AUTHOR=Huang Wei , Ma Danni , Hao Xulei , Li Jia , Xia Li , Zhang E. , Wang Pu , Wang Mingle , Guo Fei , Wang Yu , Ni Dejiang , Zhao Hua 

TITLE=CsATG101 Delays Growth and Accelerates Senescence Response to Low Nitrogen Stress in Arabidopsis thaliana

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.880095

DOI=10.3389/fpls.2022.880095

ISSN=1664-462X

ABSTRACT=<p>For tea plants, nitrogen (N) is a foundational element and large quantities of N are required during periods of roundly vigorous growth. However, the fluctuation of N in the tea garden could not always meet the dynamic demand of the tea plants. Autophagy, an intracellular degradation process for materials recycling in eukaryotes, plays an important role in nutrient remobilization upon stressful conditions and leaf senescence. Studies have proven that numerous autophagy-related genes (<italic>ATGs</italic>) are involved in N utilization efficiency in <italic>Arabidopsis thaliana</italic> and other species. Here, we identified an <italic>ATG</italic> gene, <italic>CsATG101</italic>, and characterized the potential functions in response to N in <italic>A. thaliana</italic>. The expression patterns of <italic>CsATG101</italic> in four categories of aging gradient leaves among 24 tea cultivars indicated that autophagy mainly occurred in mature leaves at a relatively high level. Further, the <italic>in planta</italic> heterologous expression of <italic>CsATG101</italic> in <italic>A. thaliana</italic> was employed to investigate the response of <italic>CsATG101</italic> to low N stress. The results illustrated a delayed transition from vegetative to reproductive growth under normal N conditions, while premature senescence under N deficient conditions in transgenic plants vs. the wild type. The expression profiles of 12 <italic>AtATGs</italic> confirmed the autophagy process, especially in mature leaves of transgenic plants. Also, the relatively high expression levels for <italic>AtAAP1</italic>, <italic>AtLHT1</italic>, <italic>AtGLN1;1</italic>, and <italic>AtNIA1</italic> in mature leaves illustrated that the mature leaves act as the source leaves in transgenic plants. Altogether, the findings demonstrated that <italic>CsATG101</italic> is a candidate gene for improving annual fresh tea leaves yield under both deficient and sufficient N conditions <italic>via</italic> the autophagy process.</p>