Reproductive development and phenotypic differences in garlic are associated with expression and splicing of LEAFY homologue gaLFY

Abstract

Modern garlic (Allium sativum L.) cultivars are sterile and propagated only vegetatively. The recent discovery of fertile genotypes in Central Asia and the restoration of flowering and fertility by environmental manipulations open the way for in-depth florogenetic, genetic, and molecular research in garlic. In the present work, two bolting garlic accessions were employed: #3026, developing normal flowers and seeds, and #2509, in which flowers abort at the early stages of development. Morphological studies showed transition of the apical meristems from the vegetative to the reproductive stage and inflorescence initiation in both genotypes. Low temperatures promote transition of the apex and stem elongation, but have no effect on the phenotypic expression of the inflorescence development. The initial stages of reproductive development in non-flowering #2509 plants were followed by abortion of floral primordia at the differentiation stage. A search for genes involved in the control of flowering in garlic resulted in identification of the garlic LEAFY/FLO homologue, gaLFY. Further comparative analyses of gene expression revealed two gaLFY transcripts, differing in 64 nucleotides, with clear splicing borders. The short variant transcript was identified in both genotypes throughout all development stages, whereas the long variant appears in the flowering genotype #3026 only during reproductive development. The phenotypic differences in garlic, with regard to flowering, may be associated with the efficacy of the splicing process.

Dioscorea

“…Application of comparative genomics will further allow the transfer of knowledge from thoroughly studied model plants to yam. Discovery of genes involved in flowering in model plants such as Arabidopsis have been successfully utilized to identify homologous genes in garlic (Rotem et al 2007) and in cauliflower (Saddic et al 2006). Such approaches can be adopted for discovery of genes regulating the flowering signaling pathways in yam.…”

Flower development in garlic: the ups and downs of gaLFY expression

“…gaLFY expression patterns were analyzed by quantitative real-time PCR (qPCR) and RNA in situ hybridization, using primers and probes designed from the formerly described 682-bp fragment of the gene (Rotem et al 2007; GenBank AY563104 http://www.ncbi.nlm.nih.gov/nuccore/ 48476628).…”

“…Recently, we have demonstrated that the LFY homologue gaLFY is involved in the control of florogenesis in garlic. Further, we showed that two alternatively spliced gaLFY transcripts are expressed in flowering garlic plants (Rotem et al 2007). …”

“…The lack of sexual propagation prohibits genetic studies and conventional breeding, and fertility restoration should significantly broaden variability and make the improvement of economically important traits possible (Kamenetsky 2007). Recent introductions of fertile A. sativum accessions from Central Asia (Etoh 1985;Etoh and Simon 2002), restoration of flowering ability and fertility by environmental manipulations (Kamenetsky et al 2004b) and increased variation by seed propagation (Jenderek and Hannan 2004;Jenderek and Zewdie 2005;Kamenetsky et al 2005;Shemesh et al 2008) open the way for in-depth physiological and genetic studies, as well as conventional and molecular breeding in this plant.…”

“…However, the regulation of floral development and fertility in geophytes remains obscure, and fundamental physiological and genetic knowledge is required for both basic and applied purposes. In this context, investigation of genes involved in the control of flowering is of great importance (Benschop et al 2010;Noy-Porat et al 2010;Rotem et al 2007).…”