中国农业科学 ›› 2021, Vol. 54 ›› Issue (16): 3428-3439.doi: 10.3864/j.issn.0578-1752.2021.16.006

• 植物保护 • 上一篇    下一篇

假禾谷镰孢转录因子FpAPSES的鉴定与功能分析

赵静雅(),夏荟清,彭梦雅,凡卓,殷悦,徐赛博,张楠,陈文波,陈琳琳()   

  1. 河南农业大学植物保护学院/小麦玉米作物学国家重点实验室,郑州 450002
  • 收稿日期:2020-11-26 接受日期:2021-01-08 出版日期:2021-08-16 发布日期:2021-08-24
  • 通讯作者: 陈琳琳
  • 作者简介:赵静雅,E-mail: zhaojy0108@163.com
  • 基金资助:
    国家自然科学基金(U2004140);河南省青年人才托举工程项目(2020HYTP043);大学生创新创业训练计划(201910466015)

Identification and Functional Analysis of Transcription Factors FpAPSES in Fusarium pseudograminearum

ZHAO JingYa(),XIA HuiQing,PENG MengYa,FAN Zhuo,YIN Yue,XU SaiBo,ZHANG Nan,CHEN WenBo,CHEN LinLin()   

  1. College of Plant Protection, Henan Agricultural University/National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou 450002
  • Received:2020-11-26 Accepted:2021-01-08 Online:2021-08-16 Published:2021-08-24
  • Contact: LinLin CHEN

摘要:

【目的】假禾谷镰孢(Fusarium pseudograminearum)侵染小麦引起的小麦茎基腐病严重影响中国小麦的安全生产。查找假禾谷镰孢中的APSES转录因子,分析其在病原菌致病过程中的作用,为解析假禾谷镰孢的致病机制及小麦茎基腐病的防治提供理论依据。【方法】从GenBank获得物种中已知的APSES氨基酸序列,利用BLASTP方法在假禾谷镰孢中查找APSES同源蛋白,利用Pfam软件预测蛋白结构域,采用MEGA5.05构建APSES蛋白的系统进化树。利用实时荧光定量PCR(qRT-PCR)方法分析A组APSES转录因子基因FpAPSES1FpAPSES4在假禾谷镰孢侵染过程中的表达。通过PEG介导的原生质体转化和PCR筛选FpAPSES1FpAPSES4基因缺失的突变体菌株。在PDA培养基上测定假禾谷镰孢野生型菌株Wz2-8A、Δfpapses1和Δfpapses4突变体菌株的菌丝形态和生长速率;测定在CMC培养液中培养后的分生孢子产生情况、形态以及在无菌水中的萌发率;利用菌丝块和分生孢子接种小麦胚芽鞘和大麦叶片以及盆栽试验测定其致病性;采用ELISA方法测定小米培养基中脱氧雪腐镰刀菌烯醇(DON)的含量。【结果】假禾谷镰孢中有4个APSES同源蛋白,均含有保守的DNA结合结构域HTH。与其他物种的APSES蛋白构建系统进化树,发现FpAPSES1、FpAPSES2和FpAPSES4属于A组APSES,FpAPSES3分布在C组。FpAPSES1FpAPSES4在侵染阶段诱导表达,推测可能参与假禾谷镰孢的致病。分别获得2个FpAPSES1FpAPSES4基因缺失的突变体菌株Δfpapses1-T10、Δfpapses1-T27和Δfpapses4-T1、Δfpapses4-T2。表型测定结果显示,与野生型相比,FpAPSES1FpAPSES4基因缺失突变体在PDA平板上的生长速率明显减慢、色素积累明显增多;FpAPSES1基因缺失突变体菌丝形态无差异,而FpAPSES4基因缺失突变体菌丝弯曲、分支明显增多;FpAPSES1FpAPSES4基因缺失突变体在CMC液体中的分生孢子产生明显减少,分别比野生型下降了99.5%和97.4%,产生的分生孢子变短、隔膜减少、萌发率有所降低;与野生型相比,FpAPSES1FpAPSES4基因缺失突变体菌丝体和分生孢子对小麦胚芽鞘的致病力明显降低,菌丝在小麦胚芽鞘表皮细胞中的扩展明显受阻;FpAPSES1FpAPSES4基因缺失突变体对大麦叶片和小麦根部的致病力也明显降低;FpAPSES1FpAPSES4基因缺失突变体在小米培养基中产生的DON毒素分别比野生型下降了约78%和44%。【结论】编码A组APSES同源蛋白的FpAPSES1FpAPSES4对假禾谷镰孢的菌丝生长、分生孢子产生和致病力均具有重要作用。

关键词: 小麦茎基腐病, 假禾谷镰孢, APSES转录因子, 致病力

Abstract:

【Objective】Fusarium crown rot (FCR) caused by Fusarium pseudograminearum seriously affects wheat production in China. The objective of this study is to find and analyze the functions of APSES transcription factors in F. pseudograminearum, and to provide theoretical basis for revealing the pathogenic mechanism of F. pseudograminearum and prevention and treatment of FCR.【Method】The known APSES proteins were obtained from GenBank, and APSES candidates in F. pseudograminearum were found by BLASTP. Domains of FpAPSES proteins were determined using Pfam. The phylogenetic tree of APSES proteins was constructed using MEGA 5.05. The relative expression levels of FpAPSES1 and FpAPSES4 during infection were examined by quantitative RT-PCR (qRT-PCR). FpAPSES1 and FpAPSES4 deletion mutants were generated by polyethylene glycol (PEG)-mediated protoplast fungal transformation, and screened by PCR. The wild type, Δfpapses1 and Δfpapses4 strains were activated on PDA medium, and cultured on PDA for mycelial growth and morphology assays; mycelial blocks were introduced into liquid CMC medium to assess conidiation and conidia morphology; conidia were cultured in sterile distilled water to explore conidia germination; mycelial blocks or conidia suspension were prepared and inoculated wheat coleoptiles and barely leaves to explore pathogenicity. The pot-culture experiment was also used for virulence assay. ELISA was used to detect deoxynivalenol (DON) in inoculation millet. 【Result】 Four APSES candidates were found in F. pseudograminearum, which all contained the conserved DNA binding domain HTH. The phylogenetic tree analysis showed that FpAPSES1, FpAPSES2 and FpAPSES4 were divided into A group, while FpAPSES3 belonged to the C group. The qRT-PCR analysis revealed that FpAPSES1 and FpAPSES4 were up-regulated at infection stages, which suggested that FpAPSES1 and FpAPSES4 might play important roles in infection. Two FpAPSES1 deletion mutants (Δfpapses1-T10 and Δfpapses1-T27) and two FpAPSES4 deletion mutants (Δfpapses4-T1 and Δfpapses4-T2) were obtained. Compared with the wild type strain, both FpAPSES1- and FpAPSES4-deleted mutants exhibited significantly reduced colony growth rates. FpAPSES1-deleted mutants had normal hyphal branches, while FpAPSES4-deleted mutants exhibited curved and more branched hypha. Both FpAPSES1- and FpAPSES4-deleted mutants exhibited significantly reduced conidiation in CMC, and the conidia numbers were respectively reduced by 99.5% and 97.4% comparing with that of the wild type. Furthermore, conidia of FpAPSES1- and FpAPSES4-deleted mutants were shorter, less septa and lower germination rates. The wheat coleoptiles were point-inoculated with mycelial blocks or conidia, and the virulence of FpAPSES1- and FpAPSES4-deleted mutants was significantly reduced comparing to the wild type. Reduced pathogenicity was further observed by barely leaves inoculation and pot culture experiment. The DON levels in millet upon infection with FpAPSES1- and FpAPSES4-deleted mutants were reduced by 78% and 44% comparing to the wild type, respectively.【Conclusion】Both A group APSES homologs FpAPSES1 and FpAPSES4 play important roles in growth, conidiation and pathogenicity of F. pseudograminearum.

Key words: Fusarium crown rot, Fusarium pseudograminearum, APSES transcription factor, pathogenicity