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Promise and issues of genetically modified crops - Chen & Lin (2013) - Curr Opin Plant Biol

Promise and issues of genetically modified crops - Chen & Lin (2013) - Curr Opin Plant Biol | Biology. | Scoop.it

The growing area of genetically modified (GM) crops has substantially expanded since they were first commercialized in 1996. Correspondingly, the adoption of GM crops has brought huge economic and environmental benefits. All these achievements have been primarily supported by two simple traits of herbicide tolerance and insect resistance in the past 17 years. However, this situation will change soon. Recently, the advance of new products, technologies and safety assessment approaches has provided new opportunities for development of GM crops. In this review, we focus on the developmental trend in various aspects of GM crops including new products, technical innovation and risk assessment approaches, as well as potential challenges that GM crops are currently encountering...

GM crops have been commercially grown for 17 years, but it is still hard to say that they have acquired wide acceptance and support from the public, especially in Europe. For many consumers, it is possibly simply because consuming GM products has no direct benefit for them, as both herbicide tolerance (HT) and insect resistance (IR), which are two primarily targeted traits in GM crops, which only benefit the growers. Consumer preference studies confirmed that GM food would be more desirable for consumers if they provide additional health benefits. The coming of the next generation of GM crops that benefit consumers will soon change the situation. The main target traits of the next generation of GM crops so far include: micronutrients (vitamin A, iron, folate, and ascorbate), fatty acid composition (oleic acid, omega-3 fatty acid), resistant starch, and antioxidants (anthocyanins), etc. … 

In line with the development of new GM products, novel technologies in genetic engineering have been developed as well. Recently, the concept of ‘new biotechnologies’ was proposed by Lusser et al. In their article, seven methods are listed as new biotechnologies: that is, zinc- finger nuclease (ZFN), oligonucleotide-directed muta- genesis (ODM), cisgenesis/ intragenesis, RNA-depend- ent DNA methylation (RdDM), grafting (on GM rootstock), reverse breeding and agro-infiltration. Although most of these new biotechnologies are not really new, they share a ‘new’ core principle: to produce non- GM products based on a genetic modification process. Differing from traditional genetic modification, these new biotechnologies avoid the introduction of novel genetic elements or proteins in the final products, and therefore they take advantage of transgenic process with the reduction of potential risks and the increase of public acceptance… 

Risk assessment of GM crops is required for the approval of commercialization to ensure food/feed and environ-ment safety. In most countries, risk assessment of GM crops is generally based on the principle of ‘substantial equivalence’ that was initially proposed by the Organisation for Economic Co-operation and Development and further elaborated Food and Agriculture Organization of the United Nations/World Health Organization. In the concept of substantial equivalence, a new GM crop is compared to a comparator, which is generally its conventional parent line, at the agronomic/phenotypic level and by compositional analysis… Increasing numbers of studies have begun using various high-throughput profiling techniques to study unintended effects as non-targeted and unbiased approaches. The differences in various ‘omes’… of GM crops and their comparators are compared... Different profiling studies of various GM plants with different events and transgenes are conducted at different developmental stages and in different environments and the results of these studies draw highly diverse conclusions. However, it is noted that many studies showed that the environment and even conventional methods caused more variation in ‘omes’ than genetic modification, which should be taken into account when analyzing unintended effects… 

The emergence of various next generation GM products may improve public perception of GM crops, while the development of new biotechnologies and non-targeted safety assessment approaches mitigate the potential risk of GM crops. All of these will substantially support the sustainable development of GM crops in the future…


Via Alexander J. Stein
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Rescooped by Micaela Illy from Ag Biotech News
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Disease-resistant tomatoes fight lethal pests - Cornell U (2013)

Disease-resistant tomatoes fight lethal pests - Cornell U (2013) | Biology. | Scoop.it

In the battle against thrips, Cornell breeder Martha Mutschler-Chu has developed a new weapon: a tomato that packs a powerful one-two punch to deter the pests and counter the killer viruses they transmit. The “dual resistant” insect and virus varieties may reduce or even eliminate the need for pesticides…

 

Thrips are tiny insects that pierce and suck fluids from hundreds of species of plants, including tomatoes, grapes, strawberries and soybeans. They also transmit such diseases as the tomato spotted wilt virus, causing millions of dollars in damage to U.S. agricultural crops each year.

 

Adapting a novel form of insect resistance discovered in a wild plant native to Peru, Mutschler-Chu…  first isolated the resistance. She found that it was mediated by droplets of sugar esters, called acylsugars, that are produced and exuded from hairs (trichomes) that cover the plants. The acylsugars don’t kill the insects, but deter them from feeding or laying eggs on the plants…

 

After successfully transferring the resistance into new lines and breeding out undesirable traits, her team added a second layer of protection: one or both of two natural genes known to resist the so-called TOSPO viruses, which include tomato spotted wilt virus. “If some thrips get through with the virus, the virus resistance genes are there to mop it up… It brings us closer and closer to something that can be used commercially to essentially eliminate the need for pesticides in many growing regions,” Mutschler-Chu said.

 

The project rests on a foundation that was built over 20 years, supported by college-level funding and federal HATCH grants. During that time, new tools of molecular biology were developed, from PCR-based markers and SNP markers to the sequencing of the tomato genome. Using the new methods, it took Mutschler-Chu 10 years to develop the first tomato line with enough acylsugar, then four years to create a better series of 30 lines.

 

The impact could be far-reaching, she said. Not only would it be a boon to the U.S agricultural economy, it could also have significant impact in the developing world, where tomatoes are one of the most popular vegetable cash crops, especially for small subsistence farmers. “This is even more critical, because they don’t have the resources to buy pesticides, and there is often misuse of pesticides”… 


Via Alexander J. Stein
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