Isolation and analysis of a-expansin genes in the tree Anthocephalus chinensis (Rubiaceae)

• Published in: Genetics and molecular research 2013-01, Vol.12 (2), p.1061-1073
• Main Authors: Ouyang, K X, Liu, M Q, Pian, R Q, Liu, S S, Chen, X Y
• Format: Article
• Language: English
• Subjects: Anthocephalus chinensis; Rubiaceae
• ISSN: 1676-5680; 1676-5680
• DOI: 10.4238/2013.April.10.2

Expansins are cell wall-associated proteins that induce wall extension and relax stress by disrupting noncovalent bonds between cellulose microfibrils and cross-linking glycan chains, thereby promoting wall creep. Anthocephalus chinensis is a very fast-growing economically important tree found mainly in South Asia. Sixteen cDNAs, designated AcEXPA1 to AcEXPA16 (GenBank accession Nos. FJ417847, JF922686-JF922700) with corresponding genomic DNA sequences (GenBank accession Nos. GQ228823, JF922701-JF922715), were isolated by amplifying conserved domain binding with genomic walking and RACE techniques from four differential growth tissues in A. chinensis. These alpha -expansin homologues were highly conserved in size and sequence; they had the same sequence structures as an N-terminal signal peptide, three exons and two introns. Their amino acid alignment showed that A. chinensis expansin genes are divided into three subgroups: A, B and C. This study is the first report on expansin genes from A. chinensis. It will be used for a tissue-specific expression model and for studying the relationship between expansin genes, growth rate and wood quality of the xylem in this fast-growing tree.