Fatores de transcrição bHLH em Vitis spp. : caracterização e modulação transcricional sob inoculação bacteriana

Abstract

The vine is one of fruit species of great importance for agribusiness. It’s cultivated from the semi-arid to temperate climate, which can reach more than two harvest per year in São Francisco Valley (SVSF) sub-middle region, States of Pernambuco and Bahia. However, viticulture has suffered with phytosanitary problems related to Xanthomonas citri bacterial infection, which causes bacterial canker, which has impaired several species of Vitis cultivated in this region, therefore, this plant/pathogen relationship needs to be understood, the transcription factors (TFs) are proteins responsible for regulating target genes that participate in metabolic pathways involved in several biological processes, including response to abiotic and biotic stresses. Basic helix-loop-helix (bHLH) proteins constitute the largest family of TFs, presenting role recognized in tolerance/resistance to abiotic and biotic stress. There are no reports about the role of these proteins in pathogenic interaction between grapevine and X. citri bacteria. Thus, the present work aimed to evaluate bHLH TFs role related to defense process of Vitis spp. inoculated with X. citri evaluating its expression, diversity, and function. RNA-Seq libraries (Illumina HiSeq2500) were generated from an experimental assay using clones of two cultivars (Red Globe and IAC-572) inoculated with X. citri. Owning the transcriptome, in silico analyzes were performed using bioinformatics tools, where, initially, probe sequences available in public databases (NCBI and Uniprot) were obtained for mining candidate sequences in Vitis vinifera genome available in Phytozome, where were identificated 102 sequences, with complete domain analyzed in the batch CD-search, the conserved motifs were analyzed in the MEME, and they were corresponding for the basic region and the helix loop helix which constitute the characteristic domain of TFs bHLH. The phenetic tree generated using MEGA7 with sequences from V. davidii formed 25 subgroups. The gene ontology analysis was enriched using the GO consortium data, and made it possible to verify that biological process more enriched corresponded to bacterial detection and protein kinase activity. The in silico expression profile observed through heatmaps generated by the software CLUSTER 3.0, and visualized in the TreeView, identified 34 diferencially expressed genes (Log2FC>0.50 e <-0.50), with most transcripts being induced in the hybrid IAC-572. The identification of these genes is of great importance for use in further studies involving transformation events or genetic editing in grapevine, which could contribute to development of resistant cultivars to bacterial infection.