Relationship between microbial diversity and nitrogenase activity of Stipagrostis pennata rhizosheath

Abstract

Nitrogen is the key factor for plant survival and growth, especially in the desert. Stipagrostis pennata, a sand born drought-resistant plant, could colonize pioneerly in Gurbantunggut Desert during revegetation. One strategy for their environment adaptation was the rhizosheath formatted by root-hair, mucilaginous exudates, microbial components, and soil particles, for which not only provides a favorable living microenvironment but also supplies essential nutrients. To understand the relationship between microorganisms living in rhizosheaths and the nitrogen nutrition supply, the microbial diversity and nitrogenase activity was estimated during the growth of S. pennata. Five samples of the rhizosheath, which based on the development periods of the plant, regreen, flowering, filling, seed maturating, and withering period, were collected. The nitrogenase activity was estimated by acetylene reduction and the microbial diversity was analyzed by 16S rRNA high-throughput sequencing. The results showed that the nitrogenase activity was increased slowly during regreen to flowering, while reached a peak rapidly at filling sample and then decreased gradually. A total of 274 operational taxonomic units (OTUs) were identified and significant differences in community structure and composition at each growth period. Among them, the main phyla included Actinobacteria and Proteus, which were the most abundant phyla in all periods. In addition, the microbial diversity in the grain filling period was higher than other periods in view of the analysis of alpha diversity and beta diversity. Furthermore, principal component analysis (PCA) analysis showed that the microbial communities in the filling period was low in similarity with other periods. Most importantly, the OTUs associated with nitrogen fixation is the most during the filling period, involving Phagecidae and Fucoraceae. Overall, the study not only revealed the differences in nitrogenase activity among different developmental periods in S. pennata, but also explored the potential bridges between it and community structure and diversity of bacteria. K E Y W O R D S16S rRNA Miseq, microbiome, nitrogenase activity, Stipagrostis pennata J Cell Biochem. 2019;120:13501-13508.wileyonlinelibrary.com/journal/jcb

Drought stress and plant ecotype drive microbiome recruitment in switchgrass rhizosheath

“…The rhizosheath is different from the rhizosphere in terms of its boundaries, distribution, and heterogeneity in space and time, since it has a tight outer surface and shows clear separation from bulk soil (Liu et al, 2019a). Recent studies have examined the microbial composition of the rhizosheath and its variations in the plants Stipagrostis pennata , S. sabulicola , S. seelyae , and Cladoraphis spinosa (Marasco et al, 2018; Tian et al, 2019). However, despite the increased understanding of rhizosheath microbiomes and their functions, our knowledge of rhizosheath microbiome recruitment under drought conditions remains limited.…”

Selection of the reference genes for quantitative gene expression by RT-qPCR in the desert plant Stipagrostis pennata

“…Plants growing in this area have adapted to the extreme environment. Stipagrostis pennata is a desert plant distributed in the Gurbantünggüt Desert in Xinjiang that mainly grows on mobile and semi-mobile sand dunes, having important roles in wind prevention, sand fixation, and the protection of the desert ecosystem 1 . This plant has a typical rhizosheath structure around the roots, which allows the roots to resist the unfavorable external conditions of the arid desert environment and endows the plant with sand fixation ability 2 .…”

Protocol development for somatic embryogenesis, SSR markers and genetic modification of Stipagrostis pennata (Trin.) De Winter

“…All known Stipagrostis species have a C4 photosynthetic pathway which enable them to survive in harsh and hot environments [ 4 ]. Furthermore, S. pennata has been shown to be able to host a microbiome that allows it to be a pioneer plant on nitrogen-deficient desert soils [ 5 ]. It is utilized for fixing sand in shifting and semi-fixed sandy lands, showing a strong tolerance to aridness, wind erosion, and sand embedding [ 6 ] and for grazing both in its green and dry stages, which makes this grass species important for landscaping and creating large pastures in arid and light sandy soils [ 7 ].…”