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SummaryCommercial tomato (Solanum lycopersicum) is one of the most widely grown vegetable crops worldwide. Heirloom tomatoes retain extensive genetic diversity and a considerable range of fruit quality and leaf morphological traits.Here the role of leaf morphology was investigated for its impact on fruit quality. Heirloom cultivars were grown in field conditions and BRIX by Yield (BY) and other traits measured over a fourteen-week period. The complex relationships among these morphological and physiological traits were evaluated using PLS-Path Modeling, and a consensus model developed.Photosynthesis contributed strongly to vegetative biomass and sugar content of fruits but had a negative impact on yield. Conversely leaf shape, specifically rounder leaves, had a strong positive impact on both fruit sugar content and yield. Cultivars such as Stupice and Glacier, with very round leaves, had the highest performance in both fruit sugar and yield. Our model accurately predicted BY for two commercial cultivars using leaf shape data as input.This study revealed the importance of leaf shape to fruit quality in tomato, with rounder leaves having significantly improved fruit quality. This correlation was maintained across a range of diverse genetic backgrounds and shows the importance of leaf morphology in tomato crop improvement.

Tomatobipinnate(bip) is a classic leaf mutant, with highly increased leaf complexity resulting from the loss of function of aBEL-LIKE HOMEODAMAIN(BELL) gene. Here, we analyzed severalbipmutants and their isogenic wildtype backgrounds for a suite of leaf morphology traits, ranging from leaf complexity, leaflet shape and size, to leaf vascular density to investigate how changes in leaf morphology influence fruit traits. Our analyses showed an unexpected relationship between leaf vein density and fruit sugar levels, where leaf vein density was negatively correlated with fruit BRIX. RNA-Seq analysis suggested variation inGlucose-6-phosphate translocator2(GPT2) gene expression caused correlated changes in leaf vein density and BRIX whenbipmutant and wildtype were compared, suggesting that the correlation between leaf vein density and fruit sugar may result from the genes regulating leaf vein development that are also involved in regulating leaf sugar biosynthesis. Our results provide a resource for further exploration of the genetic basis for the complex relationship between fruit quality and leaf traits in natural populations.

Domesticated plants and animals display tremendous diversity in various phenotypic traits and often this diversity is seen within the same species. Tomato (Solanum lycopersicum; Solanaceae) cultivars show wide variation in leaf morphology, but the influence of breeding efforts in sculpting this diversity is not known. Here, we demonstrate that a single nucleotide deletion in the homeobox motif ofBIPINNATA, which is aBEL-LIKE HOMEODOMAINgene, led to a highly complex leaf phenotype in an heirloom tomato, Silvery Fir Tree (SiFT). Additionally, a comparative gene network analysis revealed that reduced expression of the ortholog ofWUSCHEL RELATED HOMEOBOX 1is also important for the narrow leaflet phenotype seen in SiFT. Phylogenetic and comparative genome analysis using whole-genome sequencing data suggests that thebipmutation in SiFT is likely ade novomutation, instead of standing genetic variation. These results provide new insights into natural variation in phenotypic traits introduced into crops during improvement processes after domestication.

Olive (Olea europaea.L) is an economically important oleaginous crop and its fruit cold-pressed oil is used for edible oil all over the world. The basic region-leucine zipper (bZIP) family is one of the largest transcription factors families among eukaryotic organisms, its members play vital roles in environmental signaling, stress response, plant growth, seed maturation, and fruit development. However, a comprehensive report on the bZIP gene family in olive is lacking. In this study, 103 OebZIP genes from the olive genome were identified and divided into 12 subfamilies according to their genetic relationship with 78 bZIPs of A. thaliana. Most OebZIP genes are clustered in the subgroup that has a similar gene structure and conserved motif distribution. According to the characteristics of the leucine zipper region, the dimerization characteristics of 103 OebZIP proteins were predicted. Gene duplication analyses revealed that 22 OebZIP genes were involved in the expansion of the bZIP family. To evaluate the expression patterns of OebZIP genes, RNA-seq data available in public databases were analyzed. The highly expressed OebZIP genes and several lipid synthesis genes (LPGs) in fruits of two varieties with different oil contents during the fast oil accumulation stage were examined via qRT-PCR. By comparing the dynamic changes of oil accumulation, OebZIP1, OebZIP7, OebZIP22, and OebZIP99 were shown to have a close relationship with fruit development and lipid synthesis. Additionally, some OebZIP had a significant positive correlation with various LPG genes. This study gives insights into the structural features, evolutionary patterns, and expression analysis, laying a foundation to further reveal the function of the 103 OebZIP genes in olive.

Domesticated plants display diverse phenotypic traits. However, the influence of breeding effort on this phenotypic diversity remains unknown. Here, we demonstrate that a single nucleotide deletion in the homeobox motif of BIPINNATA, a BEL-LIKE HOMEODOMAIN gene, led to a highly complex leaf phenotype in an heirloom tomato (Solanum lycopersicum), Silvery Fir Tree (SiFT), which is used as a landscaping and ornamental plant. A comparative gene network analysis revealed that repression of SOLANIFOLIA, the ortholog of WUSCHEL RELATED HOMEOBOX 1, caused the narrow leaflet phenotype seen in SiFT. Comparative genomics indicated that the bip mutation in SiFT likely arose de novo and is unique to SiFT and not introgressed from other tomato genomes. These results provide new insights into the natural variation in phenotypic traits introduced into crops during improvement processes after domestication and establish homeobox genes as evolutionary hotspots.

Olive trees, originated from Mediterranean, have been cultivated in China for decades and show great adaption to local environment. However, research on this topic is limited. In this study, the major qualitative characteristics and changes of olive grown in southwest China were investigated. The results showed that oil accumulated during fruit development and reached its maximum value when fruit had fully ripened. Phenolic and flavonoid contents increase rapidly in the early growth stage (0-90 DAFB) and then begin to decrease as fruit ripens. Compared with olive from the Mediterranean, olive from China has special characteristics: higher moisture content in the fruit combined with lower percentages of unsaturated fatty acids and oil content. This is due to southwest China’s climate which is wetter and cooler compared to the Mediterranean. Our study suggests that southwest China’s higher annual rainfall might contribute to higher fruit moisture content while its low temperatures would be conducive to higher unsaturated fatty acid levels in the fruit.

Olive trees, originated from Mediterranean, have been cultivated in China for decades and show great adaption to local environment. However, research on this topic is limited. In this study, the major qualitative characteristics and changes of olive grown in southwest China were investigated. The results showed that oil accumulated during fruit development and reached its maximum value when fruit had fully ripened. Phenolic and flavonoid contents increase rapidly in the early growth stage (0–90 DAFB) and then begin to decrease as fruit ripens. Compared with olive from the Mediterranean, olive from China has special characteristics: higher moisture content in the fruit combined with lower percentages of unsaturated fatty acids and oil content. This is due to southwest China's climate which is wetter and cooler compared to the Mediterranean. Our study suggests that southwest China's higher annual rainfall might contribute to higher fruit moisture content while its low temperatures would be conducive to higher unsaturated fatty acid levels in the fruit.