Involvement of auxin signaling mediated by IAA14 and ARF7/19 in membrane lipid remodeling during phosphate starvation
Involvement of auxin signaling mediated by IAA14 and ARF7/19 in membrane lipid remodeling during phosphate starvation
复制标题
DOI：
10.1007/s11103-009-9589-4
复制
发表时间：
2010-03-01
影响因子：
5.1
通讯作者：
Ohta, Hiroyuki
中科院分区：
文献类型：
--
作者：
Narise, Takafumi;Kobayashi, Koichi;Ohta, Hiroyuki
在高等植物中，磷(PI)缺乏导致磷脂被非磷糖脂双半乳糖基二酰甘油(DGDG)和磺基喹诺酮基二酰甘油(SQDG)取代。参与膜脂重塑的基因在PI饥饿时被共激活，但指导这一反应的机制在很大程度上尚不清楚。在此之前，我们曾报道过在PI饥饿过程中生长素运输对DGDG积累的重要性。为了了解生长素信号在拟南芥膜脂重塑中的作用，我们分析了生长素信号抑制因子IAA14的功能获得突变体SLR-1和生长素反应因子ARF7和ARF19的功能缺失突变体arf7arf19。在SLR-1和Arf7arf19中，PI应激诱导的DGDG和SQDG的积聚被抑制。在PI缺乏条件下，这些突变体中糖脂合成酶和磷脂酶基因的上调减少，表明IAA14和ARF7/19在转录水平上影响膜脂重塑。在SLR-1和arf7arf19中，依赖于PI胁迫的非蛋白编码基因IPS1的诱导也较低，而另一种PI胁迫诱导的非蛋白编码基因AT4的表达、花青素的积累和磷酸二酯酶的诱导在新梢中并没有减少。在SLR-1和arf7arf19中，即使在缺PI的条件下也能观察到较高的游离PI含量，这表明这些突变体在PI饥饿过程中的PI动态平衡发生了变化。这些结果证明了IAA14和ARF7/19介导的生长素信号对拟南芥低PI适应的需要。
In higher plants, phosphate (Pi) deficiency induces the replacement of phospholipids with the nonphosphorous glycolipids digalactosyldiacylglycerol (DGDG) and sulfoquinovosyldiacylglycerol (SQDG). Genes involved in membrane lipid remodeling are coactivated in response to Pi starvation, but the mechanisms that guide this response are largely unknown. Previously, we reported the importance of auxin transport for DGDG accumulation during Pi starvation. To understand the role of auxin signaling in Arabidopsis membrane lipid remodeling, we analyzed slr-1, a gain-of-function mutant of IAA14 (a repressor of auxin signaling), and arf7arf19, a loss-of-function mutant of auxin response factors ARF7 and ARF19. In slr-1 and arf7arf19, Pi stress-induced accumulation of DGDG and SQDG was suppressed. Reduced upregulation of glycolipid synthase and phospholipase genes in these mutants under Pi-deficient conditions indicates that IAA14 and ARF7/19 affect membrane lipid remodeling at the level of transcription. Pi stress-dependent induction of a non-protein-coding gene, IPS1, was also lower in slr-1 and arf7arf19, whereas expression of At4 (another Pi stress-inducible non-protein-coding gene), anthocyanin accumulation, and phosphodiesterase induction were not reduced in the shoot. High free Pi content was observed in slr-1 and arf7arf19 even under Pi-deficient conditions, suggesting that Pi homeostasis during Pi starvation is altered in these mutants. These results demonstrate a requirement of auxin signaling mediated by IAA14 and ARF7/19 for low-Pi adaptation in Arabidopsis.