Involvement of fusaric acid detoxification by Pseudomonas fluorescens strain Pf10 in the biological control of Fusarium wilt of banana caused by Fusarium oxysporum f. sp cubense
R. Thangavelu et al., Involvement of fusaric acid detoxification by Pseudomonas fluorescens strain Pf10 in the biological control of Fusarium wilt of banana caused by Fusarium oxysporum f. sp cubense, Z PFLANZENK, 108(5), 2001, pp. 433-445
Citations number
53
Categorie Soggetti
Plant Sciences
Journal title
ZEITSCHRIFT FUR PFLANZENKRANKHEITEN UND PFLANZENSCHUTZ-JOURNAL OF PLANT DISEASES AND PROTECTION
Several strains of Pseudomonas fluorescens were isolated from the rhizosphe
re of banana (Musa sp.). These isolates were tested for their antagonistic
effect towards the banana Fusarium wilt pathogen, Fusarium oxysporum f. sp.
cubense (Foc) in vitro. Among the 11 isolates tested, Pf10 was the most ef
fective in inhibiting the mycelial growth of Foc. The strain Pf10 was capab
le of growing in medium containing fusaric acid (100 mug/ml), a toxin isola
ted from the culture filtrate of Foc. The detoxification of fusaric acid (F
A) by P. fluorescens was demonstrated in tomato by the loss of wilt-inducin
g ability of the culture filtrate of P. fluorescens that had been grown in
medium containing FA. Several proteins were secreted by P. fluorescens stra
in Pf10 into the culture medium when it was grown in medium containing fusa
ric acid. Among them, the 60-kDa protein was predominant. The N-terminal am
ino acid sequence of the 60-kDa protein shows substantial sequence homology
(above 90%) with amino-peptidase of Pseudomonas aeruginosa. To investigate
whether the gene (s) involved in fasaric acid detoxification resides on th
e plasmids in P. fluorescens, plasmid deficient strain of P. fluorescens st
rain Pf10 was developed by plasmid curing. The plasmid deficient strain (Pf
10P(-)) lost its ability to detoxify fusaric acid. The P. fluorescens strai
n Pf10 and Pf10P(-) were tested for their efficacy in controlling Fusarium
wilt of banana under greenhouse conditions. Soil application of banana with
P. fluorescens strain Pf10 reduced the wilt incidence by 50% compared with
the control. Whereas, the plasmid deficient strain of P. fluorescens faile
d to control Fusarium wilt.