Characterization of the Arabidopsis glycerophosphodiester phosphodiesterase (GDPD) family reveals a role of the plastid-localized AtGDPD1 in maintaining cellular phosphate homeostasis under phosphate starvation
Characterization of the Arabidopsis glycerophosphodiester phosphodiesterase (GDPD) family reveals a role of the plastid-localized AtGDPD1 in maintaining cellular phosphate homeostasis under phosphate starvation
复制标题
DOI：
10.1111/j.1365-313x.2011.04538.x
复制
发表时间：
2011-06-01
期刊：
影响因子：
7.2
通讯作者：
Huang, Jirong
中科院分区：
文献类型：
--
作者：
Cheng, Yuxiang;Zhou, Wenbin;Huang, Jirong
甘油磷酸二酯磷酸二酯酶（glycerophosphodiester phosphodiester，GDPD）是一种重要的酶，它能将甘油磷酸二酯水解为甘油3磷酸（glycerol 3-phosphate，G-3-P）和相应的醇类，在原核生物和真核生物的多种生理过程中发挥重要作用。然而，对GDPD在植物中的生理意义知之甚少。在这里，我们的特点是拟南芥GDPD家族，可分为典型的GDPD（AtGDPD 1 -6）和GDPD样（AtGDPDL 1 -7）亚家族。体外酶活性分析表明，AtGDPD 1和AtGDPDL 1可水解甘油磷酸甘油、甘油磷酸胆碱和甘油磷酸乙醇胺，但AtGDPD 1的最大酶活性远高于AtGDPDL 1。基因表达模式分析表明，所有的AtGDPD基因除了AtGDPD 4在花和角果转录活跃。此外，该基因家族在根、叶和茎中表现出重叠但可区分的表达模式，表明GDPD基因的功能冗余和特异性。AtGDPDs而不是AtGDPDLs被无机磷酸盐（P-i）饥饿上调。与野生型（WT）相比，AtGDPD 1的失活导致GDPD活性、G-3-P含量、P-i含量和幼苗生长速率仅在P-i饥饿条件下显著降低。然而，在P-1-剥夺幼苗的膜脂组成之间的AtGDPD 1敲除突变体和WT保持不变。因此，我们认为GDPD介导的脂质代谢途径可能参与了在P-i饥饿期间从磷脂释放P-i。
P>Glycerophosphodiester phosphodiesterase (GDPD), which hydrolyzes glycerophosphodiesters into sn-glycerol-3-phosphate (G-3-P) and the corresponding alcohols, plays an important role in various physiological processes in both prokaryotes and eukaryotes. However, little is known about the physiological significance of GDPD in plants. Here, we characterized the Arabidopsis GDPD family that can be classified into canonical GDPD (AtGDPD1-6) and GDPD-like (AtGDPDL1-7) subfamilies. In vitro analysis of enzymatic activities showed that AtGDPD1 and AtGDPDL1 hydrolyzed glycerolphosphoglycerol, glycerophosphocholine and glycerophosphoethanolamine, but the maximum activity of AtGDPD1 was much higher than that of AtGDPDL1 under our assay conditions. Analyses of gene expression patterns revealed that all AtGDPD genes except for AtGDPD4 were transcriptionally active in flowers and siliques. In addition, the gene family displayed overlapping and yet distinguishable patterns of expression in roots, leaves and stems, indicating functional redundancy as well as specificity of GDPD genes. AtGDPDs but not AtGDPDLs are up-regulated by inorganic phosphate (P-i) starvation. Loss-of-function of the plastid-localized AtGDPD1 leads to a significant decrease in GDPD activity, G-3-P content, P-i content and seedling growth rate only under P-i starvation compared with the wild type (WT). However, membrane lipid compositions in the P-i-deprived seedlings remain unaltered between the AtGDPD1 knockout mutant and WT. Thus, we suggest that the GDPD-mediated lipid metabolic pathway may be involved in release of P-i from phospholipids during P-i starvation.