Thioredoxins m are major players in the multifaceted light-adaptive response in Arabidopsis thaliana

背景回顾：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 TRXs m1, m2 and m4 from Arabidopsis thaliana are considered functionally related. 

提出假设：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. 

研究目的和方法：To uncover the physiological and developmental processes which depend on TRX-m signalling, we carried out a comprehensive study of Arabidopsis single, double and triple mutants defective in the TRXs 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. 

结果1：We provide experimental evidence relating the lack of TRXs m and the appearance of novel phenotypic features concerning mesophyll structure, stomata biogenesis and stomatal conductance.

结果2：We also report new data indicating that the isoforms of TRXs m fine-tune the response to HL including the accumulation of the protective pigment anthocyanin. 

结论：These results reveal novel signalling functions for the TRXs m and underline their importance for plant growth and fulfilment of the acclimation/response to HL conditions.

硫氧还蛋白（Thioredoxins，TRXs）是一类十分重要的氧化还原信号分子，其能够对靶蛋白进行翻译后修饰。叶绿体TRXs可分为不同的类型，在光能吸收和初级代谢调控方面起着十分重要的作用。拟南芥的TRXs m1、m2和m4异构体被认为在功能上具有相关性。因其在植物代谢中处于比较核心的位置，作者假设TRX-m信号转导的破环不仅会对叶绿体代谢产生负面影响，同时还会有损植物不同阶段的发育过程。为了揭示依赖于TRX-m信号转导的生理和发育过程，作者对拟南芥TRXs m1、m2和m4蛋白的单、双和三突变体进行了全面的研究。由于光和氧化还原信号转导具有密切的关联，作者研究了TRX-m信号转导不同程度的受损对于植物响应强光的影响。作者发现了TRXs m的缺乏与植物叶肉结构、气孔发生和气孔导度有关的新表型特征的出现有关。作者的研究还表明TRXs m异构体精细调控了植物对于高光强的响应，包括保护性色素花青素的积累。本文的研究结果揭示了TRXs m新的信号转导功能，并进一步凸显了其对植物生长和适应高光强环境的重要性。