Evaluation of temporary immersion bioreactors for in vitro micropropagation of banana (Musa spp.) and genetic fidelity assessment using flow cytometry and simple-sequence repeat markers

Abstract

Temporary immersion bioreactor (TIB) technology offers a cost-effective means of in vitro micropropagation for large-scale plantlet production, and is increasingly being recognized as a valuable tool in the plant tissue culture industry. However, the limited accessibility of the bioreactor in certain markets is hindering its potential benefits. Here, we report three different TIB systems for large-scale plantlet production in banana. Shoot tip explants of commercially important banana cultivars such as Grand Naine (AAA), Red Banana (AAA), Nendran (AAB), and Ney Poovan (AB) were initiated aseptically in semisolid medium and cultured in the TIB systems using liquid medium supplemented with 4.0 mg/l 6- benzylaminopurine (BAP), 0.2 mg/l indole-3-acetic acid (IAA), and 30 g/l sucrose for shoot multiplication and liquid medium supplemented with 1.0 mg/l indole-3-butyric acid (IBA) and 2.0 mg/l 1-naphthaleneacetic acid (NAA) for rooting of shoots. The liquid media were supplied periodically (2 min for every 6-hr frequency) to the growth vessels and recorded the data on number of shoots per explant, shoot length and number of roots per shoot. The data were compared with explants cultured in semisolid medium. The three TIBs showed superior response over semisolid culture system in shoots per explant, shoot length and number of roots per shoot. There was no significant difference within TIBs in photosynthetic efficiency as measured by chlorophyll pigment analysis. Plantlets cultured in TIBs showed better survival under ex vitro conditions. The genetic integrity of the plantlets grown in TIBs were confirmed by flow cytometry and simple-sequence repeat (SSR) markers analysis. The developed TIBs and protocol can be utilized for commercial purpose.