Abstract
There is increasing interest in understanding how the microbial communities on roots can be manipulated to improve plant productivity. Root systems are not homogeneous organs but are comprised of different root types of various ages and anatomies that perform different functions. Relatively little is known about how this variation influences the distribution and abundance of microorganisms on roots and in the rhizosphere. Such information is important for understanding how root-microbe interactions might affect root function and prevent diseases. This study tested specific hypotheses related to the spatial variation of bacterial and fungal communities on wheat (Triticum aestivum L.) and rice (Oryza sativa L.) roots grown in contrasting soils. We demonstrate that microbial communities differed significantly between soil type, between host species, between root types, and with position along the root axes. The magnitude of variation between different root types and along individual roots was comparable with the variation detected between different plant species. We discuss the general patterns that emerged in this variation and identify bacterial and fungal taxa that were consistently more abundant on specific regions of the root system. We argue that these patterns should be measured more routinely so that localised root-microbe interactions can be better linked with root system design, plant health and performance.
Highlights
The biology of the microbial communities on and around roots has attracted increasing interest because of their potential to affect plant growth and productivity (Lareen et al 2016; Mitter et al 2019)
The null hypotheses tested were: (1) no differences exist between the microbiomes in the bulk soil and on the roots; (2) no differences exist between the microbiome communities on wheat and rice roots; and (3) no differences exist between the microbiome communities at the root tips and the root bases
The count of unique operational taxonomic units (OTUs) (Sobs), as well as the Chao1 and Shannon indices for a diversity, tended to be lower on the root samples compared with the bulk soil, but the differences were significant for wheat only (Table 1)
Summary
The biology of the microbial communities on and around roots has attracted increasing interest because of their potential to affect plant growth and productivity (Lareen et al 2016; Mitter et al 2019). The root microbiome can be compartmented into the communities living in the external periphery of roots (ectorhizosphere), those colonising the outer surface of roots and perhaps forming biofilms (rhizoplane), and those organisms spending part of their life cycle within the root tissues (endorhizosphere). These fractions can be separated and examined individually by a series of washing, sonication and lysozyme treatments (Bulgarelli et al 2012; Lakshmanan et al 2017; Chaluvadi and Bennetzen 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
