title: Expression patterns of a cinnamyl alcohol dehydrogenase gene involved in lignin biosynthesis and environmental stress in Ginkgo biloba.
abstract: The cinnamyl alcohol dehydrogenase (CAD) is a key enzyme in lignin biosynthesis as it catalyzes the final step in the synthesis of monolignols. A cDNA sequence encoding the CAD gene was isolated from the leaves of Ginkgo biloba L, designated as GbCAD1. The full-length cDNA of GbCAD1 was 1,494 bp containing a 1,074 bp open reading frame encoding a polypeptide of 357 amino acids with a calculated molecular mass of 38.7 kDa and an isoelectric point of 5.74. Comparative and bioinformatic analyses revealed that GbCAD1 showed extensive homology with CADs from other gymnosperm species. Southern blot analysis indicated that GbCAD1 belonged to a multi-gene family. Phylogenetic tree analysis revealed that GbCAD1 shared the same ancestor in evolution with other CADs and had a further relationship with other gymnosperm species. GbCAD1 was an enzyme being pH-dependent and temperature-sensitive, and showing a selected catalyzing. Tissue expression pattern analysis showed that GbCAD1 was constitutively expressed in stems and roots, especially in the parts of the pest and disease infection, with the lower expression being found in two- to four-year-old stem. Further analysis showed the change in lignin content had some linear correlation with the expression level of GbCAD1 mRNA in different tissues. The increased expression of GbCAD1 was detected when the seedling were treated with exogenous abscisic acid, salicylic acid, ethephon, ultraviolet and wounding. These results indicate that the GbCAD1 gene may play a role in the resistance mechanism to biotic and abiotic stresses as well as in tissue-specific developmental lignification.
authors.affiliation: Economic Forest Germplasm Improvement and Comprehensive Utilization of Resources of Hubei Key Laboratories, Hubei, Huanggang 438000, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Cheng
authors.forename: Linling
authors.initials: L
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Shuiyuan
authors.initials: S
authors.lastname: Cheng
authors.forename: Fuliang
authors.initials: F
authors.lastname: Cao
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Honghui
authors.initials: H
authors.lastname: Yuan
authors.forename: Dezhi
authors.initials: D
authors.lastname: Jiang
authors.forename: Conghua
authors.initials: C
authors.lastname: Wu
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D018076:DNA, Complementary / Q000737:chemistry; D004777:Environment; D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D020441:Ginkgo biloba / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D008031:Lignin / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013312:Stress, Physiological; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D018076:DNA, Complementary; D010937:Plant Growth Regulators; D011994:Recombinant Proteins; D008031:Lignin; D000429:Alcohol Oxidoreductases; C018656:cinnamyl alcohol dehydrogenase