烟草野火病叶际微生物群落结构与多样性

Microbial community structure and diversity of leaf phyllosphere in tobacco plants infected with wildfire disease

关键词:  烟草野火病, 高通量测序, 病叶, 群落结构, 多样性指数, 丰富度指数

Key words:  tobacco wildfire disease, high-throughput sequencing, diseased leaf, community structure, diversity index, richness index

摘要:

叶际微生物种群稳定与烟株健康密切相关。为揭示感染野火病烟株叶际微生态特征,该文采用Illumina高通量测序技术对不同发病程度烟株叶片的病斑和健康组织进行微生物群落结构与多样性分析。结果表明:(1)病斑组织与健康组织优势菌为变形菌门(Proteobacteria)和子囊菌门(Ascomycota),并且其在病斑组织的相对丰度显著高于健康组织; 优势属为假单胞菌属(Pseudomonas)、泛菌属(Pantoea)、链格孢属(Alternaria)、小不整球壳属(Plectosphaerella)和锥盖伞属(Conocybe),仅假单胞菌属在病斑组织的相对丰度显著高于健康组织。(2)病斑组织细菌群落多样性和丰富度高于健康组织,并且随病害程度的增加,多样性指数和丰富度指数分别呈先减后增和先增后减的趋势; 病斑组织真菌群落丰富度和多样性指数随病害程度的增加先增后减,轻度和中度病叶病斑组织真菌群落多样性指数和丰富度高于健康组织,但重度病叶病斑组织真菌群落多样性指数和丰富度低于健康组织。(3)病斑和健康组织细菌的基因功能信息及相对丰度基本类似,主要为代谢、遗传信息处理和环境信息处理3类; 真菌的优势功能类群为植物病原菌、动物病原菌-内生真菌-植物病原菌-木质腐生真菌、未定义腐生真菌、木质腐生真菌和植物病原菌-木质腐生真菌。该研究结果为认识烟草野火病演变规律及叶际微生物群落特征提供了科学依据。

Abstract:

The stability of phyllosphere microbial community is closely related to plant health. In order to understand the microecological characteristics of tobacco leaves infected with wildfire disease, community structure and diversity of phyllosphere microbiome in diseased spots and healthy tissues of tobacco leaves with different degrees of disease were analyzed using high-throughput sequencing technology in this paper. The results were as follows:(1)The dominant microorganisms in diseased and healthy tissues were Proteobacteria and Ascomycota, and their relative abundance in diseased tissues was significantly higher than that in healthy tissues. The dominant genera were Pseudomonas, Pantoea, Alternaria, Plectosphaerella and Conocybe, and only the relative abundance of Pseudomonas in diseased tissues was significantly higher than that in healthy tissues.(2)The diversity and richness of bacterial communities in diseased spots were higher than those in healthy tissues, and the diversity index showed a trend of decreasing and then increasing with the increase of the disease degree, and the richness index showed a trend of increasing and then decreasing. The richness and diversity index of fungal communities in diseased spots showed a trend of increasing and then decreasing with the increase of the disease degree, and the diversity index and richness of fungal communities in diseased spot tissues of mildly and moderately diseased leaves were higher than those in healthy tissues, but the diversity index and richness of fungal communities in heavily diseased tissues were lower than those in healthy tissues.(3)Gene functional information and relative abundance of bacteria in diseased spots and healthy tissues were generally similar, primarily were metabolism, genetic information processing and environmental information processing. The dominant functional taxa of fungus were plant pathogen, animal pathogen-endophyte-plant pathogen-wood saprotroph, undefined saprotroph, wood saprotroph and plant pathogen-wood saprotroph. The results provide a reference for the understanding of evolutionary pattern of tobacco wildfire disease and characterization of the phyllosphere microbial community.