Enhanced stability of thylakoid membrane proteins and antioxidant competence contribute to drought stress resistance in the tasg1 wheat stay-green mutant

Abstract

A wheat stay-green mutant, tasg1, was previously generated via mutation breeding of HS2, a common wheat cultivar (Triticum aestivum L.). Compared with wild-type (WT) plants, tasg1 exhibited delayed senescence indicated by the slower degradation of chlorophyll. In this study, the stability of proteins in thylakoid membranes was evaluated in tasg1 under drought stress compared with WT plants in the field as well as in seedlings in the laboratory. Drought stress was imposed by controlling irrigation and sheltering the plants from rain in the field, and by polyethylene glycol (PEG)-6000 in the laboratory. The results indicated that tasg1 plants could maintain higher Hill activity, actual efficiency (ΦPSII), maximal photochemical efficiency of PSII (Fv/Fm), and Ca2+-ATPase and Mg2+-ATPase activities than the WT plants under drought stress. Furthermore, the abundance of some polypeptides in thylakoid membranes of tasg1 was greater than that in the WT under drought stress. Expression levels of TaLhcb4 and TaLhcb6 were higher in tasg1 compared with the WT. Under drought stress, the accumulation of superoxide radical (O2·–) and hydrogen peroxide (H2O2) was lower in tasg1 compared with the WT not only at the senescence stage but also at the seedling stages. These results suggest greater functional stability of thylakoid membrane proteins in tasg1 compared with the WT, and the higher antioxidant competence of tasg1 may play an important role in the enhanced drought tolerance of tasg1.

Stress-Induced Chloroplast Degradation in Arabidopsis Is Regulated via a Process Independent of Autophagy and Senescence-Associated Vacuoles

“…Senescence and stressinduced synthesis of cytokinin synthesis delay the degradation of photosynthetic complexes in transgenic plants expressing P SARK -IPT, which displayed enhanced drought tolerance (Rivero et al, 2010). In addition, a wheat (Triticum aestivum) stay-green mutant (tasg1) displays delayed chlorophyll turnover and improved tolerance to drought because of the enhanced stability of thylakoid membranes (Tian et al, 2013). The stable chloroplasts also could contribute to maintain photorespiration, which has been shown to increase tolerance to abiotic stress by protecting the photosynthetic apparatus from oxidative damage and optimizing photosynthesis (Rivero et al, 2009;Voss et al, 2013).…”

Lipids and proteins—major targets of oxidative modifications in abiotic stressed plants

“…Available literature reflects a differential extent of protein oxidation in plants under drought (Bartoli et al 2004;Gong et al 2005;Pyngrope et al 2013;Tian et al 2013) and salinity (Melgar et al 2009;Roychoudhury et al 2011;Shi et al 2011;Ferreira-Silva et al 2012;Tanou et al 2012). Leaf mitochondria of T. aestivum were noted to contain several-folds higher concentrations of oxidatively damaged proteins (protein carbonyls) than the chloroplasts or peroxisomes under drought stress (Bartoli et al 2004).…”

“…Drought stress-accrued increase in protein carbonylation was reported in the leaves of mutant (tasg1) and wild-type (WT) cultivars of T. aestivum (Tian et al 2013). However, a greater functional stability of thylakoid membrane proteins (measured as protein carbonylation level) in tasg1 compared with the WT, and the higher antioxidant competence of tasg1, was argued to play an important role in the enhanced tolerance of tasg1 to drought-mediated oxidative stress.…”

Abscisic acid, ethylene and antioxidative systems in rice grains in relation with grain filling subjected to postanthesis soil-drying

“…Grain filling is generally believed to be a process, regulated either genetically or environmentally (Yoshida 1972;Saini and Westgate 2000). Water or drought stress is one of the most important factors limiting crop yields worldwide (Passioura 1996(Passioura , 2007Tian et al 2013). Water stress during the early grain development curtails the kernel sink potential by reducing the number of endosperm cells and amyloplasts formed, thus diminishing grain weight as a result of the decrease in the capacity of endosperm to accumulate starch, both in rate and duration (Bouman and Tuong 2001;Samejima et al 2004).…”