Texas Research Should Help With HLB

Ernie NeffHLB Management, Research

Interior of oranges impacted by citrus greening. (Texas A&M AgriLife photo)

Texas A&M AgriLife Research scientists have made a discovery that should help combat fastidious or “unculturable” pathogens, such as Candidatus Liberibacter asiaticus, the HLB causal agent. HLB is also known as citrus greening disease.

Kranthi Mandadi, a researcher with Texas A&M, and his colleagues have been working several years on developing new technologies to fight the fastidious pathogens. Mandadi and his team work at the Texas A&M AgriLife Research and Extension Center in Weslaco, Texas. The results of their work, “Plant hairy roots enable high throughput identification of new antimicrobials against Candidatus Liberibacter spp.,” were recently published in Nature Communications.   

Fastidious plant pathogens infect citrus and numerous other crops. “The greatest obstacle to understanding and controlling fastidious pathogens was the inability to cultivate them in a laboratory setting and to screen for lots of potential therapies,” said Leland “Sandy” Pierson, head of Texas A&M’s Department of Plant Pathology and Microbiology. “But Dr. Mandadi and his team have developed a breakthrough method as an alternative means to propagate fastidious bacteria.”

The breakthrough came in the form of the “hairy root” system. This technology utilizes the pathogen-infected host tissues to produce so-called hairy roots that can serve as biological vessels for the propagation of these pathogens in the laboratory.  

“Use of this technique has already led to the discovery of six new antimicrobial peptides with proven efficacy in plant materials,” Mandadi said. “These antimicrobials, either singly or in combination, could be used as near- and long-term therapies to control citrus greening, potato zebra chip and tomato vein greening diseases.”

In addition to his team, Mandadi collaborates with scientists at Texas A&M University-Kingsville Citrus Center, University of Florida, University of California and industry shareholders. Those shareholders include the Citrus Research and Development Foundation (CRDF), Texas Citrus Pest and Disease Management Corporation and Bayer.

Southern Gardens Citrus, a subsidiary of U.S. Sugar in Florida, has partnered with Texas A&M to commercialize the hairy root system as well as new therapies for application in the field.

Mandadi said use of the hairy root system has already been instrumental in finding several potential new treatments for citrus greening and potato zebra chip.

Mandadi was one of four researchers from around the country who recently summarized their work on culturing the causal agent of HLB in a panel discussion hosted by CRDF. Learn more about that discussion here.

Source: Texas A&M AgriLife Communications

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