Open AccessCharacterization of a gene from chromosome 1B encoding the large subunit of ADPglucose pyrophosphorylase from wheat: evolutionary divergence and differential expression of Agp2 genes between leaves and developing endosperm
Author(s) -
Thorneycroft David,
Hosein Felicia,
Thangavelu Madan,
Clark Joanna,
Vizir Igor,
Burrell Michael M.,
Ainsworth Charles
Publication year - 2003
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1046/j.1467-7652.2003.00025.x
Subject(s) - biology , endosperm , gene , aleurone , genetics , complementary dna , genomic dna , reporter gene , gus reporter system , coding region , gene expression , microbiology and biotechnology , cdna library , genomic library , peptide sequence
Summary A full‐length genomic clone containing the gene encoding the large subunit of the ADPglucose pyrophosphorylase ( Agp2 ), was isolated from a genomic library prepared from etiolated shoots of hexaploid wheat ( Triticum aestivum L., cv, Chinese Spring). The coding region of this gene is identical to one of the cDNA clones previously isolated from a developing wheat grain cDNA library and is therefore an actively transcribed gene. The sequence represented by the cDNA spans 4.8 kb of the genomic clone and contains 15 introns. 2852 bp of DNA flanking the transcription start site of the gene was cloned upstream of the GUS (β‐glucuronidase) reporter gene. This Agp2 ::GUS construct and promoter deletions were used to study the pattern of reporter gene expression in both transgenic tobacco and wheat plants. Histochemical analysis of GUS expression in transgenic tobacco demonstrated that the reporter gene was expressed in guard cells of leaves and throughout the seed. In transgenic wheat, reporter gene expression was confined to the endosperm and aleurone with no expression in leaves. The cloned Agp2 gene was located to chromosome 1B by gene‐specific PCR with nullisomic–tetrasomic lines. Northern analysis demonstrated that the Agp2 genes are differentially expressed in leaves and developing endosperm; while all three classes of Agp2 genes are transcribed in developing wheat grain endosperm, only one is transcribed in leaves. The differences between the Agp2 genes are discussed in relation to the evolution of hexaploid wheat.