可变剪接因子MaSR45a介导香蕉响应枯萎病（Foc4）侵染的分子机制研究

Banana (Musa spp.) is an important tropical and subtropical fruit, but is sensitive to the infection of Fusarium oxysporum f. sp, so the interaction between Fusarium oxysporum f. sp and banana is the hot spot in recent research. Based on analysis of RNA-seq data from banana leaves and roots infected by Fusarium oxysporum f. sp. Cubense 4 (Foc 4), we identified a large number of plant disease resistance (R) genes, transcrition factors and protein kinases undergo alternative splicing (AS) after infection. We also found the expression of AS regulators MaSR45a/b were induced during Foc 4 infection. Resistance of Fusarium Wilt and the expression of MaSR45a were significantly increased by the inducer of BTH which were plant disease resistance inducer. In order to examine whether MaSR45a/b is involved in response to Foc 4 infection by mediating AS of disease resistance genes, based on the 6 MaSR45a over-expression transgenic banana lines obtained, low-expression transgenic banana will be generated. Then, we will identify down-stream genes, molecular function and signaling transduction pathway of MaSR45a. This achievements will be useful to understanding the pathogen infection responses mechanism in banana, supply the gene resource and direction for banana molecular breeding.

香蕉产业近年来受香蕉枯萎病冲击巨大，香蕉与香蕉枯萎病的相互作用机制是当前研究的重点。通过对香蕉枯萎病菌4号小种侵染前后香蕉叶片和根的转录组数据进行深入挖掘，发现大量抗病相关的R基因、转录因子、蛋白激酶的可变剪接转录本以及可变剪接关键调控因子MaSR45a/b的表达受病原菌显著诱导。植物抗病诱导剂苯并噻二唑（BTH）能显著提高香蕉的抗枯萎病能力和MaSR45a的表达。我们推测MaSR45a/b通过调控抗病基因的可变剪接参与香蕉响应枯萎病的侵染过程。本项目将在前期已经获得6个MaSR45a过量表达的转基因香蕉株系的基础上，进一步构建MaSR45a低表达的转基因香蕉株系，通过生物信息学和分子生物学的研究方法，对MaSR45a作用的分子机制及调控网络进行分析和验证。研究结果有助于加深对香蕉响应枯萎病菌侵染机制的理解，为香蕉抗病育种提供新的基因资源和理论依据。

香蕉枯萎病具有破坏性强、易传染、治理难度大等特点，严重制约香蕉产业发展。解析香蕉与枯萎病菌的互作机理、开发枯萎病生化防治方法、培育抗病品种是提高蕉园产量的重要手段。植物抗病诱导剂苯并噻二唑（BTH）能显著提高香蕉的抗枯萎病能力，通过分析BTH、香蕉枯萎病菌4号小种处理前后的香蕉叶片和根的转录组数据，发现植物激素茉莉酸信号通路和大量抗病相关转录因子、剪接因子MaSR45a均受BTH的调控。为了探究香蕉MaSR45a参与抗病反应的分子机制，本项目以MaSR45a过表达转基因番茄为材料，鉴定了MaSR45a调控的下游基因及遗传通路，阐明了MaSR45a的介导抗病反应的分子作用机制。研究成果有助于揭示香蕉与枯萎病菌的互作机制，为香蕉分子定向育种提供基因资源。同时利用BTH和植物激素开发出可提高植物抗枯萎病的生化防治制剂，应用前景广泛。