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.
Highlights
Waterlogging is one of the major abiotic stresses limiting agricultural production around the globe (Setter and Waters, 2003)
For the first time in the literature, we report a major quantitative trait loci (QTL) for the membrane potential (MP)
Two treatments were used in the present experiment: (1) control (BSM, aerated); and (2) hypoxia (BSM solution made with 0.2% agar and bubbled with N2 gas)
Summary
Waterlogging is one of the major abiotic stresses limiting agricultural production around the globe (Setter and Waters, 2003). The transport of nutrients from roots to shoots is severely disturbed under waterlogged conditions (Smethurst et al, 2005; Colmer and Voesenek, 2009), which affects plant growth and yield (Malik et al, 2001; Colmer et al, 2011). Salinity is another limiting factor for crop production. To meet the target of more than 70% increase in food production by 2050 (Garnett et al, 2013), it is important to improve the plant’s tolerance to cope with different abiotic stresses, including waterlogging and salinity
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