Physiological and molecular responses of 'Dusa' avocado rootstock to water stress: insights for drought tolerance

The aim of this study was to evaluate the physiological response and the expression analysis of `Dusa´ avocado rootstocks subjected to two different levels of water stress, and their subsequent recovery. At the beginning of the experiment, avocado plants were divided in Control plants (watered to field capacity (Fc) throughout the experiment) and stressed plants that were subjected to controlled substrate drying-up until they reached 50% of Fc (mild-WS) and 25% of Fc (severe-WS), respectively. Afterwards, plants were fully irrigated to assess drought recovery response. A set of physiological measurement were taken at leaf and whole-plant levels to assess avocado response to each level of water stress and rewatering. Root samples were collected in mild-WS and severe-WS and gene expression analysis was carried out using a targeted cDNA avocado stress microarray containing transcripts from de novo sequencing of 'Dusa' in response to biotic and abiotic stress. Avocado gene expression profiles under different levels of water stress are discussed in order to shed light on the molecular mechanisms associated with water deprivation in Dusa avocado rootstocks. Direct comparison, three biological replicates control vs stress for Mild-WS, two biological replicates control vs stress for Severe-WS