烟草根结线虫病对烟株根际土壤真菌群落结构及多样性的影响

Effects of tobacco root⁃knot nematode disease on structure and diversity of fungal community in tobacco rhizosphere soil

【目的】通过研究根结线虫病患病烟株与健康烟株根际土壤真菌群落结构及多样性,明确烟草根结线虫病发生的微生态机制。【方法】利用Illumina MiSeq高通量测序技术分析根结线虫病患病烟株与健康烟株根际土壤真菌群落结构和土壤养分变化特征。【结果】根际土壤真菌OUTs数健康烟株与病株分别为2120和1170个,健康烟株土壤真菌OUTs数是病株的1.81倍,特有OTUs数是病株的3.31倍;病株根际土壤的Shannon、ACE和Chao1等指数分别较健康烟株降低12.16%、52.96%、50.40%。病株根际土壤中桑尼被孢霉(Mortierellasarnyensis)、未分类被孢霉菌属(unclassified_g__Mortierella)、未分类真菌界(unclassified_k__Fungi)和未分类青霉菌属(unclassified_g__Penicillium)的相对丰度较健康烟株分别增加139.01%、134.83%、203.27%和361.94%,且差异均达到显著水平(P<0.05);根际土壤真菌群落组成的PCoA分析结果表明,健康烟株与病株根际土壤真菌物种组成存在明显差异。烤烟根际土壤真菌群落结构与土壤养分变化存在一定相关性,其中土壤pH与土壤常见病原菌镰刀菌属(Fusarium)呈显著负相关,水解氮、有效磷和速效钾等土壤养分与土壤有益微生物被孢霉属(Mortierella)呈极显著正相关。【结论】烟草根结线虫病发生明显降低了真菌OUT丰度,影响烟株根际土壤真菌群落的分布和相对丰度。烤烟根际土壤真菌群落与土壤养分互作,共同影响根结线虫病的发生。

【Objective】The microecological mechanism of tobacco root⁃knot nematode disease was clarified by studying the structure and di⁃versity of fungal community in rhizosphere soil of diseased tobacco plants and healthy tobacco plants.【Method】Illumina MiSeq high⁃through⁃put sequencing was used to compare and analyze the fungal community structure and variation characteristics of soil nutrients in rhizosphere soil of diseased tobacco plants and healthy tobacco plants.【Result】The OUT abundance of fungi in rhizosphere soil of diseased plants and healthy tobacco plants were 1170 and 2120,respectively.The OUT abundance of fungi in healthy tobacco plants was 1.81 times higher than that of diseased plants,and the number of unique OTUs was 3.31 times higher than that of diseased plants;The Shannon,ACE and Chao1 indexes of rhizosphere soil of diseased plants decreased by 12.16%,52.96%and 50.40%,respectively.The relative abundance of M.sarnyensis,unclassified_g_Mortierella,unclassified_k_Fungiandunclassified_g_Penicilliumin rhizosphere soil of diseased plants in⁃creased by 139.01%,134.83%,203.27%and 361.94%,respectively,compared with healthy tobacco plants,and all reached significant indigenous levels(P<0.05);The PCoA analysis of rhizosphere soil fungal community composition showed that there were significant differ⁃ences between healthy tobacco plants and diseased tobacco plants;There was a certain correlation between the fungal community structure in rhizosphere soil of flue⁃cured tobacco and the change of soil nutrients,in which the soil pH was significantly negatively correlated with the common soil pathogen(Fusarium),and the soil nutrients such as hydrolyzable nitrogen,available phosphorus and available potassium were significantly positively correlated with the beneficial soil microorganism(Mortierella).【Conclusion】The occurrence of tobacco root knot nematode disease significantly reduced the OUT abundance of fungi,and affected the distribution and relative abundance of the fungal com⁃munity in rhizosphere soil of flue⁃cured tobacco.Rhizosphere soil fungal communities interact with soil nutrients and jointly affect the occur⁃rence of tobacco root knot nematode disease.