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Antagonist effects of Bacillus spp. strains against Fusarium graminearum for protection of durum wheat (Triticum turgidum L. subsp. durum)

Zalila-Kolsi, Imen, Ben Mahmoud, Afif, Ali, Hacina, Sellami, Sameh, Nasfi, Zina, Tounsi, Slim, Jamoussi, Kaïs
Microbiological research 2016 v.192 pp. 148-158
Bacillus amyloliquefaciens, Bacillus subtilis, Fusarium graminearum, Paenibacillus polymyxa, Triticum turgidum subsp. durum, antagonists, bacteria, biological control, biological control agents, carotenoids, chlorophyll, cultivars, culture media, durum wheat, iturin, microbial culture, phenolic compounds, plant diseases and disorders, plant pathogenic fungi, polymyxins, ribosomal DNA, seed germination, surfactin
Bacillus species are attractive due to their potential use in the biological control of fungal diseases. Bacillus amyloliquefaciens strain BLB369, Bacillus subtilis strain BLB277, and Paenibacillus polymyxa strain BLB267 were isolated and identified using biochemical and molecular (16S rDNA, gyrA, and rpoB) approaches. They could produce, respectively, (iturin and surfactin), (surfactin and fengycin), and (fusaricidin and polymyxin) exhibiting broad spectrum against several phytopathogenic fungi. In vivo examination of wheat seed germination, plant height, phenolic compounds, chlorophyll, and carotenoid contents proved the efficiency of the bacterial cells and the secreted antagonist activities to protect Tunisian durum wheat (Triticum turgidum L. subsp. durum) cultivar Om Rabiia against F. graminearum fungus. Application of single bacterial culture medium, particularly that of B. amyloliquefaciens, showed better protection than combinations of various culture media. The tertiary combination of B. amyloliquefaciens, B. subtilis, and P. polymyxa bacterial cells led to the highest protection rate which could be due to strains synergistic or complementary effects. Hence, combination of compatible biocontrol agents could be a strategic approach to control plant diseases.