Gene-silencing sprays on their way to a field near you?

Monsanto has announced that its RNAi-based pesticide for control of the Colorado potato beetle will now undergo formal product development, according to a paywalled article for Genomeweb.

Such RNAi-based pesticides are genetically engineered and work through silencing or otherwise interfering with genes in the target pest, to kill it or render it ineffective.

The danger of these products is that genes in non-target organisms, including the consumers of the food crop sprayed with the pesticide, might be silenced or their expression altered, too.

RNAi-based GM plants have also been developed in which the plant’s native genes are silenced.

Monsanto's Colorado potato RNAi pesticide is part of its so-called BioDirect pipeline, which centers around the use of RNAi-based sprays for pest, weed, and disease control in crop plants, Genomeweb notes.

Monsanto sees BioDirect as a way for Monsanto to apply RNAi to crops for which the development of GMO plants isn't economically viable. The development and launch of GMO plants is expensive, and is therefore generally reserved for large-acre row crops, Robert McCarroll, vice president of global chemistry technology at Monsanto and head of the BioDirect initiative, told Genomeweb.

Monsanto is developing a GM corn, SmartStax Pro, aimed at killing corn rootworms by expressing Bt toxin proteins along with a molecule designed to silence a gene essential to the insects.

Monsanto’s Vistive Gold soybeans were developed using RNAi gene-silencing technology. The soybeans were altered to have lower levels of saturated fats.

In 2013 Jack Heinemann and colleagues published an open-access paper warning that regulators were not adequately assessing the risks of RNAi products. They recommended new targeted regulatory approaches to better assess the potential hazards.

In 2014 the European Food Safety Authority (EFSA) held a scientific workshop to address the risks of RNAi-based GM plants. The conclusions acknowledged many uncertainties on the effects. It’s unlikely, however, that EFSA will draw the sensible conclusion that it’s premature to allow the commercialisation of these new GMOs.