Tolerance and elimination of oxolic acid by Trichoderma spp.
Tolerance and elimination of oxolic acid by Trichoderma spp.
复制标题
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Wu Xiaoqing;Luo Yuping;Ren He;Zhao Xiaoyan;Zhao Zhongjuan;Z. Guangzhi;Li Jishun;Zhang Xinjian;Yang He-tong
中科院分区：
文献类型：
--
作者：
Wu Xiaoqing;Luo Yuping;Ren He;Zhao Xiaoyan;Zhao Zhongjuan;Z. Guangzhi;Li Jishun;Zhang Xinjian;Yang He-tong
[目的] 草酸（OA）是多种植物病原体的毒力因子，例如：核盘菌和灰葡萄孢。木霉属的一些菌株。具有消除OA从而降低发病率的能力，但消除OA的途径和机制尚未得到很好的发现。 [方法]本研究中,在30 mmol/L OA胁迫下,T. harzianum LTR-2在42株木霉菌株中表现出最好的OA消除能力。采用形态学和原位观察方法分析了OA胁迫下LTR-2的发育特征。分析了不同 OA 胁迫下的 OA 消除率、环境 pH 值和生物量。然后描述了以OA为唯一碳源条件下LTR-2的生长状况。最后采用Real-time PCR分析OXDC编码基因LTR_4445的表达水平。 [结果]LTR-2在含有不同浓度OA的PDA平板上培养。当OA浓度为50~80 mmol/L时，LTR-2可以存活，但不能形成正常结肠。在30~50 mmol/L OA下，LTR-2首先发育厚垣孢子，随后萌发菌丝并形成正常结肠。 LTR-2可以消除液体培养中的OA。 LTR-2在20 mmol/L OA下表现出最高的OA消除率，为66.50%，在10 mmol/L OA下表现出最高的55.06%。当OA浓度提高到50−80 mmol/L时，OA消除率下降至6.75%−38.94%。不同OA胁迫下，随着OA的消除，培养滤液的pH值均有不同程度的升高，且在10和20 mmol/L浓度下升高幅度最大。有趣的是，当浓度低于20 mmol/L时，OA表现出促生长作用。此外，当 OA (<20 mmol/L) 是培养基中唯一的碳源时，LTR-2 可以形成肉眼可见的菌丝体颗粒。 LTR_4445 的转录水平在 OA 应激下上调。 [结论]我们的研究表明木霉菌。除了退化之外，在 OA 压力下还可以采用多种策略，例如抗应激模式转变、将OA转化为营养物质前体等。
[Objective] Oxalic acid (OA) is a virulence factor of several plant pathogens, e.g. Sclerotinia sclerotiorum and Botrytis cinerea. Some strains of Trichoderma spp. have the ability to eliminate OA and thereby reduce disease incidence, while the pathways and mechanism of OA elimination have not been well discovered. [Methods] In this study, T. harzianum LTR-2, performed the best capacity of OA elimination among 42 Trichoderma strains under the stress of 30 mmol/L OA. The developmental features of LTR-2 under OA stresses were analyzed using morphology and in situ observational methods. OA elimination rates, ambient pH and biomass under different OA stresses were analyzed. Then, the growing states of LTR-2 were described under the condition of OA as the sole carbon source. In the end, Real-time PCR was used to analyze expression level of OXDC coding gene LTR_4445. [Results] LTR-2 was cultured on PDA plate containing different concentrations of OA. With 50−80 mmol/L of OA, LTR-2 could survive, but didn’t form normal colon. With 30−50 mmol/L of OA, LTR-2 developed chlamydospores firstly, which then germinated hypha and formed normal colon. LTR-2 could eliminate OA in liquid culture. LTR-2 showed the highest OA elimination rate of 66.50% under 20 mmol/L OA, and the second highest of 55.06% under 10 mmol/L. When OA concentration was enhanced to 50−80 mmol/L, the OA elimination rate was dropped down to 6.75%−38.94%. pH of culture filtrate was enhanced to varying extents along with OA elimination under different OA stresses, and the highest increase occurred under the concentration of 10 and 20 mmol/L. Interestingly, OA showed growth-promoting effect when concentration was under 20 mmol/L. Moreover, LTR-2 could develop macroscopic mycelium pellet when OA (<20 mmol/L) was the sole carbon source in media. Transcriptional level of LTR_4445 was up-regulated under OA stress. [Conclusion] Our study implied that Trichoderma spp. may employ several strategies under OA stress besides degradation, e.g. transformation on stress-resistance mode, converting OA into a precursor of nutrients, etc.