Bananas are the world’s number four food commodity after rice, wheat, and corn. In 2013, world banana productivity reached 105.96 million tons, Indonesia ranked sixth banana-producing countries with a total production of 6% 5680 ton / ha) with the export value of 2979 US dollars of the total world production (FAOSTAT Production and Trade, 2016). One of the local banana cultivars Indonesia that have economic potential is pisang tongka langit (Musa troglodytarum L.). pisang tongka langit grow naturally only in eastern Indonesia, namely in Maluku to the territory of French Polynesia (Lim, 2012). Pisang tongka langit has unique characteristics compared with bananas in general that has bunches that grow upwards, has purple sap and are generally resistant to pests and diseases. Maluku is being developed pisang tongka langit as an alternative foodstuff and used as a raw material for medicine (Karuwal, 2011).
Pisang tongka langit is an interspecific hybrids, that including bananas group Australimusa (Ploetz et al, 2007). However, the genetic data of the banana fei still very little reported. One of the advantages of pisang tongka langit more than others banana is higher beta-carotene in the pulp. Beta-carotene is a carotenoid pigment that is widely used in industry as a nutraceutical supplements, additives to enrich the nutritional content of the food, cosmetic and pharmaceutical industries (Reyes et al, 2013; Zao et al, 2013). ?-carotene is a precursor of vitamin A that is necessary in the human diet, because beta-carotene is more efficiently converted into retinol (West, 2000). Pisang tongka langit which processed in a way cooking contains 4960 mg of beta-carotene per 100 g (ref?). The content of beta-carotene in pisang tongka langit can be observed with ages of pisang tongka langit until it reaches the friut ripening process. Moreno et al (2013) showed that the gene Lcyb namely DcLcyb1 expressed in leaves and tubers carrot roots during development and correlates with increasing amount of carotenoids. Similarly, Smita et al (2013) showed that the process of fruit ripening tomatoes is associated with changes in carotenoid profile and the accumulation of lycopene.
Bananas are included in the group climateric fruit which the ripening stages are associated with an increased rate of respiration and ethylene production. The ripening process of the climateric fruit regulated by three consecutive enzymes that SAM synthetase (S-adenosylmethionine synthetase), ACC synthase (ACS) and ACC oxidase (ACO). SAM synthetase catalyses methionine to SAM (S-adenosylmethionine). SAM became MTA (5-methylthioadenine) which entered into methionine cycle into a sulfur atom and 1-aminocyclopropane-1-carboxylic acid (ACC) is catalyzed by ACC synthase (ACS). Furthermore, in the presence of oxygen, ACC oxidase (ACO) will catalyze the ACC into ethylene and CO2 (Yang and Hoffmann, 1987). ACC synthase enzyme encoded by the gene ACS while ACC oxidase encoded by ACO genes. ACS and ACO genes are a gene family whose expression regulated by many different signals such as the environment, the development of the fruit, and the number of plant hormones. Research on both genes are widely performed in the banana Musa acuminata but has never been studied in pisang tongka langit (Musa troglodytarum L.). Therefore, this preliminary study is important to compare gene homology of both genes between pisang tongka langit (Musa troglodytarum L.) and other bananas.