Scheible Wolf-Rüdiger, Fry Barbara, Kochevenko Andrej, Schindelasch Dana, Zimmerli Laurent, Somerville Shauna, Loria Rosemary, Somerville Chris R
Max Planck Institute of Molecular Plant Physiology, 14476 Golm, Germany.
Plant Cell. 2003 Aug;15(8):1781-94. doi: 10.1105/tpc.013342.
Thaxtomin A is a phytotoxin produced by Streptomyces scabies and other Streptomyces species, the causative agents of common scab disease in potato and other taproot crops. At nanomolar concentrations, thaxtomin causes dramatic cell swelling, reduced seedling growth, and inhibition of cellulose synthesis in Arabidopsis. We identified a mutant of Arabidopsis, designated txr1, that exhibits increased resistance to thaxtomin as a result of a decrease in the rate of toxin uptake. The TXR1 gene was identified by map-based cloning and found to encode a novel, small protein with no apparent motifs or organelle-targeting signals. The protein, which has homologs in all fully sequenced eukaryotic genomes, is expressed in all tissues and during all developmental stages analyzed. Microarray transcript profiling of some 14,300 genes revealed two stomatin-like genes that were expressed differentially in the txr1 mutant and the wild type. We propose that TXR1 is a regulator of a transport mechanism.
燕麦酸A是由疮痂链霉菌和其他链霉菌属物种产生的一种植物毒素，这些链霉菌属物种是马铃薯和其他主根作物中常见疮痂病的病原体。在纳摩尔浓度下，燕麦酸会导致细胞显著肿胀、幼苗生长减缓以及拟南芥中纤维素合成受到抑制。我们鉴定出一个拟南芥突变体，命名为txr1，由于毒素摄取速率降低，该突变体对燕麦酸表现出增强的抗性。通过图位克隆鉴定出TXR1基因，发现它编码一种新型的小蛋白，没有明显的基序或细胞器靶向信号。该蛋白在所有已完成全基因组测序的真核生物基因组中都有同源物，在所有分析的组织和发育阶段均有表达。对约14,000个基因进行的微阵列转录谱分析揭示了两个类气孔蛋白基因，它们在txr1突变体和野生型中差异表达。我们认为TXR1是一种转运机制的调节因子。
