干旱条件下棉花根际真菌多样性分析

Fungi diversity analysis of rhizosphere under drought conditions in cotton

植物根际微生物群落对植物生长和适逆性至关重要,本研究对干旱条件下棉花根际真菌群落进行分析,旨在探明干旱胁迫对棉花根际真菌多样性和群落结构的影响,为利用有益微生物提高棉花水分利用率提供理论依据。以陆地棉Jin 668(Gossypium hirsutum cv.Jin668)为试验材料,采用盆栽控水方式,对处于开花期的棉花根际土壤(SDP)和未种植棉花土壤(SOPD)进行干旱处理,正常浇水的棉花根际土壤(SPN)和无棉花土壤(SNPN)为对照。从中采集土壤样品,提取DNA,采用Illumina Miseq对真菌ITS1区域进行高通量测序,研究土壤中真菌多样性。结果共鉴定到970个OTUs,SNPN、SOPD、SPN和SDP样品中真菌OTUs数量分别为481、528、743和752个,其中288个OTUs为所有组共有。对获得OTUs进行门、纲、目、科和属5个分类水平的划分表明,棉花根际真菌群落结构主要由子囊菌门(82.70%)和担子菌门(10.15%)组成;干旱处理使粪壳菌纲(Sordariomycetes)、粪壳菌目(Sordariales)和毛壳菌科(Chaetomiaceae)丰度显著降低,而散囊菌目(Eurotiales)、发菌科(Trichocomaceae)、曲霉属(Aspergillus)和青霉属(Penicillum)的丰度显著增加。多样性分析结果显示,与未种棉花的土壤相比,有棉花的土壤中真菌群落的α多样性显著增加;同时,SPN和SDP之间的真菌群落结构更相似,而与SNPN和SOPD间差异较大。研究表明,棉花根际存在丰富的真菌群落,干旱对土壤中真菌的丰度和多样性有显著影响。本研究从微生物的角度为提高棉花耐旱性的研究提供新见解。

Plant rhizosphere microorganisms play important roles in plant growth and the adaptability of plants to adverse environmental stresses.In this study,cotton rhizosphere fungal communities were analyzed under drought conditions,aiming to explore the effects of drought stress on the diversity and community structures of cotton rhizosphere fungi,and to provide a theoretical basis for improving cotton water use efficiency by using beneficial microorganisms.Drought stress was applied to upland cotton(Gossypium hirsutum cv.Jin 668)at flowering stage(SDP),while the soil without plants was also subjected to drought(SOPD).Simultaneously,the plants(SPN)and pots without plants(SNPN)regularly watered were used as controls.The soil samples were collected,the microbial DNA was isolated,and Illumina Miseq was conducted for a high-throughput sequencing of fungi ITS1 regions to study the diversity of the rhizosphere fungal communities.As a result,a total of 970 OTUs were identified,and the numbers of fungal OTUs in the samples of SNPN,SOPD,SPN,and SDP were 481,528,743,and 752,respectively,among which 288 OTUs were shared by all samples.The OTUs were classified to different levels of phyla,class,order,family,and genus of fungi.The rhizosphere fungal community of cotton was predominantly consisted of the phyla Ascomycota(82.70%)and Basidiomycota(10.15%).The abundance of Sordariomycetes,Sordariales,and Chaetomiaceae decreased,while the abundance of Eurotiales,Trichocomaceae,Aspergillus,and Penicillum increased significantly under drought stress.Moreover,the diversity of fungal community in the soil with cotton plants significantly higher than that in the soil without cotton plants.Meanwhile,the fungi community structures of SPN and SDP resembling each other and differing greatly from SNPN and SOPD.These results revealed that the cotton rhizosphere had a rich pool of fungal communities,and drought stress had a significant effect on the abundances and diversity of fungi in cotton rhizosphere.This study provided new insights for the researches of improving drought tolerance of cotton in terms of soil microorganisms.