Serrato Antonio J, Rojas-González José A, Torres-Romero Diego, Vargas Paola, Mérida Ángel, Sahrawy Mariam
Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín (EEZ), Consejo Superior de Investigaciones Científicas (CSIC), Granada, 18008, Spain.
Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), Universidad de Sevilla y Consejo Superior de Investigaciones Científicas (CSIC), Seville, 41092, Spain.
Plant J. 2021 Oct;108(1):120-133. doi: 10.1111/tpj.15429. Epub 2021 Aug 10.
Thioredoxins (TRXs) are well-known redox signalling players, which carry out post-translational modifications in target proteins. Chloroplast TRXs are divided into different types and have central roles in light energy uptake and the regulation of primary metabolism. The isoforms TRX m1, m2, and m4 from Arabidopsis thaliana are considered functionally related. Knowing their key position in the hub of plant metabolism, we hypothesized that the impairment of the TRX m signalling would not only have harmful consequences on chloroplast metabolism but also at different levels of plant development. To uncover the physiological and developmental processes that depend on TRX m signalling, we carried out a comprehensive study of Arabidopsis single, double, and triple mutants defective in the TRX m1, m2, and m4 proteins. As light and redox signalling are closely linked, we investigated the response to high light (HL) of the plants that are gradually compromised in TRX m signalling. We provide experimental evidence relating the lack of TRX m and the appearance of novel phenotypic features concerning mesophyll structure, stomata biogenesis, and stomatal conductance. We also report new data indicating that the isoforms of TRX m fine-tune the response to HL, including the accumulation of the protective pigment anthocyanin. These results reveal novel signalling functions for the TRX m and underline their importance for plant growth and fulfilment of the acclimation/response to HL conditions.
硫氧还蛋白（TRXs）是众所周知的氧化还原信号传导分子，可对靶蛋白进行翻译后修饰。叶绿体TRXs可分为不同类型，在光能吸收和初级代谢调节中起核心作用。拟南芥中的TRX m1、m2和m4亚型被认为在功能上相关。鉴于它们在植物代谢中心的关键地位，我们推测TRX m信号的受损不仅会对叶绿体代谢产生有害影响，还会在植物发育的不同层面产生影响。为了揭示依赖于TRX m信号的生理和发育过程，我们对TRX m1、m2和m4蛋白缺陷的拟南芥单突变体、双突变体和三突变体进行了全面研究。由于光信号和氧化还原信号密切相关，我们研究了TRX m信号逐渐受损的植物对高光（HL）的响应。我们提供了实验证据，证明TRX m的缺失与叶肉结构、气孔发生和气孔导度等新表型特征的出现有关。我们还报告了新数据，表明TRX m亚型可微调对高光的响应，包括保护性色素花青素的积累。这些结果揭示了TRX m的新信号功能，并强调了它们对植物生长以及适应/响应高光条件的重要性。
