Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China.
Facility Horticulture Institute, Ministry of Agriculture Planning and Design Research Academy, Beijing, China.
PLoS One. 2020 Dec 29;15(12):e0244198. doi: 10.1371/journal.pone.0244198. eCollection 2020.
High temperatures induce early bolting in lettuce (Lactuca sativa L.), which decreases both quality and production. However, knowledge of the molecular mechanism underlying high temperature promotes premature bolting is lacking. In this study, we compared lettuce during the bolting period induced by high temperatures (33/25 °C, day/night) to which raised under controlled temperatures (20/13 °C, day/night) using iTRAQ-based phosphoproteomic analysis. A total of 3,814 phosphorylation sites located on 1,766 phosphopeptides from 987 phosphoproteins were identified after high-temperature treatment,among which 217 phosphoproteins significantly changed their expression abundance (116 upregulated and 101 downregulated). Most phosphoproteins for which the abundance was altered were associated with the metabolic process, with the main molecular functions were catalytic activity and transporter activity. Regarding the functional pathway, starch and sucrose metabolism was the mainly enriched signaling pathways. Hence, high temperature influenced phosphoprotein activity, especially that associated with starch and sucrose metabolism. We suspected that the lettuce shorten its growth cycle and reduce vegetative growth owing to changes in the contents of starch and soluble sugar after high temperature stress, which then led to early bolting/flowering. These findings improve our understanding of the regulatory molecular mechanisms involved in lettuce bolting.
高温会诱导生菜（Lactuca sativa L.）早期抽薹，从而降低其品质和产量。然而，目前对于高温促进生菜过早抽薹的分子机制还知之甚少。在本研究中，我们使用 iTRAQ 基于磷酸化蛋白质组学分析，比较了高温（33/25°C，昼/夜）诱导和受控温度（20/13°C，昼/夜）下生菜抽薹期的表型。在高温处理后，共鉴定到 3814 个位于 1766 个磷酸肽上的磷酸化位点，来自 987 个磷酸化蛋白质，其中 217 个磷酸化蛋白质的表达丰度发生了显著变化（116 个上调，101 个下调）。大多数磷酸化蛋白质与代谢过程有关，主要的分子功能是催化活性和转运活性。就功能途径而言，淀粉和蔗糖代谢是主要富集的信号通路。因此，高温影响了磷酸蛋白的活性，特别是与淀粉和蔗糖代谢相关的磷酸蛋白。我们推测，由于高温胁迫后淀粉和可溶性糖含量的变化，生菜缩短了其生长周期，减少了营养生长，从而导致早期抽薹/开花。这些发现提高了我们对生菜抽薹调控分子机制的理解。
