Chan Aaron, Stasolla Claudio
Department of Plant Science, University of Manitoba, Winnipeg, R3T2N2, Canada.
Department of Plant Science, University of Manitoba, Winnipeg, R3T2N2, Canada.
Plant Physiol Biochem. 2023 Feb;195:163-169. doi: 10.1016/j.plaphy.2023.01.007. Epub 2023 Jan 10.
The requirement of light on somatic embryogenesis (SE) has been documented in many species; however, no mechanism of action has been elucidated. Using Arabidopsis SE as a model, the effect of red light (660 nm) during the induction phase corresponding to the formation of the embryogenic tissue was examined. Analyses of several phytochrome mutants revealed that red light signaling, conducive to SE, was mediated by PHYTOCHROME E (PHYE). Both phyE and darkness were sufficient to repress the formation of somatic embryos and reduced the expression of CONSTITUTIVE PHOTOMORPHIC DWARF 3 (CPD3), a rate limiting step in brassinosteroid (BR) biosynthesis, as well as AGAMOUS LIKE 15 (AGL15), a key inducer of many SE genes. We further integrated BR signaling and nitric oxide (NO) with PHYE by demonstrating that applications of both compounds to phyE explants and WT explants cultured in the dark partially restored AGL15 expression. These results demonstrate that SE induction by red light operates via PHYE through BR signaling and NO required to induce AGL15.
许多物种都记录了光对体细胞胚胎发生（SE）的需求；然而，尚未阐明其作用机制。以拟南芥SE为模型，研究了红光（660nm）在与胚性组织形成相对应的诱导阶段的作用。对几种光敏色素突变体的分析表明，有利于SE的红光信号由光敏色素E（PHYE）介导。PHYE和黑暗都足以抑制体细胞胚的形成，并降低组成型光形态建成矮化3（CPD3）的表达，CPD3是油菜素类固醇（BR）生物合成中的限速步骤，以及许多SE基因的关键诱导因子AGAMOUS LIKE 15（AGL15）。我们通过证明将这两种化合物应用于phyE外植体和在黑暗中培养的野生型外植体可部分恢复AGL15的表达，进一步将BR信号和一氧化氮（NO）与PHYE整合。这些结果表明，红光诱导SE是通过PHYE通过BR信号和诱导AGL15所需的NO起作用的。
