Comparative Study of the Rhizosphere and Root Endosphere Microbiomes of Cholistan Desert Plants

Rhizosphere microbiome plays a significant role in the functioning of plants and provides information regarding plant physiology (osmoregulation) and development. Very limited information has been available on the microbial diversity from arid environments of Pakistan. Hence in the current study, we used Illumina MiSeq high-throughput sequencing based on 16S rRNA gene to compare the microbial diversity from the rhizospheric and non-rhizospheric soils of xerophytes (Opuntia humifusa, Aerva javanica, Zygophyllum simplex and Haloxylon salicoricum) collected from Cholistan desert of Pakistan. Metagenomic analysis indicated that Proteobacteria and Actinobacteria were the most dominant phyla detected from the rhizospheric soils while Firmicutes and Bacteroidetes were the most dominant phyla detected from the non-rhizospheric soils. Acidobacteria, Bacteriodetes, Planctomycetes, Cyanobacteria, Verrucomicrobia, Choroflexi and Gemmatimonadetes were less abundant phyla identified from all the soil samples. At the genus level, sequences of Bacillus, Enterobacter, Pseudomonas, Burkholderia, Halomonas, Nocardioides and Solirubrobacter were prevalent in the rhizospheric soils while Nocardioides, Meiothermus, Methylotenera, Acinetobacter, Staphylococcus and Streptomyces were abundant in the non- rhizospheric soils.

根际微生物组（rhizosphere microbiome）对植物的生命活动发挥着关键调控作用，同时可提供有关植物生理（渗透调节）与生长发育的相关信息。目前针对巴基斯坦干旱环境下的微生物多样性研究资料仍较为匮乏。因此本研究基于16S rRNA基因，采用Illumina MiSeq高通量测序技术，对采自巴基斯坦乔斯坦沙漠的旱生植物（梨果仙人掌*Opuntia humifusa*、白花灰毛木*Aerva javanica*、霸王*Zygophyllum simplex*、盐节木*Haloxylon salicoricum*）的根际与非根际土壤微生物多样性进行了比较分析。宏基因组分析结果显示，根际土壤中检出的优势菌门为变形菌门（Proteobacteria）与放线菌门（Actinobacteria），而非根际土壤的优势菌门则为厚壁菌门（Firmicutes）与拟杆菌门（Bacteroidetes）。在所有土壤样本中，丰度较低的菌门包括酸杆菌门（Acidobacteria）、拟杆菌门（Bacteroidetes）、浮霉菌门（Planctomycetes）、蓝细菌门（Cyanobacteria）、疣微菌门（Verrucomicrobia）、绿弯菌门（Choroflexi）以及芽单胞菌门（Gemmatimonadetes）。在属水平上，根际土壤中优势分布的菌属包括芽孢杆菌属（Bacillus）、肠杆菌属（Enterobacter）、假单胞菌属（Pseudomonas）、伯克霍尔德菌属（Burkholderia）、盐单胞菌属（Halomonas）、诺卡氏菌属（Nocardioides）以及索里鲁布杆菌属（Solirubrobacter）；而非根际土壤中丰度较高的菌属则为诺卡氏菌属（Nocardioides）、梅氏热杆菌属（Meiothermus）、甲基营养杆菌属（Methylotenera）、不动杆菌属（Acinetobacter）、葡萄球菌属（Staphylococcus）以及链霉菌属（Streptomyces）。