Graduate School of Agriculture, Kyoto University, Takatsuki, Osaka, Japan.
J Plant Res. 2013 Sep;126(5):675-84. doi: 10.1007/s10265-013-0564-4. Epub 2013 Apr 30.
Plants in tropical regions experience temperature fluctuation only in non-extreme ambient temperatures. Thus, moderate changes in temperatures, which they never experience in their local environments, might be sufficient to manifest the locally hidden phenotype caused by natural mutation. To validate this hypothesis, temperature-treating experiments were performed on Capsicum accessions collected from tropical regions. Thirty-six Capsicum accessions, collected from Caribbean countries, were screened for temperature sensitivity. Similarities in their temperature sensitivities were compared with Sy-2 (C. chinense) from Seychelles, which was previously found to be a temperature-sensitive accession. Tr-13 from Trinidad & Tobago exhibited developmental abnormalities at temperatures below 24 °C. Expression of defense-related genes was induced, and salicylic acid, which is a key molecule in the plant's defense response, accumulated in Tr-13 at temperatures below 24 °C. Tr-13 and Sy-2 appeared normal when they were grown at temperatures simulating those in Trinidad and Seychelles, respectively. Crossing Tr-13 with No. 3341 or Sy-2 revealed that the temperature-sensitive phenotype of Tr-13 was caused by a genetic mutation in the same locus as Sy-2. Plants having a temperature-sensitive phenotype that is caused by natural mutations evade artificial selection and exist as crops in specific environments, such as tropical regions.
在热带地区的植物仅在非极端环境温度下经历温度波动。因此，适度的温度变化，在它们的当地环境中从未经历过，可能足以表现出由自然突变引起的当地隐藏表型。为了验证这一假设，对来自热带地区的辣椒品种进行了温度处理实验。对来自加勒比国家的 36 个辣椒品种进行了温度敏感性筛选。来自特立尼达和多巴哥的 Tr-13 在低于 24°C 的温度下表现出发育异常。防御相关基因的表达被诱导，水杨酸作为植物防御反应的关键分子，在低于 24°C 的温度下在 Tr-13 中积累。Tr-13 和 Sy-2 在模拟特立尼达和塞舌尔温度的条件下生长时，表现正常。将 Tr-13 与 No.3341 或 Sy-2 杂交表明，Tr-13 的温度敏感表型是由与 Sy-2 相同基因座的基因突变引起的。由于自然突变而表现出温度敏感表型的植物逃避了人工选择，作为作物存在于特定环境中，如热带地区。
