四株滇牡丹内生木霉的鉴定及促生抗病功能分析

Identification and characterization of four endophytic Trichoderma strains capable of promoting plant growth and inhibiting plant pathogens from Paeonia delavayi

摘要:

【背景】滇牡丹生长周期较长且容易受到多种病害侵染，亟待寻求安全、生态和高效的滇牡丹促生抗病新方法。【目的】鉴定4株滇牡丹优势内生木霉(Trichoderma)种类并开展促生抗病功能筛选，以确定具有促生抗病功能的潜力菌株。【方法】采用分子系统发育分析和形态学方法鉴定4株滇牡丹内生木霉种类，结合定性和定量方法测定4株木霉的溶磷、解钾、产吲哚-3-乙酸(indole-3-acetic acid, IAA)和产铁载体活性，并采用平板对峙法测定4株木霉对滇牡丹主要病害病原真菌的抑制效果。【结果】4株滇牡丹内生木霉鉴定为装絮木霉(Trichoderma tomentosum)、东方木霉(T. orientale)、盖姆斯木霉(T. gamsii)和近渐绿木霉(T. paraviridescens)。促生抗病功能筛选的结果表明，T. gamsii具有溶磷能力，溶磷活性为14.89 mg/L，T. gamsii和T. orientale具有解钾能力，解钾活性分别为24.16 mg/L和26.32 mg/L。同时，T. paraviridescens和T. orientale具有固氮活性。另外，T. gamsii还具有产IAA和产铁载体能力，其产IAA能力为51.92 mg/L，铁载体含量为56.70%。此外，T. gamsii对滇牡丹3种主要病害病原真菌交链孢霉(Alternaria alternata)、刺盘孢菌(Collectorichum sp.)和枝孢菌(Cladosporium sp.)的抑制率分别为52.24%、44.23%和31.78%，显著高于其余3株木霉。【结论】4株滇牡丹内生木霉T. tomentosum、T. orientale、T. gamsii和 T. paraviridescens均具有一定的促生或抗病功能，其中T. gamsii同时具有溶磷、解钾、产IAA、产铁载体和抗病能力，是理想的功能型潜力菌株。

Abstract:

[Background] Paeonia delavayi has a long growth period and is susceptible to a variety of diseases. It is urgent to find a safe, eco-friendly, and efficient method for promoting the growth and enhancing the disease resistance of P. delavayi. [Objective] To identify four dominant endophytic Trichoderma strains of P. delavayi and examine their functions of promoting plant growth and inhibiting plant pathogens. [Methods] Molecular phylogenetic analysis and morphological observation were employed to identify the four endophytic Trichoderma strains from P. delavayi. Qualitative and quantitative methods were used to determine the phosphorus-solubilizing, potassium-solubilizing, indole-3-acetic acid (IAA)-producing, and siderophore-producing activities of the four strains. The plate confrontation method was employed to determine the inhibitory effects of the four strains on the main pathogenic fungi of P. delavayi. [Results] The four endophytic Trichoderma strains were identified as T. tomentosum, T. orientale, T. gamsii, and T. paraviridescens. T. gamsii had the ability to solubilize phosphorus, with the phosphorus-solubilizing activity of 14.89 mg/L. T. gamsii and T. orientale had the ability to solubilize potassium, with the potassium-solubilizing activities of 24.16 mg/L and 26.32 mg/L, respectively. T. paraviridescens and T. orientale had nitrogen-fixing activity. Furthermore, T. gamsii had the ability to produce IAA and siderophores, with the IAA production of 51.92 mg/L and the siderophore content of 56.70%. The inhibition rates of T. gamsii on Alternaria alternata, Collectorichum sp., and Cladosporium sp. were 52.24%, 44.23%, and 31.78%, respectively, which were significantly higher than those of the other three Trichoderma strains. [Conclusion] T. tomentosum, T. orientale, T. gamsii, and T. paraviridescens could promote plant growth and inhibit plant pathogens. Among them, T. gamsii had the abilities to solubilize phosphorus and potassium, produce IAA and siderophores, and inhibit plant pathogens, serving as an ideal functional potential strain.