Alleviating damage of photosystem and oxidative stress from chilling stress with exogenous zeaxanthin in pepper (Capsicum annuum L.) seedlings

• Published in: Plant physiology and biochemistry 2021-05, Vol.162, p.395-409
• Main Authors: Tang, Chaonan, Xie, Jianming, Lv, Jian, Li, Jing, Zhang, Jing, Wang, Cheng, Liang, Guoping
• Format: Article
• Language: English
• Subjects: Capsicum; Chilling tolerance; Chlorophyll; Chlorophyll a fluorescence; Cold Temperature; Hydrogen Peroxide; Oxidative Stress; Photoinhibition; Plant Leaves; Seedlings; Vegetables; Zeaxanthin; Zeaxanthins
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2021.03.010

As a typical thermophilous vegetable, the growth and yield of peppers are easily limited by chilling conditions. Zeaxanthin, a crucial carotenoid, positively regulates plant abiotic stress responses. Therefore, this study investigated the regulatory mechanisms of zeaxanthin-induced chilling tolerance in peppers. The results indicated that the pretreatment with zeaxanthin effectively alleviated chilling damage in pepper leaves and increased the plant fresh weight and photosynthetic pigment content under chilling stress. Additionally, alterations in photosynthetic chlorophyll fluorescence parameters and chlorophyll fluorescence induction curves after zeaxanthin treatment highlighted the participation of zeaxanthin in improving the photosystem response to chilling stress by heightening the quenching of excess excitation energy and protection of the photosynthetic electron transport system. In chill-stressed plants, zeaxanthin treatment also enhanced antioxidant enzyme activity and transcript expression, and reduced hydrogen peroxide (H2O2) and superoxide anion (O2•-) content, resulting in a decrease in biological membrane damage. Additionally, exogenous zeaxanthin upregulated the expression levels of key genes encoding β-carotene hydroxylase (CaCA1, CaCA2), zeaxanthin epoxidase (CaZEP) and violaxanthin de-epoxidase (CaVDE), and promoted the synthesis of endogenous zeaxanthin during chilling stress. Collectively, exogenous zeaxanthin pretreatment enhances plant tolerance to chilling by improving the photosystem process, increasing oxidation resistance, and inducing alterations in endogenous zeaxanthin metabolism. [Display omitted] •Zeaxanthin pretreatment enhanced the chilling tolerance in pepper seedlings.•Under chilling stress, Zeaxanthin could alleviate the membrane damage.•Zeaxanthin mitigated chilling photoinhibition by quenching excitation energy, protecting photosynthetic electron transport.•Zeaxanthin alleviated oxidative stress from chilling stress by enhancing oxidation resistance.•Exogenous zeaxanthin involved chilling tolerance by inducing accumulation of endogenous zeaxanthin.