Improved callus induction from immature seed of Indonesian wild banana (Musa acuminata ssp. malaccensis and rutilifes) for gene editing materials

Abstract

As a country rich in biodiversity, Indonesia possesses large numbers of wild bananas as valuable germplasm which are potential for banana breeding as they are rich of genetic variability for disease resistance, stress tolerance and other beneficial characteristics. Conventional breeding is hampered by low fertility which has caused inefficiency in producing improved varieties. Tissue culture has been applied to harness banana genetic improvement to produce massive banana plants that are identical to their parents which callus could also be used as materials for modern genetic engineering. This paper aims at investigating the response of several M. acuminata subspecies i.e. ssp. malaccensis and ssp. rutilifes in differ. Calli of these subspesies were induced from immature seeds that were inoculated using modified macronutrient and plant growth regulator. The research was designed using a completely randomized design with two factors, modified macro substances (Murashige and Skoog MS and modified Gamborg’s B5 BDS) and modification of growth regulators combination, including 2,4D, NAA, IAA and BA. Different macro elements led to different percentage of callus formed on Musa acuminata seeds. Ratio of callus production of var. malaccensis was higher on BDS media (67.49%) than on MS media (58.17%). In contrast, that of seeds of Musa acuminata var. rutilifes was higher on MS media (67.34%) than BDS media (65.29%). Growth regulator composition and concentration were also critical as media containing 2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L) were better than a combination of 2,4D (1 mg/L) + NAA (1 mg/L) and BA (1 mg/L) in callus induction in both Musa acuminata subspecies malaccensis and rutilifes (68.14% and 68.42% respectively). Meanwhile, the growth regulator treatment combination of (2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L)) has induced 68.14% calli and 68.42% of spp, malaccensis and rutilifes respectively. Therefore, for propagating banana ssp. malaccensis and rutilifes as source of materials for genetic transformation using gene editing, BDS media containing (2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L)) will be used. Embryogenic callus as the source of protoplasts would be the best regeneration procedure of transformed gene edited wild banana in the near future.