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CsCuAOs associate with CsAMADH1 confer drought tolerance through putrescine-derived γ-aminobutyric acid accumulation in tea plants
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  • Kexin Zhang,
  • Yu Duan,
  • Fang Li,
  • Yu Cao,
  • Yiwen Chen,
  • Zhongwei Zou,
  • Qiang Shen,
  • WANPING FANG,
  • XUJUN ZHU
Kexin Zhang
Nanjing Agricultural University College of Horticulture
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Yu Duan
Nanjing Agricultural University College of Horticulture
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Fang Li
Nanjing Agricultural University College of Horticulture
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Yu Cao
Nanjing Agricultural University College of Horticulture
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Yiwen Chen
Nanjing Agricultural University College of Horticulture
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Zhongwei Zou
University of Manitoba Department of Plant Science
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Qiang Shen
Guizhou Provincial Academy of Agricultural Sciences
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WANPING FANG
Nanjing Agricultural University College of Horticulture
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XUJUN ZHU
Nanjing Agricultural University College of Horticulture

Corresponding Author:[email protected]

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Abstract

Polyamines are potential source of γ-aminobutyric acid (GABA) in plants under abiotic stress. However, the correlation between polyamine degradation and GABA accumulation in tea plants exposed to drought stress is unclear. In the present study, the contents of GABA and putrescine in tea leaves were increased significantly under drought stress, but the glutamate level did not change. At the same time, five copper-containing amine oxidase ( CuAO) and eight aminoaldehyde dehydrogenase ( AMADH) genes involved in putrescine-derived GABA pathway were identified from Tea Plant Information Archive. Expression analysis indicated that CsCuAO1, CsCuAO3, as well as CsAMADH1 were induced to play important function in response to exogenous putrescine or under drought stress. Thus, the three genes were cloned and their soluble recombinant proteins were produced in Escherichia coli. The catalytic efficiency, the pH and temperature optima of them were determined. CsCuAOs and CsAMADH1 exhibited indispensable function in the GABA production from putrescine in vitro. Subcellular localization assays indicated that CsAMADH1 was localized in plastid, while both CsCuAO1 and CsCuAO3 were localized in peroxisome. In addition, the synergistic effects of CsCuAOs and CsAMADH1 were investigated by transient co-expression system in Nicotiana benthamiana. The overexpression of CsAMADH1 lines in Arabidopsis showed increased GABA level supplemented with exogenous putrescine. Our data suggests that these three genes participate the GABA production through putrescine degradation in tea plants that associate with the response to drought stress.