infection. It not only sheds light on the complex defense strategies employed by tea plants but also identifies candidate genes and metabolites crucial for enhancing tea plant breeding and resistance to SM.
煤污病菌（SM）由枝孢属引起，是茶树健康的普遍威胁，影响树冠结构和作物产量。尽管其意义重大，但对于茶树在不同受 SM 感染的树冠层中防御基因和代谢物之间的复杂相互作用的理解仍然有限。我们的研究采用高光谱成像、转录组分析和代谢组分析来破译茶树对 SM 感染反应的复杂机制。
我们的高光谱成像技术确定了与不同程度 SM 感染相关的三个关键波长（552、673 和 800nm）拐点。这种非侵入性方法可以精确评估疾病的进展。同时，转录组分析揭示了大量在代谢途径、次生代谢物生物合成和植物-病原体相互作用中富集的差异表达基因（DEGs）。聚类分析突出了 A2 和 A3 样本中增强的免疫反应。全面的代谢组学分析确定了 SM 感染叶片中 733 个共同变化的代谢物，A1 中醇类、脂质（游离脂肪酸）、碳氢化合物和氨基酸显著积累，而 A2 和 A3 中黄酮类化合物主要上调。加权基因共表达网络分析（WGCNA）发现了五个枢纽基因（休眠相关蛋白、丝氨酸/苏氨酸蛋白磷酸酶、ABC 转运蛋白和一些未知功能蛋白）和两个枢纽代谢物（D-甘露醇和 17-羟基亚麻酸），它们与 DEGs 和代谢物表现出显著的关系。进一步的共表达分析表明，茶树主要利用与次生代谢物生物合成、植物激素信号转导和植物-病原体相互作用相关的基因和代谢物来对抗 SM。
本研究为了解茶树在不同树冠层对 SM 感染的免疫机制奠定了基础。它不仅揭示了茶树所采用的复杂防御策略，还确定了增强茶树育种和对 SM 抗性的关键候选基因和代谢物。
