Abstract：
Seashore paspalum (Paspalum vaginatum O. Swartz) is an important warm-season turfgrass species with extreme salt tolerance, but investigations on its salt tolerance mechanism are limited. A salt induced PvWAK3 from halophyte seashore paspalum was identified in this study. Overexpression of PvWAK3 in Arabidopsis led to increased salt tolerance. Transgenic plants had higher levels of seed germination rate, root length, number of lateral roots, shoot weight, survival rate, Fv/Fm, ETR, and NPQ compared with the wild type (WT) under salt stress. Na+ content was increased and K+ content was decreased after salinity treatment, with lower levels of Na+ and Na+/K+ ratio but higher level of K+ in transgenic plants than in WT under salt stress. The improved maintenance of Na+ and K+ homeostasis was associated with the higher transcript levels of K + -Uptake Permease 4 (KUP4), Potassium Transport 2/3 (AKT2), Salt Overly Sensitive 1 (SOS1) and High-Affinity K + Transporter 5 (HAK5) in transgenic plants compared with WT. Superoxide dismutase (SOD), catalase (CAT) and ascorbate-peroxidase (APX) activities, proline concentration, and P5CS1 transcript were increased after salinity treatment, with higher levels in transgenic lines compared with WT, which led to reduced accumulation of O2·- and H2O2 under salt stress. It is suggested that PvWAK3 regulates salt tolerance positively, which is associated with promoted Na+ and K+ homeostasis, activated antioxidant enzymes, and proline biosynthesis under salt stress.
摘要：
海滨paspalum（PaspalumvaginatumO.Swartz）是一种重要的温暖季节草坪草，具有极端的耐盐性，但对其耐盐机制的研究还很有限。在这项研究中，从盐生植物海滨paspalum中鉴定了盐诱导的PvWAK3。PvWAK3在拟南芥中的过表达导致耐盐性增加。转基因植物有较高的种子发芽率，根长,侧根的数量，射击重量，存活率,Fv/Fm,ETR,和NPQ在盐胁迫下与野生型(WT)相比。盐度处理后Na+含量增加,K+含量降低,在盐胁迫下，转基因植物的Na水平和Na/K比率较低，但K水平高于WT。Na+和K+稳态的改善维持与较高的K+摄取渗透酶4(KUP4)转录水平相关,钾转运2/3（AKT2），与WT相比，转基因植物中的盐过度敏感1（SOS1）和高亲和力K转运蛋白5（HAK5）。超氧化物歧化酶(SOD),过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性，脯氨酸浓度,盐度处理后，P5CS1转录本增加，与WT相比，转基因品系中的水平更高，这导致盐胁迫下O2·-和H2O2的积累减少。建议PvWAK3积极调节耐盐性，与促进的Na+和K+稳态有关，活化的抗氧化酶，和盐胁迫下脯氨酸的生物合成。
