Studying the possibility of usage of culture filtrate produced by a non-pathogenic Fusarium sambucinum isolate FS-94 for carrot protection against Alternaria radicina

A high-molecular weight fraction produced by a nonpathogenic F. sambucinum isolate FS-94 was obtained from cultural liquid of the fungus using an ultrafiltration membrane MWCO 30 kDa, and the ability of this fraction to protect carrot plants against black rot (A. radicina) was studied. Application of the investigated fraction on plant tissue simultaneously with inoculation by the causative agent or one day before the inoculation resulted in significant reduction of lesion area on isolated petioles and root dises in carrot cultivars with different susceptibility to the pathogen. It was shown that the tested fraction suppressed A. radicina spore germination and induced an oxidative burst in a suspension culture of plant cells. The potential of the use of FS-94 extracellular metabolites for carrot protection against black rot disease is discussed.