Allelic characterization of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) gene from sugarcane in response to infection by the fungus that causes smut disease (Sporisorium scitamineum)

Abstract

Sugarcane smut disease, caused by the fungus Sporisorium scitamineum, represents the most important fungal disease of sugarcane, causing a decrease in sugar levels, a reduction in the photosynthetic rate, physiological changes in the plant and inhibition of the expression of genes related to the plant's defense systems. While investigating these alterations, our research group (Dr. Claudia Vitorello) identified interactions between effector proteins from S. scitamineum and transcription factors (TFs) from sugarcane, called Squamosa Promoter-Binding Proteins (SBPs). These TFs are part of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) gene family and are associated with the modulation of flowering time and leaf growth, for example. Interestingly, these molecular interactions cause changes in the progression of the vegetative and reproductive stages differentially between the sugarcane genotypes used as resistance and susceptibility standards (genotype-dependent). Furthermore, the transcriptional profile of SPL presents itself in a contrasting way between the genotypes, being induced in sensitive genotypes and repressed in resistant genotypes. However, the characterization of different sugarcane SPL alleles and their expression levels against S. scitamineum infection have not yet been investigated. Therefore, the aim of this project is to elucidate the allelic responsiveness of SPL to S. scitamineum in two sugarcane varieties with different responses to charcoal: 'IACSP02-1064' (sensitive) and 'SP80-3280' (resistant) . Thus, the identification of the alleles involved in the defense response of sugarcane to S. scitamineum can be applied in our gene knockout studies (CRISPR/Cas) aiming at the development of genotypes resistant to the sugarcane disease, as proposed in NPOP sugarcane subproject (FAPESP 2020/07045-3).