Genetic analysis of mechanisms linking cell wall integrity with growth control in Arabidopsis

细胞壁物质代表了大多数植物中的主要碳水化合物组分。最近的研究已经确定了编码参与合成不同细胞壁组分的酶的基因，但细胞壁功能和组织的许多其他方面仍有待研究。我们最近已经表明，几个突变体的基因编码的酶合成糖注定纳入细胞壁多糖表现出强烈的糖依赖性的生长和发育表型在黑暗和淀粉水平升高。这些表型需要一种参与调节糖、激素和光反应的充分表征的蛋白质。我们还表明，细胞壁结构/组成的变化是最有可能负责观察到的表型。我们的目标是使用遗传筛选来定义这一途径的其他组成部分，并与已知的糖反应途径建立联系。这项研究的结果将可能首次确定植物细胞壁的组成和水平是根据碳水化合物的可用性来调节的。这些知识将有助于了解资源如何分配给细胞壁合成，也可能有助于设计将更多资源分配给细胞壁生物质的作物。了解植物细胞壁成分是如何控制的是目前高度相关的目标，因为细胞壁材料转化为生物燃料和化学原料的潜力。这一领域的主要研究目标是改变生物质作物如快速生长的杨柳、白杨和多年生禾本科植物的细胞壁组成。几项研究表明，试图改变细胞壁的组成会导致重大的，有些意想不到的细胞变化，如应激和防御反应的激活。这些然后导致细胞活性和细胞壁组成的不期望的变化。这些结果表明，试图改变细胞壁组成，例如调整细胞壁组成以更有效地降解，需要更多关于如何控制细胞壁组成的知识。这里描述的工作将增加这方面的知识，在模式植物拟南芥。有关基因的知识最终可能被用于改造生物质作物中细胞壁的控制，例如增加细胞壁多糖的水平。这些作物可以为燃料生产提供可持续和具有成本效益的来源，并通过更有效地利用全球碳循环来帮助缓解气候变化。

Cell wall materials represent the major carbohydrate component in most plants. Recent research has identified genes encoding enzymes involved in synthesising different cell wall components, but many other aspects of cell wall function and organisation remain to be investigated. We have recently shown that several mutants in genes encoding enzymes synthesising sugars destined for incorporation into cell wall polysaccharides exhibit strong sugar-dependent growth and developmental phenotypes in the dark and elevated starch levels. These phenotypes require a well characterised protein involved in regulating sugar, hormone and light responses. We also showed that changes in cell wall structure/composition are most likely responsible for the observed phenotypes. We aim to define other components of this pathway using genetic screens and establish links with known sugar- response pathways. The outcomes of this research will establish, possibly for the first time, that plant cell wall composition and levels are regulated in response to carbohydrate availability. This knowledge will provide an understanding of how resources are allocated to cell wall synthesis and may also help design crops that allocate more resources to cell wall biomass. Understanding how plant cell wall composition is controlled is a highly relevant objective at the moment because of the potential for converting cell wall material to biofuels and chemical feedstocks. A major research objective in this area is to alter cell wall composition in biomass crops such as rapidly growing willow, poplar and perennial grasses. Several studies show that attempts to alter cell wall composition lead to major, and somewhat unexpected, cellular changes such as activation of stress and defence responses. These then lead to undesirable changes in cell activity and cell wall composition. These results suggest that attempts to alter cell wall composition, for example to tailor cell wall composition for more efficient degradation, require a lot more knowledge about how the composition of the cell wall is controlled. The work described here will add to this knowledge in the model plant Arabidopsis. Knowledge of the genes involved might ultimately be used to engineer altered cell wall control in biomass crops, for example to increase levels of cell wall polysaccharides. These crops may provide sustainable and cost-effective sources for fuel production and help to ameliorate climate change by more effective use of the global carbon cycle.