Betterle Nico, Ballottari Matteo, Baginsky Sacha, Bassi Roberto
Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy (N.B., M.B., R.B.); andInstitute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany (S.B.).
Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy (N.B., M.B., R.B.); andInstitute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany (S.B.)
Plant Physiol. 2015 Feb;167(2):457-71. doi: 10.1104/pp.114.252379. Epub 2014 Dec 10.
Phosphorylation of the photosystem II antenna protein CP29 has been reported to be induced by excess light and further enhanced by low temperature, increasing resistance to these stressing factors. Moreover, high light-induced CP29 phosphorylation was specifically found in monocots, both C3 and C4, which include the large majority of food crops. Recently, knockout collections have become available in rice (Oryza sativa), a model organism for monocots. In this work, we have used reverse genetics coupled to biochemical and physiological analysis to elucidate the molecular basis of high light-induced phosphorylation of CP29 and the mechanisms by which it exerts a photoprotective effect. We found that kinases and phosphatases involved in CP29 phosphorylation are distinct from those reported to act in State 1-State 2 transitions. In addition, we elucidated the photoprotective role of CP29 phosphorylation in reducing singlet oxygen production and enhancing excess energy dissipation. We thus established, in monocots, a mechanistic connection between phosphorylation of CP29 and nonphotochemical quenching, two processes so far considered independent from one another.
据报道，光系统II天线蛋白CP29的磷酸化由过量光照诱导，并在低温下进一步增强，从而增加对这些胁迫因素的抗性。此外，高光诱导的CP29磷酸化在单子叶植物（包括C3和C4植物）中被特别发现，而单子叶植物包含了绝大多数粮食作物。最近，水稻（单子叶植物的模式生物）中已有基因敲除文库。在这项工作中，我们利用反向遗传学结合生化和生理分析，来阐明高光诱导CP29磷酸化的分子基础及其发挥光保护作用的机制。我们发现，参与CP29磷酸化的激酶和磷酸酶与那些在状态1-状态2转变中起作用的激酶和磷酸酶不同。此外，我们阐明了CP29磷酸化在减少单线态氧产生和增强过剩能量耗散方面的光保护作用。因此，我们在单子叶植物中建立了CP29磷酸化与非光化学猝灭之间的机制联系，而这两个过程迄今被认为是相互独立的。
