Identificação e caracterização da família de genes SnRKs em Psidium guajava L.: perspectivas para tolerância ao estresse salino

Abstract

Salinity is one of the major problems facing agriculture today. It has caused considerable losses all over the world, mainly damaging crops in arid and semi-arid regions, where there is a high evaporation rate of surface water from the soil, which makes this process even worse. Other factors can also increase salinization in these areas, such as low rainfall, groundwater depletion and inadequate agricultural practices. The guava tree, Psidium guajava L., is widely cultivated in arid and semi-arid regions. In Brazil, the northeast region is listed as the country's largest producer, so it is clear that improving the species for this condition is valuable. In plants, the SnRKs kinase gene family (subdivided into three subfamilies SnRK1, SnRK2 and SnRK3) is known for its participation in several abiotic stress response and adaptation pathways, including abscisic acid (ABA) signaling, reactive oxygen species (ROS) signaling, regulation of ion homeostasis and oxidative stress, and is widely indicated as being responsive to salt stress tolerance. Initially, analyses were carried out to identify and characterize gene sequences of the SnRKs family in the reference genome of the species, and in the draft construct of two Brazilian cultivars Cortibel RM and Paluma. A total of 53 genes were identified in the two genomes, of which 16 were shared, 10 exclusive in the reference genome and 27 exclusive in the draft. Of which 2 were classified as belonging to the SnRK1 subfamily, 38 to SnRK2 and 13 to SnRK3. Gene structure analyses revealed 7 to 8 exons for the SnRK1 genes, 3 to 26 exons for the SnRk2 genes and 1 to 15 exons for the SnRK3 genes. Investigations of conserved motifs showed great variation between the groups and gene expression studies showed a possible difference in expression between the cultivars with Cortibel RM with tissue-specific variations in the genes expressed in terms of subfamily. In addition, the experimental analysis showed that the hydroponics system was suitable, although it was necessary to use seedlings at the same stage of development. The other studies indicated that the RNA extracted was of good quality for molecular biology studies.