Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia.
Planta. 2010 Oct;232(5):1023-32. doi: 10.1007/s00425-010-1237-3. Epub 2010 Aug 3.
Microbe-plant interactions often lead to a decrease in the reactive oxygen species (ROS) level of plant cells, which allows pathogen survival through the suppression of plant immune responses. In the present investigation, we tested whether transformation of Rubia cordifolia cells by Agrobacterium rhizogenes had a similar effect. We isolated partial cDNA sequences of ascorbate peroxidase, catalase and Cu/Zn superoxide dismutase genes (RcApx1, RcApx2, RcApx3, RcCAT1, RcCAT2, RcCSD1, RcCSD2 and RcCSD3) from plant tissues, as well as pRiA4-transformed and normal calli of Rubia cordifolia, and studied their expression by real-time PCR. Transcription profiling revealed that ascorbate peroxidase (RcApx1) and Cu/Zn superoxide dismutase (RcCSD1) were the most abundant transcripts present in both plant tissues and non-transformed calli. Catalase genes were weakly expressed in these samples. The pRiA4-transformed calli showed enhanced expression of several genes encoding ROS-detoxifying enzymes. Confocal microscopy imaging revealed decreased ROS level in pRiA4-transformed calli compared to the control. These results demonstrate that A. rhizogenes, like other plant pathogens, uses a strategy aimed at decreasing ROS levels in host cells through the general upregulation of its antioxidant genes.
微生物-植物相互作用通常会导致植物细胞内活性氧（ROS）水平下降，从而通过抑制植物免疫反应来允许病原体存活。在本研究中，我们测试了根癌农杆菌转化的茜草细胞是否具有类似的效果。我们从植物组织中分离了抗坏血酸过氧化物酶、过氧化氢酶和 Cu/Zn 超氧化物歧化酶基因（RcApx1、RcApx2、RcApx3、RcCAT1、RcCAT2、RcCSD1、RcCSD2 和 RcCSD3）的部分 cDNA 序列，以及转化了 pRiA4 的和正常的茜草根愈伤组织，并通过实时 PCR 研究了它们的表达。转录谱分析表明，抗坏血酸过氧化物酶（RcApx1）和 Cu/Zn 超氧化物歧化酶（RcCSD1）是在植物组织和未转化的愈伤组织中丰度最高的转录本。这些样本中过氧化氢酶基因的表达较弱。pRiA4 转化的愈伤组织表现出几种 ROS 解毒酶编码基因的表达增强。共聚焦显微镜成像显示，与对照相比，pRiA4 转化的愈伤组织中的 ROS 水平降低。这些结果表明，根癌农杆菌与其他植物病原体一样，采用了一种策略，通过普遍上调其抗氧化基因来降低宿主细胞内的 ROS 水平。
