Frerigmann Henning, Hoecker Ute, Gigolashvili Tamara
Department of Plant-Microbe Interactions and Cluster of Excellence on Plant Sciences, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
BioCenter, Botanical Institute and Cluster of Excellence on Plant Sciences, University of Cologne, Cologne, Germany.
Front Plant Sci. 2021 Jul 1;12:680255. doi: 10.3389/fpls.2021.680255. eCollection 2021.
The biosynthesis of defensive secondary metabolites, such as glucosinolates (GSLs), is a costly process, which requires nutrients, ATP, and reduction equivalents, and, therefore, needs well-orchestrated machinery while coordinating defense and growth. We discovered that the key repressor of light signaling, the CONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYTOCHROME A-105 (COP1/SPA) complex, is a crucial component of GSL biosynthesis regulation. Various mutants in this COP1/SPA complex exhibited a strongly reduced level of GSL and a low expression of jasmonate (JA)-dependent genes. Furthermore, , which is known to accumulate DELLA proteins in the dark, shows reduced gibberellin (GA) and JA signaling, thereby phenocopying other DELLA-accumulating mutants. This phenotype can be complemented by a dominant gain-of-function allele of and by crossing with a mutant having low DELLA protein levels. Hence, SPA1 interacts with DELLA proteins in a yeast two-hybrid screen, whereas high levels of DELLA inhibit MYC function and suppress JA signaling. DELLA accumulation leads to reduced synthesis of GSL and inhibited growth. Thus, the COP1/SPA-mediated degradation of DELLA not only affects growth but also regulates the biosynthesis of GSLs.
防御性次生代谢产物（如芥子油苷，GSLs）的生物合成是一个消耗巨大的过程，需要营养物质、ATP和还原当量，因此，在协调防御和生长时需要精心编排的机制。我们发现，光信号的关键阻遏物，组成型光形态建成1/光敏色素A-105抑制因子（COP1/SPA）复合体，是GSL生物合成调控的关键组成部分。该COP1/SPA复合体中的各种突变体表现出GSL水平大幅降低以及茉莉酸（JA）依赖基因的低表达。此外，已知在黑暗中积累DELLA蛋白的[此处原文缺失相关内容]表现出赤霉素（GA）和JA信号传导减少，从而模拟其他积累DELLA的突变体的表型。这种表型可以通过[此处原文缺失相关内容]的显性功能获得等位基因以及与具有低DELLA蛋白水平的突变体杂交来互补。因此，在酵母双杂交筛选中，SPA1与DELLA蛋白相互作用，而高水平的DELLA抑制MYC功能并抑制JA信号传导。DELLA的积累导致GSL合成减少和生长受抑制。因此，COP1/SPA介导的DELLA降解不仅影响生长，还调节GSL的生物合成。
