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Plant Cell：番茄GA响应受体多样性

已有 3304 次阅读 2019-5-12 17:37 |个人分类:每日摘要|系统分类:论文交流

Multiple gibberellin receptors contribute to phenotypic stability under changing environments

First author: Natanella Illouz-Eliaz; Affiliations: The Hebrew University of Jerusalem (耶路撒冷希伯来大学): Rehovot, Israel

Corresponding author: David Weiss

The pleiotropic and complex gibberellin (GA) response relies on targeted proteolysis of DELLA proteins mediated by a GA-activated GIBBERELLIN-INSENSITIVE DWARF1 (GID1) receptor. The tomato (Solanum lycopersicum) genome encodes for a single DELLA protein, PROCERA (PRO), and three receptors, SlGID1a (GID1a), GID1b1 and GID1b2, that may guide specific GA responses. In this work, CRISPR-Cas9-derived gid1 mutants were generated and their effect on GA responses was studied. The gid1 triple mutant was extremely dwarf and fully insensitive to GA. Under optimal growth conditions, the three receptors function redundantly and the single gid1 mutants exhibited very mild phenotypic changes. Among the three receptors, GID1a had the strongest effects on germination and growth. Yeast two-hybrid assays suggested that GID1a has the highest affinity to PRO. Analysis of lines with a single active receptor demonstrated a unique role for GID1a in protracted response to GA that was saturated only at high doses. When the gid1 mutants were grown in the field under ambient changing environments, they showed phenotypic instability, the high redundancy was lost and gid1a exhibited dwarfism that was strongly exacerbated by the loss of another GID1b receptor gene. These results suggest that multiple GA receptors contribute to phenotypic stability under environmental extremes.

植物赤霉素GA响应的多效性和复杂性多依赖于由受GA激活的GID1受体所介导的DELLA蛋白的靶向蛋白酶解。番茄基因组编码一个DELLA蛋白PRO和三个受体GID1a、GID1b1和GID1b2，这些可能参与了特异性的GA响应。在本文中，作者利用CRISPR-Cas9系统构建了一个gid1突变体，并且研究了该突变体在GA响应方面的影响。gid1三突植株十分矮小，并且对于GA完全不敏感。在最优生长条件下，这三个受体功能存在冗余，而且gid1单突植株的表型改变并不明显。在这三个受体中，GID1a对于萌发和生长的作用最为强烈。酵母双杂试验显示GID1a与PRO具有最高的亲和力。对于只有一个激活受体的株系的分析显示GID1a具有延长GA响应的独特作用，并且该功能只有在高剂量的时候达到饱和。当gid1突变体生长在环境不稳定的大田条件下，这些突变体植株的表型也不是很稳定，不同GID1蛋白的冗余性消失，同时gid1a突变体的矮化程度要比gid1b更加严重。本文的研究结果显示番茄中存在多个GA受体作用于极端环境条件下的表型稳定。