Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Sun, Yanxia [1], Xiang, Qiuyun [1], Liu, Xiang [1], Zhang, Jian [1], Franks, Robert [1].

Differential expression patterns and gene sequence divergence of ACL5 and MPK6 homologs in Cornus L.

The dogwood genus Cornus L. is an excellent natural system for studying the molecular basis of inflorescence evolution due to distinct inflorescence morphology among closely related lineages. Through comparative transcriptome 454 sequencing of two species, Cornus canadensis L. (inflorescence minute, branched and slightly elongated) and C. florida L. (inflorescences branched, but not elongated), we identified Arabidopsis ACL5 and MPK6 expressed differentially in the inflorescence buds of these species. In Arabidopsis, ACL5 is required for internode and cell elongation and loss of function of MPK6 results in shortened pedicels and clustered inflorescences, or changes in stress responses. The functions of these genes in other taxa are rarely known and reports of cDNA/mRNA sequences are rare. To gain insights into the potential roles of these genes in regulating inflorescence elongation in Cornus, we compare the expression patterns of ACL5 and MPK6 in developing inflorescences of four species different in inflorescence architectures, with biological duplicates for each. We also isolated the cDNA sequences of the two genes from these species. By conducting phylogenetic analyses of the data including all sequences from Cornus and several other taxa we could found in Genbank, we tested the phylogenetic orthology and examine if molecular divergence is correlated with expression pattern and/or morphology. Our results from qRT-PCR analyses show a pattern of expression levels of ACL5 consistent with the prediction from inflorescence morphology based on the functions found in Arabidopsis. While the pattern of MPK6 expression cannot be simply explained by morphology. Sequence alignment and phylogenetic analyses of DNA and protein sequences indicate that the gene sequences are well-conserved within families and the 5' and 3' ends are more variable than the internal portion among lineages. Present results suggest a potential role of ACL5 in controlling the inflorescence divergence among Cornus lineages, which can be tested using ACL5-knock out experiments in C. canadensis in the future. Relationship between ACL5 sequence variation to expression patterns among Cornus species will be examined on the genus phylogeny.

1 - North Carolina State University, Plant And Microbial Biology, Gardner Hall 2115, Campus Box 7612, Raleigh, NC, 27695, USA

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Topics
Session: 46
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 4:30 PM
Number: 46004
Abstract ID:407
Candidate for Awards:None