Shelden, M. | Search bioRxiv

bioRxiv2026

IDENTIFICATION OF CANDIDATE GENES UNDERLYING A NOVEL QTL FOR ROOT LENGTH AND DIAMETER IN BARLEY IN RESPONSE TO SALINITY

Salinity is a major agricultural problem that decreases growth and yield of crops and is expected to worsen with climate change. Improving salt tolerance through breeding could be facilitated by identification of genetic loci and candidate genes affecting root traits that enhance water and nutrient uptake while limiting accumulation of toxic ions. In this study, a Clipper x Sahara 3771 doubled haploid (DH) barley mapping population was screened for root growth responses to saline conditions in a controlled environment. Quantitative trait loci (QTLs) were mapped for root traits including seminal root length, root diameter and root potassium. Major QTLs affecting seminal root length and average root diameter were detected in the distal region of the short arm of chromosome 2H, indicating that this region is a key determinant of root architecture under both control and saline conditions. The linkage map was improved by using newly designed assays for SNPs on chromosome 2H and a 2.5-Mb interval was identified for investigation of candidate genes. Bulked segregant RNA sequencing (BSR-Seq) of contrasting salt-tolerant and salt-sensitive DH lines identified differentially expressed genes associated with root growth maintenance and ion homeostasis in root tips. These findings identify specific region on chromosome 2H as a major genomic region affecting barley root architecture, especially under saline conditions, and identify differentially expressed candidate genes in that region.

plant biology↗

bioRxiv2019

Integrative Multi-Omics Analysis of Barley Genotypes Shows Differential Salt-Induced Osmotic Barriers and Response Phases Among Rootzones

The mechanisms underlying rootzone-localised responses to salinity stress during early stage of barley development remains fragmentary and elusive. Here, we performed a comprehensive detection of the multi-root-omes (transcriptomes, metabolomes, lipidomes) of a domesticated barley cultivar (Clipper) and a landrace (Sahara) with seedling root growth maintained and restricted in response to salt stress, respectively. Novel generalized linear models were designed to determine differentially expressed genes (DEG) or abundant metabolites (DAM) specific to salt treatments, genotypes, or rootzones (meristematic Z1, elongation Z2, maturation Z3). Based on pathway over-representation of the DEG and DAM, phenylpropanoid biosynthesis is the most statistically over-represented biological pathways among all salinity responses observed. Together with the histological evidence, an intense salt-induced lignin impregnation was found only at the stelic cell wall of Clipper Z2, comparing to a unique elevation of suberin deposition across Sahara Z2. This suggests two differential salt-induced modulations of apoplastic flow between the genotypes. Based on global correlation network construction of the DEG and DAM, callose deposition that potentially adjusted the symplastic flow in roots was almost independent of salinity in rootzones of Clipper, but was markedly decreased in that of Sahara. Through closer examinations of molecular and hormonal clues, we further demonstrate that the salinity response in rootzones of Clipper were mostly at recovery phase, comparing to Sahara with rootzones retained at quiescence. Taken together, we propose that two distinctive salt tolerance mechanisms could exist in Clipper (growth-sustaining) and Sahara (salt-shielding), providing important clues for improving crop plasticity to cope with the deteriorating global salinization of soil.

plant biology↗