Cell-Based Phenotyping Reveals QTL for Membrane Potential Maintenance Associated with Hypoxia and Salinity Stress Tolerance in Barley

Abstract

Waterlogging and salinity are two major abiotic stresses that hamper crop production world-wide resulting in multibillion losses. Plant abiotic stress tolerance is conferred by many interrelated mechanisms. Amongst these, the cell’s ability to maintain membrane potential (MP) is considered to be amongst the most crucial traits, a positive relationship between the ability of plants to maintain highly negative MP and its tolerance to both salinity and waterlogging stress. However, no attempts have been made to identify quantitative trait loci (QTL) conferring this trait. In this study, the microelectrode MIFE technique was used to measure the plasma membrane potential of epidermal root cells of 150 double haploid (DH) lines of barley (Hordeum vulgare L.) from a cross between a Chinese landrace TX9425 and Japanese malting cultivar Naso Nijo under hypoxic conditions. A major QTL for the MP in the epidermal root cells in hypoxia-exposed plants was identified. This QTL was located on 2H, at a similar position to the QTL for waterlogging and salinity tolerance reported in previous studies. Further analysis confirmed that MP showed a significant contribution to both waterlogging and salinity tolerance. The fact that the QTL for MP was controlled by a single major QTL illustrates the power of the single-cell phenotyping approach and opens prospects for fine mapping this QTL and thus being more effective in marker assisted selection.

Identification of new QTL for salt tolerance from rice variety Pokkali

“…This approach has been successfully used to reveal the linkage between the correlated traits (Fan, Shabala, Ma, Xu, & Zhou, ; Gill et al, ; Ma et al, ; Wang et al, ). For examples, a new drought tolerant QTL was confirmed to have no significant effect on agronomic trait (Fan et al, ) and a significant contribution of membrane potential to both waterlogging and salinity tolerance was identified (Gill et al, ). In the present study, SIS revealed the closest correlation with SNaC and all the three QTL for SIS were located at similar positions to those for SNaC.…”

“…The use of covariates in QTL analysis makes it possible to detect the influences of the covariates on the traits analysed (van Ooijen, 2009). This approach has been successfully used to reveal the linkage between the correlated traits (Fan, Shabala, Ma, Xu, & Zhou, 2015;Gill et al, 2017;Ma et al, 2015;Wang et al, 2018).…”

Improving Flooding Tolerance of Crop Plants

“…Recently, a higher K + loss through the membrane under oxygen deficiency was associated with lower viability of the root cells [115]. A subsequent QTL analysis of a cross between the two cultivars revealed a major QTL on chromosome 2H underlying this tolerance trait [106]. However, it is currently not clear which gene is responsible for this trait, and whether proton pumps or K + channels are involved in the observed tolerance.…”

Dowsing for salinity tolerance related genes in chickpea through genome wide association and in silico PCR analysis

“…On the other hand, due its easy development it could provide a viable alternative for estimating the relation between various genotypes 109110 . DArT technology was successfully applied in population genetics in order to detect useful loci associated with salinity tolerance in barley 35,111,112 and bread wheat 17,113 .…”