Since banana is a vegetatively propagated crop, its production is affected due to the build-up of several pests and pathogens, particularly where several co-exist (Tripathi et al., 2020). The most significant diseases are banana Xanthomonas wilt (BXW), Black Sigatoka, fusarium wilt, banana bunchy top disease, and banana streak disease and pests such as nematodes and weevils.
The use of disease-resistant varieties for many plants has been a productive and economically viable strategy for managing diseases. Yet, no source of resistance has been found against BXW in any cultivated banana varieties; only in the wild-type diploid banana progenitor “Musa balbisiana” exhibits resistance to this pathogen. Transferring the disease resistance trait from wild-type bananas to farmer-preferred cultivars through conventional breeding is a lengthy and challenging process due to the sterility of most cultivars coupled with polyploid and the long generation times.
The lack of natural resistance to this bacterium and the difficulties of conventional breeding with this sterile crop favors biotechnological applications.
The research team developed transgenic bananas expressing the sweet pepper hypersensitive response-assisting protein (Hrap) or plant ferredoxin-like protein (Pflp) genes were developed and tested in the greenhouse and field conditions (Tripathi et al., 2010; Namukwaya et al., 2012). These transgenic bananas show enhanced resistance to BXW through successive crop cycles and have agronomic performance comparable to uninfected control non-transgenic bananas under confined field trials in Uganda. The Pflp and Hrap genes enhance the hypersensitive response (HR) upon pathogen attack and provide resistance to bacterial pathogens. Since pathogens can evolve, and single gene-based disease resistance can break down quickly, we stacked the two genes (Hrap and Pflp) to enhance the trait durability of the product. The transgenic events expressing stacked (Hrap and Pflp) genes showed high resistance to the pathogen similar to the single gene events.
Read the complete research at www.openaccessgovernment.org.