产黄青霉菌剂防治苹果腐烂病的作用机制研究

The preparation of Penicillium chrysogenum developed by our group displayed very good anti-fungi effect on Apple canker in the field. However, the mechanism remains unknown.Previously we found that the content of phlorizin degradation products, such as phorbol, p-hydroxybenzoic acid and protocatechuic acid was significantly reduced after treatment with the preparation of Penicillium chrysogenum, while the PAL activity is increased. Therefore, we proposed that the preparation of Penicillium chrysogenum may directly or indirectly interfere the degradation of phlorizin. The relative higher accumulation of phlorizin in the wound area is regulating the auxin transportation, which resulted in the limitation of pathogen infection. To demonstrate this hypothesis, the RNAseq sequencing and metabolomics analysis will be used to verify whether the preparation of Penicillium chrysogenum could affect the gene expression of phlorizin directed by the pathogen of Apple canker or involve in phenylalanine metabolic pathway and promoting the accumulation of phlorizin. Further by measuring the differences in the content of auxin at the wound site to investigate whether phlorizin accumulation promotes auxin transportation, leading to rapid wound healing. The results not only can reveal the possible mechanism of Penicillium chrysogenum in preventing and curing apple tree of Huangtaiping against pathogen infection, but also have important significance for the control of apple canker in the field application.

课题组自主研发的产黄青霉菌剂涂抹伤口治疗苹果腐烂病效果好，但其抑菌机理仍不清楚。前期研究发现产黄青霉菌剂处理发病树干后，根皮苷的降解产物根皮酸、对羟基苯甲酸和原儿茶酸的含量显著降低，而苯丙氨酸解氨酶活性显著升高。推测产黄青霉菌剂可能直接或间接干扰了根皮苷的降解，而根皮苷的积累调控了树皮组织生长素运输，促进了伤口愈合加速，导致病菌进一步侵染受阻。本研究拟以黄太平苹果为试材，利用转录组测序和代谢组学技术研究产黄青霉菌剂是否通过抑制对病原菌降解根皮苷的关键基因表达，抑制了对根皮苷的降解；或通过促进苯丙氨酸代谢途径中关键组分，间接促进影响根皮苷的积累量提高；进一步通过测定伤口部位的生长素含量差异，研究根皮苷的积累是否促进生长素的定向运输，导致了伤口快速愈合。研究结果不仅能够揭示产黄青霉菌剂有效防治黄太平腐烂病的可能机制，而且对生产实践中利用该菌剂高效防治苹果腐烂病具有重要意义。

课题组在前期研究过程中发现产黄青霉菌剂涂抹感染了苹果腐烂病的病树伤口后，伤口可以恢复，因此提出开展《产黄青霉菌剂防治苹果腐烂病的作用机制研究》的设想，并获得国家自然科学基金项目资助。在项目资助下，课题组利用转录组结合代谢组技术开展了产黄青霉菌剂防治苹果腐烂病的机制研究。通过研究证明，产黄青霉菌剂是通过促进根皮苷的积累来促进生长素的定向运输，从而防控苹果腐烂病。截止目前，在国家自然科学基金项目资助下发表论文8篇，其中SCI 论文2篇，北大中文核心期刊论文6篇；出版《苹果腐烂病及其防治机理的研究》专著一部；获批《防治苹果树腐烂病的生物农药》发明专利1项；培养已毕业硕士研究生2名，在读硕士研究生1名。该项目为应用性基础研究，对苹果生产中腐烂病这一重要病害的防控开展攻关，除了获得了有效的防治手段外，还明确了其防治机制，为该产品的应用及产业化奠定了基础。