Changes in gene expression in the drought-sensitive genotype Quercus robur under moisture stress

Abstract This study investigated the response of a drought-sensitive Quercus robur L. genotype, revealing 60 differentially expressed genes (DEGs) (15 upregulated and 45 downregulated). Functional enrichment analysis indicated the involvement of these DEGs in diverse biological processes, including lipid metabolism and biosynthesis, regulation of small molecule and phytohormone biosynthesis, metal ion transport, antioxidant activity, and growth and development. The results suggest that sensitivity to water deprivation in this Q. robur L. genotype may be associated with compromised reactive oxygen species (ROS) utilization and impaired membrane integrity maintenance, as well as imbalances in the biosynthesis of phytohormones relevant to abiotic stress responses, specifically abscisic acid (ABA) and jasmonic acid. Notably, downregulated DEGs encoding COPT6 and metallothionein-like protein type 2 were identified as potentially significant. COPT6, involved in transmembrane copper ion transport, may indirectly influence the biosynthesis of ABA, an important phytohormone in drought stress response. Furthermore, reduced expression of the metallothionein-like protein type 2 gene likely impacts ROS content and Na+ ion homeostasis. Altered expression of WAT1-related protein At1g70260 and a TMV resistance protein N-like protein suggests potential activation of salicylic acid-mediated signaling pathways. These findings contribute to a more comprehensive understanding of the molecular genetic mechanisms of woody plant adaptation to abiotic stress and highlight potential candidate molecular markers for use in breeding programs aimed at enhancing drought tolerance.