Glycosyl hydrolases of cell wall are induced by sugar starvation in Arabidopsis
Glycosyl hydrolases of cell wall are induced by sugar starvation in Arabidopsis
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DOI：
10.1093/pcp/pcm009
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发表时间：
2007-03-01
影响因子：
4.9
通讯作者：
Koizumi, Nozomu
中科院分区：
文献类型：
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作者：
Lee, Eun-Jeong;Matsumura, Yasuhiro;Koizumi, Nozomu
糖饥饿诱导了3个拟南芥基因编码β -半乳糖苷酶（At5g56870）、β -木糖苷酶（At5g49360）和β -葡萄糖苷酶（At3g60140）。推导出的蛋白分别属于糖基水解酶家族35、3和1。它们被预测为分泌蛋白，在基于氨基酸相似性的细胞壁多糖修饰中起作用。At5g56870编码的β -半乳糖苷酶经质谱分析鉴定为悬浮细胞培养基中的分泌蛋白。这种蛋白在糖缺乏的条件下被特异性抗体检测到。这些基因的诱导在半乳糖、木糖和葡萄糖以及蔗糖培养的悬浮细胞中受到抑制。在植物中，当光合作用受到抑制时，检测到基因的表达和蛋白质的积累。糖饥饿期间抗半乳糖的糖基水解酶活性也增加。糖饥饿使离体叶片果胶中单糖和半纤维素含量降低。这些发现表明，细胞壁除了为植物体提供物理支持外，还可能具有碳储存的功能。
Three Arabidopsis genes encoding a putative beta-galactosidase (At5g56870), beta-xylosidase (At5g49360) and beta-glucosidase (At3g60140) are induced by sugar starvation. The deduced proteins belong to the glycosyl hydrolase families 35, 3 and 1, respectively. They are predicted to be secretory proteins that play roles in modification of cell wall polysaccharides based on amino acid similarity. The beta-galactosidase encoded by At5g56870 was identified as a secretory protein in culture medium of suspension cells by mass spectrometry analysis. This protein was specifically detected under sugar-starved conditions with a specific antibody. Induction of these genes was repressed in suspension cells grown with galactose, xylose and glucose, as well as with sucrose. In planta, expression of the genes and protein accumulation were detected when photosynthesis was inhibited. Glycosyl hydrolase activity against galactan also increased during sugar starvation. The amount of monosaccharide in pectin and hemicellulose in detached leaves decreased in response to sugar starvation. These findings suggest that the cell wall may function as a storage reserve of carbon in addition to providing physical support for the plant body.