Induction of somatic embryogenesis in recalcitrant Musa spp. by media manipulation
In banana (Musa L.), somatic embryogenesis (SE) is a high throughput technique for mass propagation of quality planting material, genetic transformation and induced mutations. Through SE, a large number of plantlets can be generated from 1 mL settled cell volume of embryogenic cell suspension (ECS). Although SE is well reported in selected banana cultivars, most of the commercial cultivars are recalcitrant to SE. Knowledge of the genes responsible for SE is important to induce SE in recalcitrant cultivars. So attempts were made to identify the genes responsible for embryogenic callus (EC) induction, regeneration and germination of somatic embryos in ‘Grand Naine’ (subgenome: AAA) through proteomic approaches. Based on the results of proteomic analysis, the callus induction and somatic embryo germination medium was modified and validated in four recalcitrant cultivars (‘Red Banana’ - AAA, ‘Monthan’ - ABB, ‘Karpuravalli’ - ABB and ‘Ney Poovan’ - AB) with one potential ‘Grand Naine’ as control. It was observed that tryptophan supplemented media induced more EC in two recalcitrant cultivars, ‘Ney Poovan’ and ‘Monthan’, than the others. Greatest EC was induced for ‘Red Banana’ using media supplemented with kinetin, whereas it was greatest using CaCl2 supplemented media for ‘Karpuravalli’. The above results revealed that EC induction in banana is not only genome specific but also cultivar specific. ECS was successfully established in all recalcitrant cultivars tested in the experiment. Simultaneously, different media were tested for germination success. The highest proportion of germination for ‘Grand Naine’ was achieved in media supplemented with naphthalene acetic acid and gibberellic acid, whereas for ‘Rasthali’, more somatic embryos germinated in CaCl2 enriched media than in others. Further analysis of available proteomic data will be useful to the scientific community for the establishment of SE in other commercial cultivars. The ECS obtained will be further multiplied using bioreactors for large scale production of quality planting material. As a result, more plantlets will be efficiently produced in a shorter time, thus reducing costs for small and marginal farmers. The results obtained from the present study will help meet the growing demand for quality planting material, and improve commercial cultivars through genetic transformation and mutation breeding.
Kumaravel Marimuthu won an ISHS Young Minds Award for the best poster presentation at the XI International Symposium on Banana: ISHS-ProMusa Symposium on Growing and Marketing Banana under Subtropical Conditions at the IHC2018 in Turkey, in August 2018.
Kumaravel Marimuthu, Crop Improvement Division, ICAR - National Research Centre for Banana, Thayanoor post, Tiruchirappalli, Tamil Nadu, India, Mobile: +919940229272, e-mail: email@example.com
The article is available in Chronica Horticulturae