Development and characterization of microsatellite loci in Ulex parviflorus Pourr. And its cross-transferability to other Genisteae.

BACKGROUND: The genus Ulex is composed by 15 species distributed in Europe and Africa, but the majority of them are restricted to the Iberian Peninsula and Northwest Africa. Some of these species are common elements at the landscape level, and others contribute to global biodiversity as narrow endemics. Assayed nuclear and plastid Sanger-sequenced regions do not provide enough resolution to perform evolutionary studies on the genus, neither at the intraspecific population level nor at the interspecific phylogenetic level. Thus, we have developed and characterized a set of nuclear microsatellite loci in U. parviflorus to provide new highly polymorphic molecular markers for the genus Ulex. METHODS AND RESULTS: Genomic DNA enriched in microsatellite motifs using streptavidin-coated M-280 magnetic beads attached to 5'-biotinylated oligonucleotides was sequenced in a 454GS Junior System. After primer design, fluorescent-dyed amplicons were analyzed through capillary sequencing (ABI3730XL). Here we present twelve new high polimorphic SSRs markers developed in U. parviflorus specimens and tested in 120 individuals. The 12 SSR loci amplified a total of 152 alleles, and detected expected heterozygosities that ranged from 0.674 to 0.725 in the genotyped populations. Successful cross-species transferability of the 12 SSR loci to the rest of species included in the genus Ulex and three other representative Genisteae was achieved. CONCLUSIONS: The 12 novel proposed SSRs loci will contribute to perform evolutionary studies and genetic research on the genus Ulex and in other Genisteae.

The FLOWERING LOCUS T LIKE 2-1 gene of Chenopodium triggers precocious flowering in Arabidopsis seedlings.

The FLOWERING LOCUS T (FT) gene is the essential integrator of flowering regulatory pathways in angiosperms. The paralogs of the FT gene may perform antagonistic functions, as exemplified by BvFT1, that suppresses flowering in Beta vulgaris, unlike the paralogous activator BvFT2. The roles of FT genes in other amaranths were less investigated. Here, we transformed Arabidopsis thaliana with the FLOWERING LOCUS T like (FTL) genes of Chenopodium ficifolium and found that both CfFTL1 and CfFTL2-1 accelerated flowering, despite having been the homologs of the Beta vulgaris floral promoter and suppressor, respectively. The floral promotive effect of CfFTL2-1 was so strong that it caused lethality when overexpressed under the 35S promoter. CfFTL2-1 placed in an inducible cassette accelerated flowering after induction with methoxyphenozide. The spontaneous induction of CfFTL2-1 led to precocious flowering in some primary transformants even without chemical induction. The CqFT2-1 homolog from Chenopodium quinoa had the same impact on viability and flowering as CfFTL2-1 when transferred to A. thaliana. After the FTL gene duplication in Amaranthaceae, the FTL1 copy maintained the role of floral activator. The second copy FTL2 underwent subsequent duplication and functional diversification, which enabled it to control the onset of flowering in amaranths to adapt to variable environments.

The FLOWERINGLOCUS T like 2­1 gene of Chenopodium ficifolium andChenopodium quinoa acts as a strong activator of flowering in Arabidopsis, triggering flowering at cotyledon stage and causing lethality when overexpressed.

The high concentrations of abscisic, jasmonic, and salicylic acids produced under long days do not accelerate flowering in Chenopodium ficifolium 459.

The survival and adaptation of angiosperms depends on the proper timing of flowering. The weedy species Chenopodium ficifolium serves as a useful diploid model for comparing the transition to flowering with the important tetraploid crop Chenopodium quinoa due to the close phylogenetic relationship. The detailed transcriptomic and hormonomic study of the floral induction was performed in the short-day accession C. ficifolium 459. The plants grew more rapidly under long days but flowered later than under short days. The high levels of abscisic, jasmonic, and salicylic acids at long days were accompanied by the elevated expression of the genes responding to oxidative stress. The increased concentrations of stress-related phytohormones neither inhibited the plant growth nor accelerated flowering in C. ficifolium 459 at long photoperiods. Enhanced content of cytokinins and the stimulation of cytokinin and gibberellic acid signaling pathways under short days may indicate the possible participation of these phytohormones in floral initiation. The accumulation of auxin metabolites suggests the presence of a dynamic regulatory network in C. ficifolium 459.

The transcriptomic (RNA-Sequencing) datasets collected in the course of floral induction in Chenopodium ficifolium 459.

The transition from vegetative growth to reproduction is the essential commitment in plant life. It is triggered by environmental cues (day length, temperature, nutrients) and regulated by the very complex signaling gene network and by phytohormones. The control of flowering is well understood in Arabidopsis thaliana and in some crops, much less is known about the other angiosperms. We performed the detailed transcriptomic survey of the course of floral induction in seedlings of Chenopodium ficifolium accession 459, a close relative of the important crop Chenopodium quinoa. It flowers earlier under short days (6 hours light) than under long days (18 hours light). Plants were sampled at the age 14, 18, 21 and 24 days in the morning and afternoon, both at long and short day, for RNA-Sequencing, and also for phytohormone analyses. We employed Illumina NovaSeq6000 platform to generate raw reads, which were cleaned and mapped against the de novo constructed transcriptome of C. ficifolium. The global gene expression levels between long and short days were pairwise compared at each time points. We identified differentially expressed genes associated with floral induction in C. ficifolium 459. Particular attention was paid to the genes responsible for phytohormone metabolism and signaling. The datasets produced by this project contributed to better understanding of the regulation of growth and development in the genus Chenopodium.

Transcriptomic study of the night break in Chenopodium rubrum reveals possible upstream regulators of the floral activator CrFTL1.

The transition from vegetative to reproductive phases is the most fundamental and tightly controlled switch in the life of flowering plants. The short-day plant Chenopodium rubrum is a fast cycling annual plant lacking a juvenile phase. It can be induced to flowering at the seedling stage by exposure to a single period of darkness. This floral induction may then be cancelled by a short pulse of red light at midnight called night break (NB), which also inhibits the floral activator FLOWERING LOCUS T LIKE 1 (CrFTL1). We performed a comparative transcriptomic study between C. rubrum seedlings treated by NB and ones growing through uninterrupted night, and found about six hundred differentially expressed genes, including the B-BOX DOMAIN (BBX) genes. We focused on the CrBBX19 and BOLTING TIME CONTROL 1 (BTC1) genes, homologous to the upstream regulators of the BvFT2, a floral inducer in sugar beet. The transcription patterns of the two genes were compatible with their putative role as a sensor of the dark period length optimal for flowering (CrBBX19), and a signal of lights-on (CrBTC1), but the participation of other genes cannot be excluded. The expression profiles of CrBBX19 and the homolog of the core endogenous clock gene LATE ELONGATED HYPOCOTYL (LHY) were highly similar, which suggested their co-regulation.

SSR markers for Filago subg. Filago (Gnaphalieae: Asteraceae) and cross-amplification in three other subgenera.

PREMISE OF THE STUDY: Microsatellite primers were developed for the first time in the genus Filago (Gnaphalieae: Asteraceae). These markers will facilitate low-scale phylogenetic, phylogeographic, and population genetic studies within the genus Filago. METHODS AND RESULTS: Ten pairs of polymorphic microsatellite primers (as well as five pairs of monomorphic primers) were identified and optimized on two species of Filago (F. gaditana and F. carpetana) using a microsatellite-enrichment library method and 454 GS-FLX technique. The polymorphic primers amplified tri- to hexanucleotide repeats and showed one to six alleles per locus for both species. Transferability was performed in 29 samples corresponding to nine representative species of Filago. CONCLUSIONS: The results indicate the utility of the newly developed markers, which will be useful to delve into the phylogenetic relationships among the taxa within Filago. These microsatellites will enable studies of phylogeographic, reproductive, and genetic variation.