Effectiveness of Fungal and Bacterial Isolates from Rhizosphere of Passion Fruits againts Fusarium oxysporum f. sp passiflorae in Vitro

Abstract

Fusarium wilt caused by Fusarium oxysporum f.sp passiflorae is the most important disease on passion fruit that causes yield losses ranging from 50 to100%. The disease is difficult to control because the pathogen systematically infected plants and can survive up to five years in the soil in the absence of its hosts. The objective of this paper was to select potential antagonistic microbes in suppressing the growth of Fusarium oxysporum f.sp passiflorae (Fop) in vitro. Antagonists were isolated from the rhizosphere of purple passion fruit (Passiflora edulis form edulis) and sweet passion fruit (Passiflora sp) from Gowa and Makassar. To obtain the best isolates, their ability to inhibit the growth of Fop and their production of cellulase, chitinase, pectinase as well as toxine compound were tested in vitro. The results showed that out of 22 fungal and bacterial isolates tested, four and three isolates respectively, gave an excellent growth inhibition to Fop. Highest percentage of growth inhibition was provided by fungal isolate U1 (86.11%) and bacterial isolate Mb2 (76.44%). The highest cellulase, chitinase and pectinase enzyme production were observed on fungal isolate U1, followed by isolates U7, M1, M2 and M4. Only two bacterial isolates Ub1 and Mb3 showed highest cellulase, chitinase and pectinase enzyme production. The presence of toxin was detected by using a thin layer chromatography on fungal isolates U1, M4 and Mb3. HCN compound from bacterial isolates were obtained from isolates Ub1 and Mb3.