Isolation and Characterization of a TERMINAL FLOWER Homolog and Its Correlation with Juvenility in Citrus

Abstract

TERMINAL FLOWER is a key regulator of floral timing in Arabidopsis and other herbaceous species. A homolog of this gene, CsTFL, was isolated from the hybrid perennial tree crop Washington navel orange (Citrus sinensis L. Osbeck). The deduced amino acid sequence of CsTFL was 65% identical to the Arabidopsis TFL1 protein. Wild-type Arabidopsis plants ectopically expressing CsTFL showed late-flowering phenotypes similar to those described for overexpression of Arabidopsis TFL1. In addition, the 35S:CsTFL transgene complemented the tfl1-2 mutant. The severity of the overexpression phenotypes correlated with the amount of CsTFL transcript that accumulated. Unlike many model systems that have been studied, C. sinensis maintains two distinguishable CsTFL alleles. CsTFL transcripts from either allele were not detected in adult vegetative tissues using reverse transcription-PCR, but CsTFL RNAs were detected in all floral organs. In addition, real-time PCR determined that juvenility in citrus was positively correlated with CsTFL transcript accumulation and negatively correlated with the floral-regulatory genes, LEAFY and APETALA1, RNA levels.

Isolation and Characterization ofTerminal Flower1Homolog Promoter from Precocious Trifoliata Mutant (Poncirus TrifoliataL. Raf.) in Transgenic Arabidopsis

“…2k, 2l). contrasted to TFL homolog expression floral organs in citrus (17,22), PtTFL promoter expression was more consistent with the expression of AtTFL1. It was detected only clearly at the switch to inflorescence identity at about day 12 onwards and then strong and found throughout upper axillary shoot meristems in the wild type were documented (20).…”

“…TFL homologue (CsTFL) in Washington navel orange (Citrus sinensis l. osbeck) encoded a 19-kD protein that shared 65% identity to the Arabidopsis tFl1 protein and Amcen proteins (12). ectopic expression of CsTFL caused a significant delay in flowering and increase in inflorescence production in both wild-type and tfl1-2 plants (17). Antisense expression of MdTFL1, a TFL 1-like gene, reduces the juvenile phase in apples (10).…”

Ambiente y reguladores de crecimiento en la expresión de Flowering Locus T en mango

“…En tropicales, los estudios generalmente incluyen una relación de la expresión del gene con la iniciación y desarrollo floral, ambiente y reguladores de crecimiento. En mandarina 'Satsuma' los niveles del gene homólogo FT incrementaron con temperaturas frías durante el tiempo de inducción floral (Nishikawa et al, 2007) y en naranjo dulce hay evidencias que los niveles de homólogos leafy (LFY) y apetala (AP1) incrementan durante y después de la inducción floral con temperaturas frías (Pillitteri et al, 2004).…”

“…In tropical, studies generally include a relationship of gene expression with initiation and floral development, environment and growth regulators. In 'Satsuma' mandarin, levels of the homologous FT gene increased with cold temperatures during floral induction time (Nishikawa et al, 2007) and in sweet orange there is evidence that levels of leafy (LFY) and apetala (AP1) homologues increase during and after floral induction with cold temperatures (Pillitteri et al, 2004).…”

Toward Positional Cloning of Everblooming Gene (Evb) in Plants: A Bac Library of Rosa Chinensis Cv. 'Old Blush'

“…To characterize the library and facilitate isolation of the evb gene, we searched the GenBank for homeologous vernalization and flowering genes cloned to date in other plant species (Zemetra and Morris 1988;Schultz 1991;Mandel et al 1992;Lee et al 1994;Chandler 1996;Dubocovsky et al 1998;Michaels and Amasino 1999;Johanson et al 2000;Kitahara and Matsumoto 2000;Kotoda et al 2000;Sheldon et al 2000;Gendall et al 2001;Kitahara et al 2001;Pelaz et al 2001;Ampomah-Dwamena et al 2002;Murai et al 2003;Yan et al 2003Yan et al , 2004Caicedo et al 2004;Pillitteri et al 2004 by comparing FASTA report common sequences (Tatusova and Madden 1999). Only the unique regions of each gene were used in the primer design for each gene.…”