Endophytic Bacillus spp. Mediated Plant Growth Promotion of Tomato Seedlings and Suppression of Meloidogyne incognita and Fusarium oxysporum Disease Complex

• Published in: Journal of plant growth regulation 2024-07, Vol.43 (7), p.2454-2469
• Main Authors: Maqsood, Ambreen, Aslam, Muhammad Naveed, Khaliq, Huma, Shakeel, Muhammad Taimoor, Wu, Haiyan, Fahad, Shah
• Format: Article
• Language: English
• Subjects: Acetic acid; Agriculture; Allelochemicals; Antifungal activity; Bacillus; Bacillus megaterium; Biological control; Biomedical and Life Sciences; Disease control; Endophytes; Fungi; Fungicides; Fusarium oxysporum; Gas chromatography; Genes; Life Sciences; Mass spectrometry; Mass spectroscopy; Meloidogyne incognita; Mortality; Nematodes; Organic compounds; Oxidative stress; Plant Anatomy/Development; Plant diseases; Plant growth; Plant Physiology; Plant Sciences; Root knot; Seedlings; Tomatoes; VOCs; Volatile compounds; Volatile organic compounds; Volatiles; Wilt
• ISSN: 0721-7595; 1435-8107
• DOI: 10.1007/s00344-024-11279-x

Bacillus volatiles to control fungus and root-knot nematodes are a topic of great interest among researchers due to their safe and environmentally friendly nature. Bacillus megaterium GIUBAM-2020 showed high nematicidal activity against Meloidogyne incognita , with 92% mortality compared with control and antifungal activity against Fusarium oxysporum by producing a 3 cm in vitro mycelial inhibition zone. Pure volatiles produced by Bacillus. megaterium GIUBAM-2020 was identified through gas chromatography and mass spectrometry (GC–MS). Among fourteen volatile organic compounds (VOCs), only one volatile compound, i.e., 2-(Ethyl-imidazol-yl) acetic acid hydrochlorid, showed strong nematicidal and antifungal activity with a mortality rate of 95% at 0.3 ng/mL after 72 h and 100% inhibition zone of fungus at 1.5 µg/mL, respectively. The VOCs-induced severe oxidative stress in nematodes, which caused rapid death. Moreover, in the presence of Bacillus megaterium GIUBAM-2020 the disease index decreased in tomato seedlings as compared to single application of F. oxysporum and M. incognita . Moreover, genes responsible for plant growth promotion SlCKX1 , SlIAA1 , Sipin6 and Exp18 showed an upsurge in expression, in tomato plants treated with bacterial antagonistic and challenged with the disease complex of Fusarium oxysporum and Meloidogyne incognita . Furthermore, the defence-related genes ( PR1 , PR5 ) in infested tomato plants were upregulated after treatment with Bacillus megaterium GIUBAM-2020. These findings suggest Bacillus megaterium GIUBAM-2020 possesses excellent biocontrol potential against Meloidogyne incognita and Fusarium oxysporum , by upregulating the key genes involved in plant growth promotion, and the defense mechanism. Therefore, it is concluded Bacillus megaterium GIUBAM-2020 efficiently controls Meloidogyne incognita and Fusarium oxysporum -infested tomato plants wilt disease complex.