Lorenzo Mancini

The extensive diversification of flower shape and organs underpins the adaptive success of angiosperms. Despite substantial knowledge of the molecular mechanisms controlling flower induction and development, few studies have quantified the variability in floral traits within species or explored their correlation with other reproductive traits. In cultivated tomato (Solanum lycopersicum L.), human selection has driven fruit diversification in terms of size and shape. In the present study, 48 landraces representing tomato diversity in reproduction-related characteristics were phenotyped for 18 flower structural or dimensional traits. Flower traits exhibited lower coefficients of variation compared to other reproductive traits, though organ numbers showed high heritability values. Flower organ number and size were tightly correlated, but the correlation between dimensional traits was weaker. This likely reflects the selective pressures on pistil traits during domestication, including specific mutations affecting carpel number and ovary morphology. While ovary and fruit size were positively correlated, no relationship was found between ovule and seed size, suggesting that genes related to seed size generally act after fruit set. The collection was genotyped at the Fasciated (Fas) locus, and 13 floral traits were significantly different in fas mutants. The phenotypic variability described in this study could help breeders select for more fertile flowers and assist reproductive biologists in linking genes to flower development.

The genetic diversity of tomato in Italy and the growing interest in high-quality food products highlight the importance of establishing varietal distinctiveness through molecular strategies to ensure agrifood product quality and traceability. In this study, four Italian potato-like leaf (PL) landraces were analyzed: “Spagnoletta di Formia e di Gaeta” (SPA) from southern Lazio, “Giagiù” (GIA) and “Patanara” (PTN) from Campania, and “Pomodoro di Mola” (MOL) from Apulia. These landraces were genotyped for the potato leaf gene (C), with two PL American genotypes and a non-allelic PL mutant line included as outgroups. Nagcarlang served as control. An allelism test confirmed C as determinant gene. The SCAR marker for C revealed that the Italian landraces presented determinants other than the most representative one responsible for PL. Whole-genome sequencing of SPA identified a private novel nonsense SNP variant allele, confirmed through dCAPS marker analysis. Additionally, two novel PL alleles responsible for missense variations were identified in GIA/PTN and MOL. In silico protein analysis suggested that novel C alleles could be functional determinants for the protein activity. Overall, PL mutations identified for the first time could serve as molecular tools for agrifood chain traceability, enabling early differentiation and recognition of genotypically similar varieties.