Genetic transformation of banana with Extracellular Secreted Plant ferredoxin-like protein (ES-Pflp) gene

Abstract

Abstract. Wanjiku SM, Runo S, Tripathi L. 2021. Genetic transformation of banana with Extracellular Secreted Plant ferredoxin-like protein (ES-Pflp) gene. Asian J Trop Biotechnol 18: 55-68. Banana Xanthomonas Wilt (BXW) is the most damaging disease of banana (Musa spp.) in East Africa. It is caused by Xanthomonas campestris pv. musacearum (Xcm). This disease has no effective control strategies. All banana cultivars are susceptible to BXW disease. Due to their sterility and long generation life cycle, most cultivated cultivars are triploids, hence difficult to enhance through conventional breeding. Genetic engineering provides an alternative and successful method of BXW disease prevention. The purpose of this work was to express the Extracellular Secreted Plant ferredoxin-like protein (ES-Pflp) gene in bananas and to assess the resistance of transgenic lines to Xcm. A signal peptide guides the Pflp to the extracellular area of the cell. In Arabidopsis, ES-Pflp has been found to provide bacterial resistance. Thus, overexpression of ES-Pflp in a banana is expected to boost resistance to Xcm. Co-cultivation of Gross Michel and Sukali Ndizzi Embryogenic Cell Suspensions (ECSs) with Agrobacterium strain EHA105 carrying the binary vector pBI-ES-Pflp, followed by the selection of kanamycin-resistant calli and regeneration of plantlets. Transgenic banana plants producing an ES-Pflp gene were produced using the constitutive promoter of the Cauliflower mosaic virus 35S. Polymerized Chain Reaction (PCR), Southern blot hybridization, and Reverse Transcription Polymerized Chain Reaction (RT-PCR) studies of transgenic lines demonstrated sustained transgene incorporation and expression. Growth research shows that most transgenic lines grew similarly to non-transgenic plants under glasshouse conditions and thus were proceeded to screening for resistance to BXW disease. Agronomic data were collected on all screened lines and compared to control lines. Transgenic lines were screened for increased resistance to BXW disease by artificial inoculation with Xcm. Developing banana cultivars resistant to BXW would increase banana production and help farmers who rely on bananas as a staple food and income crops maintain food security.