Perfil transcricional de aveia branca sob estresse osmótico no início do estádio vegetativo

Abstract

White oat (Avena sativa L.) is a crop of global and national importance. Due to its nutritional components, which are highly valued by consumers, the demand for this cereal has been increasing over time. With the worsening phenomenon of global warming, more and more regions of the planet suffer from water scarcity problems that dramatically impact agriculture. In recent years, although the area dedicated to oat production has remained stable, it has come under increasing pressure from prolonged drought events, which can severely affect the crop’s productivity. One of the strategies to mitigate losses caused by water deficit is the genetic improvement of crops. In this context, elucidating the genetic basis controlling drought stress tolerance can assist breeders. In the search for candidate genes for drought tolerance, RNA sequencing (RNA-Seq) was employed to evaluate the transcriptional profile of white oat under osmotic stress at the early vegetative stage. Three experiments were conducted with 12 cultivars from various breeding programs to identify the genotype with the best response to water deficit stress, culminating in the selection and transcriptome sequencing of the cultivar URS Altiva, which showed notable tolerance to osmotic stress. The functional prediction of differentially expressed genes (DEGs) was obtained through BLAST followed by gene ontology analysis at three levels. Considering an adjusted p-value < 0.05 and Log2 fold change < -2 and > 2, it was found that stress altered the expression of 2,843 genes in the aerial parts (2,012 upregulated and 831 downregulated) and 2,351 genes in the roots (1,378 upregulated and 973 downregulated). White oat reveals a complex adaptation to osmotic stress, in which biosynthetic pathways, cell wall components, and transcription factors play an initial role in the drought response, while genes involved in the production of secondary metabolites and hormonal signaling strengthen tolerance in seedlings. Gene ontology analysis revealed that the CYP gene family of cytochrome P450 stood out in all tissues analyzed, both in its induction and repression. This finding suggests a possible link with the osmotic stress tolerance demonstrated by the URS Altiva cultivar. However, further studies are needed to confirm and fully detail this potential correlation. Additionally, other candidate genes include members of the peroxidase family, the transcription factor families bZIP, bHLH, MYB, and WRKY, as well as ABC transporters.