野生越南槐组织特异性内生真菌组及体外抗病原菌功能

Tissue-specificity and pathogen-resistant function in vitro of endophytic fungal microbiome harbored in Sophora tonkinensis from wild type

关键词:  野生越南槐, 有益内生真菌组, 生物多样性, 组织特异性, 抗病功能

Key words:  Sophora tonkinensis from wild type, beneficial endophytic fungal microbiome, biodiversity, tissue specificity, pathogen-resistant function

摘要:

有益微生物组能帮助宿主植物防御病害。越南槐的根、茎和种子在野外环境下健康发芽生长,而栽培越南槐各组织极易感病。为了探明利用野生越南槐有益内生真菌组防治宿主病害的可能,该文在分离健康野生越南槐根、茎和种子内生真菌的基础上,并结合形态学和ITS序列特征鉴定内生真菌,通过系统发育树、α-多样性指数和β-多样性指数分别分析各内生真菌组的系统进化、多样性和相似性,通过琼脂块法和平板对峙法测试内生真菌组的体外抗病原菌功能。结果表明:(1)从越南槐根、茎和种子内生真菌组分别分离鉴定131株23个分类单元、108株23个分类单元、64株11个分类单元;(2)特有属多且所有种均为特有种显示根、茎和种子内生真菌组在属种进化上具有组织特异性;(3)根-茎/根-种子/茎-种子间极低的β-多样性显示根、茎和种子各内生真菌组间的物种相似性极低;(4)高的α-多样性显示越南槐根、茎和种子均有丰富多样的内生真菌组;(5)各内生真菌组三分之一以上的分类单元在体外均能拮抗供试病原菌,根茎内生真菌组显示了强广谱的体外抗病原细/真菌功能,种子内生真菌组显示了强广谱的体外抗病原真菌功能。该研究结果表明健康野生越南槐根、茎和种子内部均存在有益内生真菌组,其具有生物多样性、组织特异性以及强广谱的体外抗病原菌功能,在宿主各组织的抗病性方面可能发挥重要作用。这些结果将为进一步利用有益真菌组防治栽培越南槐各组织病害提供了材料和实验基础。

Abstract:

The beneficial microbiome assist the plant in disease defense. The root, stem and seed of Sophora tonkinensis from wild type were germinated and grew healthily, but they in cultivated type were susceptible to insect and pathogen attack. In order to explore the possibility of disease control using beneficial endophytic fungal microbiome harbored in S. tonkinensis from healthy wild type, endophytic fungi were isolated from the root, stem and seed of S. tonkinensis from healthy wild type, and then were further identified based on morphological characters and ITS sequence characters. Phylogenetic tree, α-diversity index and β-diversity index were used to analyze the phylogenetic evolution, diversity and similarity among different endophytic fungal microbiomes. The pathogen-resistant function in vitro of endophytic fungal microbiome was determined by the agar plug method and flat-stand method. The results were as follows:(1)131 strains with 23 taxa, 108 strains with 23 taxa, and 64 strains with 11 taxa, were respectively isolated and identified from the root, stem and seed of S. tonkinensis;(2)More endemic genera and all endemic species, indicated that endophytic fungal microbiomes harbored in the root, stem and seed had tissue specificity in genus and species evolutionary tree;(3)The extremely low β-diversity between root-stem, root-seed, and stem-seed indicated that species similarity was very low among different endophytic fungal microbiomes;(4)The high α-diversity showed that endophytic fungal microbiomes harbored in the root, stem and seed were abundant biodiversity;(5)More than one third of the taxa antagonized pathogens in vitro. Endophytic fungal microbiome harbored in the root/stem showed strong broad-spectrum pathogenic bacteria/fungi-resistant function in vitro, and endophytic fungal microbiome harbored in the seeds showed strong broad-spectrum pathogenic fungi-resistant function in vitro. These results indicated beneficial endophytic fungal microbiome with tissue-specificity, biodiversity structure, and strong broad-spectrum pathogen-resistant function in vitro, harbored in healthy root, stem and seed of S. tonkinensis from wild type, and might play an important role in pathogen resistance in host tissues. Such results will provide material and experimental basis for disease control in different tissues of S. tonkinensis using beneficial endophytic fungal microbiome.