The putative regulatory components of cyclic guanosine monophosphate (cGMP) signalling, phosphodiesterase 1 (PDE1) and cyclic GMP-dependent protein kinase (PKG), were selected for investigation in the context of stomatal closure responses to CaCl2, abscisic acid (ABA), darkness, flagellin 22 (flg22), and elf18. Also using Arabidopsis mutants in the alpha carbonic anhydrase 7 (ACA7) gene to investigate whether the known negative effect of growth at elevated CO2 on Fe and Zn accumulation could be counteracted. PDE1 and PKG function as negative regulators of CaCl2-induced stomatal closure. PDE1 and PKG also exhibited a positive regulatory role in flg22-induced stomatal closure. PDE1 and PKG did not influence the dark-induced stomatal closure response but were positive regulators of prolonged darkness-induced stomatal closure. Neither PDE1 nor PKG were necessary for ABA-induced stomatal closure. PDE1 is also not involved in elf18-induced stomatal closure. Investigating the role of ACA7 shows that aca7 under elevated CO2 accumulates higher Fe and Zn in seeds than WT, with no impact on seed weight (but with a negative effect on seed number). Research on cGMP components contributes to a deeper understanding of the cGMP signalling pathway, whereas investigating of ACA7 under elevated CO2 condition provides valuable insights into its transduction pathway, facilitating adaptation to long-term environmental changes. All findings underscore the importance of understanding signal transduction pathways in enabling plants to cope with fluctuating environments over extended periods.
Signal Transduction in Guard Cells
Noothong, F. (Author). 1 Oct 2024
Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)