Characteristics of Poppy Phytopathogen Alternaria papavericola Strain 1.39 Producing Bioherbicide (+)-cis-Sclerosporide

Phytopathogenic fungi of the genus Alternaria cause black spot (helminthosporiasis) disease and therefore apply to develop bioherbicides for controlling weeds and illegal vegetation of narcotic plants such as opium poppy (Papaver somniferum subsp. somniferum). In this report, Alternaria papavericola strain 1.39 was identified using sequencing of the ITS region and characterized. Strain 1.39 produced auxins and abscisic acid, did not produce salicylic, jasmonic, or gibberellic (GA3) acids, and did not metabolize any of these phytohormones. Strain 1.39 produced siderophores but showed no 1-aminocyclopropane-1-carboxylate deaminase activity and did not solubilize phosphates Ca3(PO4)2, Ca-phytate, Al3PO4, or Fe3PO4. Extracts from the culture liquid of strain 1.39 caused necrosis in leaves of poppy and, to a lesser extent, on creeping thistle, tomato, and wheat leaves. Strain 1.39 inhibited poppy seed germination energy by 80%, reduced shoot biomass by 77%, and resulted in the death of 75% of poppy plants in a pot experiment. The phytotoxin was isolated from the culture liquid of this fungus using chromatographic methods. Detailed study of structure of this phytotoxin by a complex of physicochemical methods revealed that it is (+)-cis-sclerosporide(1S,2S,3S,4R,5S,6R)-2,3,5-trihydroxy-4,6-dimethoxycyclohexyl-(1R,5S,6S)-5-isopropyl-8-methylbicyclo[4.4.0]deca-2,7-diene-2-carboxylate). The results showed possibility for application of A. papavericola 1.39 as bioherbicide against opium poppy.