Boesenbergia rotunda is a medicinal ginger that has been found to contain several bioactive compounds such as
boesenbergin A, panduratin A, cardamonin, pinostrobin and pinocembrin. These compounds are useful in treating various
ailments, such as oral diseases, inflammation and have also been used as an aphrodisiac. In this study, an efficient
protocol for developing and isolating protoplast cultures for B. rotunda has been established. Rhizome buds of B. rotunda
were used as explants to initiate callus growth and the established cell suspension cultures were used to optimize their
growth conditions. Our results indicated that embryogenic suspension cultures in liquid Murashige and Skoog (MS)
medium supplemented with 3% (w/v) sucrose produced the highest growth rate (µ = 0.1125), whereas no promotive effect
was seen in the presence of 2,4-dichlorophenoxyacetic acid and those that underwent sonication treatment. Amount of
protoplasts isolated ranging from 1-5 × 105
protoplast per mL were isolated using 0.25% (w/v) macerozyme and 1%
(w/v) cellulase for 24 h under continuous agitation (50 rpm) in dark condition. Of the isolated protoplasts, 54.93% were
viable according to fluorescein diacetate staining test. Micro-colonies were recovered in liquid MS medium containing
9 g/L mannitol, 2 mg/L 1-naphthaleneacetic acid and 0.5 mg/L benzylaminopurine (BAP) for 4 weeks and subsequently
transferred to solid MS medium supplemented with 0.5 mg/L BAP for callus initiation. The protoplast system established
in this study would be useful for genetic manipulation and modern breeding program of B. rotund
PR-10 is a member of pathogenesis-related (PR) genes elicited by the plant’s defense mechanism during pathogen attack.
Elevated expression of PR-10 upon different pathogen invasions has been observed in many plant species suggesting
its role as an anti-bacterial, anti-viral and anti-fungal gene. However, the effect of PR-10 in mitigating the infection of
Fusarium oxysporum f. sp. cubense (Foc), the causal agent of Fusarium wilt in banana has not been reported. In this
study, the coding sequences of PR-10 gene isolated from Foc resistant Musa acuminata ssp. malaccensis (MaPR-10)
were integrated into a local Foc susceptible commercial banana cultivar, Berangan via co-cultivation of embryogenic
cell suspension and Agrobacterium tumefaciens. Out of 17 putative transgenic lines established, 11 of them positively
harbored MaPR-10. Among these, Line-19 plantlets showed the most rapid in-vitro propagation and successfully overexpressed the transgene. Following a nursery challenge experiment with a virulent Foc race 4 (CI HIR) isolate, about 30%
of Line-19 plants showed a one-week delay in disease progression when compared to the untransformed controls. From
the final evaluation performed in the 5th week-post-inoculation, the leaf symptoms index (LSI) and rhizome discoloration
index (RDI) of Line-19 was 3.4 and 6.1, respectively, indicating the disease had progressed. The findings of this study
enrich the current existing knowledge on the roles of PR-10 in combating fungal disease in plants.