Genomic Responses Associated with Drought Stress in Walnut as Revealed Transcriptome Sequencing
Abstract Walnut production is challenged by abiotic stresses. We investigated the leaf transcriptome responses of walnut under control and drought stress in 9 and 18 days. We identified 921, 1035 differentially expressed genes (DEGs) between control and drought stress groups in 9 and 18-day, respectively. In control and drought stress conditions DEGs were significantly enriched into the abscisic acid biosynthesis, regulation of stomata closure, leaf morphogenesis, carbohydrate metabolism, oxidative stress, cell wall macromolecule catabolism, and secondary metabolite biosynthesis pathways. We confirmed our RNA-Seq data using quantitative real-time PCR (qPCR) of six candidate genes. Our results indicated that more complicated transcript regulation of drought responses following prolong exposure to drought stress. In general, walnut activated more tolerance mechanisms 18 days after drought stress. Findings of this research would be useful for future studies on breeding for drought tolerance of Persian walnut and related species.