橡胶树热激蛋白HbHSP90.1抗橡胶树白粉病菌的功能研究

Study on the function of heat shock protein HbHSP90.1 from rubber tree in resistance to powdery mildew

摘要

【目的】橡胶树白粉病严重制约天然橡胶产量，挖掘其抗病因子并解析功能对绿色防控具有重要意义。热激蛋白HSP90作为植物免疫的关键调控因子，其成员HbHSP90.1已被证实受白粉菌侵染诱导表达。因此，本研究旨在揭示HbHSP90.1在橡胶树应答白粉菌侵染中的具体功能，以明确其对抗病性的调控作用。【方法】采用抑制剂干扰HSP90活性，或利用dsRNA沉默HbHSP90.1基因，并通过橡胶树白粉菌接种，测定橡胶树对白粉病的抗性。使用可诱导抗性的植物生长调节剂类似物（水杨酸钠和乙烯利）处理橡胶树，并使用逆转录定量PCR测定HbHSP90.1表达量。沉默HbHSP90.1后，测定水杨酸和乙烯前体1-氨基环丙烷-1-羧酸（ACC）含量。【结果】抑制HbHSP90.1活性或特异性沉默该基因后，橡胶树对白粉病的感病性显著增强。进一步分析发现，HbHSP90.1在水杨酸钠处理下表达持续上调，而在乙烯利处理后则受到抑制。在沉默HbHSP90.1后接种白粉菌，叶片内源水杨酸含量显著降低，同时ACC含量显著升高，提示该基因可能通过影响植物生长调节剂平衡参与调控免疫反应。【结论】HbHSP90.1是橡胶树应答白粉菌侵染的关键正调控因子，其通过正向调控水杨酸信号通路，进而参与调控植株对白粉病的免疫反应。该研究为深入解析橡胶树抗病分子机制提供了新的理论依据。

Abstract

[Objective] Rubber tree powdery mildew severely constrains natural rubber production. Identifying disease resistance factors and elucidating their functions are of great significance for green control. Heat shock protein HSP90 is a key regulator of plant immunity, and its member HbHSP90.1 has been confirmed to be induced by powdery mildew infection. Therefore, this study aimed to reveal the specific function of HbHSP90.1 in rubber tree response to powdery mildew infection, to clarify its regulatory role in disease resistance. [Method] HSP90 activity was interfered with using an inhibitor, or HbHSP90.1 gene was silenced by dsRNA, followed by rubber tree powdery mildew inoculation to assess disease resistance. Rubber trees were treated with plant hormone analogs that induce resistance (sodium salicylate and ethephon), and HbHSP90.1 expression was measured by reverse transcription quantitative PCR. After silencing HbHSP90.1, the contents of salicylic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) were determined. [Result] Inhibiting the activity of HbHSP90.1 or silencing the gene significantly increased the susceptibility of rubber trees to powdery mildew. Expression analysis showed that HbHSP90.1 was continuously upregulated under sodium salicylate treatment, but it was suppressed under ethephon treatment. After silencing HbHSP90.1 and inoculating with powdery mildew, the endogenous salicylic acid content in the leaves decreased significantly, while ACC content increased significantly. This indicated that the gene may participate in regulating immune responses by modulating hormone balance. [Conclusion] HbHSP90.1 is a key positive regulator in the rubber tree's response to powdery mildew infection. It participates in regulating the plant's immune response to powdery mildew by positively regulating the salicylic acid signaling pathway. This study provides new experimental evidence for in-depth analysis of the molecular mechanism of disease resistance in rubber trees.

关键词

橡胶树 / 白粉菌 / 抗病性 / 水杨酸 / HSP90

Key words

rubber tree / powdery mildew / disease resistance / salicylic acid / HSP90

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基金资助

国家自然科学基金项目(32402319)

海南省科技人才创新项目(KJRC2023B14)