Molecular variability and genetic relationship among Brazilian strains of the sugarcane smut fungus

Abstract

Sporisorium scitamineum is the fungus that causes sugarcane smut disease. Despite of the importance of sugarcane for Brazilian agribusiness and the persistence of the pathogen in most cropping areas, genetic variation studies are still missing for Brazilian isolates. In this study, sets of isolates were analyzed using two molecular markers (AFLP and telRFLP) and ITS sequencing. Twenty-two whips were collected from symptomatic plants in cultivated sugarcane fields of Brazil. A total of 41 haploid strains of compatible mating types were selected from individual teliospores and used for molecular genetic analyses. telRFLP and ITS analyses were expanded to six Argentine isolates, where the sugarcane smut was first recorded in America. Genetic relationship among strains suggests the human-mediated dispersal of S. scitamineum within the Brazilian territory and between the two neighboring countries. Two genetically distinct groups were defined by the combined analysis of AFLP and telRFLP. The opposite mating-type strains derived from single teliospores were clustered together into these main groups, but had not always identical haplotypes. telRFLP markers analyzed over two generations of selfing and controlled outcrossing confirmed the potential for emergence of new variants and occurrence of recombination, which are relevant events for evolution of virulence and environmental adaptation.

Leaping into the Unknown World of Sporisorium scitamineum Candidate Effectors

“…Curiously, the Brazilian and South African isolates showed similar modifications in g1052, while Australian and Chinese strains shared the same sequence features. Benevenuto et al [47] revealed two haplotypes, which seem to maintain the same pattern in a population of 50 Brazilian isolates we have been investigating (unpublished data). The effector candidates in which we detected a unique localization pattern and expression in resistant plants (g3890 and g5159) showed polymorphic loci producing nonconservative amino acid substitutions.…”

The complete genome sequence and comparative effectorome of >i<Sporisorium panici-leucophaei>/i<: the causal smut disease agent in sourgrass (>i<Digitaria insularis>/i<)

“…Despite its high aggressiveness and rapid growth, sourgrass is also a host to several pests and pathogens such as the maize chlorotic mottle and dwarf mosaic viruses, the nematode Radopholus similis and the moth Mocis latipes, the fungus Sporisorium panici-leucophaei and the bacteria Xanthomonas citri (Invasive Species Compendium, 2018). The basidiomycete Sporisorium panici-leucophaei belongs to the Ustilaginaceae family which is commonly referred as smut fungus and comprises more than 600 species (Benevenuto et al, 2016).…”

“…Nevertheless, many smut pathogens share similar life cycles , thus suggesting a similarity to the Sporisorium scitamineum life cycle, a basidiomycete commonly known as sugarcane smut. S. scitamineum life cycle is well described Benevenuto et al, 2016). It begins when diploid teliospores (2n) germinate over the surface of sugarcane buds (internodes) ( Fig.…”

“…Chromosomes. Telomeric repeats were manually analyzed, searching for the canonical repeated sequence TTAGG (Benevenuto et al, 2016). First, Illumina reads that aligned with S. scitamineum genome were assembled generating a draft version (v1).…”