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Flowering and fruiting are processes subject to complex control by environmental and endogenous signals. Endogenous signals comprise, besides classical phytohormones, also signaling peptides and miniproteins. Tomato cystine‐knot miniproteins (TCMPs), which belong to a Solanaceous‐specific group of Cys‐rich protein family, have been recently involved in fruit development. TCMP‐1 and TCMP‐2 display a highly modulated expression pattern during flower and fruit development. A previous study reported that a change in the ratio of the two TCMPs affects the timing of fruit production. In this work, to investigate TCMP‐2 mode of action, we searched for its interacting partners. One of the interactors identified by a yeast two hybrid screen, was the B‐box domain‐containing protein 16 (SlBBX16), whose closest homolog is the Arabidopsis microProtein 1b implicated in flowering time control. We demonstrated the possibility for the two proteins to interact in vivo in tobacco epidermal cells. Arabidopsis plants ectopically overexpressing the TCMP‐2 exhibited an increased level of FLOWERING LOCUS T (FT) mRNA and anticipated flowering. Similarly, in previously generated transgenic tomato plants with increased TCMP‐2 expression in flower buds, we observed an augmented expression of SINGLE‐FLOWER TRUSS gene, the tomato ortholog of FT, whereas the expression of the antiflorigen SELF‐PRUNING was unchanged. Consistently, these transgenic plants showed alterations in the flowering pattern, with an accelerated termination of the sympodial units. Overall, our study reveals a novel function for TCMP‐2 as regulatory factor that might integrate, thanks to its capacity to interact with SlBBX16, into the signaling pathways that control flowering, and converge toward florigen regulation.

[EN] Single primer enrichment technology (SPET) is a new, robust, and customizable solution for targeted genotyping. Unlike genotyping by sequencing (GBS), and like DNA chips, SPET is a targeted genotyping technology, relying on the sequencing of a region flanking a primer. Its reliance on single primers, rather than on primer pairs, greatly simplifies panel design, and allows higher levels of multiplexing than PCR-based genotyping. Thanks to the sequencing of the regions surrounding the target SNP, SPET allows the discovery of thousands of closely linked, novel SNPs. In order to assess the potential of SPET for high-throughput genotyping in plants, a panel comprising 5k target SNPs, designed both on coding regions and introns/UTRs, was developed for tomato and eggplant. Genotyping of two panels composed of 400 tomato and 422 eggplant accessions, comprising both domesticated material and wild relatives, generated a total of 12,002 and 30,731 high confidence SNPs, respectively, which comprised both target and novel SNPs in an approximate ratio of 1:1.6, and 1:5.5 in tomato and eggplant, respectively. The vast majority of the markers was transferrable to related species that diverged up to 3.4 million years ago (Solanum pennellii for tomato and S. macrocarpon for eggplant). Maximum Likelihood phylogenetic trees and PCA outputs obtained from the whole dataset highlighted genetic relationships among accessions and species which were congruent with what was previously reported in literature. Better discrimination among domesticated accessions was achieved by using the target SNPs, while better discrimination among wild species was achieved using the whole SNP dataset. Our results reveal that SPET genotyping is a robust, high-throughput technology for genetic fingerprinting, with a high degree of cross-transferability between crops and their cultivated and wild relatives, and allows identification of duplicates and mislabeled accessions in genebanks., This work has been funded by the European Union's Horizon 2020 Research and Innovation Programme under the grant agreement number 677379 (G2P-SOL project: Linking genetic resources, genomes, and phenotypes of solanaceous crops).

With approximately 450 species, spiny Solanum species constitute the largest monophyletic group in the Solanaceae family, but a high-quality genome assembly from this group is presently missing. We obtained a chromosome-anchored genome assembly of eggplant (Solanum melongena), containing 34,916 genes, confirming that the diploid gene number in the Solanaceae is around 35,000. Comparative genomic studies with tomato (S. lycopersicum), potato (S. tuberosum) and pepper (Capsicum annuum) highlighted the rapid evolution of miRNA:mRNA regulatory pairs and R-type defense genes in the Solanaceae, and provided a genomic basis for the lack of steroidal glycoalkaloid compounds in the Capsicum genus. Using parsimony methods, we reconstructed the putative chromosomal complements of the key founders of the main Solanaceae clades and the rearrangements that led to the karyotypes of extant species and their ancestors. From 10% to 15% of the genes present in the four genomes were syntenic paralogs (ohnologs) generated by the pre-γ, γ and T paleopolyploidy events, and were enriched in transcription factors. Our data suggest that the basic gene network controlling fruit ripening is conserved in different Solanaceae clades, and that climacteric fruit ripening involves a differential regulation of relatively few components of this network, including CNR and ethylene biosynthetic genes.

Parthenocarpy, referred to as the ability to develop fruits in absence of fertilization, is a desirable genetic trait in vegetable crops grown for the commercial value of their fruits. The advantages conferred by parthenocarpy are fruit production under environmental condition prohibitive for fertilization and production of seedless fruit. Methods for achieving parthenocarpic development use either synthetic growth factors, genetic mutants, or plant altered in their ploidy level. Nevertheless, parthenocarpic cultivars have so far been available only to a limited degree. Therefore, flower buds treatment with synthetic phytohormones is commonly used to induce parthenocarpic vegetable fruit development for early or late production under protected cultivation. Transgenic parthenocarpic tobacco, eggplant and tomato plants are described which contain in their genome the coding region of the iaaM gene from Pseudomonas syringae pv. savastanoi under the control of the placental- ovule-specific defh9 gene regulator sequences from Anthirrhinum majus. Expression of the chimeric defH9- iaaM transgene starts during early flower development and causes production of marketable eggplant and tomato fruits from both emasculated and pollinated flowers under environmental conditions prohibitive for fruit setting in the untransformed controls, which did not set fruit at all. Under normal environmental conditions, production of marketable fruits took place from pollinated and unplanted transgenic flowers, while untransformed plants produced fruits of marketable size only from fertilized flowers. Field tests, performed in a cold plastic-greenhouse in the Mediterranean area, showed that three experimental transgenic parthenocarpic eggplant hybrids were able to give satisfactory winter production without need of phytohormones treatment.