Regulation of carbon reserve use in olive trees under heat, drought, and recovery

Purpose: Nonstructural carbohydrates has a major impact on trees response to meteorological conditions. The goals of this study were to define which changes in gene expression are linked to possible mechanisms used by the plant to buffer the decline in carbon source during gradual soil drying, an intensive abrupt heat wave, and recovery from drought? Methods: We combined measurements of nonstructural carbohydrates (NSC), tree physiology and expression of genes encoding starch metabolism enzymes. The experiment was conducted on potted olive (Olea europaea) trees, half of them under 28 days of soil drought. Results: We identified the gene family members relevant either to long-term or stress-induced carbon storage. Partitioning of expression patterns among ß amylase's and starch synthase's family members were identified, with some members upregulated throughout drought while other members in recovery. The daily starch metabolism machinery was different from the stress-mode starch metabolism machinery when some genes are unique to the stress-mode response. Overall design: RNA-Seq of 6 branches of 6 different olive trees, 3 samples of watered trees and 3 samples of dried trees.