Collaborative Innovation Center of Henan Grain Crops/National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou, 450002, China.
Xuchang Vocational Technical College, Xuchang, 461000, China.
Curr Genet. 2020 Feb;66(1):229-243. doi: 10.1007/s00294-019-01017-2. Epub 2019 Jul 16.
Fusarium pseudograminearum-induced crown rot causes significant reduction to wheat production worldwide. To date, efforts to develop effective resistance to this disease have been hampered by the quantitative nature of resistance trait and a lack of understanding of the molecular pathogenesis. Non-ribosomal peptides have important roles in development, pathogenicity, and toxins in many plant pathogens, while less is known in F. pseudograminearum. In this work, we studied the expression and function of a nonribosomal peptide gene FpNPS9 in F. pseudograminearum. We determined the expression of FpNPS9 which was significantly up regulated during the infection of wheat. A deletion mutant Δfpnps9 produced in this study displayed a normal growth and conidiation phenotype, however, hyphae polar growth was obviously affected. Deoxynivalenol production in this mutant was significantly reduced and the infection of wheat coleoptiles and wheat spikelet was attenuated. The Δfpnps9 showed serious defects on the extension of infectious hyphae in plant and inhibition of roots elongation compared with the wild type. The complementation assay using a FpNPS9-GFP fusion construct fully restored the defects of the mutant. GFP signal was detected in the germinating conidia and infectious hyphae in coleoptiles of the infected plants. Interestingly, the signal was not observed when it was grown on culture medium, suggesting that the expression of FpNPS9 was regulated by an unknown host factor. This observation was supported by the result of qRT-PCR. In summary, we provided new knowledge on FpNPS9 expression in F. pseudograminearum and its function in F. pseudograminearum pathogenicity in wheat.
镰刀菌小麦冠腐病引起的小麦减产在全球范围内造成了重大损失。迄今为止，由于抗性性状的数量性质和对分子发病机制的缺乏理解，开发有效抗性的努力受到了阻碍。非核糖体肽在许多植物病原体的发育、致病性和毒素中具有重要作用，而在 F. pseudograminearum 中则知之甚少。在这项工作中，我们研究了 F. pseudograminearum 中非核糖体肽基因 FpNPS9 的表达和功能。我们确定了 FpNPS9 的表达，在小麦感染过程中，其表达显著上调。在这项研究中产生的缺失突变体Δfpnps9 表现出正常的生长和分生孢子形成表型，然而，菌丝极性生长明显受到影响。该突变体中脱氧雪腐镰刀菌烯醇的产生显著减少，对小麦幼叶和小麦小穗的感染减弱。与野生型相比，Δfpnps9 在植物中感染性菌丝的延伸和根伸长的抑制方面表现出严重缺陷。使用 FpNPS9-GFP 融合构建体进行的互补测定完全恢复了突变体的缺陷。在感染植物的幼叶中，GFP 信号在萌发的分生孢子和感染的菌丝中被检测到。有趣的是，当在培养基上生长时，没有观察到信号，这表明 FpNPS9 的表达受到未知宿主因子的调控。这一观察结果得到了 qRT-PCR 结果的支持。总之，我们提供了关于 FpNPS9 在 F. pseudograminearum 中的表达及其在 F. pseudograminearum 对小麦致病性中的功能的新知识。
