Molecular changes associated with the setting up of secondary growth in aspen

• Published in: Journal of experimental botany Vol. 56; no. 418; pp. 2211 - 2227
• Main Authors: van Raemdonck, Damien, Pesquet, Edouard, Cloquet, Sophie, Beeckman, Hans, Boerjan, Wout, Goffner, Deborah, El Jaziri, Mondher, Baucher, Marie
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.08.2005; Oxford Publishing Limited (England)
• Subjects: Amino Acid Sequence; amino acid sequences; Amino acids; amplified fragment length polymorphism; AP2/ERF; aspen; Biological and medical sciences; cambium; cDNA-AFLP; Cell walls; Complementary DNA; DNA, Complementary - metabolism; DNA, Plant - metabolism; forest trees; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Profiling; Gene Expression Regulation, Developmental - physiology; Gene Expression Regulation, Plant - physiology; Genes; Genes. Genome; hybrids; in situ RT-PCR; interspecific hybridization; messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; nucleotide sequences; Phloem; plant development; Plant Proteins; Plant Stems - growth & development; Plant Stems - metabolism; plant vascular system; Plants; Populus - growth & development; Populus - metabolism; Populus alba; Populus tremula; regulator genes; regulatory proteins; Research Papers; Reverse transcriptase polymerase chain reaction; RING-H2; Scaffolds; secondary growth; Sequence Alignment; Sequence Homology, Amino Acid; transcription factors; tree growth; vascular cambium; Xylem; AP2/ERF; Xylem; Growth; in situ RT-PCR; aspen; secondary growth; Stem; cDNA-AFLP; Phloem; Complementary DNA; Gene; Development; vascular cambium; Cambium; RING-H2; Transcription factor; Polymorphism
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/eri221

Vascular secondary growth results from the activity of the vascular cambium, which produces secondary phloem and secondary xylem. By means of cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis along aspen stems, several potential regulatory genes involved in the progressive transition from primary to secondary growth were identified. A total of 83 unique transcript-derived fragments (TDFs) was found to be differentiated between the top and the bottom of the stem. An independent RT-PCR expression analysis validated the cDNA-AFLP profiles for 19 of the TDFs. Among these, seven correspond to new genes encoding putative regulatory proteins. Emphasis was laid upon two genes encoding, respectively, an AP2/ERF-like transcription factor (PtaERF1) and a RING finger protein (PtaRHE1); their differential expression was further confirmed by reverse northern analysis. In situ RT-PCR revealed that PtaERF1 was expressed in phloem tissue and that PtaRHE1 had a pronounced expression in ray initials and their derivatives within the cambial zone. These results suggest that these genes have a potential role in vascular tissue development and/or functioning.