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

James Kisaakye,Hendrika Fourie,Solomy Nakimera,Solveig Haukeland,Sevgan Subramanian,Laura Cortada,Danny Coyne,Joseph Kisitu

doi:10.3390/agriculture12020125

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.

Highlights

Banana (Musa spp.) is a major food and cash crop in more than 135 countries and territories across the tropics and subtropics
In addition to testing the fungal endophyte in a different location from where Waweru et al [25] conducted their study, our study demonstrates the potential use of endophytes to manage multiple nematode species (R. similis, H. multicinctus and Meloidogyne spp.) in dessert banana cultivars as well as in cooking bananas (EAHB), indicating the broader spectrum of applicability for fungal endophyte(s)
This study demonstrated that inoculation of the East African highland banana cultivar Mbwazirume and the dessert banana cultivar Grande Naine with the non-pathogenic endophytic fungus F. oxysporum isolate V5w2 suppresses nematode infection and increases banana productivity

Summary

Introduction

Banana (Musa spp.) is a major food and cash crop in more than 135 countries and territories across the tropics and subtropics. The crop ranks second in fruit production with a global production estimated at approximately 167 million metric tons (t) [1] feeding more than 400 million people. The cooking bananas are produced primarily for home consumption, local and regional markets, with over 85% consumed in-country. Dessert bananas are majorly cultivated for commercial purposes, and sold both on the local and international markets. In 2016, the estimated trade value for bananas was US$11.5 billion [2], with Africa responsible for approximately 33% of the global banana production. In 2018, approximately 10% of the global banana production was produced in the East African region [1]. In some East African countries, banana provides up to 60% of the daily calorie intake. Uganda has the highest consumption at >0.5 kg person−1 day−1

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