Overexpression of ATG8 in Arabidopsis Stimulates Autophagic Activity and Increases Nitrogen Remobilization Efficiency and Grain Filling
Overexpression of ATG8 in Arabidopsis Stimulates Autophagic Activity and Increases Nitrogen Remobilization Efficiency and Grain Filling
复制标题
DOI：
10.1093/pcp/pcy214
复制
发表时间：
2019-02-01
影响因子：
4.9
通讯作者：
Masclaux-Daubresse, Celine
中科院分区：
文献类型：
--
作者：
Chen, Qinwu;Soulay, Fabienne;Masclaux-Daubresse, Celine
玉米和拟南芥中的自噬敲除突变体在氮（N）再循环中受损，并且表现出降低的N向其种子的再动员水平。因此，确定较高的自噬活性是否可以反过来提高N再动员效率和种子蛋白质含量，以及在什么情况下。由于自噬机制涉及许多基因，其中18个对于核心机制是重要的，因此检查了操纵哪个AUTOPHAGY（ATG）基因以增加自噬的选择。我们选择ATG8过表达，因为已经表明该基因可以增加酵母中自噬体的大小和自噬活性。我们在这里报告的结果是原创的，因为它们首次表明，增加植物中ATG8基因的表达会增加自噬体的数量并促进自噬活性。更重要的是，我们的数据表明，当在全硝酸盐条件下培养时，已知由于从土壤中吸收足够的N而抑制N再活化，但是通过在泛素启动子的控制下过表达ATG8基因组序列，N再活化效率可以急剧且显著地增加。我们表明，过表达提高了种子N%，同时减少了N浪费在其干燥的遗骸。此外，我们表明，过表达ATG8不修改营养生物量或收获指数，因此不影响植物发育。
Autophagy knock-out mutants in maize and in Arabidopsis are impaired in nitrogen (N) recycling and exhibit reduced levels of N remobilization to their seeds. It is thus impoortant to determine whether higher autophagy activity could, conversely, improve N remobilization efficiency and seed protein content, and under what circumstances. As the autophagy machinery involves many genes amongst which 18 are important for the core machinery, the choice of which AUTOPHAGY (ATG) gene to manipulate to increase autophagy was examined. We choose ATG8 overexpression since it has been shown that this gene could increase autophagosome size and autophagic activity in yeast. The results we report here are original as they show for the first time that increasing ATG8 gene expression in plants increases autophagosome number and promotes autophagy activity. More importantly, our data demonstrate that, when cultivated under full nitrate conditions, known to repress N remobilization due to sufficient N uptake from the soil, N remobilization efficiency can nevertheless be sharply and significantly increased by overexpressing ATG8 genomic sequences under the control of the ubiquitin promoter. We show that overexpressors have improved seed N% and at the same time reduced N waste in their dry remains. In addition, we show that overexpressing ATG8 does not modify vegetative biomass or harvest index, and thus does not affect plant development.