An endophytic Fusarium sp. isolated from Monarda citriodora produces the industrially important plant-like volatile organic compound hexanal.

An endophytic fungus, MC_25L, has been isolated from the leaves of MonardacitriodoraCerv. ex Lag., a medicinal and aromatic herb from the northwestern Himalayas. It produces a fruity fragrance while growing on potato dextrose agar, suggesting that it is producing volatile organic compounds (VOCs). The endophyte inhibited the growth of plant pathogens such asSclerotiniasp. and Aspergillusflavus by virtue of VOCs. Identification of MC_25L based on morphological and microscopic features, as well as ITS-based rDNA sequence analysis, revealed that it is a Fusariumsp. GC-MS analysis revealed that this endophyte produces a unique array of VOCs, in particular hexanal, p-fluoroanisole, pentafluoropropionic acid 2-ethylhexyl, (5E)-5-ethyl-2-methyl-5-hepten-3-one, 2-butyl-2-hexanol, (7E)-2-methyl-7-hexadecene and acoradiene. Three major compounds were hexanal, (5E)-5-ethyl-2-methyl-5-hepten-3-one and acoradiene, and they account for around 84.57 % of the total VOCs. Moreover, of interest was the presence of hexanal, which has applications in the food and cosmetic industries, as well as in mycofumigation. This is the first report of a fungal endophyte producing the industrially important plant-like VOC hexanal. Hexanal is also active biologically. Thus this study indicates that Fusariumsp. (MC_25L) is a potential candidate for the up-scaling of hexanal.