Journal Article

transcriptomic approach to identify regulatory genes involved in fruit set of wild-type and parthenocarpic tomato genotypes

Ruiu, Fabrizio, Imanishi, Shunsuke, Picarella, Maurizio Enea, Mazzucato, Andrea

2015

Overview

The tomato parthenocarpic fruit (pat) mutation associates a strong competence for parthenocarpy with homeotic transformation of anthers and aberrancy of ovules. To dissect this complex floral phenotype, genes involved in the pollination-independent fruit set of the pat mutant were investigated by microarray analysis using wild-type and mutant ovaries. Normalized expression data were subjected to one-way ANOVA and 2499 differentially expressed genes (DEGs) displaying a >1.5 log-fold change in at least one of the pairwise comparisons analyzed were detected. DEGs were categorized into 20 clusters and clusters classified into five groups representing transcripts with similar expression dynamics. The “regulatory function” group (685 DEGs) contained putative negative or positive fruit set regulators, “pollination-dependent” (411 DEGs) included genes activated by pollination, “fruit growth-related” (815 DEGs) genes activated at early fruit growth. The last groups listed genes with different or similar expression pattern at all stages in the two genotypes. qRT-PCR validation of 20 DEGs plus other four selected genes assessed the high reliability of microarray expression data; the average correlation coefficient for the 20 DEGs was 0.90. In all the groups were evidenced relevant transcription factors encoding proteins regulating meristem differentiation and floral organ development, genes involved in metabolism, transport and response of hormones, genes involved in cell division and in primary and secondary metabolism. Among pathways related to secondary metabolites emerged genes related to the synthesis of flavonoids, supporting the recent evidence that these compounds are important at the fruit set phase. Selected genes showing a de-regulated expression pattern in pat were studied in other four parthenocarpic genotypes either genetically anonymous or carrying lesions in known gene sequences. This comparative approach offered novel insights for improving the present molecular understanding of fruit set and parthenocarpy in tomato.

• Publisher: Springer Netherlands,Springer Science and Business Media LLC,Springer Nature B.V
• Subject: AGR/07 / analysis of variance / anthers / Biochemistry / Biomedical and Life Sciences / cell division / Cluster Analysis / correlation / Correlation coefficient / Flavonoids / flowering / Flowers / Flowers - genetics / Flowers - metabolism / Fruit / Fruit - growth & development / Fruit set • Ovary development • Parthenocarpic mutants • Solanum lycopersicum L. • Transcription factors • Transcriptome profiling / Fruits / Gene expression / gene expression regulation / Gene Expression Regulation, Plant / Gene Expression Regulation, Plant - physiology / genotype / Genotype & phenotype / Genotypes / Hormones / Life Sciences / Lycopersicon esculentum / Lycopersicon esculentum - genetics / Lycopersicon esculentum - metabolism / meristems / metabolism / Metabolites / microarray technology / mutants / Mutation / nucleotide sequences / ovules / parthenocarpy / phenotype / Plant biology / Plant Pathology / Plant Proteins / Plant Proteins - genetics / Plant Proteins - metabolism / Plant Sciences / Pollination / proteins / quantitative polymerase chain reaction / regulator genes / reverse transcriptase polymerase chain reaction / Secondary metabolites / Solanum lycopersicum / Tomatoes / transcription factors / Transcriptome / Transcriptome - physiology / transcriptomics / Variance analysis