A public-private partnership (PPP) between Philadelphia-based AUM LifeTech and the United States Department of Agriculture has developed a novel RNA silencing approach that may prove significant in the battle against citrus greening.

In a release, AUM LifeTech claimed the RNA silencing FANA technology for bacteria, insect and pathogen control was non-GMO, and had been used to combat plant pathogenic bacteria Candidatus Liberibacter and citrus pests like citrus root weevil and Asian citrus psyllid (ACP), the vector that carries citrus greening disease Huanglongbing (HLB).

The group said preliminary results showed an increase in insect mortality and reduction of bacteria within citrus trees, which was the first evidence of the successful delivery of  FANA Antisense Oligonucleotides (FANA ASOs) into plants through foliar sprays, root absorption and tree trunk injections. 

AUM LifeTech said this provided a new approach for managing agricultural pests and plant pathogens. 

"Given the resistance of conventional pesticides, there is an ever-growing need for new innovative technologies to protect plants," said company founder and CEO Veenu Aishwarya.

"We are excited to share that, in this collaborative study with USDA Agricultural Research Service (USDA-ARS), our next-generation FANA RNA silencing approach has shown very promising data in the management of agricultural pests and pathogens due to its ability to kill or manipulate bacteria, insects or viruses. 

"We hope that our combined efforts with USDA can soon help to save billions of dollars of citrus industry."

Aishwarya said it was important to note while the technology worked at a genetic level, it did not create genetically modified organisms.

"This is a very beneficial aspect in agriculture especially from an EPA (Environmental Protection Agency) registration perspective and may potentially help in a faster approval time."

Further explanation

GMOs are a hot topic right now, and at www.freshfruitportal.com we reached out to Aishwarya to learn how a technology can be considered non-GMO if it silences genes. The following was his response:

"As you know typically a plant is considered as a GMO when we alter (or engineer) its genetic makeup (permanently) so that it can achieve desirable traits. Companies developing GMOs typically play around with the genes of the plant and alter them permanently," he said. 

"Additionally, some are also using RNAi technologies in which they express double stranded RNA within the plants to achieve the desirable traits - again this is permanent. This can also be a big problem if there are any off target effects. All these approaches involve manipulating the plant's (or insect's) genetic material which we feel is not the best way. 

"We do not permanently alter the genetic makeup of the plants or insects. Instead, in this study we temporarily reduced the number of genes (of bacteria/insect) which are required for their survival."

Aishwarya emphasized "temporary" was the key word in the last sentence.

"This is good enough to kill them. It is like giving the insect some poison at the genetic level," he said.

"More importantly - it will only kill the disease causing insect/bacteria as we only target the genes of the disease causing bacteria (without interfering with the beneficial insects)."

The executive then offered further background about the technology.

"We use a single stranded antisense oligonucleotide approach to silence genes. Antisense approaches for gene knock down are well established for therapeutic development.

"As you can appreciate that in human therapeutics genetic modifications are not much appreciated; and thus we have developed ways to treat diseases by knocking down the genes (without permanently deleting the genes).

"At AUM LifeTech, we are working on various diseases like HIV, Cancer, Alzheimer, Psoriasis and a few genetic diseases. We have learned a lot from therapeutic development and are now using our experience to kill an insect/bacteria in the same way."

He said the FANA antisense approach was not as complex as RNAi and was mediated by an enzyme known as RNase H, as opposed to RISC machinery as is the case with RNAi.

"Delivery is also relatively easy due to our next generation FANA technology which also provides high stability, potency and better knockdown," he said.

"Here we are not engineering a plant, bacteria or insect. In basic terms, it is just like a pesticide, but instead of targeting a downstream pathway (to kill and insect/bacteria) we are targeting the genetic pathway. 

"Most importantly, the beauty about this approach is that it does not interfere or permanently alter with the genetic make up of the plant. This is why we are also hopeful that we may have a better chance in getting approval from EPA as this approach is not GMO.

"In our work with USDA, we have identified certain genes that are critical for the survival of the bacteria/insect and we are targeting those genes. The idea is that once we silence those genes the insect will die."

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