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背景：Nitrogen (N) is a major nutrition element for tea plant. However, application of high levels of N negatively causes environmental problems. Therefore, improved N use efficiency (NUE) of tea plant will be highly desirable and crucial for sustainable tea cultivation. Autophagy plays a central role in N recycling and holds potential to improve N utilization, and many AuTophaGy-related genes (ATGs) are involved in the autophagy process. 結(jié)果：Here, CsATG3a was identified from Camellia sinensis, and the functions involved in N utilization was characterized in arabidopsis (Arabidopsis thaliana). The transcript level of CsATG3a in tea leaves increases with their maturity. Relative to the wild type (WT) arabidopsis, two CsATG3a-overexpressing (CsATG3a-OE) lines exhibited improved vegetative growth, delayed reproductive stage, and upregulated expression of AtATGs (AtATG3, AtATG5 and AtATG8b) in a low N (LN) hydroponic condition. The expression levels of AtNRT1.1, AtNRT2.1, AtNRT2.2, AtAMT1.1 and AtAMT1.3 for N uptake and transport in roots were all significantly higher in CsATG3a-OE lines compared with those in the WT under LN. Meanwhile, the overexpression of CsATG3a in arabidopsis also increased N and dry matter allocation into both rosette leaves and roots under LN. Additionally, compared with WT, improved HI (harvest index), NHI (N harvest index), NUtE (N utilization efficiency) and NUE (N use efficiency) of CsATG3a-OE lines were further confirmed in a low-N soil cultured experiment. 結(jié)論：Together, these results concluded that CsATG3a is involved in N recycling and enhances tolerance to LN, indicating that CsATG3a holds potential promise to improve NUE in tea plant.. 氮（N）是茶樹的主要營養(yǎng)元素。然而，施用高水平的氮會(huì)造成環(huán)境問題。因此，提高茶樹的氮利用效率（NUE）對于可持續(xù)的茶樹栽培是非常重要的。自噬在氮循環(huán)中起著核心作用，并具有提高氮利用率的潛力，許多自噬相關(guān)基因（ATG）參與了自噬過程。在這里，CsATG3a從茶樹中鑒定出來，并且在擬南芥中表征了N利用的功能。茶葉中CsATG3a的轉(zhuǎn)錄水平隨著成熟度的增加而增加。相對于野生型（WT）擬南芥，在低氮（LN）水培條件下，兩個(gè)CsATG3a過表達(dá)（CsATG3a-OE）系表現(xiàn)出改善的營養(yǎng)生長、延遲的生殖階段和上調(diào)的AtATG（AtATG3、AtATG5和AtATG8b）表達(dá)。與LN下的WT相比，CsATG3a-OE系中根系中氮吸收和運(yùn)輸?shù)腁tNRT1.1、AtNRT2.1、AtNRT2.2、AtAMT1.1和AtAMT1.3的表達(dá)水平均顯著升高。同時(shí)，CsATG3a在擬南芥中的過表達(dá)也增加了氮和干物質(zhì)在LN下分配到蓮座葉和根中。此外，與WT相比，在低氮土壤培養(yǎng)實(shí)驗(yàn)中，CsATG3a OE系的HI（收獲指數(shù)）、NHI（N收獲指數(shù)），NUtE（N利用效率）和NUE（N使用效率）得到了進(jìn)一步證實(shí)。總之，這些結(jié)果得出結(jié)論，CsATG3a參與了氮的循環(huán)，并增強(qiáng)了對LN的耐受性，這表明CsATG3a具有改善茶樹NUE的潛力。
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