G6PD5 在拟南芥种子萌发和根生长过程中 ABA 反应中的作用。

Involvement of G6PD5 in ABA response during seed germination and root growth in Arabidopsis.

机构信息

Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, People's Republic of China.

State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai, 810016, People's Republic of China.

出版信息

BMC Plant Biol. 2019 Jan 30;19(1):44. doi: 10.1186/s12870-019-1647-8.

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PDH or G6PD) functions in supply of NADPH, which is required for plant defense responses to stresses. However, whether G6PD functions in the abscisic acid (ABA) signaling pathway remains to be elucidated. In this study, we investigated the involvement of the cytosolic G6PD5 in the ABA signaling pathway in Arabidopsis.

RESULTS

We characterized the Arabidopsis single null mutant g6pd5. Phenotypic analysis showed that the mutant is more sensitive to ABA during seed germination and root growth, whereas G6PD5-overexpressing plants are less sensitive to ABA compared to wild type (WT). Furthermore, ABA induces excessive accumulation of reactive oxygen species (ROS) in mutant seeds and seedlings. G6PD5 participates in the reduction of HO to HO in the ascorbate-glutathione cycle. In addition, we found that G6PD5 suppressed the expression of Abscisic Acid Insensitive 5 (ABI5), the major ABA signaling component in dormancy control. When G6PD5 was overexpressed, the ABA signaling pathway was inactivated. Consistently, G6PD5 negatively modulates ABA-blocked primary root growth in the meristem and elongation zones. Of note, the suppression of root elongation by ABA is triggered by the cell cycle B-type cyclin CYCB1.

CONCLUSIONS

This study showed that G6PD5 is involved in the ABA-mediated seed germination and root growth by suppressing ABI5.

背景

葡萄糖-6-磷酸脱氢酶（G6PDH 或 G6PD）的功能是提供 NADPH，这是植物应对胁迫的防御反应所必需的。然而，G6PD 是否在脱落酸（ABA）信号通路中发挥作用仍有待阐明。在这项研究中，我们研究了质体 G6PD5 在拟南芥 ABA 信号通路中的作用。

结果

我们对拟南芥的单突变体 g6pd5 进行了表征。表型分析表明，该突变体在种子萌发和根生长过程中对 ABA 更为敏感，而 G6PD5 过表达植物对 ABA 的敏感性比野生型（WT）低。此外，ABA 诱导突变体种子和幼苗中活性氧（ROS）的过度积累。G6PD5 参与了抗坏血酸-谷胱甘肽循环中 HO 到 HO 的还原。此外，我们发现 G6PD5 抑制了 Abscisic Acid Insensitive 5（ABI5）的表达，ABI5 是休眠控制中主要的 ABA 信号成分。当 G6PD5 过表达时，ABA 信号通路被失活。一致地，G6PD5 负调控 ABA 阻断的分生组织和伸长区的主根生长。值得注意的是，ABA 引发的根伸长抑制是由细胞周期 B 型细胞周期蛋白 CYCB1 触发的。