Zhang Zhiwei, Yang Fan, Na Ren, Zhang Xiaoluo, Yang Shuqing, Gao Jing, Fan Mingshou, Zhao Yan, Zhao Jun
Department of Agronomy, Inner Mongolia Agricultural University, Huhhot, Inner Mongolia, 010019, China.
Institutes of Genetics and Developmental Biology, Chinese Academy of Science, Beijing, 100101, China.
BMC Plant Biol. 2014 Dec 30;14:392. doi: 10.1186/s12870-014-0392-2.
Small GTPases are monomeric guanine nucleotide-binding proteins. In plants, ROPs regulate plant cell polarity, plant cell differentiation and development as well as biotic and abiotic stress signaling pathways.
We report the subcellular localization of the AtRop1 protein at the plasma membrane in tobacco epidermal cells using GFP fusions. Additionally, transient and stable expression of a dominant negative form (DN) of the Arabidopsis AtRop1 in potato led to H2O2 accumulation associated with the reduced development of Phytophthora infestans Montagne de Bary and smaller lesions on infected potato leaves. The expression of the Strboh-D gene, a NADPH oxidase homologue in potato, was analyzed by RT-PCR. Expression of this gene was maintained in DN-AtRop1 transgenic plants after infection with P. infestans. In transgenic potato lines, the transcript levels of salicylic acid (SA) and jasmonic acid (JA) marker genes (Npr1 and Lox, respectively) were analyzed. The Lox gene was induced dramatically whereas expression of Npr1, a gene up-regulated by SA, decreased slightly in DN-AtRop1 transgenic plants after infection with P. infestans.
In conclusion, our results indicate that DN-AtROP1 affects potato resistance to P. infestans. This is associated with increased NADPH oxidase-mediated H2O2 production and JA signaling.
小GTP酶是单体鸟嘌呤核苷酸结合蛋白。在植物中，ROP蛋白调节植物细胞极性、植物细胞分化与发育以及生物和非生物胁迫信号通路。
我们利用绿色荧光蛋白融合技术报道了拟南芥AtRop1蛋白在烟草表皮细胞质膜上的亚细胞定位。此外，拟南芥AtRop1显性负性形式（DN）在马铃薯中的瞬时和稳定表达导致过氧化氢积累，这与致病疫霉发育受抑制以及感染马铃薯叶片上病斑变小有关。通过逆转录聚合酶链反应（RT-PCR）分析了马铃薯中NADPH氧化酶同源物Strboh-D基因的表达。致病疫霉感染后，DN-AtRop1转基因植物中该基因的表达得以维持。分析了转基因马铃薯品系中水杨酸（SA）和茉莉酸（JA）标记基因（分别为Npr1和Lox）的转录水平。致病疫霉感染后，DN-AtRop1转基因植物中Lox基因显著诱导表达，而SA上调的Npr1基因表达略有下降。
总之，我们的结果表明DN-AtROP1影响马铃薯对致病疫霉的抗性。这与NADPH氧化酶介导的过氧化氢产生增加和JA信号传导有关。
