Cloning and function analysis of DlWRKY9 gene in longan (Dimocarpus longan)

Dengwei JUE; Yuxin XIA; Qigao GUO; Huan LIU; Xuelian SANG

doi:10.15835/nbha50312916

Authors

Dengwei JUE Southwest University, College of Horticulture and Landscape, Chongqing, 400715; Chongqing University of Arts and Sciences, College of Landscape Architecture and Life Science, Yongchuan 402160, Chongqing (CN)
Yuxin XIA Chongqing University of Arts and Sciences, College of Landscape Architecture and Life Science, Yongchuan 402160, Chongqing (CN)
Qigao GUO Southwest University, College of Horticulture and Landscape, Chongqing, 400715 (CN)
Huan LIU Chongqing University of Arts and Sciences, College of Landscape Architecture and Life Science, Yongchuan 402160, Chongqing (CN)
Xuelian SANG Chongqing University of Arts and Sciences, College of Landscape Architecture and Life Science, Yongchuan 402160, Chongqing (CN) https://orcid.org/0000-0001-5975-063X

DOI:

https://doi.org/10.15835/nbha50312916

Keywords:

DlWRKY9, flowering, longan, transgenic Arabidopsis

Abstract

WRKY is one of the largest plant transcription factors (TFs) which is widely involved in plant growth, development, and responses to stresses. In the present study, a WRKY TF DlWRKY9 was cloned from longan (Dimocarpus longan). The coding sequence (CDS) of DlWRKY9 is 762 bp in length and encodes 253 amino acids. It has a typical WRKY domain and zinc finger structure which belongs to type IIa WRKY protein. The molecular weight of DlWRKY9 protein was 30.27kda and the theoretical isoelectric point (PI) was 5.24. It is an unstable hydrophilic protein. The secondary structure of DlWRKY9 protein consists of helical structure (17.39%), extended chain (8.70%) and other structures (turn and random coil) (73.91%). The amino acid sequence of DlWRKY9 protein had the highest similarity with DlWRKY9 (xp_006450293.1) of citrus Clementina. DlWRKY9 gene promoter elements contain light, abscisic acid, gibberellin, jasmonic acid and other response elements. The results of qRT-PCR showed that the relative expression level of DlWRKY9 gene in pericarp was higher, followed by young fruits and floral organs. Meanwhile, DlWRKY9 gene specifically down-regulated in the early stage of flower induction in ‘Sijimi’ (SJ) longan. The results of transient expression of Arabidopsis protoplasts showed that the fluorescence signal was mainly concentrated in the nucleus. Moreover, overexpression of DlWRKY9 in Arabidopsis promoted early flowering. These results provide useful information for revealing the biological roles of DlWRKY9 in longan and increase our understanding of the WRKY family in fruit trees.

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