Survey of endophytic Alternaria species isolated from plants in the Brazilian restinga biome

Abstract

Saprophytic, endophytic and pathogenic Alternaria have been isolated from a wide range of environments. Endophytic fungi from Brazilian "restingas" have not been studies to date. Here endophytic Alternaria isolates from a range of restinga plants were investigated. One hundred and fifty seven plant species were screened, from which 71 endophytic Alternaria isolates were provisionally identified. Nineteen isolates were selected for DNA sequencing and phylogenetic analysis. All 19 isolates were confirmed as Alternaria with a division into two distinct clades. Seventeen of these isolates were screened for anti-fungal activity against 4 species of plant pathogenic fungi: Colletotrichum gloeosporioides, Thielaviopsis paradoxa, Ceratocystis paradoxa and Myrothecium roridum.Alternaria isolates 1B, 5B1 and 7A3 inhibited T. paradoxa mycelial growth by 50, 40 and 10% respectively. The non-volatile metabolites produced by 1B were fungistatic against T. paradoxa, reducing mycelial development by 89% and 99% after incubation for 4 and 11 days respectively. This isolate is a promising candidate for use in biological control of this phyto-pathogen, demonstrated the potential of the restinga biome as a source of interesting endophytic fungi.