biologia plantarum

Biologia plantarum 59:645-653, 2015 | DOI: 10.1007/s10535-015-0532-z

Molecular cloning and characterization of the chloride channel gene family in trifoliate orange

Q. J. Wei^1,2, Q. Q. Gu², N. N. Wang¹, C. Q. Yang¹, S. A. Peng^1,*

¹ College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, P.R. China

² College of Agronomy, Jiangxi Agricultural University, Nanchang, P.R. China

Chloride channels (CLCs) play pivotal roles in plant development and anion transport. However, little research has been conducted about the CLC in fruit-bearing plants. Here we provide an insight into the evolution and expression patterns of CLC gene family members in various tissues of trifoliate orange [Poncirus trifoliata (L.) Raf.] and their responses to several treatments. Genome-wide analysis identified six PtrCLC genes. The predicted proteins had similar numbers of amino acids, but shared a low sequence identity. Phylogenetic analysis revealed that PtrCLC were classified into two separate subgroups, and PtrCLC4 and PtrCLC6 in subgroup II were more closely related to bacterial CLCs. Sequence comparison with EcCLCA from Escherichia coli reveals that PtrCLC showed amino acid divergence in anion selectivity of CLC proteins. Real time qPCR analysis shows that PtrCLC genes, particularly PtrCLC6, preferentially expressed in leaves. Nitrogen deficiency irreversibly inhibited expression of PtrCLC genes except for PtrCLC1. In contrast, NaCl stress profoundly induced expression of PtrCLC genes, particularly PtrCLC2 and PtrCLC4, both of which were also upregulated by ABA treatment. The results presented here provide a solid foundation for a future functional research on citrus CLC genes.

Keywords: abscisic acid; gene expression; nitrogen supply; Poncirus trifoliata; salt stress; sequence analysis

Subjects: molecular cloning; chloride channel; anion transport; nitrogen supply; salinity; amino acid sequence; phylogenetic tree; trifoliate orange

Received: August 18, 2014; Revised: February 26, 2015; Accepted: March 4, 2015; Published: December 1, 2015  Show citation