Andrade Galan Ana Gabriela, Doll Jasmin, Faiß Natalie, Weber Patricia, Zentgraf Ulrike
Center for Plant Molecular Biology (ZMBP), University of Tuebingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
Antioxidants (Basel). 2024 Mar 5;13(3):315. doi: 10.3390/antiox13030315.
The transcription factor WRKY53 of the model plant is an important regulator of leaf senescence. Its expression, activity and degradation are tightly controlled by various mechanisms and feedback loops. Hydrogen peroxide is one of the inducing agents for expression, and a long-lasting intracellular increase in HO content accompanies the upregulation of at the onset of leaf senescence. We have identified different antioxidative enzymes, including catalases (CATs), superoxide dismutases (SODs) and ascorbate peroxidases (APXs), as protein interaction partners of WRKY53 in a WRKY53-pulldown experiment at different developmental stages. The interaction of WRKY53 with these enzymes was confirmed in vivo by bimolecular fluorescence complementation assays (BiFC) in protoplasts and transiently transformed tobacco leaves. The interaction with WRKY53 inhibited the activity of the enzyme isoforms CAT2, CAT3, APX1, Cu/ZuSOD1 and FeSOD1 (and vice versa) while the function of WRKY53 as a transcription factor was also inhibited by these complex formations. Other WRKY factors like WRKY18 or WRKY25 had no or only mild inhibitory effects on the enzyme activities, indicating that WRKY53 has a central position in this crosstalk. Taken together, we identified a new additional and unexpected feedback regulation between HO the antioxidative enzymes and the transcription factor WRKY53.
模式植物中的转录因子WRKY53是叶片衰老的重要调节因子。其表达、活性和降解受到多种机制和反馈回路的严格控制。过氧化氢是其表达的诱导剂之一，在叶片衰老开始时，WRKY53上调伴随着细胞内过氧化氢含量的持续增加。在不同发育阶段的WRKY53下拉实验中，我们鉴定出了不同的抗氧化酶，包括过氧化氢酶（CATs）、超氧化物歧化酶（SODs）和抗坏血酸过氧化物酶（APXs），作为WRKY53的蛋白质相互作用伙伴。通过原生质体中的双分子荧光互补分析（BiFC）和瞬时转化的烟草叶片，在体内证实了WRKY53与这些酶的相互作用。与WRKY53的相互作用抑制了CAT2、CAT3、APX1、Cu/ZuSOD1和FeSOD1等酶同工型的活性（反之亦然），而这些复合物的形成也抑制了WRKY53作为转录因子的功能。其他WRKY因子如WRKY18或WRKY25对酶活性没有或只有轻微的抑制作用，这表明WRKY53在这种相互作用中处于核心地位。综上所述，我们发现了过氧化氢、抗氧化酶和转录因子WRKY53之间一种新的额外且意想不到的反馈调节。
