Chilling Tolerance of Wheat Seedlings Is Related to an Enhanced Alternative Respiratory Pathway

Abstract

Pretreatment with exogenous hydrogen peroxide (H2O2) mitigated the water loss of wheat leaves exposed to 4°C for 24 h. The same treatment also partially reduced the increases of electrolyte leakage and H2O2 production of the chilled plants. These observations suggest that H2O2 pretreatment could effectively induce chilling tolerance. The capacity of the alternative respiratory pathway and the expression of the gene encoding the alternative oxidase (AOX1) were substantially elevated by H2O2 treatment under either normal or chilling conditions. Salicylhydroxamic acid (SHAM, an inhibitor of the alternative respiratory pathway) decreased the tolerance of plants to chilling conditions and reversed the chilling tolerance induced by exogenous application of H2O2. These observations indicate that the tolerance of plants to chilling might be related to an enhanced alternative respiratory pathway.

Involvement of hydrogen peroxide, calcium, and ethylene in the induction of the alternative pathway in chilling-stressed Arabidopsis callus

“…The role of AOX in alleviating ROS generation is well documented in mitochondria as well as at the cellular and even the tissue level, particularly in response to abiotic stresses such as chilling and salinity (Maxwell et al 1999;Umbach et al 2005;Feng et al 2008;Wang et al 2010). To reveal the molecular mechanism of chilling-induced AP capacity, we checked the effects of chilling, ACC, and AOA on the transcriptional regulation of AOX in WT calli.…”

“…AP contributes to the whole respiration of plant cells to greater or lesser degrees depending on the environmental and physiological conditions. It is known that AP is involved in plant thermogenesis and responses to environmental stresses, including ozone, salinity, low temperature, and pathogen invasion Ederli et al 2006;Feng et al 2008;Wang et al 2010). The AP capacity is a useful parameter to study an AOX response by using respiratory inhibitors.…”

“…The protein abundance and the activity of AOX are low in plants under normal conditions, whereas AP is enhanced by environmental stimuli, e.g. low-temperature, ozone, and plant diseases (Purvis and Shewfelt 1993;Ederli et al 2006;Feng et al 2008). AP is therefore implicated in stress alleviation.…”

“…AP is therefore implicated in stress alleviation. Growing evidence suggests that chilling tolerance of plants is associated with enhanced AP (Hu et al 2006;Feng et al 2008). It has been demonstrated that AOX can function as an antioxidant enzyme in tobacco cells (Maxwell et al 1999) and Arabidopsis callus (Wang et al 2010).…”

“…H 2 O 2 generation is induced by a wide variety of abiotic and biotic stresses, including ozone, salinity, chilling, wounding, and pathogen attack (Neill et al 2002a;Ederli et al 2006;Feng et al 2008;Wang et al 2010). It has been demonstrated that plant plasma membrane-localized NADPH oxidase, a homolog of the mammal gp91 phox in neutrophils, is an important generator of H 2 O 2 in plants under stresses (Torres et al 2002;Kwak et al 2003;Zhang et al 2007).…”