Exogenous abscisic acid increases antioxidant enzymes and related gene expression in pepper (Capsicum annuum) leaves subjected to chilling stress

Abstract

ABSTRACT. To elucidate how physiological and biochemical mechanisms of chilling stress are regulated by abscisic acid (ABA) pretreatment, pepper variety (cv. 'P70') seedlings were pretreated with 0.57 mM ABA for 72 h and then subjected to chilling stress at 10°/6°C (day/night). Chilling stress caused severe necrotic lesions on the leaves and increased malondialdehyde and H 2 O 2 levels. Activities of monodehydroascorbate reductase (DHAR), dehydroascorbate reductase, glutathione reductase, guaiacol peroxidase, ascorbate peroxidase, ascorbate, and glutathione increased due to chilling stress during the 72 h, while superoxide dismutase and catalase activities decreased during 24 h, suggesting that chilling stress activates the AsA-GSH cycle under catalase deactivation in pepper leaves. ABA pretreatment induced significant increases in the above-mentioned enzyme activities and progressive decreases in ascorbate and glutathione levels. On the other hand, ABA-pretreated seedlings under chilling stress increased superoxide dismutase and guaiacol peroxidase activities and lowered concentrations of other antioxidants compared with untreated chilling-stressed plants. These seedlings showed concomitant decreases in foliage damage symptoms, and levels of malondialdehyde and H 2 O 2 . Induction of Mn-SOD and POD was observed in chilling-stressed plants treated with ABA. The expression of DHAR1 and DHAR2 was altered by chilling stress, but it was higher in the presence than in the absence of ABA at 24 h. Overall, the results indicate that exogenous application of ABA increases tolerance of plants to chilling-induced oxidative damage, mainly by enhancing superoxide dismutase and guaiacol peroxidase activities and related gene expression.

Role of exogenous abscisic acid in adapting of ‘Sultana’ grapevine to low-temperature stress

“…This finding is in full agreement with Guo et al (2012), who found that ABA significantly alleviated the effect of chilling stress-induced leaf damage in pepper. These results indicated that pretreatment with ABA can effectively alleviate the damage from LTS in 'Sultana' grapevine.…”

“…Under LTS, ABA has a close interaction with cell biomembrane phospholipids to preserve their integrity and normal function (Guschina et al 2002). Moreover, it plays a role in alleviating oxidative damages by increasing the activity of ROS scavenging enzymes (Jiang and Zhang 2004;Guo et al 2012). It is possible that exogenous ABA may induce plant metabolic defense responses directly (such as increase in soluble carbohydrate, proline and phenolic compounds) and indirectly (through ROS) and improve the integrity of the cell membrane and FT.…”

“…In plant tissues, changes in the endogenous ABA content after exposure to LTS is assumed to be probably associated with subsequent increase in freezing tolerance (FT) of plants during the hardening phase (Faltusová-Kadlecová et al 2002). Therefore, chilling tolerance induced by exogenous application of ABA has been reported in various herbaceous plants (Meng et al 2008;Guo et al 2012;) and some trees (Li et al 2003;Yang et al 2011;Zhang and Dami 2012).…”

Arabidopsis HOOKLESS1 regulates responses to pathogens and abscisic acid through interaction with MED18 and acetylation of WRKY33 and ABI5 chromatin

“…Many studies implicate exogenous ABA treatment in increased plant tolerance to abiotic stresses such as chilling and osmotic stress (Jiang and Zhang, 2002;Guo et al, 2012;Ozfidan et al, 2012), but ABA is often implicated as a suppressor of plant resistance (Curvers et al, 2010). The mechanism underlying this disparity between plant responses to biotic and abiotic stress responses is unclear.…”

Research Article Genetic effects of in vitro germination and plantlet development in chilli pepper.

“…In pepper, for example, the germination is affected for temperature stresses (Guo et al, 2012). Since the experiment was conducted in controlled environment, the response found was due the genotypic differences.…”