Getting to the Root of the Problem: Fastidious Pathogens

Year Awarded  2017

FFAR award amount   $299,992

Total award amount   $600,000

Location   College Station, TX

Matching Funders   Texas A&M AgriLife Research

  • Next Generation Crops

Can Researchers Grow Unculturable Pathogens?

Candidatus Liberibacter spp. are fastidious—or unculturable—pathogens that cause billions of dollars of damage to crops annually. 

With a $299,992 FFAR grant and matching funds from Southern Gardens Citrus, Texas A&M AgriLife Research scientists, led by Dr. Kranthi Mandadi, developed a way to grow fastidious bacteria in a laboratory setting and evaluate new treatments. The AgriLife team is using modified plant host tissues, hairy roots, to mimic the bacteria’s natural environment for its growth and downstream therapeutic evaluation—testing different potential treatments to control the pathogens.

This breakthrough offers new tools for disease management strategies that can prevent crop and economic losses.

Credit: Dr. Kranthi Mandadi

Hairy Roots to the Rescue

Developing solutions for diseases like potato zebra chip or citrus greening is challenging. It requires a ready supply of the pathogens, ideally in a laboratory setting, and being able to evaluate treatments faster.

Inspired by seminal work on mammalian virus culturing in animal/host tissues that led to the 1954 Nobel Prize in medicine, Texas A&M University AgriLife researchers and collaborators have successfully created a plant/host tissue system via hairy roots for culturing fastidious pathogens such as Candidatus Liberibacter spp. The hairy roots containing the pathogens can be produced on demand using host plant tissues and can be grown or maintained in laboratory growth chambers to provide a continuous supply of the pathogen.

The hairy root system also has the advantage of enabling high throughput screening of a variety of treatments such as resistance genes, genome-editing/CRISPR targets and antimicrobial chemicals to control Candidatus Liberibacter spp. Researchers were able to identify several potential treatments by screening hundreds of candidate therapies using this method in a fraction of the time it takes for traditional screening methods. 

The researchers believe using the hairy root system to screen therapies will open new possibilities to fight several other devastating fastidious plant pathogens and threats.

More About This Research

Dr. Mandadi’s article in Nature Communications about this breakthrough can be found here

Our $299,992 investment in this research is part of our New Innovator in Food & Agriculture Research Award.

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