Identificação genômica da família WRKY e o perfil de expressão sob déficit hídrico e moléculas sinalizadoras em Eucalyptus

Abstract

Eucalyptus species represent most of planted forests in worldwide forestry sector. The high productivity and future perspectives indicate that world market will require highers demand for wood products, which may probably not be supplied in the next coming years. One of the most serious problems affecting final production is the low water availability of some sites. That highlights the requirement for increasing production areas and to accelerate forest tree breeding programs. The aim of this work was to identify members of WRKY transcription factor family in Eucalyptus grandis, through bioinformatics analyzes, and analyze the relative expression via RT-qPCR, from the application of signaling molecules and water deficit, in two clones contrasting with the water deficit of E. camaldulensis Dehnh. x E. urophylla S.T.Blake in order to indicate possible candidates for genetic engineering. Bioinformatics analyzes were performed to identify the WRKY sequences. The relative expression of some genes was quantified in experiment with different signaling molecules (MeJa, AS, ABA and H2O2) and exposure to PEG6000, mimicking water stress. We identified 74 putative WRKY genes in the genome of E. grandis that were classified in groups I, II and III, and in subdivisions of group II (II-a-IIe), distributed across its 11 chromosomes. Synteny analysis exhibited 16 paralogs in E. grandis and 23 orthologs with Arabidopsis thaliana, besides presenting 5 regions with tandem gene duplication. Analysis of gene expression by RT-qPCR show changes in expression for EgrWRKY3, EgrWRKY11, EgrWRKY15, EgrWRKY20 e EgrWRKY45 in response to signaling molecules used. The relative expression of the same genes also presented changes after the imposition of the water deficit, presenting higher expression of EgrWRKY3 and 11 in the tolerant clone at some point in the analysis. Furthermore, network analysis revealed that genes Ecgr.J00502.1 and Ecgr.D01960.1 are correlated with some EgrWRKYs and their gene expression results showed Ecgr.J00502.1 may be related to the responses to the experiment with PEG6000. Taken together, these findings may contribute to selection of potential candidate genes for genetic engineering purposes involving plant responses to water deficit.