` Researchers Use Phages to Eradicate Disease Caused by Xylella Fastidiosa in Grapevines

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Researchers Use Phages to Eradicate Disease Caused by Xylella Fastidiosa in Grapevines

Sep. 9, 2015
By Isabel Putinja

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A research team from Texas A&M Uni­ver­sity in Col­lege Sta­tion, Texas, has cre­ated a cock­tail of four dif­fer­ent phages (viruses of bac­te­ria) which they used to treat grapevines affected by Pierce’s Dis­ease (PD). The dis­ease is caused by the Xylella fas­tidiosa (Xf) bac­terium that has attacked olive groves and dev­as­tated the olive crop in the Puglia region of Italy.
See more: Com­plete Cov­er­age of the Xylella Fas­tidiosa Out­break
Pierce’s Dis­ease is spread by sharp­shoot­ers, a type of large leafhop­per insect which feeds on the xylem of plants, has caused exten­sive dam­age to vine­yards in Cal­i­for­nia.

The sci­en­tists cre­ated the phage mix by com­bin­ing four vir­u­lent phages which they tested on grapevines. The results of the study pub­lished in Plos One Jour­nal, Con­trol of Pierce’s Dis­ease by Phage,” revealed that Xf lev­els in the grapevines they treated with the cock­tail were sig­nif­i­cantly reduced.

The phage cock­tail was used both as a ther­a­peu­tic treat­ment to treat the dis­ease as well as a pro­phy­lac­tic treat­ment to pre­vent the dis­ease from occur­ring. They found that symp­toms of PD were con­trolled only one week after treat­ment, while no symp­toms occurred in the plants that received the pre­ven­ta­tive treat­ment.

Hav­ing suc­cess­fully treated grapevines affected by Pierce’s Dis­ease, there may be the poten­tial to use a sim­i­lar approach to treat and pre­vent Xf infec­tions in olive trees. Car­los Gon­za­lez, one of the authors of the study, is opti­mistic: At this time we can only spec­u­late since we have not been able to test the Xylella fas­tidiosa strains from Italy,” he told Olive Oil Times.

Dr. Carlos Gonzalez, Texas A&M University

How­ever, based on our results with grapevines and the genetic sim­i­lar­ity of the olive strains, the phages have a high prob­a­bil­ity of work­ing (on olives). Lab­o­ra­tory exper­i­ments have already con­firmed that Xylella fas­tidiosa sub­species caus­ing almond, ole­an­der or cof­fee leaf scorch are sen­si­tive to our four cock­tail phages. The only way to really know is to do the exper­i­ment with appro­pri­ate Xylella fas­tidiosa strains from the dis­eased olive trees.”

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The use of this potent phage cock­tail could be a break­through since there has been no way to pre­vent or treat the dis­eases caused by Xf, and the only effec­tive con­trol was through the use of insec­ti­cides.

Car­los Gon­za­lez explains why this is not ideal: The pri­mary defense against Xylella fas­tidiosa dis­eases has been the use of neon­i­coti­noid insec­ti­cides against the insects that spread the bac­te­ria. How­ever, the Euro­pean Com­mis­sion has banned these chem­i­cals because of chronic and acute effects on bee colony sur­vival and devel­op­ment. In 2013, the US Envi­ron­men­tal Pro­tec­tion Agency issued label­ing require­ments warn­ing of the dan­ger these insec­ti­cides pose to pol­li­na­tors and this year announced that new appli­ca­tions for their out­door use are unlikely to be approved, pend­ing the out­come of an ongo­ing EPA review of the effects of the neon­i­coti­noids on bee devel­op­ment.”

These events,” Gon­za­les explained, in par­al­lel with the grow­ing threat of Xylella dis­eases to impor­tant crops, add new urgency to the devel­op­ment of nat­ural treat­ments for this bac­te­r­ial pest. Clearly, our phage cock­tail offers an envi­ron­men­tally-friendly, effec­tive, and sus­tain­able bio­con­trol treat­ment for dis­eases caused by Xylella fas­tidiosa.”



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