Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Kirschallee, Bonn, Germany.
J Exp Bot. 2018 Jun 27;69(15):3773-3784. doi: 10.1093/jxb/ery173.
Reproductive structures of plants (e.g. seeds) and vegetative tissues of resurrection plants can tolerate desiccation. Many genes encoding desiccation-related proteins (DRPs) have been identified in the resurrection plant Craterostigma plantagineum, but the function of these genes remains mainly hypothetical. Here, the importance of the DRP gene pcC13-62 for desiccation tolerance is evaluated by analysing its expression in C. plantagineum and in the closely related desiccation-tolerant species Lindernia brevidens and the desiccation-sensitive species Lindernia subracemosa. Quantitative analysis revealed that pcC13-62 transcripts accumulate at a much lower level in desiccation-sensitive species than in desiccation-tolerant species. The study of pcC13-62 promoters from these species demonstrated a correlation between promoter activity and gene expression levels, suggesting transcriptional regulation of gene expression. Comparison of promoter sequences identified a dehydration-responsive element motif in the promoters of tolerant species that is required for dehydration-induced β-glucuronidase (GUS) accumulation. We hypothesize that variations in the regulatory sequences of the pcC13-62 gene occurred to establish pcC13-62 expression in vegetative tissues, which might be required for desiccation tolerance. The pcC13-62 promoters could also be activated by salt stress in Arabidopsis thaliana plants stably transformed with promoter::GUS constructs.
植物的生殖结构（如种子）和复苏植物的营养组织可以耐受干燥。在复苏植物 Craterostigma plantagineum 中已经鉴定出许多编码与干燥相关的蛋白质（DRPs）的基因，但这些基因的功能仍然主要是假设性的。在这里，通过分析 DRP 基因 pcC13-62 在 C. plantagineum 及其密切相关的耐旱物种 Lindernia brevidens 和耐旱敏感物种 Lindernia subracemosa 中的表达，评估了该基因对干燥耐受性的重要性。定量分析表明，pcC13-62 转录本在耐旱敏感物种中的积累水平远低于耐旱物种。对这些物种的 pcC13-62 启动子的研究表明，启动子活性与基因表达水平之间存在相关性，提示基因表达的转录调控。启动子序列的比较鉴定出耐受物种启动子中的脱水响应元件基序，该基序是脱水诱导β-葡萄糖醛酸酶（GUS）积累所必需的。我们假设，pcC13-62 基因的调控序列的变异发生在营养组织中建立 pcC13-62 的表达，这可能是干燥耐受性所必需的。pcC13-62 启动子也可以在稳定转化有启动子::GUS 构建体的拟南芥植物中被盐胁迫激活。
