Identification of differentially expressed genes involved in spine formation on seeds ofDaucus carota L. (carrot), using annealing control primer (ACP) system

Abstract

Carrot seeds normally have surface spines. The availability of a spineless mutant would be agronomically beneficial, eliminating the current efforts to remove those spines pre-sowing. Furthermore, the identification of spine-specific genes would provide insights into spine development in wild-type carrot seed. This effort could be facilitated through the use of an annealing control primer (ACP) system. Here, we employed a new and accurate reverse transcriptionpolymerase chain reaction (RT-PCR) that involves ACPs for identifying genes of interest. With these techniques, 11 expressed sequence tags (ESTs) were obtained for cloning and sequencing the genes that are differentially expressed in wild-type spiny seeds, but not in the spineless mutant. In all, 7 cDNAs exhibited significant sequence similarity with known genes from other species. These included cell wall-associated hydrolase, tail fiber assembly protein, transcriptional regulatory protein, berberine bridge enzyme, S-adenosyl methionine synthase, transketolase, and phenylalanyl t-RNA synthetase beta chain. Four other cDNA sequences had no significant identities with known genes. As revealed by RT-PCR, these genes regulate spine formation during the developmental stage. Our results suggest that PCR-based differential display RT-PCR techniques are a very useful tool for identifying spine-specific genes from carrot seeds.