Thioredoxin h2 and o1 Show Different Subcellular Localizations and Redox-Active Functions, and Are Extrachloroplastic Factors Influencing Photosynthetic Performance in Fluctuating Light

Arabidopsis contains eight different h-type thioredoxins (Trx) being distributed in cell organelles. Although Trx h2 is deemed to be confined mitochondria, its subcellular localization and function are discussed controversially. Here, fractionation studies were used clarify this question, showing protein exclusively localized microsomes rather than mitochondria. Furthermore, trxo1, trxh2 trxo1h2 mutants analyzed compare the role of with mitochondrial o1. Under medium light, trxo1 showed impaired growth, while was similar wild type. In line this, clustered differently from type respect nocturnal metabolite profiles, revealing a decrease ascorbate glutathione redox states. fluctuating these genotypic differences attenuated. Instead, double mutant an improved NADPH balance, compared type, accompanied by increased photosynthetic efficiency, specifically high-light phases. Conclusively, o1 differentially respectively, which associated redox-active functions effects on plant growth constant there joint both Trxs regulating balance performance light.