Physiological and transcriptomic cooperative regulatory mechanisms of Cotinus Coggygria in response to drought and rewatering processes

Global drought represents a pressing environmental challenge, necessitating a deeper comprehension of how plant species at various stages of drought response adapt to such stress. Cotinus coggygria, a deciduous tree species known for its autumn color transformation, holds significance for arid and semi-arid ecological contexts. Presently, investigations into C. coggygria primarily concentrate on the effect of drought on its leaf color, with limited examination of the fundamental mechanisms involved. Through the merging of physiological and transcriptomic data analysis of C. coggygria exposed to drought conditions, crucial physiological markers and alterations in metabolic pathways under drought stress can be clarified, which holds significant importance for the utilization of ornamental tree species in arid and semi-arid areas. Seedlings of C. coggygria were subjected to five distinct drought durations (30, 50, 70, 90, and 110 days) followed by a 20-day rewatering period. Increasing drought severity led to reductions in growth parameters, leaf water potential, and nitrogen and phosphorus contents across plant organs, while showing notable increases in stomatal traits, pigment content and osmotic adjustment substances. Towards the later stages of stress, there was an accumulation of hydrogen peroxide content, alongside a reduction in hydroxyl radical content, coupled with elevations in levels of antioxidant enzymes and compounds. The stress-induced response amplifies water retention attributes at the cost of the growth of C. coggygria. Following short-term rewatering, most physiological parameters of C. coggygria did not fully recover to control levels. Transcriptomic analysis revealed 2684 up-regulated and 4017 down-regulated differentially expressed genes (DEGs) under 110 days of stress, and 1923 up-regulated and 1541 down-regulated DEGs following 20 days of rewatering, highlighting genes modulating phytohormone signaling pathways, metabolic pathways associated with key physiological indicators, and differentially expressed transcription factors. The research revealed that C. coggygria demonstrated synchronized physiological and transcriptomic reactions to both drought stress and subsequent rehydration. These reactions encompassed alterations in growth metrics, nutrient levels, physiological characteristics, antioxidant system functionality, and gene expression profiles. The results offer significant understanding into the adaptive mechanisms of C. coggygria under drought stress conditions and may have implications for comprehending and mitigating drought effects on plant species in arid and semi-arid regions.