Luo Jianhao, Liu Mingxi, Zhang Chendong, Zhang Peipei, Chen Jingjing, Guo Zhenfei, Lu Shaoyun
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural UniversityGuangzhou, China.
Department of Grassland Science, College of Agronomy, Hunan Agricultural UniversityChangsha, China.
Front Plant Sci. 2017 Sep 22;8:1655. doi: 10.3389/fpls.2017.01655. eCollection 2017.
Centipedegrass ( [Munro] Hack.) is an important warm-season turfgrass species. Transgenic centipedgrass plants overexpressing from bermudagrass () that was induced in response to cold were generated in this study. Higher levels of transcript and sperimidine (Spd) and spermin (Spm) concentrations and enhanced freezing and chilling tolerance were observed in transgenic plants as compared with the wild type (WT). Transgenic plants had higher levels of polyamine oxidase (PAO) activity and HO than WT, which were blocked by pretreatment with methylglyoxal bis (guanylhydrazone) or MGBG, inhibitor of SAMDC, indicating that the increased PAO and HO were a result of expression of . In addition, transgenic plants had higher levels of nitrate reductase (NR) activity and nitric oxide (NO) concentration. The increased NR activity were blocked by pretreatment with MGBG and ascorbic acid (AsA), scavenger of HO, while the increased NO level was blocked by MGBG, AsA, and inhibitors of NR, indicating that the enhanced NR-derived NO was dependent upon HO, as a result of expression . Elevated superoxide dismutase (SOD) and catalase (CAT) activities were observed in transgenic plants than in WT, which were blocked by pretreatment with MGBG, AsA, inhibitors of NR and scavenger of NO, indicating that the increased activities of SOD and CAT depends on expression of , HO, and NR-derived NO. Our results suggest that the elevated cold tolerance was associated with PAO catalyzed production of HO, which in turn led to NR-derived NO production and induced antioxidant enzyme activities in transgenic plants.
假俭草（[门罗]哈克）是一种重要的暖季型草坪草种。本研究培育了过表达来自狗牙根（）的、在低温诱导下产生的转基因假俭草植株。与野生型（WT）相比，转基因植株中观察到转录本水平更高，亚精胺（Spd）和精胺（Spm）浓度更高，且冻害和冷害耐受性增强。转基因植株的多胺氧化酶（PAO）活性和HO水平高于WT，用甲基乙二醛双（脒腙）或MGBG（S-腺苷甲硫氨酸脱羧酶抑制剂）预处理可阻断这种情况，表明PAO和HO的增加是表达的结果。此外，转基因植株的硝酸还原酶（NR）活性和一氧化氮（NO）浓度更高。用MGBG和HO清除剂抗坏血酸（AsA）预处理可阻断NR活性的增加，而用MGBG、AsA和NR抑制剂可阻断NO水平的增加，表明增强的NR衍生的NO依赖于HO，这是表达的结果。与WT相比，转基因植株中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性升高，用MGBG、AsA、NR抑制剂和NO清除剂预处理可阻断这种情况，表明SOD和CAT活性的增加取决于、HO和NR衍生的NO的表达。我们的结果表明，耐寒性的提高与PAO催化产生HO有关，这反过来又导致NR衍生的NO产生，并诱导转基因植株中的抗氧化酶活性。
