Molecular Basis of the cauliflower Phenotype in Arabidopsis

Abstract

Genetic studies demonstrate that two Arabidopsis genes, CAULIFLOWER and APETALA1, encode partially redundant activities involved in the formation of floral meristems, the first step in the development of flowers. Isolation of the CAULIFLOWER gene from Arabidopsis reveals that it is closely related in sequence to APETALA1. Like APETALA1, CAULIFLOWER is expressed in young flower primordia and encodes a MADS-domain, indicating that it may function as a transcription factor. Analysis of the cultivated garden variety of cauliflower (Brassica oleracea var. botrytis) reveals that its CAULIFLOWER gene homolog is not functional, suggesting a molecular basis for one of the oldest recognized flower abnormalities.

Gene duplications, robustness and evolutionary innovations

“…A loss of function in this gene has no phenotype. However, in combination with mutations in its closely related duplicate APETALA1 (AP1) gene, mutations in CAL give a characteristic cauliflower-like phenotype 46 .…”

“…A loss of function in this gene has no phenotype. However, in combination with mutations in its closely related duplicate APETALA1 (AP1) gene, mutations in CAL give a characteristic cauliflower-like phenotype 46 .In addition to such redundancy, many duplicate MADS box gene functions have also diversified within and among species 47,48 . This is expected if robustness caused by gene duplications provides the substrate for morphological evolution.…”

Molecular characters and morphological genetics of CAL gene in Chinese cabbage

“…More than six pairs of degenerated primers that specify the character of CAL gene were designed according to the published sequences of AtCAL (A. thaliania), B o CAL (cabbage) [6], BoiCAL (broccoli) [8] and PCR was performed to amplify two overlapping DNA fragments, covering the entire coding region of the CAL gene. Three pairs of primers were used to produce DNA upstream fragment of while other three pairs of primers to get the downstream fragment.…”

“…The resultant sequences were evaluated using Sequencer (Geme Codes, Ann Arbor, MI) for contig assembly and sequence editing. Splice sites were determined by comparison with cDNA sequences of BobCAL [6] and BoiCAL [8], using the software program Net Plant Gene available at internet.…”

“…It has been suggested that the molecular basis for the inflorescence structure in cauliflower (Brassica oleracea var. botrytis), which is similar to the cauliflower phenotype in Arabidopsis, is in part due to a stop codon mutation in the fifth exon5 of BobCAL gene [6]. To extend the knowledge of floral development further, we have focused on CAL genes and other related genes in Brassica species.…”