Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Agricultural Engineering, Horticulture, Agriculture, banana, Musa spp., genetic engineering, field trials, GMO, embryogenic cell suspension, Agrobacterium transformation, particle bombardment, EMBRYOGENIC-CELL SUSPENSIONS, AGROBACTERIUM-MEDIATED TRANSFORMATION, MUSA SPP., GENE-EXPRESSION, PLANTAIN MUSA, RESISTANCE, ACUMINATA, AAA, MODEL, ESTABLISHMENT, 0607 Plant Biology, 0706 Horticultural Production, Plant Biology & Botany, 3008 Horticultural production, 3108 Plant biology

Abstract:

Edible bananas comprise several characteristics that make them an ideal target for improvement through genetic engineering: (i) they constitute the N° 1 fresh fruit crop in the world, (ii) they are highly sterile which makes classical breeding extremely difficult but at the same time prevents transgene drift via pollen into the environment, (iii) their cultivation is monoclonal, and (iv) they are susceptible to a wide range of pests and diseases. The latest outbreak of Fusarium wilt disease caused by Fusarium oxysporum f. sp. cubense "Tropical Race 4 or TR4", which is seriously threatening the international banana trade, strengthens the need for developing resistant bananas. Despite these facts, the number of publications and research groups dealing with genetic engineering of banana remains low compared to other crops. Possible reasons are among others the difficulties in obtaining transformation competent tissues (in case of banana embryogenic cell suspensions or ECS), the duration to obtain fully transformed plants, the cost and effort of maintaining transgenic lines, the lack of a proper and functional legal biosafety system for testing and culturing GMOs in many banana producing countries and the size of individual banana plants rendering large scale testing of transgenes extremely costly. In this review, we discuss the 19 years history of banana genetic modification. An overview of the different transformation methodologies will be given, from the first reports on protoplast electroporation to Agrobacterium-mediated transformation of ECS. Also the applications of this technology for banana improvement (agronomic treats, quality treats, etc.) will be discussed along with examples of confined field trials of genetically modified bananas. Finally, a brief overview of the research topics on banana genetic engineering at the Laboratory of Tropical Crop Improvement (LTCI, KU Leuven, Belgium) is discussed. Topics include selectable marker genes, promoter and gene characterization as well as molecular breeding for fungus and drought resistance.