Cao Yuxin, Xiang Xian, Geng Mengting, You Qin, Huang Xi
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan UniversityHaikou, China.
Front Plant Sci. 2017 Apr 10;8:470. doi: 10.3389/fpls.2017.00470. eCollection 2017.
Dehydrin is a type of late embryogenesis abundant (LEA) protein. The dehydrin genes, and , in were previously found to be induced at the wounding site of epicormic shoots, with local tissue dehydration identified as the key signal for laticifer differentiation. However, the exact role of the HbDHNs remains unknown. In this study, and expression was examined under multiple abiotic stresses; namely, cold, salt, drought, wounding, abscisic acid (ABA), ethylene (ET), and jasmonic acid (JA) treatment. Although, both HbDHNs were defined as SK2-type dehydrin, they showed different cellular localizations. Overexpression of the HbDHNs in further revealed a significant increase in tolerance to salt, drought and osmotic stresses. Increased accumulation of proline and a reduction in electrolyte leakage were also observed under salt and drought stress, and a higher water content was indicated under osmotic stress. The transgenic plants also showed higher activity levels of ascorbate peroxidase (APX), superoxide dismutase (SOD) and catalase, and accumulated less hydrogen peroxide (HO) and superoxide ([Formula: see text]). Given that reactive oxygen species (ROS) are thought to be a key signal for laticifer differentiation, these findings suggest that HbDHNs act as ROS scavengers, directly or indirectly affecting laticifer differentiation. Both HbDHNs therefore influence physiological processes, improving plant tolerance to multiple abiotic stresses.
脱水素是一种胚胎发育晚期丰富（LEA）蛋白。先前发现橡胶树中的脱水素基因HbDHN1和HbDHN2在潜伏芽的伤口部位被诱导，局部组织脱水被确定为乳管分化的关键信号。然而，HbDHNs的确切作用仍不清楚。在本研究中，检测了HbDHN1和HbDHN2在多种非生物胁迫下的表达；即冷、盐、干旱、创伤、脱落酸（ABA）、乙烯（ET）和茉莉酸（JA）处理。虽然，这两种HbDHNs都被定义为SK2型脱水素，但它们显示出不同的细胞定位。在橡胶树中过表达HbDHNs进一步揭示了对盐、干旱和渗透胁迫的耐受性显著增加。在盐和干旱胁迫下还观察到脯氨酸积累增加和电解质渗漏减少，在渗透胁迫下表明含水量更高。转基因植物还表现出较高水平的抗坏血酸过氧化物酶（APX）、超氧化物歧化酶（SOD）和过氧化氢酶活性，并且积累较少的过氧化氢（H₂O₂）和超氧阴离子（[公式：见原文]）。鉴于活性氧（ROS）被认为是乳管分化的关键信号，这些发现表明HbDHNs作为ROS清除剂，直接或间接影响乳管分化。因此，这两种HbDHNs都影响生理过程，提高植物对多种非生物胁迫的耐受性。
