Identification and Partial Characterization of an Alanine Aminotransferase Gene CsAlaAT2 in Response to Shade in Tea (Camellia sinensis)

Autor: Yuanda Li, Qinzheng Xiang, Xiuxiu Zhao, Jinhe Wang, Min Li, Wenzhen Chen
Rok vydání: 2020
Předmět:
Zdroj: Journal of Plant Biology. 64:23-33
ISSN: 1867-0725
1226-9239
DOI: 10.1007/s12374-020-09273-3
Popis: Alanine contributes to the taste and nutritional quality of tea and is an important member of alanine metabolism catalyzed by alanine aminotransferase (AlaAT, EC 2.6.1.2). However, the molecular mechanism underlying alanine metabolism in tea plants has not been fully elucidated. In this study, an increase in enzyme activity of AlaAT2 was detected in vitro, and the alanine aminotransferase activity was higher level in leaves than that in other tissues of tea plant, while the CsAlaAT2 transcription was high in leaves and root. Using phylogenetic analysis, an alanine aminotransferase gene CsAlaAT2 was identified as a member of group C, which was located in the mitochondrion. Additionally, the molecular mass of CsAlaAT2 protein was found to be approximately 53 kDa by SDS-PAGE and western blotting. The CsAlaAT2 expression level and the alanine content in photosynthetic tissues increased in response to the shade treatment. Furthermore, the involvement of CsAlaAT2 in alanine biosynthesis was confirmed based on transient suppression assays in tea leaves, and the alanine content and CsAlaAT2 transcript level decreased when CsAlaAT2 expression was suppressed in tea leaves. Thus, this study suggests that CsAlaAT2 is essential for the alanine metabolism in tea plants grown and its response to shade.
Databáze: OpenAIRE
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