Two ADP-glucose pyrophosphorylase subunits, OsAGPL1 and OsAGPS1, modulate phosphorus homeostasis in rice
Two ADP-glucose pyrophosphorylase subunits, OsAGPL1 and OsAGPS1, modulate phosphorus homeostasis in rice
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两个 ADP-葡萄糖焦磷酸化酶亚基 OsAGPL1 和 OsAGPS1 调节水稻中的磷稳态
DOI：
10.1111/tpj.14998
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发表时间：
2020-11-06
期刊：
影响因子：
7.2
通讯作者：
Xu, Guohua
中科院分区：
文献类型：
--
作者：
Meng, Qi;Zhang, Wenqi;Xu, Guohua
植物对磷（Pi）饥饿胁迫的适应性反应包括碳水化合物（糖和淀粉）的积累。然而，是否改变内源性碳水化合物的配置文件可以反过来影响植物磷饥饿反应仍然广泛未探索。在这里，两个基因编码的ADP-葡萄糖焦磷酸化酶（AGP）的大小亚基在水稻（Oryza sativa），AGP大亚基1（AGPL 1）和AGP小亚基1（AGPS 1），功能上的特点是关于维持磷（P）的稳态和调节磷饥饿信号。AGPL 1和AGPS 1对缺氮和缺磷都有显著的正响应，除根的分生组织和成熟区外，几乎在所有组织中都有表达。AGPS 1和AGPL 1在叶绿体中相互作用，催化淀粉合成的限速步骤。与野生型植株相比，低氮（LN）和低磷（LP）引发的叶片淀粉积累在agpl 1，agps 1和apgl 1 agps 1突变体中受损。相反，AGPL 1和/或AGPS 1的突变导致在对照和LN条件下叶鞘和根中的主要糖，蔗糖的含量增加。此外，在控制和LN条件下，但不是LP条件下的突变体中的Pi积累增强。值得注意的是，LN诱导的对Pi积累的抑制由于AGPL 1和/或AGPS 1的突变而受损。此外，增加的Pi积累伴随着OsSPX 2的特异性抑制和几个Pi转运蛋白基因的激活。这些结果表明，碳水化合物的平衡水平是至关重要的维持植物磷稳态。
Plant acclimatory responses to phosphate (Pi) starvation stress include the accumulation of carbohydrates, namely sugar and starch. However, whether altered endogenous carbohydrate profile could in turn affect plant Pi starvation responses remains widely unexplored. Here, two genes encoding the large and small subunits of an ADP-glucose pyrophosphorylase (AGP) in rice (Oryza sativa), AGP Large Subunit 1 (AGPL1) and AGP Small Subunit 1 (AGPS1), were functionally characterized with regard to maintenance of phosphorus (P) homeostasis and regulation of Pi starvation signaling. AGPL1 and AGPS1 were both positively responsive to nitrogen (N) or Pi deprivation, and expressed in almost all the tissues except in the meristem and mature zones of root. AGPL1 and AGPS1 physically interacted in chloroplast, and catalyzed the rate-limiting step of starch biosynthesis. Low-N- (LN) and low-Pi (LP)-triggered starch accumulation in leaves was impaired in agpl1, agps1 and apgl1 agps1 mutants compared with the wild-type plants. By contrast, mutation of AGPL1 and/or AGPS1 led to an increase in the content of the major sugar, sucrose, in leaf sheath and root under control and LN conditions. Moreover, the Pi accumulation was enhanced in the mutants under control and LN conditions, but not LP conditions. Notably, the LN-induced suppression of Pi accumulation was compromised attributed to the mutation of AGPL1 and/or AGPS1. Furthermore, the increased Pi accumulation was accompanied by the specific suppression of OsSPX2 and activation of several Pi transporter genes. These results indicate that a balanced level of carbohydrates is vital for maintaining plant P homeostasis.