生长素和赤霉素代谢介导铜钱树砧抗枣疯病的分子机理研究

Paliurus hemsleyanus Rehd., one kind of deciduous tree in the family of Rhamnaceae, Paliurus, has high grafted-compatibility with Ziziphus jujube Mill., so has been widely used as the rootstock in the jujube production regions of South China. The findings of metabolomic analysis in our previous experiments indicated that jujube plants grafted with Paliurus rootstock have high resistance to witche’s broom, however, the exact molecular mechanism is still unclear. In this study, jujube plants with different grafting combinations of scion/rootstock (jujube/ paliurus, jujube/ jujube) were used as the materials, the contents of IAAs and GAs were examined and the transportation between scion and rootstock was investigated using LC-MS and 3H labeled isotope tracer. Transcriptome sequencing analysis was performed to screen the genes related to the metabolic pathways of auxins and gibberellins, which might be closely related to the resistance of Jujube witche’s broom. Combining with the changes of IAAs and GAs, the relationship of gene expression will be analyzed, and further used to detect the functional genes related to the resistance to witche’s broom acquired from Chinese paliurus rootstock. Then, the Y2H and BiFC methods were applied for the discovering of the transcription factors regulating the metabolism of IAAs and GAs. The functions of determined genes and transcript factors would be verified by gene over-expression. This project will be of great significance in exploring the molecular mechanism of Jujube witche’s broom resistance acquired with grafting Chinese paliurus rootstock, and guiding the reasonable application in the breeding of jujube rootstocks for enhancing the resistance to Jujube witche’s broom by gene transformation.

铜钱树为鼠李科马甲子属落叶乔木，与栽培枣树嫁接具有良好亲和性，在我国南方部分枣产区用作枣树砧木。课题组前期研究结果证实，铜钱树砧嫁接枣树具有良好的抗枣疯病能力，并主要通过生长素和赤霉素代谢途径的介导，但确切的分子机理尚不明确。本项目以不同砧穗组合（枣/铜钱树砧、枣/本砧）嫁接枣树为试材，采用液质联用和3H标记的同位素示踪技术，明确枣不同砧穗组合的主要差异IAAs、GAs组分及其在砧穗之间运输情况。通过转录组测序分析，并结合激素含量与基因表达的相关性分析，确定与枣疯病抗性反应密切相关的IAAs、GAs代谢基因；采用酵母双杂交和双分子荧光互补方法分析鉴定上游转录因子。在此基础上，选取重要IAAs、GAs代谢基因及其转录因子，进行基因转化与功能验证。本项目研究不仅对于阐明铜钱树砧抗枣疯病的分子机理，而且为进一步通过抗性相关基因转化选育抗枣疯病砧木，都具有重要的理论研究意义和实际应用价值。

铜钱树为鼠李科马甲子属落叶乔木，与栽培枣树嫁接具有良好亲和性，在我国南方部分枣产区用作枣树砧木。课题组前期研究结果证实，铜钱树砧嫁接枣树具有良好的抗枣疯病能力，并主要通过生长素和赤霉素代谢途径的介导，但确切的分子机理尚不明确。本项目以不同砧穗组合（枣/铜钱树砧、枣/本砧）嫁接枣树为试材，通过转录组测序，并结合激素代谢网络分析，确定与枣疯病抗性反应密切相关的JA代谢路径，及其关键基因ZjJAZ1，介导了其他激素（IAA、GA等）代谢。在此基础上，通过基因转化技术，进一步进行其功能验证。本项目研究不仅对于阐明铜钱树砧抗枣疯病的分子机理，而且为进一步通过抗性相关基因转化选育抗枣疯病砧木，都具有重要的理论研究意义和实际应用价值。