Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : A conserved chloroplast retrograde signal regulates stomatal closure for drought tolerance in plants

Auteur : Zhao, Chenchen

Université de soutenance : University of Western Sydney

Grade : Doctor of Philosophy (PhD) 2019

Résumé partiel
Stomata are the pores on leaves that are responsible for transpiration and exchange of gases with the surrounding atmosphere. In agriculture, about 90% of transpirational water loss is via these tiny pores of various crops. Therefore, understanding the mechanisms involved in stomatal closure will potentially provide important clues for breeding crops with high water use efficiency and drought tolerance. This thesis aimed to understand mechanisms from both physiological and molecular aspects of a chloroplast retrograde signal [3’-phosphoadenosine-5’-phosphate (PAP) and 3’,5’- bisphosphate nucleotidase 1 (SAL1)] that enhances plant drought tolerance by regulating stomatal closure.
Stomatal closure is modulated by stress (e.g. drought) signalling and downstream transport of ions and solutes mediated by various active ion transporters or channels. To some extent, ion transporters and channels contribute to plant drought tolerance. However, there is limited information regarding the interactions among retrograde signals, membrane transporters and plant drought tolerance. In Chapter 1, information regarding chloroplast-initiated signals, in particular those associated with PAP, and related to ion channels in relation to plant drought tolerance is summarised. I also proposed the following questions. How does this sulfate metabolism-related signal regulate stomatal closure ? Does the PAP signalling pathway join abscisic acid (ABA)- induced stomatal signalling or does it form a separate signalling pathway ?

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