Recent developments in modern biotechnology such as the use of RNA interference (RNAi) have broadened the scope of crop genetic modification. RNAi strategies have led to significant achievements in crop protection against biotic and abiotic stresses, modification of plant traits, and yield improvement. As RNAi-derived varieties of crops become more useful in the field, it is important to examine the capacity of current regulatory systems to deal with such varieties, and to determine if changes are needed to improve the existing frameworks. We review the biosafety frameworks from the perspective of developing countries that are increasingly involved in modern biotechnology research, including RNAi applications, and make some recommendations. Malaysia and India have approved laws regulating living modified organisms and products thereof, highlighting that the use of any genetically modified step requires regulatory scrutiny. In view of production methods for exogenously applied double-stranded RNAs and potential risks from the resulting double-stranded RNA-based products, we argue that a process-based system may be inappropriate for the non-transformative RNAi technology. We here propose that the current legislation needs rewording to take account of the non-transgenic RNAi technology, and discuss the best alternative for regulatory systems in India and Malaysia in comparison with the existing frameworks in other countries.
The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6). Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.