Characterization of Transcription Factors Differentially Expressed Under Drought Conditions in Sugarcane (Saccharum spp)

From a previous experiment conduced with sugarcane with two contrasting genotypes to drought tolerance (IACSP97-7065 – sensitive and IACSP94-2094 – tolerant), focused on RNAseq and microarray analysis conducted at greenhouse and at field conditions respectively, this present project aimed to analyze a set of Transcription Factors (TFs) differently expressed identified and characterize their role on drought tolerance using rice as a model. Ten TFs (bZIP_1, bZIP_2, MYB_1, MYB_2, HLH, ZFP, NAN, DREB, AP2_1 and AP2_2) were selected for qPCR validation. The TFs bZIP_1 and MYB_2 showed a higher gene expression in IACSP94-2094 when compared to IACSP97-7065, and were selected for functional analysis. Two sequences were selected (19bZIP2094and 17MYB2094) for overexpression under control of Maize Ubiquitin constitutive promoter. using hygromycin as a selectable marker. The efficiency of rice transformation ranged from 50 to 60%. All rice transgenic plants were confirmed by PCR: 21 for the TF bZIP_1 (19bZIP2094) and 30 for TF MYB_2 (17MYB2094). The gene expression profiles of the transgenic plants were analyzed by qPCR and events expressing up to 7.9 and 8.9 times more than the event with the smallest value of gene expression for the TF bZIP_1 and Ft MYB_2 respectively were identified. The estimation of transgene copy number was evaluated by qPCR for transgenic rice 17MYB2094. The copy number ranged from 1 to 4. Complementary, the first generation (T1) of the events of transgenic rice will be submitted to drought conditions for physiological analyzes aiming to evaluate the function of these genes with drought response.