An endophyte of Macrochloa tenacissima (esparto or needle grass) from Tunisia is a novel species in the Fusarium redolens species complex.

Here, we report on the morphological, molecular, and chemical characterization of a novelFusariumspecies recovered from the roots and rhizosphere ofMacrochloa tenacissima(halfa, esparto, or needle grass) in central Tunisia. Formally described here asF. spartum, this species is a member of theFusarium redolensspecies complex but differs from the other two species within the complex,F. redolensandF. hostae, by its endophytic association withM. tenacissimaand its genealogical exclusivity based on multilocus phylogenetic analyses. To assess their sexual reproductive mode, a polymerase chain reaction (PCR) assay was designed and used to screen the three strains ofF. spartum, 51 ofF. redolens, and 14 ofF. hostaefor mating type (MAT) idiomorph. Genetic architecture of theMATlocus in the former two species suggests that if they reproduce sexually, it is via obligate outcrossing. By comparison, results of the PCR assay indicated that 13/14 of theF. hostaestrains possessedMAT1-1andMAT1-2idiomorphs and thus might be self-fertile or homothallic. However, when theF. hostaestrains were selfed, 11 failed to produce perithecia and one only produced several small abortive perithecia. Cirrhi with ascospores, however, were only produced by 8/28 and 4/84 of the variable size perithecia, respectively, ofF. hostaeNRRL 29888 and 29890. The potential for the threeF. redolensclade species to produce mycotoxins, pigments, and phytohormones was assessed by screening whole genome sequence data and by analyzing extracts on cracked maize kernel cultures via liquid chromatography-mass spectrometry.