Zhao Lei, Wang Yue, Kong Shuang
College of Life Science, Shandong Normal University, Jinan, 250014, China.
Int Microbiol. 2020 Nov;23(4):501-509. doi: 10.1007/s10123-020-00122-4. Epub 2020 Feb 20.
Iron (Fe) deficiency is one of the major limiting factors affecting crop yields. Trichoderma asperellum Q1, a biocontrol and plant growth promoting fungus, can produce the siderophore which has a high affinity to Fe in the absence of iron. In this study, Trichoderma asperellum Q1 was found to be able to promote growth of Arabidopsis thaliana in an iron-deficient or insoluble iron-containing (FeO) medium. It also can produce more siderophore and indole-3-acetic acid (IAA) as the concentration of iron ions decreased. However, it is unclear that the relationship between siderophore and IAA in promoting plant growth. Both Trichoderma asperellum Q1 and siderophore promotes not only the DR5::GFP transgenic Arabidopsis thaliana seedlings, in which the root IAA is labeled by green fluorescent protein gene, but also increases the content of endogenous IAA in the roots, which was shown by the fluorescence study. The strongest fluorescence was observed in the treated group inoculated with Trichoderma asperellum Q1 under the condition of insoluble iron. In the case of iron-free medium, adding siderophore also increased the observed fluorescence intensity. These results suggest that the siderophores produced by Trichoderma asperellum Q1 increased the content of IAA in Arabidopsis roots by enhancing the conversion of poorly soluble iron or by the siderophore itself.
缺铁是影响作物产量的主要限制因素之一。棘孢木霉Q1是一种具有生物防治和促进植物生长作用的真菌，在缺铁条件下能产生对铁具有高亲和力的铁载体。在本研究中，发现棘孢木霉Q1能够在缺铁或含不溶性铁（FeO）的培养基中促进拟南芥生长。随着铁离子浓度降低，它还能产生更多的铁载体和吲哚-3-乙酸（IAA）。然而，铁载体与IAA在促进植物生长方面的关系尚不清楚。棘孢木霉Q1和铁载体不仅促进了DR5::GFP转基因拟南芥幼苗（其中根IAA由绿色荧光蛋白基因标记）的生长，荧光研究还表明它们增加了根中内源IAA的含量。在不溶性铁条件下，接种棘孢木霉Q1的处理组观察到最强的荧光。在无铁培养基的情况下，添加铁载体也增加了观察到的荧光强度。这些结果表明，棘孢木霉Q1产生的铁载体通过增强难溶性铁的转化或铁载体本身增加了拟南芥根中IAA的含量。
