Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713, Republic of Korea.
Planta. 2012 Jun;235(6):1369-82. doi: 10.1007/s00425-011-1580-z. Epub 2011 Dec 31.
In plants, biotic and abiotic stresses regulate the expression and activity of various peroxidase isoforms. Capsicum annuum EXTRACELLULAR PEROXIDASE 2 (CaPO2) was previously shown to play a role in local and systemic reactive oxygen species bursts and disease resistance during bacterial pathogen infection. Here, we report CaPO2 expression patterns and functions during conditions of biotic and abiotic stress. In pepper plants, CaPO2 expression was strongly induced by abscisic acid, but not by defense-related plant hormones such as salicylic acid, ethylene and jasmonic acid. CaPO2 was also strongly induced by abiotic and biotic stress treatments, including drought, cold, high salinity and infection by the hemibiotrophic fungal pathogen Colletotrichum coccodes. Loss-of-function of CaPO2 in virus-induced gene silenced pepper plants led to increased susceptibility to salt- and osmotic-induced stress. In contrast, CaPO2 overexpression in transgenic Arabidopsis thaliana plants conferred enhanced tolerance to high salt, drought, and oxidative stress, while also enhancing resistance to infection by the necrotrophic fungal pathogen Alternaria brassicicola. Taken together, these results provide evidence for the involvement of pepper extracellular peroxidase CaPO2 in plant defense responses to various abiotic stresses and plant fungal pathogens.
在植物中，生物和非生物胁迫调节各种过氧化物酶同工型的表达和活性。先前已经表明，辣椒细胞外过氧化物酶 2（CaPO2）在细菌病原体感染期间局部和系统的活性氧爆发和抗病性中起作用。在这里，我们报告了 CaPO2 在生物和非生物胁迫条件下的表达模式和功能。在辣椒植物中，CaPO2 的表达被脱落酸强烈诱导，但不被防御相关的植物激素如水杨酸、乙烯和茉莉酸诱导。CaPO2 也被非生物和生物胁迫处理强烈诱导，包括干旱、寒冷、高盐度和半活体真菌病原体炭疽菌的感染。在病毒诱导基因沉默的辣椒植物中敲除 CaPO2 功能会导致对盐和渗透胁迫的敏感性增加。相比之下，在转基因拟南芥植物中过表达 CaPO2 赋予了对高盐、干旱和氧化胁迫的增强耐受性，同时也增强了对坏死真菌病原体链格孢菌的抗性。总之，这些结果为辣椒细胞外过氧化物酶 CaPO2 参与植物对各种非生物胁迫和植物真菌病原体的防御反应提供了证据。
