摘要：

旨为揭示不同品种以及不同器官中内生菌的多样性特征,初步明确内生菌群落结构与宿主品种、器官类型及病害抗感特性的相关性。选取抗赤霉病的冀谷22、红谷、陇谷11号和感赤霉病的小青谷、石榴子、嫩选16号共6个谷子品种,取其根、茎、叶片、叶鞘、成熟谷穗,提取DNA,针对16S rDNA V3—V4区域,进行PCR扩增,基于Miseq高通量测序平台,对样本进行微生物多样性分析。感病品种与抗病品种内生菌物种组成具有明显差异。供试样本在门水平上的优势种群为变形菌门和放线菌门,其次是拟杆菌门和厚壁菌门,粘菌门、绿弯菌门、芽单胞菌门和梭杆菌门相对丰度较低。Alpha多样性分析表明,抗病品种的叶片、成熟谷穗群落丰富度较高,叶片、根、成熟谷穗多样性较高;而感病品种则是根和茎群落丰富度较高,茎和叶鞘多样性相对较高;PCoA分析则表明,器官类型比品种对内生菌群落结构影响更大。物种组成分析表明,谷子内生菌群的多样性受到不同品种及不同器官的影响,不同器官所含内生菌种类相差较大。感病品种小青谷、石榴子和嫩选16与抗病品种冀谷22、红谷和陇谷11的内生菌群多样性差异较大,抗病品种在叶鞘时期都具有NB1-j菌门,成熟谷穗都具有酸杆菌门。明确了不同品种、不同器官对谷子内生菌的多样性及群落结构的影响,器官类型比品种对内生菌群落结构的影响更大。

关键词: 谷子, 谷子赤霉病, 内生菌, 多样性

Abstract:

To reveal the diversity characteristics of endophytic bacteria in different cultivars and organs,and clarify the correlation between endophytic bacteria community structure and host varieties,organ types and disease resistance and susceptible characteristics.Six different varieties of foxtail millet,Jigu 22,Honggu,Longgu No.11 and Xiaoqinggu,Shiliuzi and Nenxuan 16,which were resistant (susceptible) to Fusarium head blight,were selected as materials.The leaves,roots,stems,leaf sheaths and mature spikes of foxtail millet,were taken respectively.DNA was extracted for PCR amplification of 16S rDNA V3—V4 region,and Miseq library was constructed for high-throughput sequencing.Microbial diversity was analyzed by Major biological cloud platform.There were certain differences in endophyte species composition between susceptible and resistant varieties,the dominant populations of endophytes were Proteobacteria and Actinobacteriota,followed by Bacteroidota and Firmicutes,Myxococota and Chloroflexi were lower relative abundance followed by Gemmatimondota and Fusobacteriota.Alpha diversity analysis showed that the resistant cultivars had higher panicle community richness at leaf and maturity spikes and higher panicle diversity at leaf,root and maturity spikes.The susceptible varieties had higher richness of root and stem community and higher diversity of stem and leaf sheath;PCoA analysis showed that organ type had more effect on endophytic community structure than variety.Species composition analysis showed that the diversity of endophytic flora in foxtail millet was affected by different varieties and different parts,and the species of endophytic flora in different parts were quite different.The diversity of endophytic flora between susceptible cultivars Xiaoqinggu,Shiliuzi and Nenxuan 16 and resistant cultivars Jigu 22,Honggu and Longgu No.11 was quite different.The resistant cultivars had NB1-j in leaf sheath stage,and the ears had Acidobacteriota in mature stage.The study showed that the diversity and community structure of endophytic bacteria were affected by different organs and varieties of the foxtail millet,and the organ types had more influence on the community structure of endophytic bacteria than varieties.

Key words: Foxtail millet, Fusarium head blight, Endogenic bacteria, Diversity