The Lack of Alternative Oxidase 1a Restricts in vivo Respiratory Activity and Stress-Related Metabolism for Leaf Osmoprotection and Redox Balancing Under Sudden Acute Water and Salt Stress in Arabidopsis thaliana
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Frontiers
Materia
Water stress Salinity Alternative oxidase Oxygen-isotope fractionation Primary metabolism Photosynthesis Arabidopsis thaliana
Date
2022-05-17Referencia bibliográfica
Del-Saz NF... [et al.] (2022) The Lack of Alternative Oxidase 1a Restricts in vivo Respiratory Activity and Stress-Related Metabolism for Leaf Osmoprotection and Redox Balancing Under Sudden Acute Water and Salt Stress in Arabidopsis thaliana. Front. Plant Sci. 13:833113. doi: [10.3389/fpls.2022.833113]
Sponsorship
National Agency for Research and Development (ANID) CTM2014-53902-C2-1-P 1191118; Spanish Government; European Commission PRE2018-083610; Spanish Government RYC2019-027244-I/AEI/10.13039/501100011033; European Social Fund (ESF)Abstract
In plants salt and water stress result in an induction of respiration and accumulation of
stress-related metabolites (SRMs) with osmoregulation and osmoprotection functions
that benefit photosynthesis. The synthesis of SRMs may depend on an active respiratory
metabolism, which can be restricted under stress by the inhibition of the cytochrome
oxidase pathway (COP), thus causing an increase in the reduction level of the ubiquinone
pool. However, the activity of the alternative oxidase pathway (AOP) is thought to
prevent this from occurring while at the same time, dissipates excess of reducing
power from the chloroplast and thereby improves photosynthetic performance. The
present research is based on the hypothesis that the accumulation of SRMs under
osmotic stress will be affected by changes in folial AOP activity. To test this, the
oxygen isotope-fractionation technique was used to study the in vivo respiratory
activities of COP and AOP in leaves of wild-type Arabidopsis thaliana plants and of
aox1a mutants under sudden acute stress conditions induced by mannitol and salt
treatments. Levels of leaf primary metabolites and transcripts of respiratory-related
proteins were also determined in parallel to photosynthetic analyses. The lack of in vivo
AOP response in the aox1a mutants coincided with a lower leaf relative water content and a decreased accumulation of crucial osmoregulators. Additionally, levels of oxidative
stress-related metabolites and transcripts encoding alternative respiratory components
were increased. Coordinated changes in metabolite levels, respiratory activities and
photosynthetic performance highlight the contribution of the AOP in providing flexibility
to carbon metabolism for the accumulation of SRMs.