Use of somatic embryogenesis as a vehicle for cotton transformation

Cotton has been aptly described as the prosperity plant owing to its unrivalled economic importance as a source of feedstock, food and oil, as well as raw material for diverse industrial applications, ranging from textile and footwear to automobiles, energy, medical and pharmaceutical. As such, over 180 million people of the world depend on its production for livelihood. However, cotton production is grossly hampered, and has long been peaked in many regions where it is being grown. Without prejudice to the genetic improvement already made by conventional breeding with respect to yield and quality over the years, genetic transformation is arguably the last recourse for further development of cotton, especially with respect to the prevailing production constraints of insect pests, weeds, environmental stresses and diseases. This review therefore focuses on the use of somatic embryogenesis as a vehicle for cotton genetic transformation. It indeed attempts to overview the challenges of cotton transformation with respect to narrow genetic base coupled with the recalcitrant nature of the crop species, as well as the research success achieved so far. It then discusses the underlying mechanisms of somatic embryogenesis as well as the current constraints and various strategies being used to overcome them; all with the aim of motivating interest groups to initiate research activities in cotton biotechnology and to strive for its optimization for further genetic improvement.