Endophytic Non-Pathogenic Fusarium oxysporum-Derived Dual Benefit for Nematode Management and Improved Banana (Musa spp.) Productivity

Abstract

The banana weevil (Cosmopolites sordidus) and the burrowing nematode Radopholus similis represent two of the most important pests of bananas. Previously, colonization of banana plants by the non-pathogenic Fusarium oxysporum (isolate V5w2) and the entomopathogenic Beauveria bassiana (isolate WA) have been shown to increase host resistance to various banana pests and diseases. However, there is limited data on how the combined inoculation of these isolates would affect field performance of bananas. In this study, the fungal endophytes were inoculated separately and in combination. Tissue cultured plantlets of cooking banana cultivar Mbwazirume and dessert banana cultivar Grande Naine were inoculated by root drenching with a suspension of 1.0 × 107 spores mL−1 of the endophytes on three occasions, separated 4 weeks apart, before transplanting into the field. Each plantlet was further inoculated with 1800 nematodes, composed primarily of R. similis. Inoculation of banana plants with the fungal endophytes significantly reduced nematode densities by >34%. Similarly, plant toppling was lower in the endophyte-enhanced plants (<16.5%) compared with the control (23.3%). We also observed improved yield of the first crop cycle in the endophyte-enhanced plants, which yielded >11 t ha−1 year−1 versus 9 t ha−1 year−1 achieved in the non-inoculated plants. These findings demonstrate the benefits of fungal endophytes in improving the yield of both cooking and dessert bananas via suppression of nematode densities and nematode-related damage.

Soil Microbes Determine Outcomes of Pathogenic Interactions Between Radopholus similis and Fusarium oxysporum V5w2 in Tissue Culture Banana Rhizospheres Starved of Nitrogen, Phosphorus, and Potassium

“…Inoculation of banana plants with F. oxysporum V5w2 is expected to suppress R. similis multiplication and the associated root damage in banana plants (Kumar and Dara, 2021;Kisaakye et al, 2022). This was the case in the study that utilized Nstarved banana plants.…”

“…Potassium deficiency appears to provide physiological conditions that favor pathogenicity of F. oxysporum V5w2 by constraining plant growth, especially in terms of leaf development. These are part of issues that could inform the application of microbial services in Sustainable Food Systems (Timmis et al, 2017), particularly in the pending decision on registration of F. oxysporum V5w2 as a commercial biopesticide (Dubois et al, 2006(Dubois et al, , 2011zum Felde, 2011;Ochieno, 2020Ochieno, , 2021Kisaakye et al, 2022), in line with International Standards for Phytosanitary Measures (ISPM) among other related policies (Wabule et al, 2003;Avedi et al, 2014;KEPHIS, 2014;FAO-ISPM, 2021).…”

“…Induced systemic resistance is among the key mechanisms said to be involved in pest suppression by F. oxysporum V5w2 among other microbial biological control agents (Vu et al, 2006;Paparu et al, 2007Paparu et al, , 2009aPaparu et al, ,b, 2010Bubici et al, 2019;Damodaran et al, 2020). However, future research is still necessary to elucidate the mechanisms underpinning nematode suppression and increased banana yield observed after treatment with F. oxysporum V5w2 (Kisaakye et al, 2022). This is partly because F. oxysporum V5w2 has been reported to be a non-beneficial endophyte that interacts with R. similis in a wilt disease complex of banana (Ochieno, 2020(Ochieno, , 2021.…”

Soil Sterilization Eliminates Beneficial Microbes That Provide Natural Pest Suppression Ecosystem Services Against Radopholus similis and Fusarium Oxysporum V5w2 in the Endosphere and Rhizosphere of Tissue Culture Banana Plants

“…Induced systemic resistance is the main mechanism through which F. oxysporum V5w2 among other strains suppress various pests and diseases of banana (Vu et al, 2006;Paparu et al, 2007Paparu et al, , 2009aPaparu et al, ,b, 2010Paparu et al, , 2013. However, future research is still necessary to elucidate the mechanisms underpinning nematode suppression and increased banana yield observed after treatment with F. oxysporum V5w2 (Kisaakye et al, 2022). Besides this, F. oxysporum V5w2 has been reported to be a non-beneficial endophyte that interacts with R. similis in a wilt disease complex of banana (Ochieno, 2020(Ochieno, , 2021.…”

Endophytic fungi improve management of the burrowing nematode in banana (Musa spp.) through enhanced expression of defence-related genes

“…The shoot tip or TC culture technique (Vuylsteke, 1998), however, also eliminates any beneficial microbes that would otherwise naturally occur and confer protection against pests and diseases ( Pereira et al, 1999). Inoculation of beneficial microbes into TC banana plants at the weaning stage can facilitate their re-establishment into the plant (Paparu et al, 2006;Kisaakye et al, 2022). Identifying the most useful endophytes, however, requires a thorough screening of potential, naturally occurring microbial isolates to assess their performance against key target pest(s) and to confirm the non-phytotoxicity of the potential beneficial microbial isolate(s) to the banana plant.…”