Sequence characterization of BAMH1 in sugarcane cultivars varying smut resistance level

Abstract

The culture of sugarcane (Saccharum spp.) has great importance on the national scene. Their by-products, such as sugar and ethanol, are sources of wealth for the Brazilian economy, as evidenced by the large area of cultivation and production of this crop. However, sugarcane can be affected by various diseases caused by microorganisms generating considerable economic losses. Among these diseases stands out sugarcane smut, caused by the fungus biotrophic Sporisorium scitamineum. Host colonization by this basidiomycete produces a structure similar to a whip in susceptible varieties, which is the most characteristic symptom of the disease. The whip is responsible for the formation and maturation of teliospores that can easily spread in the field by the wind or rain. The infection begins again with the germination of teliospores in gems giving rise to sexual compatible haploid cells compatible that will fuse forming the infective hyphae able to colonize plant tissues. Other symptoms of the disease are the decrease of sucrose and juice quality and increase of tillering, which negatively influence the production of sugar and ethanol. Understanding the biology of S. scitamineum x sugarcane interaction is essential to develop varieties more resistant to smut. Plants have several mechanisms to prevent the attack of pathogens, including pre- or post-formed defenses that act as mechanical or biochemical barriers. Several studies have shown differential expression of sugarcane defense genes associated with S. scitamineum infection. In previous work a transcriptomic approach enabled the detection of differential gene expression of RGAs (Resistance Gene Analogs) which encode transmembrane proteins RLKs (receptor like kinases). These genes are described as important in the recognition mechanism of pathogens and activation of specific defense responses. The objective of this project is to compare the DNA sequence of BAMH1 among different varieties of sugarcane with different levels of resistance to smut, as well as to evaluate the their expression in the early stages of infection with S. scitamineum.