Análise dos transcriptomas de Paspalum notatum Flúggé e Paspalum vaginatum Swartz em condição de déficit hídrico

Abstract

Drought is one of the abiotic stresses that most affect plant growth and productivity. Grasses of the genus Paspalum are used successfully in pastures and lawns, and some ecotypes of Paspalum notatum (bahiagrass) have good forage quality, while some Paspalum vaginatum (seashore paspalum) have high tolerance to salinity. In addition, the potential for drought resistance of both species has already been described, making them interesting for transcriptome studies under water deficit. The aim of the project is to evaluate the gene expression profile of two Paspalum genotypes in response to water deficit. Two genotypes (P. vaginatum BGP 114 and P. notatum BGP 216) with different drought resistance strategies were selected from five accessions of Paspalum (P. indecorum Mez BGP 24, P. notatum Flüggé BGP 216, P. vaginatum Swartz BGP 114, P. modestum Mez BGP 23 and BGP 32) previously evaluated according to their physiological characteristics under water deficit. Leaf samples in two water conditions were collected: without water stress (soil relative moisture 28%) and with 6% soil moisture reached after five days of water stress for P. notatum and eight days for P. vaginatum. RNAs were extracted from the samples and cDNA libraries were prepared, which were sequenced on the Illumina HiSeq 2500 platform. Bioinformatics analyzes were carried out to: characterize the quality of the de novo assembly transcriptomes; analyze the differential gene expression between plants with and without water stress and perform the functional annotation of genes and metabolic pathways. The gene expressions found in silico were validated via real-time PCR. From the physiological and molecular analyzes it was possible to identify that the genotypes combine different strategies to resist drought, and the avoidance and tolerance dehydration strategies were found in both accessions. The enrichment of gene ontology terms enabled the identification of specific strategies for each genotype, such as escape dehydration for P. vaginatum and dormancy for P. notatum. The characterization and classification of these accessions regarding their water stress tolerance strategies and a better understanding of the molecular and physiological mechanisms involved may contribute to the identification of genes of interest aiming at gene editing in order to develop stress-tolerant grasses better adapted to the different scenarios and climate changes.