Long-term drought stress induces structural and functional reorganization of photosystem II

Abstract

Abstract. Long-term drought stress on photosystem II (PSII) was studied in pea (Pisum sativum L.) seedlings. Drought stress (reduction of water content by 35-80%) led to a considerable depletion of the PSII core, and the remaining PSII complex appeared to be functional and reorganized, with a unit size (LHCP/PSII core) twofold greater than that of well-irrigated plants. By immunoblotting analysis of the PSII proteins from grana and stroma lamellae, the enhanced degradation of CP43 and D1 proteins was observed in water-stressed plants. Also, water stress caused increased phosphorylation of the PSII core and increased D1 protein synthesis. Water-stress-mediated increase in D1 synthesis did not occur when plants were exposed to photoinhibitory light. The depletion of the PSII core was essentially reversed when water-stressed plants grown at low visible irradiance were watered. We suggest that the syndrome caused by the effect of long-term water stress on photosynthesis is a combination of at least two events: a reduction in the number of active PSII centres caused by a physical destabilization of the PSII core and a PSII reorganization with enhanced D1 turnover to counteract the core depletion. Key words: D1 protein (turnover, modification) - DroughtHigh irradiance -Photosystem II (core phosphorylation) -Pisum sativum (drought stress) -Stress syndrome

Physiological and comparative proteomic analyses of Thai jasmine rice and two check cultivars in response to drought stress

“…A consequence of this damage is a reduction in chlorophyll content, chl a fluorescence parameters, and D1 protein levels (Giardi et al 1996;Pieters & Souki 2005). In this study, we observed that the contents of chl a and chl b were progressively reduced after 24 h of water stress (Figures 2c and 2d).…”

“…Under drought stress, levels of abscisic acid are increased, resulting in closing of stomata, which is accompanied by reduced concentrations of CO 2 in photosynthetic cells. In addition, photosynthetic apparatuses, especially in photosystem II (PSII), are damaged by drought stress (Giardi et al 1996) altering the electron transport chain and ultimately leading to a reduction in photosynthetic ability, growth and yield of rice (Giardi et al 1996;Yamane et al 2003;Pieters & Souki 2005).…”

Environmentally Modulated Phosphoproteome of Photosynthetic Membranes in the Green Alga Chlamydomonas reinhardtii

“…It is worth noting that until our present work, reversible phosphorylation of the D1 protein has been considered as plant-specific (13,15,16). Phosphorylation of thylakoid proteins in plants has also been implicated in adaptive responses to a number of environmental stress factors, such as high light (17,18), cold stress (19), combined high light and cold treatment (20), heat shock (21), combined magnesium and sulfur deficiency (22), and waterdeficient conditions (23). However, molecular mechanisms underlying regulation of photosynthesis by environmentally dependent thylakoid protein phosphorylation are still largely unknown.…”

Study of Nutrient Solution Management in Soilless Rose Cultivation Through the Analysis of Physiological Parameters and Nutrient Absorption

“…Only after the end of vase life, in some seasons and when using certain concentration treatments, -when shoot water reserves declined to critical levels (RWC around 64%)-, did this parameter fall heavily, probably due to a decrease in the fraction of operational PSII centres caused by photodamage. The same pattern of F v /F m during increasing water deficit was also observed by Woo et al (2008) in Arabidopsis thaliana, by Tezara et al (1999) in sunflowers, by Giardi et al (1996) in peas, and by Calatayud et al (2006) in rose plants. This fact reveals that studies which only measure F v /F m as a stress indicator provide incomplete information that may lead to incorrect conclusions.…”