Streptomyces Strains Induce Resistance to Fusarium oxysporum f. sp. lycopersici Race 3 in Tomato Through Different Molecular Mechanisms

• Published in: Frontiers in microbiology Vol. 10; p. 1505
• Main Authors: Abbasi, Sakineh, Safaie, Naser, Sadeghi, Akram, Shamsbakhsh, Masoud
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 03-07-2019
• Subjects: Fusarium wilt; induced systemic resistance; Microbiology; siderophore production; Streptomyces; tomato growth promoting; Streptomyces; induced systemic resistance; tomato growth promoting; Fusarium wilt; siderophore production
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2019.01505

Plant growth promoting rhizobacteria (PGPR) are potential natural alternatives to chemical fungicides in greenhouse production via inducing plant immune system against biotic stresses. In this research, 126
isolates were recovered from rhizosphere soils of 13 different commercial vegetable greenhouses in Iran.
isolates were screened for
Plant growth promoting (PGP) traits and ability to antagonize
f. sp.
race 3 (
), the causal agent of Fusarium wilt of tomato (FWT). Six isolates with the highest antagonistic activity and at least three PGP traits were selected and compared with chemical fungicide Carbendazim
in a greenhouse experiment. All bacterial treatments mitigated FWT disease symptoms like chlorosis, stunting and wilting at the same level or better than Carbendazim
. Strains IC10 and Y28 increased shoot length and shoot fresh and dry weight compared to not inoculated control plants. Phenotypic characterization and 16S rRNA gene sequencing showed, strains IC10 and Y28 were closely related to
and
, respectively. The ability of the superior biocontrol strains to induce antioxidant enzymes activity and systemic resistance (ISR) was investigated. Increased activity of catalase (CAT) in plant treated with both strains as well as an increase in peroxidase (POX) activity in plants treated with Y28 pointed to a strain specific-induced systemic resistance (ss-ISR) in tomato against
. The differential induced expression of
and
(two transcription factors involved in plant defense) and
and
by the analyzed
strains, especially after inoculation with
, suggests that ss-ISR is triggered at the molecular level.