Liu Zhoubin, Song Jingshuang, Miao Wu, Yang Bozhi, Zhang Zhuqing, Chen Wenchao, Tan Fangjun, Suo Huan, Dai Xiongze, Zou Xuexiao, Ou Lijun
College of Horticulture, Hunan Agricultural University, Changsha, China.
ERC for Germplasm Innovation and New Variety Breeding of Horticultural Crops, Changsha, China.
Front Plant Sci. 2021 Aug 27;12:730489. doi: 10.3389/fpls.2021.730489. eCollection 2021.
Pepper is a typical warmth-loving vegetable that lacks a cold acclimation mechanism and is sensitive to cold stress. Lysine acetylation plays an important role in diverse cellular processes, but limited knowledge is available regarding acetylation modifications in the resistance of pepper plants to cold stress. In this study, the proteome and acetylome of two pepper varieties with different levels of cold resistance were investigated by subjecting them to cold treatments of varying durations followed by recovery periods. In total, 6,213 proteins and 4,574 lysine acetylation sites were identified, and this resulted in the discovery of 3,008 differentially expressed proteins and 768 differentially expressed acetylated proteins. A total of 1,988 proteins were identified in both the proteome and acetylome, and the functional differences in these co-identified proteins were elucidated through GO enrichment. KEGG analysis showed that 397 identified acetylated proteins were involved in 93 different metabolic pathways. The dynamic changes in the acetylated proteins in photosynthesis and the "carbon fixation in the photosynthetic organisms" pathway in pepper under low-temperature stress were further analyzed. It was found that acetylation of the PsbO and PsbR proteins in photosystem II and the PsaN protein in photosystem I could regulate the response of pepper leaves to cold stress. The acetylation levels of key carbon assimilation enzymes, such as ribulose bisphosphate carboxylase, fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase, glyceraldehyde 3-phosphate dehydrogenase, phosphoribulokinase, and triosephosphate isomerase decreased, leading to decreases in carbon assimilation capacity and photosynthetic efficiency, reducing the cold tolerance of pepper leaves. This study is the first to identify the acetylome in pepper, and it greatly expands the catalog of lysine acetylation substrates and sites in Solanaceae crops, providing new insights for posttranslational modification studies.
辣椒是典型的喜温蔬菜，缺乏冷驯化机制，对冷胁迫敏感。赖氨酸乙酰化在多种细胞过程中发挥重要作用，但关于辣椒植株抗冷胁迫中的乙酰化修饰的知识有限。在本研究中，通过对两个抗冷性不同的辣椒品种进行不同时长的冷处理及恢复期，研究了其蛋白质组和乙酰化蛋白质组。总共鉴定出6213种蛋白质和4574个赖氨酸乙酰化位点，结果发现了3008种差异表达蛋白质和768种差异表达的乙酰化蛋白质。在蛋白质组和乙酰化蛋白质组中总共鉴定出1988种蛋白质，并通过基因本体论（GO）富集阐明了这些共同鉴定蛋白质的功能差异。京都基因与基因组百科全书（KEGG）分析表明，鉴定出的397种乙酰化蛋白质参与了93条不同的代谢途径。进一步分析了低温胁迫下辣椒光合作用及“光合生物中的碳固定”途径中乙酰化蛋白质的动态变化。发现光系统II中的PsbO和PsbR蛋白以及光系统I中的PsaN蛋白的乙酰化可调节辣椒叶片对冷胁迫的响应。关键碳同化酶，如核酮糖二磷酸羧化酶、果糖-1,6-二磷酸酶、景天庚酮糖-1,7-二磷酸酶、甘油醛-3-磷酸脱氢酶、磷酸核酮糖激酶和磷酸丙糖异构酶的乙酰化水平降低，导致碳同化能力和光合效率下降，降低了辣椒叶片的耐寒性。本研究首次鉴定了辣椒的乙酰化蛋白质组，极大地扩展了茄科作物中赖氨酸乙酰化底物和位点的目录，为翻译后修饰研究提供了新的见解。
