Transient virus-induced gene silencing of MaBAM9b efficiently suppressed starch degradation during postharvest banana fruit ripening
Mengting Liu, Meng Li, Yudi Wang, Jingyi Wang, Hongxia Miao, Zhuo Wang, Biyu Xu, Xinguo Li, Zhiqiang Jin and Juhua Liu
Plant Biotechnology Reports 15: 527–536.
2021
บทคัดย่อ
The genetic basis of metabolic pathways that operate during fruit ripening needs to be understood before the nutritional value of the banana can be improved. The banana is a typical starch conversion fruit, and β-amylase is a key enzyme that may play an important role in starch degradation during the ripening process. Musa acuminata β-amylase 9b (MaBAM9b) is closely related to starch degradation. However, its exact function in starch degradation has not been demonstrated in banana. Stable genetic transformation to identify gene function is a time- and energy-consuming process. Thus, an efficient and rapid method is needed for functional identification. Virus-induced gene silencing (VIGS) is a reverse-genetics method based on RNA-mediated antiviral plant defense that has been used to rapidly identify gene functions in plants. The aim of this study was to optimize a transient VIGS system and functionally elucidate MaBAM9b in postharvest banana fruit. Using 2- to 4-mm-thick fruit slices, vacuum infiltration of suspensions of Agrobacterium strains carrying TRV1 and TRV2-MaBAM9b, 0.5% iodine-potassium-iodide (I2-KI) staining for 150 s, and 1:3 TRV1:TRV2-MaBAM9b cultivation at 30 mmHg for 30 s achieved an optical density (OD) of 0.8 at 600 nm; after being incubated on Murashige and Skoog (MS) media for 5 days (d), starch degradation was efficiently suppressed during postharvest banana fruit ripening, as determined by I2-KI staining, total starch content, β-amylase activity, soluble sugar content, and endogenous MaBAM9b expression. The system described here is particularly useful for studying genes and networks involved in starch conversion in fruits, which alone would not produce a visual phenotype. This system will provide a platform for functional genomics and fruit quality improvement in banana.