河北省玉米穗腐病病原菌鉴定及潜在产伏马毒素镰孢菌系统发育分析

 为明确河北省夏玉米区玉米穗腐病的发生情况、病原菌组成及地区对病原菌种类的影响,本团队于2016年和2017年在玉米收获前期对玉米穗腐病的发生情况进行调查,并通过生物学方法对随机采回的样本进行分离鉴定。田间调查结果表明,与2016年相比,2017年河北省玉米种植面积有所减少,玉米穗腐病的发病率有所下降。分离鉴定结果表明,引起河北省夏玉米区穗腐病的优势病原菌为拟轮枝镰孢菌(Fusarium verticillioides),分离频率为63.49%,其他病原菌如层出镰孢菌(F. proliferatum)、禾谷镰孢菌(F. graminearum)、变红镰孢菌(F. incarnatum)、黑曲霉(Aspergillus niger)、黄曲霉(A. flavus)、草酸青霉(Penicillium oxalicum)和哈茨木霉(Trichoderma harzianum)的分离频率分别为19.05%、6.35%、1.59%、14.29%、3.17%、9.52%和1.59%。为明确伏马毒素基因在潜在产伏马毒素镰孢菌鉴定中的作用,拟轮枝镰孢菌、层出镰孢菌和藤仓镰孢菌(F. fujikuroi)分别以EF-1α和FUM1基因序列为基础构建系统发育树。结果表明,两个系统发育树拓扑结构相似,伏马毒素基因可用于潜在产伏马毒素镰孢菌种的鉴定,基于FUM1基因的种间遗传距离大于基于EF-1α基因的种间遗传距离,而种内遗传距离的结论则与之相反。

Identification of pathogens causing maize ear rot and the phylogenetic analysis of fumonisins-producing Fusarium species in Hebei province

In order to confirm the occurrence of maize ear rot, pathogenic composition and the regional variation, the survey was conducted before harvesting in 2016 and 2017, and the diseased samples were randomly collected for pathogen identification. The results of field survey indicated that the corn planting area and the incidence of maize ear rot had decreased in 2017, compared with 2016. Identification results showed that the predominant pathogen of maize ear rot in summer corn region of Hebei Province was Fusarium verticillioides with isolation frequency of 63.49%, and the other pathogens included F. proliferatum, F. graminearum, F.incarnatum, Aspergillus niger, A. flavus, Penicillium oxalicum and Trichoderma harzianum with frequency of 19.05%, 6.35%, 1.59%, 6.35%, 3.17%, 9.52% and 1.59%, respectively. To clear the role of fumonisin gene for identification of fumonisin-producing Fusarium species, the phylogenetic trees of F. verticillioides, F. proliferatum and F. fujikuroi were generated based on the sequences of EF-1α and FUM1 gene, respectively. The similar topology in the two phylogenetic tree indicated that the fumonisin gene could be used for the purpose of identification in which the interspecific genetic distance based on FUM1 gene was greater than that of EF-1α gene, while the intraspecific genetic distance was opposite.