Solanum lycopersicum CLASS-II KNOX genes regulate fruit anatomy via gibberellin-dependent and independent pathways

Abstract The pericarp is the predominant tissue determining the structural characteristics of most fruits. However, the molecular and genetic mechanisms controlling pericarp development remain only partially understood. Previous studies have identified that CLASS-II KNOX genes regulate fruit size, shape, and maturation in Arabidopsis thaliana and Solanum lycopersicum. Here we characterized the roles of the S. lycopersicum CLASS-II KNOX (TKN-II) genes in pericarp development via a detailed histological, anatomical, and karyotypical analysis of TKN-II gene clade mRNA-knockdown (35S:amiR-TKN-II) fruits. We identify that 35S:amiR-TKN-II pericarps contain more cells around their equatorial perimeter and fewer cell layers than the control. In addition, the cell sizes but not the ploidy levels of these pericarps were dramatically reduced. Further, we demonstrate that fruit shape and pericarp layer number phenotypes of the 35S:amiR-TKN-II fruits can be overridden by the procera mutant, known to induce a constitutive response to the plant hormone gibberellin. However, neither the procera mutation nor exogenous gibberellin application can fully rescue the reduced pericarp width and cell size phenotype of 35S:amiR-TKN-II pericarps. Our findings establish that TKN-II genes regulate tomato fruit anatomy, acting via gibberellin to control fruit shape but utilizing a gibberellin-independent pathway to control the size of pericarp cells

Additional file 3: Table S3. of Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

Number of olive trees assigned to different multi-locus lineages (MLLs). (XLSX 18 kb

Additional file 4: Figure S1. of Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

Number of private alleles per locus in combinations of populations. A to D present values for the combination of two to five populations (treating scions and suckers of old olive trees as populations). (PDF 217 kb

Additional file 5: Figure S2. of Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

∆K values for the different Ks were calculated according to Evanno et al. [56], showing that K = 3 is the optimal K for the Structure analysis. (PDF 69 kb

Additional file 1: Table S1. of Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

SSR markers used, their expected size range, repeated motives and number of alleles found in naturally growing olive populations. Raw microsatellite data is available and enclosed as Additional file 2: Table S2. (PDF 188 kb

Additional file 6: Figure S3. of Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

Location of populations of naturally growing olives analyzed in this study and of groves of cultivated old olive trees sampled in our previous study (Barazani et al. [33]). (PDF 79 kb