DOI: 10.5061/dryad.tdz08kq2p
title: Soil microbial community shifts explain habitat heterogeneity in two Haloxylon species from a nutrient perspective

description: 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. ammodendron on microbial activity and abundance of bacteria
 and nitrogen-fixing microbes was greater than that of H. persicum.
 However, the fertile island effect of H. ammodendron was weaker than that
 of H. persicum. Moreover, there existed distinct differences in microbial
 community structure between the two rhizosphere soils. Soil-available
 nitrogen, especially nitrate nitrogen was shown to be a driver of
 microbial community differentiation among rhizosphere and non-rhizosphere
 soils in the desert. In general, the rhizosphere of H. ammodendron
 recruited more copiotrophs (e.g. Firmicutes, Bacteroidetes and
 Proteobacteria), nitrogen-fixing microbes and ammonia-oxidizing bacteria,
 and with stronger microbial activities. This helps it maintain a
 competitive advantage in relatively nutrient-rich lowlands. H. persicum
 relied more on fungi, actinomycetes, archaea (including ammonia-oxidizing
 archaea) and eukarya, with higher nutrient use efficiency, which help it
 adapt to the harsher dune crests. This study provides insights into the
 microbial mechanisms of habitat heterogeneity in two Haloxylon species in
 the poor desert soil.
description: This study focuses on the
 rhizosphere soils (0–60 cm) of <em>H</em>.
 <em>ammodendron</em> and <em>H</em>.
 <em>persicum</em> 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.