Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China.
Department of Viticulture and Oenology, Institute for Wine Biotechnology, Stellenbosch University, Matieland 7602, South Africa.
Plant Cell Physiol. 2019 Dec 1;60(12):2707-2719. doi: 10.1093/pcp/pcz160.
Boea hygrometrica can survive extreme drought conditions and has been used as a model to study desiccation tolerance. A genome-wide transcriptome analysis of B. hygrometrica showed that the plant can survive rapid air-drying after experiencing a slow soil-drying acclimation phase. In addition, a weighted gene co-expression network analysis was used to study the transcriptomic datasets. A network comprising 22 modules was constructed, and seven modules were found to be significantly related to desiccation response using an enrichment analysis. Protein ubiquitination was observed to be a common process linked to hub genes in all the seven modules. Ubiquitin-modified proteins with diversified functions were identified using immunoprecipitation coupled with mass spectrometry. The lowest level of ubiquitination was noted at the full soil drying priming stage, which coincided the accumulation of dehydration-responsive gene BhLEA2. The highly conserved RY motif (CATGCA) was identified from the promoters of ubiquitin-related genes that were downregulated in the desiccated samples. An in silico gene expression analysis showed that the negative regulation of ubiquitin-related genes is potentially mediated via a B3 domain-containing transcription repressor VAL1. This study suggests that priming may involve the transcriptional regulation of several major processes, and the transcriptional regulation of genes in protein ubiquitination may play a hub role to deliver acclimation signals to posttranslational level in the acquisition of desiccation tolerance in B. hygrometrica.
波叶海桐能够在极端干旱条件下生存，并被用作研究耐旱性的模型。对波叶海桐的全基因组转录组分析表明，在经历缓慢土壤干燥适应阶段后，植物能够在快速空气干燥后存活。此外，还使用加权基因共表达网络分析研究了转录组数据集。构建了一个包含 22 个模块的网络，通过富集分析发现，有 7 个模块与干燥响应显著相关。使用免疫沉淀结合质谱鉴定了具有多样化功能的泛素化修饰蛋白。在完全土壤干燥引发阶段观察到最低水平的泛素化，这与脱水响应基因 BhLEA2 的积累相吻合。在干燥样本中下调的泛素相关基因的启动子中鉴定到高度保守的 RY 基序（CATGCA）。计算机基因表达分析表明，泛素相关基因的负调控可能是通过含有 B3 结构域的转录抑制因子 VAL1 介导的。本研究表明，引发可能涉及几个主要过程的转录调控，而蛋白质泛素化基因的转录调控可能在波叶海桐获得耐旱性的过程中发挥枢纽作用，将适应信号传递到翻译后水平。
