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Title: Genetic and physiological analysis of salt tolerance in almond rootstocks

item Sandhu, Devinder
item KAUNDAL, AMITA - University Of California - Cooperative Extension Service
item Ferreira, Jorge
item Suarez, Donald

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/17/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Salinity is one of the most important abiotic stresses that adversely affect plant growth and productivity globally. To understand underlying genetic and biochemical mechanisms for the salt tolerance process, we evaluated 16 commercial almond rootstocks under 5 different treatments of irrigation water that included control, sulfate dominant water with mixed cations, chloride dominant water with mixed cations, sodium dominant water with mixed anions, and calcium and magnesium dominant water with mixed anions. An increased salinity from 1.4 dS m-1 (control) to 3 dS m-1 (treatments) caused significant reductions in trunk diameter, chlorophyll SPAD (SPAD), photosynthetic rate (Pn), stomatal conductance (gs), transpiration (Tr) and water use efficiency (WUE) for most rootstocks. The treatment, where sodium and chloride were the predominant ions, presented maximum reduction. Expression analysis was carried out for a set of 10 genes selected for their involvement in salt stress. These include genes known to be associated with Na+ efflux from root to soil (SOS1, SOS2 and SOS3), genes involved in sequestration of Na+ in vacuoles (NHX1, NHX2 and AVP1), genes important for retrieving Na+ from xylem (HKT1 and AKT1), and genes involved in signal transduction during salt stress (SAL1 and SERF1). The expression analyses revealed that the treatment with chloride dominant water and the treatment with sodium dominant water both led to induction of majority of salt associated genes during salt stress, suggesting importance of both the chloride and sodium toxicities during salt stress in almonds. Important genes involved in salt tolerance mechanism were identified and the most tolerant rootstocks were selected. Correlations among gene expression, trunk diameter, biochemical markers and tissue ion concentrations allowed us to identify the component of salt tolerance mechanism that is the most critical in a particular genotype in almonds and that may be manipulated to improve its salt tolerance.