University of Florida: Newest tool to fight citrus diseases may be found in citrus microbiome

The next key to winning the battle against citrus diseases such as citrus canker may be in the tiniest microbes that live inside the citrus tree. University of Florida researchers hope to discover how these microbes may benefit citrus trees in their natural fight against diseases. The end result may be an environmentally friendly and sustainable tool to control plant pathogens.

Nian Wang, professor of microbiology and cell science and Chris Oswalt, UF/IFAS Extension citrus agent for Polk and Hillsborough counties, will identify the beneficial traits of microbes within plants that have the potential to specifically impact citrus pathogens. The project is funded through a $749,990 grant from the U.S. Department of Agriculture National Institute of Food and Agriculture (USDA NIFA).

“A better understanding of the plant microbiome and innovative approaches in application are required to engineer the plant microbiome for successful disease control,” said Wang, who has extensive experience in citrus microbiome research. “This grant will help us gather important information that moves us closer to that goal.”

Microbes can affect plant health and fitness, stimulate plant growth, and protect plants from biotic and abiotic stress. They can live externally on or internally in their host plants. Microbes that live outside their host plants are either epiphytic, i.e., living on the plant leaf surface, or rhizospheric, i.e., inhabiting plant roots within the soil. Conversely, microbes that live and thrive inside their host plant are called endophytic microbes.

Endophytic microbes, especially endophytic bacteria, are functional in that they may carry nutrients into plants, modulate plant development, increase the stress tolerance of plants, suppress the virulence of pathogens, increase disease resistance in plants, and suppress the development of competitor plant species. Endophytic bacteria have been suggested to significantly reduce the use of agrochemicals (fertilizers, fungicides, insecticides, and herbicides) in the cultivation of crop plants ultimately contributing to sustainable agriculture and healthy food production.

The development of new technologies, such as next-generation genome sequencing, and a better understanding of the plant microbiome have triggered enthusiasm in taking advantage of diverse microbes for improving agricultural productivity and environmentally friendly and sustainable agricultural production.

Successful completion of this project will generate useful information regarding the function of endophytic bacteria. The grant project includes engineering a synthetic root endophytic bacterial microbiome and a synthetic leaf endophytic bacterial microbiome. Completing this has the potential to put the knowledge learned into action to benefit crop production.

The grant will start in 2021 and run through 2025.