Abstract
Interfering RNA technology has been established as an effective strategy to protect plants against viral infection. Despite this success, interfering RNA (RNAi) has rarely been applied due to the regulatory barriers that confront genetically engineered plants and concerns over possible environmental and health risks posed by non-endogenous small RNAs. ‘HoneySweet’ was developed as a virus-resistant plum variety that is protected by an RNAi-mediated process against Sharka disease caused by the plum pox virus. ‘HoneySweet’ has been approved for cultivation in the United States but not in countries where the plum pox virus is endemic. In this study, we evaluated the long-term efficacy of virus resistance in ‘HoneySweet,’ the nature and stability of its sRNA profile, and the potential health risks of consuming ‘HoneySweet’ plums. Graft-challenged ‘HoneySweet’ trees carrying large non-transgenic infected limbs remained virus-free after more than 10 years in the field, and the viral sequences from the non-transgenic infected limbs showed no evidence of adaptation to the RNAi-based resistance. Small RNA profiling revealed that transgene-derived sRNA levels were stable across different environments and, on average, were more than 10 times lower than those present in symptom-less fruits from virus-infected trees. Comprehensive 90-day mouse feeding studies showed no adverse health impacts in mice, and there was no evidence for potential siRNA off-target pathologies predicted by comparisons of the most abundant transgene-derived sRNAs to the mouse genome. Collectively, the data confirmed that RNAi provides a highly effective, stable, and safe strategy to combat virus diseases in crop plants.
Highlights
The recent decision by the European Food Safety Authority (EFSA) to regulate gene-edited crops has sparked a re-evaluation of past and future advanced breeding strategies for crop improvement
Derived from genetic engineering in the mid-1990s (Gottula and Fuchs, 2009). These first-generation crops were developed based on the concept of pathogen-derived resistance (PDR), which relied on the overexpression of viral coat protein genes in the plant (Beachy, 1997)
Fruit and leaf material were shipped from Europe under Animal and Plant Health Inspection Service (APHIS) permit number P526P-11-02618 to APHIS inspection facilities before being forwarded from APHIS to the United States Department of Agriculture (USDA), Kearneysville, West Virginia (WV) where the tissue was frozen in liquid N2, lyophilized, and stored at −20◦C
Summary
The recent decision by the European Food Safety Authority (EFSA) to regulate gene-edited crops has sparked a re-evaluation of past and future advanced breeding strategies for crop improvement. Derived from genetic engineering in the mid-1990s (Gottula and Fuchs, 2009) These first-generation crops were developed based on the concept of pathogen-derived resistance (PDR), which relied on the overexpression of viral coat protein genes in the plant (Beachy, 1997). It was not until the late 1990s that RNA interference (RNAi) mechanisms were discovered and later attributed to the resistance observed in some of these plants (Fire et al, 1998; Ruiz et al, 1998; Hamilton and Baulcombe, 1999). This broader use of RNAi technology has prompted renewed concerns over its stability, long-term efficacy, and health and environmental risks
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
