Regulation of DELLA Activity by Post-Translational Modifications and Complex Formation in Arabidopsis

赤霉素（GA）是一种重要的植物生长激素，在高等植物中具有促进种子萌发、叶片膨大、茎伸长和花发育的作用。 在60年代的绿色革命中培育的小麦和水稻矮秆品种显著地提高了粮食产量。 最近的研究表明，这些品种的GA生产或GA的反应，说明这种激素在调节植物发育和农业中的重要作用进行了修改。 GA促进的生长和发育是由DELLA蛋白调节的，DELLA蛋白是GA反应的主要负调节因子（阻遏物）。 PI实验室（由NSF资助）最近的工作已经取得了改变性的发现，即GA受体直接靶向DELLA进行降解。 也有证据表明DELLA蛋白活性的多层调节。 DELLA是一种主要的生长抑制因子，它不仅整合GA信号，而且整合其他激素信号以及生物和非生物信号（如光照条件、病原体、寒冷和干旱胁迫）。 尽管DELLA在调节植物生长中起着如此关键的作用，但关于DELLA活性是如何调节的知之甚少。 初步数据支持蛋白质修饰在调节DELLA功能中起重要作用。 本项目的未来研究将阐明所涉及的分子机制。更广泛的影响：DELLA蛋白在拟南芥和许多作物中功能高度保守。 例如，半矮秆小麦品种，绿色革命的重要组成部分，在编码DELLA蛋白的Rht基因座中含有突变。 这项研究可能会对提高农作物质量产生更广泛的影响。 此外，一名博士后研究员和四名本科生将在这个项目中获得研究经验。 这项研究的结果将被纳入杜克大学的三门本科课程。 学生将学会欣赏如何从模型植物系统的研究中获得的信息可以用来改善农业实践和造福社会。

Gibberellin (GA) is an important plant growth hormone, which promotes seed germination, leaf expansion, stem elongation and flower development in higher plants. The dwarf cultivars of wheat and rice developed during the Green Revolution in the 60s remarkably increased the grain yields. Recent studies revealed that these cultivars are modified in their GA production or responses to GA, illustrating the important role of this hormone in regulating plant development and in agriculture. GA-promoted growth and development is modulated by DELLA proteins, which are major negative regulators (repressors) of GA responses. Recent work in the PI's laboratory (funded by NSF) has made transforming findings that the GA receptor directly targets DELLA for degradation. There is also evidence suggesting multiple layers of regulation on the DELLA protein activity. DELLA is a master growth repressor, which integrates not only the GA signal, but also other hormone signals as well as biotic and abiotic signals (such as light conditions, pathogens, cold and drought stresses). Although DELLA plays such a pivotal role in regulating plant growth, very little is known about how DELLA activity is regulated. Preliminary data support that protein modifications play important roles in modulating DELLA function. Future research in this project will elucidate the molecular mechanisms involved. Broader Impacts:DELLA proteins are functionally highly conserved in Arabidopsis and in many crop plants. For example, the semi-dwarf wheat cultivars, an essential component of the Green Revolution, contain mutations in the Rht loci that encode DELLA proteins. This study will likely to have a broader impact in improving quality of agricultural crops. In addition, a postdoctoral fellow and four undergraduate students will gain research experience in this project. The findings of this study will be incorporated into three undergraduate courses at Duke University. Students will learn to appreciate how the information gained from studies in a model plant system can be used to improve agriculture practice and benefit society.