Agricultural Ministry Key Lab of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China.
Plant Physiol Biochem. 2013 Dec;73:106-13. doi: 10.1016/j.plaphy.2013.08.011. Epub 2013 Sep 5.
A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses.
深入了解天然产物对植物生长和保护的影响将为植物生产的新产品开发提供支撑。本研究描述了从哈茨木霉 SQR-T037 菌株中分离和鉴定的一种已知次生代谢产物哈茨醇的过程，并研究了该纯化合物以及粗代谢产物提取物在促进植物生长和诱导系统抗性方面的生物活性。结果表明，与对照相比，浓度为 0.1 ppm 的哈茨醇可使番茄幼苗的生长（干重）显著提高 2.5 倍。根扫描结果表明，木霉的次生代谢产物可能通过更好的根系发育来影响植物生长的早期阶段，从而增强根长和根尖。纯化的哈茨醇和粗代谢产物提取物均能提高一些防御相关酶的活性，以应对氧化应激。通过实时反转录-PCR 分析检测到的 6 种防御相关基因的表达表明，哈茨醇诱导了与水杨酸（PR1 和 GLU）和茉莉酸/乙烯（JERF3）信号通路相关的基因的表达，而粗代谢产物提取物抑制了番茄植物中与基础防御相关的一些基因表达（CHI-II 和 PGIP）。进一步的实验表明，用病原菌核盘菌处理哈茨醇预处理过的植物后，通过减少病变面积，植物表现出更高的系统抗性。这些结果表明，木霉属的次生代谢产物，如哈茨醇，可能在植物生长调节和植物防御反应中发挥新的作用。
