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

Accueil du site → Doctorat → Australie → 2020 → The generation and analysis of transgenic Arabidopsis plants with improved capacity to recover from severe drought stress

Flinders University of South Australia (2020)

The generation and analysis of transgenic Arabidopsis plants with improved capacity to recover from severe drought stress

Waterman Christopher

Titre : The generation and analysis of transgenic Arabidopsis plants with improved capacity to recover from severe drought stress

Auteur : Waterman Christopher

Université de soutenance : Flinders University of South Australia

Grade : Doctor of Philosophy (PhD) 2020

Résumé partiel
The alternative pathway (AP) is a non-phosphorylating respiratory pathway present in plant mitochondria as well as being found in lower eukaryotes and other organelles, such as the chloroplast. Flux through this pathway generates heat from the energy carried in, the electron carriers NAD(P)H and FADH2, rather than conserving the energy in ATP synthesis. Despite its seemingly wasteful nature, the AP plays an important role in stress tolerance and signalling. Although it clearly plays a role in general stress tolerance, how this benefit is conveyed is still unclear. Previous experimenters have highlighted the importance of alternative oxidase (AOX1a) in stress tolerance using RNAi and overexpressor (OEX) models under a range of stressors, with clear detriments and benefits being found respectively. Other research has also found this isoform is commonly co-expressed with another AP member, type II NADH dehydrogenase (NDB2) in response to many stressors, but far less is known regarding its role in stress tolerance. In this study we aimed to generate lines co-overexpressing both of these AP members and exposing them to a combined drought and light stress, determining their response using a variety of different methodologies.

Three dual OEX lines generated from individual insertion events all showed increased expression of Ndb2 and Aox1a both at the transcriptional and protein level. Activity was assessed using isolated mitochondria and is the first example to show the Arabidopsis NDB2 to be NADH specific and calcium activated in a homologous expression system. Previous single Ndb2 OEX lines generated in our lab have failed to show any changes to activity. Interestingly, the co-OEX model generated in our hands were able to show significant increases in activity and further increases in the presence of AOX activators, highlighting the important connectedness these two AP members share.

Mots clés : Alternative Oxidase, Type II NAD(PH Dehydrogenase, Arabidopsis, Drought, Abiotic Stress, Alternative Pathway, Mitochondria, Transgenic, Recovery, AOX, NDB2

Présentation

Page publiée le 21 mai 2021