Identification of barley genetic regions influencing plant–microbe interactions and carbon cycling in soil

Abstract

Purpose Rhizodeposition shapes soil microbial communities that perform important processes such as soil C mineralization, but we have limited understanding of the plant genetic regions influencing soil microbes. Here, barley chromosome regions affecting soil microbial biomass-C (MBC), dissolved organic-C (DOC) and root biomass were characterised. Methods A quantitative trait loci analysis approach was applied to identify barley chromosome regions affecting soil MBC, soil DOC and root biomass. This was done using barley Recombinant Chromosome Substitution Lines (RCSLs) developed with a wild accession (Caesarea 26-24) as a donor parent and an elite cultivar (Harrington) as recipient parent. Results Significant differences in root-derived MBC and DOC and root biomass among these RCSLs were observed. Analysis of variance using single nucleotide polymorphisms genotype classes revealed 16 chromosome regions influencing root-derived MBC and DOC. Of these chromosome regions, five on chromosomes 2H, 3H and 7H were highly significant and two on chromosome 3H influenced both root-derived MBC and DOC. Potential candidate genes influencing root-derived MBC and DOC concentrations in soil were identified. Conclusion The present findings provide new insights into the barley genetic influence on soil microbial communities. Further work to verify these barley chromosome regions and candidate genes could promote marker assisted selection and breeding of barley varieties that are able to more effectively shape soil microbes and soil processes via rhizodeposition, supporting sustainable crop production systems.

Identifying Plant Genes Shaping Microbiota Composition in the Barley Rhizosphere

“…Although this feature is distinct to observations in a genome-wide investigation of root-associated communities of Arabidopsis 47 , our observation is consistent with recently reported results for the rhizosphere microbiota of maize, where individual host genes shaped the bacterial but not the fungal microbiota 10 . Third, once we characterised these lines for additional traits that could be intuitively considered to be implicated in shaping the microbiota in the barley rhizosphere, such as root system architecture 30 and rhizodeposition of primary metabolites 48 , we failed to identify significant associations between these traits and allelic composition at QRMC-3HS. While differences in the genetic background of the tested plants prevent us from drawing firm conclusions when considering these studies, our observations suggest that QRMC-3HS may code for a novel component of the host genetic control of barley microbiota recruitment.…”

“…We therefore employed a root RNA-seq experiment to gain mechanistic insights into the regulation of the microbiota mediated by QRMC-3HS . One of the candidate genes found to be significantly up-regulated in plants harbouring elite alleles at locus QRMC-3HS putatively encodes an NLR protein 49 . This class of protein represents one of the two main groups of immune receptors capable of selectively recognising and terminating microbial proliferation via effector recognition 50 .…”

Straw Return and Nitrogen Fertilization to Maize Regulate Soil Properties, Microbial Community, and Enzyme Activities Under a Dual Cropping System

“…Straw decomposition is a complex process ( Zhao and Zhang, 2018 ; Zhao et al, 2019 ), which is predominantly mediated by soil microorganisms with specialized functions ( Zhao and Zhang, 2018 ). A variety of microbial communities play significant roles in the crop residues decomposition, such as bacteria preferring to decompose labile compounds and dominating straw degradation at the initial stage of decomposition ( Mwafulirwa et al, 2021 ; Wu et al, 2021 ). In contrast, fungi decompose more abrasive materials principally in the final stages of decomposition ( Marschner et al, 2011 ).…”

Genetic control of rhizosheath formation in pearl millet

“…For example, greater mass of mucilage exuded by chickpea roots were linked with the formation of larger and more porous rhizosheaths capable of storing more soil moisture in drought tolerant cultivars 27 . In annual crops such as wheat, barley and maize, there is evidence of the remarkable plant genetic influence in the formation of rhizosheath and the processes of rhizodeposition influencing rhizosphere microbial activities 18 , 28 – 30 , however few studies have aimed to dissect the genetics underlying the conformation of this extended root phenotype 18 , 28 , 31 , 32 .…”