壳聚糖诱导提高胶红酵母对草莓采后病害防治效力的分子机制研究

Biological control of postharvest diseases of fruits with antagonistic yeasts as an alternative to synthetic fungicides has shown great potential. However, the control efficacy of antagonistic yeasts is less effective than synthetic fungicides. The results by our research team showed that the biological control efficacy of Rhodotorula mucilaginosa to postharvest diseases of strawberries was effectively enhanced by inducing incubation with chitosan. But the molecular mechanisms of improving biocontrol efficacy of R. mucilaginosa induced by chitosan are unclear yet. In this study, the R. mucilaginosa strain isolated by our research team is selected to be the model strain. The key differentially expressed proteins and genes related to improving biocontrol efficacy of R. mucilaginosa induced by chitosan will be analyzed and screened using proteomics technology (iTRAQ technology), transcriptome sequencing technology and bioinformatics. Hereby, the key genes (including the corresponding genes of the key proteins) knockout mutants and overexpression strains of R. mucilaginosa will be constructed to prove the definite function of the key genes. And the relations between the key genes and related transcription factors，as well as the regulation role of the transcription factors in improving biocontrol efficacy of R. mucilaginosa induced by chitosan, will be analyzed and ascertained on the base of the transcription factor knockout ones, so as to reveal the molecular mechanisms of improving the biocontrol efficacy of R. mucilaginosa induced by chitosan. The research will provide theoretic evidence for improving biological control efficacy of antagonistic yeasts and accelerate the application of antagonistic yeasts in biological control of postharvest diseases of fruits.

利用拮抗酵母代替化学杀菌剂对水果采后病害进行生物防治已显示出良好的应用前景。然而拮抗酵母的防治效果往往不如化学杀菌剂。我们课题组以壳聚糖诱导培养胶红酵母，发现胶红酵母对草莓采后病害的防治效力显著提高，但其分子机制尚不明确。本研究拟以课题组分离的胶红酵母为模式菌株，利用蛋白质组学技术（iTRAQ技术）和转录组测序技术，结合生物信息学分析筛选与壳聚糖诱导提高胶红酵母防治效力相关的关键差异蛋白和差异基因；并据此构建关键基因（包括关键蛋白对应基因）的敲除突变体和过表达菌株，验证基因功能，确认关键蛋白和关键基因；同时构建关键基因转录因子的敲除突变株，确定关键基因与转录因子的相互关系及转录因子在壳聚糖诱导提高胶红酵母防治效力中的调控作用，从而从分子水平上阐明壳聚糖诱导提高胶红酵母防治效力的机制。研究结果可以为提高拮抗酵母对水果采后病害的防治效力、加快拮抗酵母的商业化进程提供理论支撑。

项目利用转录组和蛋白质组（TMT）技术，并结合生物信息学方法分析壳聚糖诱导培养提高R. mucilaginosa拮抗效力的分子机制以及诱导培养的R. mucilaginosa提高草莓抗病性的分子机制，从而阐释壳聚糖诱导培养提高该拮抗酵母防治草莓采后病害防治效力的机制。R. mucilaginosa转录组和蛋白质组结果揭示壳聚糖诱导培养提高其拮抗效力的分子机制包括：诱导培养提高酵母生长繁殖、能量合成、抗氧化和抗不良环境胁迫相关基因和蛋白以及生物膜形成及粘附相关基因、病原真菌细胞壁降解酶的表达，从而增强其拮抗效力。草莓转录组结果和蛋白质组结果揭示壳聚糖诱导培养的R. mucilaginosa提高草莓抗病性的分子机制为：提高草莓激素信号转导途径相关基因及下游抗性基因和蛋白、抗病物质合成和ROS调节相关基因和蛋白、细胞壁强度相关基因的表达，从而增强其抗病性。项目的研究结果为提高拮抗酵母对果蔬采后病害的生防效力提供了新思路和新方法，以加速拮抗酵母的实际应用进程。