Soil microbial community shifts explain habitat heterogeneity in two Haloxylon species from a nutrient perspective

Haloxylon ammodendron and Haloxylon persicum (as sister taxa) are dominant shrubs in the Gurbantunggut Desert. The former grows in inter-dune lowlands while the latter in sand dunes. However, little information is available regarding the possible role of soil microorganisms in their habitat heterogeneity from a nutrient perspective in deserts. Rhizosphere is the interface of plant-microbe-soil interactions and fertile islands usually occur around the roots of desert shrubs. Given this, we applied quantitative real-time PCR combined with MiSeq amplicon sequencing to compare their rhizosphere effects on microbial abundance and community structures at three soil depths (0–20, 20–40, and 40–60 cm). The rhizosphere effects on microbial activity (respiration) and soil properties had also been estimated. The rhizospheres of both shrubs exerted significant positive effects on microbial activity and abundance (e.g. eukarya, bacteria and nitrogen-fixing microbes). The rhizosphere effect of H. amm..., This study focuses on the rhizosphere soils (0–60 cm) of H. ammodendron and H. persicum and their corresponding soil environments in the Gurbantunggut Desert. Given that N is the most crucial limiting nutrient factor for plant growth in arid area, we applied quantitative real-time PCR (qPCR) to evaluate the variations in the abundance of bacteria, eukarya, archaea and N-transforming microorganisms (N-fixing microbes, ammonia-oxidizing bacteria and ammonia-oxidizing archaea), as affected by the habitat and rhizosphere. Meanwhile, the study also evaluated compositional shifts in bacterial and eukaryal communities using MiSeq amplicon sequencing. On this basis, we compared rhizosphere effects between these two shrubs in term of microbial activity (i.e., respiration), abundance and community structure, as well as for soil properties.,

梭梭（Haloxylon ammodendron）与白梭梭（Haloxylon persicum）作为姐妹类群（sister taxa），是古尔班通古特沙漠的优势灌木。前者生长于丘间低地，后者则分布于沙丘之上。然而当前鲜有研究从养分视角探讨土壤微生物在二者生境异质性中可能发挥的潜在作用。
根际（rhizosphere）是植物-微生物-土壤互作的界面，荒漠灌木根系周围通常会形成肥岛（fertile islands）。鉴于此，本研究采用实时荧光定量PCR（quantitative real-time PCR, qPCR）结合MiSeq扩增子测序（MiSeq amplicon sequencing）技术，对比两种灌木在三个土壤深度（0–20、20–40、40–60 cm）下的根际效应对微生物丰度与群落结构的影响，并评估了根际效应对微生物活性（呼吸作用）及土壤理化性质的作用。
两种灌木的根际均对微生物活性与丰度（如真核生物、细菌与固氮微生物）产生显著正向影响。
本研究聚焦古尔班通古特沙漠内梭梭与白梭梭的根际土壤（0–60 cm）及其对应生境的土壤环境。鉴于氮是干旱区植物生长最关键的限制性养分因子，本研究通过实时荧光定量PCR（qPCR），评估生境与根际效应影响下，细菌、真核生物、古菌以及氮转化微生物（N-transforming microorganisms，包括固氮微生物（nitrogen-fixing microbes）、氨氧化细菌（ammonia-oxidizing bacteria）与氨氧化古菌（ammonia-oxidizing archaea））的丰度变化。同时，本研究利用MiSeq扩增子测序技术分析细菌与真核生物群落的组成变迁。在此基础上，本研究对比了两种灌木的根际效应在微生物活性（即呼吸作用）、丰度与群落结构，以及土壤理化性质方面的差异。