A Brassica oleracea Gene Expressed in a Variety-Specific Manner May Encode a Novel Plant Transmembrane Receptor

Abstract

The species Brassica oleracea includes several agricultural varieties characterized by the proliferation of different types of meristems. Using a combination of subtractive hybridization and PCR (polymerase chain reaction) techniques we have identified several genes which are expressed in the reproductive meristems of the cauliflower curd (B. oleracea var. botrytis) but not in the vegetative meristems of Brussels sprouts (B. oleracea var. gemmifera) axillary buds. One of the cloned genes, termed CCE1 (CAULIFLOWER CURD EXPRESSION 1) shows specific expression in the botrytis variety. Preferential expression takes place in this variety in the meristems of the curd and in the stem throughout the vegetative and reproductive stages of plant growth. CCE1 transcripts are not detected in any of the organs of other B. oleracea varieties analyzed. Based on the nucleotide sequence of a cDNA encompassing the complete coding region, we predict that this gene encodes a transmembrane protein, with three transmembrane domains. The deduced amino acid sequence includes motifs conserved in G-protein-coupled receptors (GPCRs) from yeast and animal species. Our results suggest that the cloned gene encodes a protein belonging to a new, so far unidentified, family of transmembrane receptors in plants. The expression pattern of the gene suggests that the receptor may be involved in the control of meristem development/arrest that takes place in cauliflower.

Genome sequencing sheds light on the contribution of structural variants toBrassica oleraceadiversification

“…4c), indicating its repressor role in flower bud development, as reported in Arabidopsis (Liu et al, 2009). A cauliflower curd-specific gene, BoCCE1, was reported to have a potential role in the control of meristem development/arrest (Palmer et al, 2001;Duclos and Björkman, 2008). Here, we identified a 1,505-bp insertion (SV_b_67089a) covering the entire BoCCE1 gene body in Korso.…”

Genome sequencing sheds light on the contribution of structural variants to Brassica oleracea diversification

“…4 c), indicating its repressor role in flower bud development, as reported in Arabidopsis [ 53 ]. A cauliflower curd-specific gene, BoCCE1 , was reported to have a potential role in the control of meristem development/arrest [ 29 , 54 ]. Here, we identified a 1505-bp insertion (SV_b_67089a) covering the entire BoCCE1 gene body in Korso.…”

Meristem identity gene expression during curd proliferation and flower initiation in Brassica oleracea

“…CCE1 could have a putative role in the suppression of class Band C-function genes. How CCE1 fulfils this role is an interesting question since this protein belongs to a new, so far unidentified, family of transmembrane receptors (Palmer et al, 2001).…”

“…Two other genes have been specifically associated with the cauliflower curd: CAULIFLOWER CURD EX-PRESSION 1 (CCE1) and REPRODUCTIVE MERISTEM 1 (BoREM1). CCE1 could potentially be a gene involved in maintaining the arrest (as TFL1 does in Arabidopsis) (Palmer et al, 2001), while BoREM1 could break the arrest (as LFY does in Arabidopsis) to allow continued reproductive development (Franco-Zorrilla et al, 1999). The candidate gene approach permits the use of quantitative real-time PCR, a technique sensitive enough to detect low-abundance genes such as BoTFL1 and to distinguish paralogues with high sequence similarity.…”