New Spray Could Protect Olive Trees from Xylella

A research team at the Institute of Plant Molecular and Cellular Biology has cre­ated a ground­break­ing tech­nol­ogy for pre­cise and long-last­ing inac­ti­va­tion of plant genes using a sin­gle spray appli­ca­tion.

The find­ings, pub­lished in Nucleic Acids Research, detail an inno­v­a­tive approach employ­ing a benign virus that releases cus­tom-designed small RNA mol­e­cules to selec­tively silence tar­get genes with­out alter­ing the plan­t’s genetic makeup.

This fea­ture holds sig­nif­i­cant impor­tance within the European Union, where reg­u­la­tion around genet­i­cally mod­i­fied organ­isms (GMOs) is strin­gent. Consequently, the research team has sub­mit­ted a European patent appli­ca­tion to safe­guard this tech­nol­ogy jointly owned by the Spanish National Research Council (CSIC) and the Technical University of Valencia.

The tech­nol­ogy hinges on using arti­fi­cial microRNAs (amiRNAs) – minus­cule RNA mol­e­cules that exhibit DNA-like char­ac­ter­is­tics but are sig­nif­i­cantly smaller.

These amiRNAs are metic­u­lously designed to ensure high speci­ficity, pre­vent­ing unin­tended gene inac­ti­va­tion. They are derived from larger pre­cur­sor mol­e­cules whose size was opti­mized using Arabidopsis thaliana, a fre­quently employed herba­ceous plant in mol­e­c­u­lar biol­ogy and plant genet­ics research.

This method opens up pos­si­bil­i­ties for wide­spread adop­tion in the mar­ket. It has appli­ca­tions in enhanc­ing crop pro­duc­tiv­ity, shield­ing plants from dis­eases, and for­ti­fy­ing their resilience to envi­ron­men­tal shifts.

The spray, which con­tains a harm­less virus, is applied to the tar­get plant. Once inside the plant, the virus mul­ti­plies and dis­charges the arti­fi­cial RNA mol­e­cules nec­es­sary for inac­ti­vat­ing the desired gene.

“On the one hand, we have suc­ceeded in con­sid­er­ably reduc­ing the size of the pre­cur­sor mol­e­cules of the arti­fi­cial microRNAs with­out affect­ing their activ­ity,” said Alberto Carbonell, a researcher at CSIC.

“On the other hand, we have proven that we can inac­ti­vate plant genes by spray­ing plant extracts that include innocu­ous viral vec­tors that pro­duce amiRNAs from min­i­mal pre­cur­sor mol­e­cules,” he added.

This tech­nol­ogy offers a range of ben­e­fits. Firstly, a sin­gle spray appli­ca­tion can intro­duce the innocu­ous virus and pro­duce amiRNAs in the tar­geted plant tis­sues, elim­i­nat­ing the need for mul­ti­ple treat­ments and low­er­ing appli­ca­tion costs.

For instance, researchers demon­strated the inac­ti­va­tion of genes asso­ci­ated with chloro­phyll biosyn­the­sis using a sin­gle spray, lead­ing to the yel­low­ing of affected tis­sues.

Carbonell said this approach could poten­tially rev­o­lu­tion­ize crop agri­cul­ture by selec­tively inac­ti­vat­ing gene expres­sion, enhanc­ing crop yield and bol­ster­ing their resilience to chang­ing envi­ron­men­tal con­di­tions.

Additionally, the tech­nol­ogy could be employed to immu­nize crops against var­i­ous pathogens, includ­ing viruses.

Silencing spe­cific genes within olive trees can enhance their resis­tance to Olive Quick Decline Syndrome (OQDS), a dev­as­tat­ing dis­ease caused by the bac­terium Xylella fas­tidiosa. Researchers have iden­ti­fied key genes within olive trees that, when silenced, could bol­ster their abil­ity to fend off OQDS.

Olive trees have defense mech­a­nisms, and researchers are explor­ing ways to strengthen these nat­ural safe­guards. By tar­get­ing spe­cific genes within the olive trees them­selves, researchers aim to enhance their resis­tance to OQDS.

The pre­cise genes iden­ti­fied for silenc­ing play a vital role in the tree’s inter­ac­tion with Xylella fas­tidiosa. Some of these genes are involved in the tree’s response to the bac­terium, influ­enc­ing the sever­ity of OQDS symp­toms. By silenc­ing these spe­cific genes, researchers hope to alter the olive tree’s response to Xylella fas­tidiosa, mak­ing it more resis­tant to the dis­ease.

Silencing these genes within the olive tree offers a poten­tial solu­tion to com­bat OQDS while min­i­miz­ing the need for broad-spec­trum pes­ti­cides. This approach would not only enhance the tree’s resis­tance to the dis­ease but also con­tribute to sus­tain­able and envi­ron­men­tally friendly agri­cul­tural prac­tices.