Wheat and Arabidopsis employ different strategies to optimize the adjustment of photosynthesis to fluctuating light under drought stress

ABSTRACT: Drought is a major cause of crop yield loss worldwide. Plants can adopt different mechanisms to survive under water deficit, where stomatal closure leads to CO2 limitation. This requires increased dissipation of light energy as heat by non-photochemical quenching (NPQ), changes in the structural configuration of light-harvesting complexes, or changes in the mode of photosynthetic electron flow (i.e. linear vs. cyclic). Under field conditions, where light intensity can change rapidly, this problem becomes even more challenging. Particularly the slow release from photoprotection (NPQ relaxation) was recently shown to cause significant loss of potential yield. We analyzed the acclimation of two different wheat varieties and compared their molecular acclimation strategy to Arabidopsis under moderate drought stress at a slow soil dehydration rate, mimicking realistic field conditions. We monitored their photosynthetic activity under fluctuating light intensities and integrated functional and structural data, based on a detailed analysis of photosynthetic parameters combined with biochemical analysis and unbiased shot-gun proteomics. Contrary to previous models based on the damage of photosynthetic complexes as consequence of drought, we found that plants actively preserve and fine-tune their photosynthetic machinery under drought to adjust the photosynthetic electron transfer to fast changes of light intensity. Strikingly, Arabidopsis and wheat use different molecular strategies for this acclimation. While clear differences in NPQ relaxation and phosphorylation levels of photosynthetic proteins were observed in wheat, Arabidopsis modified the light energy distribution among photosynthetic complexes without changing PSII-LHCII phosphorylation. The fine-tuning of NPQ relaxation can therefore represent a potential trait for crop breeding.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Triticum Aestivum (wheat)

TISSUE(S): Plant Cell, Photosynthetic Cell, Leaf

SUBMITTER: Valentin Roustan  

LAB HEAD: Prof. Dr. Markus Teige

PROVIDER: PXD011110 | Pride | 2022-03-02

REPOSITORIES: Pride