Genome-Wide Analysis of the Cycling DOF Transcription Factors from Tomato and Analysis of Their Role in Plant Development and in Stress Responses

Tomato (Solanum lycopersicum L.) is one of the horticultural crops of major economic importance. However, its production is being affected by adverse environmental conditions such as salinity, drought and extreme temperatures. Recent studies have shown that the use of regulatory genes such as transcription factors (TFs) represents a power tool to obtain new tomato varieties with greater tolerance to abiotic stresses. The DOF (DNA binding with One Finger) proteins form a family of plant-specific TFs that are involved in the regulation of particular plant processes but their precise roles in abiotic stress tolerance are almost unknown.

We report a group of five tomato DOF genes, homologous to Arabidopsis Cycling DOF Factors (CDFs), that function as transcriptional regulators involved in responses to drought and salt stress and flowering-time control in a gene-specific manner. Arabidopsis plants overexpressing SlCDF1 and SlCDF3 showed increased drought and salt tolerance and increased expression levels of various stress-responsive genes. In addition the overexpression of SlCDF3 in Arabidopsis also results in the late flowering phenotype through the modulation of the expression of flowering control genes such as CONSTANS (CO) and FLOWERING LOCUS T (FT).Overall, our data connect SlCDFs showed functions related to abiotic stress tolerance and flowering time through the regulation of specific target genes and increase specific metabolites.