Investigating Drought Stress Response and Memory in sunflower (Helianthus annuus) and tomato (Solanum lycopersicum)

Drought stress is a major limiting factor in plant growth and productivity; this challenge is compounded by the rapid growth of the global population and the increasing food demands, particularly dealing with important economic crops such as sunflower (Helianthus annuus) and tomato (Solanum lycopersicum). In this study, we examine the response and memory of sunflower and tomato plants subjected to drought stress and subsequent recovery, drought stress was applied through withholding water in the first stage of plant growth, followed by a rewatering period. Morphological and physiological alterations such as leaf wilting, stomatal conductance and transpiration parameters were evaluated to assess stress conditions and time points for sample collection. Moreover, to better understand plant chromatin regulation and transcriptomic under stress, ChIP protocol and RNA analysis were also evaluated. The results of both morphological and physiological analysis showed minimal alteration in sunflower genotypes under drought stress, while tomato plants exhibited more severe effects, reaching quasi-complete stomatal closure and a decrease in all measured parameters. However, both plants demonstrated fast recovery upon rewatering. Chromatin extraction, sonication and purification for immunoprecipitation, as well as RNA extraction, were performed successfully on leaf tissue samples. The PCR amplification of specific drought stress genes in sunflower plants was also achieved. This study provides valuable information on the differential drought responses of sunflower and tomato plants using integrated morphological, physiological and molecular techniques. The developed ChIP protocol can proceed with the application of ChiP seq along with RNA seq enabling the investigation of drought effects on plants, their response and memory providing new hints on drought tolerance crop improvement.