Dr. Zhengzhou Tobacco Research Institute of China National Tobacco Corporation Zhengzhou, Henan, China (People's Republic)
Body of Abstract:
Abstract
Background
Lignin is a major structural component of plant cell walls, and it functions to plays important roles in plant development,defense against pathogens, abiotic stress resistance. Cinnamyl alcohol dehydrogenase (CAD; EC1.1.1.95) catalyzes the final step of monolignol biosynthesis and is responsible for various monolignols.The CAD family members have been investigated in a number of plant species, but not completely defined in tobacco (Nicotiana tabacum) yet.
Methods
we identified 10 putative CAD genes in tobacco, and then we analyzed the locations of each member of the tobacco CAD gene family in their respective genomes, the intron/exon organization, the alignment and evolutionary of their relationships, the promoter of CAD genes, as well as the expression patterns of CAD genes in different tissues, and their potential roles in responses to various plant hormones.
Results
The ORF length of NtCADs ranged from 945 to 1092 nucleotides, and the exons of all CAD genes ranged from 4 to 8. The alignment of the ten deduced NtCAD protein sequences showed that ten NtCADs possessed the classic motifs of CADs. We found that transcripts of most homologous NtCAD genes showed similar patterns of expression in different organs. We identified some cis elements involved in the response to various hormones such as SA, ABA, MeJA, GA, and auxin, which involved in responses to biotic and abiotic stresses. The results showed that five NtCADs were induced by IAA. In contrast, most of NtCADs gene expression were depressed by ABA and GA treatments.
Conclusions
In the present study, ten NtCADs were identified and a systematic functional analysis was conducted. NtCADs responded to different plant hormones. The results of this study provide evidence for the functional divergence of NtCADs and indicate their possible roles in response to abiotic and biotic stresses.