Cellulose perturbation has broad impacts on resource allocation in Arabidopsis thaliana putatively mediated by glycine rich peptides. Cellulose perturbation has broad impacts on resource allocation in Arabidopsis thaliana putatively mediated by glycine rich peptides

The interplay between plant chemistry and architecture was investigated using a pharmacological approach combined with mutant analysis. Due to the high abundance and essential role of cellulose in plant development and function, it was hypothesized that perturbation of cellulose biosynthesis would have far-reaching effects on plant chemistry and resource allocation. The impact of cellulose disruption was studied through comprehensive multiphase-NMR (CMP-NMR) using the Arabidopsis thaliana cellulose synthase mutant ectopic lignification1 (eli1). CMP-NMR confirmed several known metabolic impacts of cellulose disruption including increased lignification, increased starch production, and a shift from crystalline to amorphous cellulose. It also revealed unexpected metabolic impacts such as increased methanol production, increased seed-derived lipid content, and the presence of the peptide pentaglycine, which had not been previously observed in plants. It was further hypothesized that the metabolic impacts of cellulose disruption are mediated by one or more signal molecules that would be elevated in cellulose synthase mutants such as eli1. The presence of one or more signal molecules in eli1 that induce a lignification response was confirmed by exposing wild-type seedlings to ground tissue from eli1. Treatment of wild-type seedlings with pentaglycine suggested that the peptide may be at least partially responsible for mediating this response. A case is made for glycine rich proteins (GRPs) as the source of pentaglycine in vivo, and for wall associated kinases (WAKs) as receptors that trigger either developmental or defence responses through differential binding of intact GRPs and oligoglycine peptides. Overall design: Examination of two different genotypes (wild type and eli1) in the absence and presence of glucose, with two biological replicates

本研究采用药理学方法结合突变体分析，探究了植物化学组分与结构形态之间的相互作用。鉴于纤维素在植物生长发育与功能行使中含量丰富且发挥关键作用，研究假设纤维素生物合成受到扰动后，会对植物化学组分及资源分配产生深远影响。本研究以拟南芥（Arabidopsis thaliana）纤维素合酶突变体异位木质化1（ectopic lignification1, eli1）为材料，结合综合多相核磁共振（comprehensive multiphase-NMR, CMP-NMR）技术，探究纤维素破坏所产生的影响。CMP-NMR分析证实了纤维素破坏已知的数种代谢效应，包括木质化程度提升、淀粉合成增加，以及纤维素从晶态向非晶态的转变；同时还揭示了此前未在植物中观测到的意外代谢变化：甲醇生成量升高、种子来源脂质含量增加，以及五甘氨酸肽的出现。研究进一步假设，纤维素破坏所带来的代谢效应，由一种或多种在纤维素合酶突变体（如eli1）中含量升高的信号分子所介导。将野生型幼苗暴露于eli1的研磨组织中，证实了eli1中存在一种或多种可诱导木质化反应的信号分子。通过用五甘氨酸处理野生型幼苗的实验，表明该肽可能至少部分介导了这一反应。本研究提出，富含甘氨酸的蛋白（glycine rich proteins, GRPs）是体内五甘氨酸的来源，而细胞壁关联激酶（wall associated kinases, WAKs）作为受体，通过完整GRPs与寡甘氨酸肽的差异性结合，触发发育或防御反应。整体实验设计：设置两种基因型（野生型与eli1），分别在有葡萄糖和无葡萄糖的条件下开展实验，每组设置2次生物学重复。