Panter S N, Hammond-Kosack K E, Harrison K, Jones J D G, Jones D A
Research School of Biological Sciences, Australian National University, Canberra, ACT.
Mol Plant Microbe Interact. 2002 Nov;15(11):1099-107. doi: 10.1094/MPMI.2002.15.11.1099.
Cf-9 confers resistance to tomato seedlings and mature plants against Cladosporium fulvum races expressing the Avr9 elicitor. It is the central member of a cluster of five paralogous genes in an introgressed segment of chromosome 1 derived from Lycopersicon pimpinellifolium. The other four genes have been named Hcr9-9A, Hcr9-9B, Hcr9-9D, and Hcr9-9E. Hcr9-9B, here designated Cf-9B, encodes weaker resistance than Cf-9, recognizes a different elicitor, and protects only mature plants from infection. The onset of Cf-9B-mediated resistance and the molecular basis for its developmental control were investigated in this study. Fungal inoculation of tomato plants containing reciprocal Cf-9/Cf-9B promoter-coding region swaps, analysis of tomato plants containing promoter-gusA fusions, and a reverse transcriptase-polymerase chain reaction study of Cf-9 and Cf-9B transcripts in tomato plants suggested that transcriptional control of Cf-9B did not account for the late onset of Cf-9B-mediated resistance. Alternative explanations for the onset of Cf-9B-mediated resistance in mature plants are discussed.
Cf-9使番茄幼苗和成熟植株对表达Avr9激发子的番茄叶霉病菌小种产生抗性。它是来源于醋栗番茄的1号染色体渐渗片段中五个旁系同源基因簇的核心成员。其他四个基因已被命名为Hcr9-9A、Hcr9-9B、Hcr9-9D和Hcr9-9E。Hcr9-9B（此处命名为Cf-9B）编码的抗性比Cf-9弱，识别不同的激发子，且仅保护成熟植株免受感染。本研究对Cf-9B介导的抗性的起始及其发育控制的分子基础进行了研究。对含有相互交换的Cf-9/Cf-9B启动子-编码区的番茄植株进行真菌接种、对含有启动子-gusA融合体的番茄植株进行分析，以及对番茄植株中Cf-9和Cf-9B转录本进行逆转录酶-聚合酶链反应研究，结果表明Cf-9B的转录调控不能解释Cf-9B介导的抗性的延迟起始。文中讨论了成熟植株中Cf-9B介导的抗性起始的其他解释。
