Induction, growth, and characteristics of embryonic cell suspension culture of wild bananas (Musa acuminata ssp.)

Abstract

Wild bananas and their relatives are potentially utilized for pre-breeding due to their genetic diversity, disease resistance, and tolerance to abiotic stress, and other desirable traits. The embryonic suspension culture of wild bananas provides a means to harness this genetic diversity for banana genetic improvement. This paper elucidates the response of different subspecies M. acuminata (ssp. malaccensis, microcarpa, sumatrana, and breviformis) to the induction, growth, and behavior of suspension cultures and their regeneration into plantlets. Different subspecies exhibit varied responses starting from the embryogenic culture induction stage, culture proliferation, to plantlet formation. The highest competence for plant regeneration through somatic embryogenesis was found in ssp. malaccensis, followed by microcarpa, sumatrana, and breviformis. The wild banana embryogenic culture consists of somatic embryos, somatic embryo masses, proembryos, and proembryonic masses, and it proliferates through somatic embryo budding and proembryo proliferation. Maintenance and proliferation of suspension cultures were achieved through subculturing medium-sized cell aggregates (300 to 1000 µm). With an inoculum density of 0.3 g per 30 mL medium, the culture’s proliferation rate reached seven times within 25 d. Embryogenic cultures from the suspensions of ssp. malaccensis and microcarpa were capable of forming somatic embryos upon transfer to a semi-solid somatic embryo development medium and later developed shoots on a semi-solid plant regeneration medium, with conversion efficiencies of 35% and 17%, respectively.