Battling bubbles: How plants protect themselves from killer fungus

May 17, 2018

RIVERSIDE, Calif. -- In the battle between plants and pathogens, molecules called small RNAs are coveted weapons used by both invaders and defenders.

In a paper publishing online Thursday (May 17) in the journal Science, researchers at the University of California, Riverside report how plants package and deliver the small RNAs, or sRNAs, they use to fight back against plant pathogens. The study focused on Botrytis cinerea, a fungus that causes a grey mold disease in almost all fruits, vegetables, and many flowers.

Hailing Jin, a professor of microbiology and plant pathology in UCR's College of Natural and Agricultural Sciences, has been studying the role of sRNAs in plant immunity and disease. Her goal is to develop effective and environmentally friendly strategies to control plant diseases and to secure food production.

During a phenomenon called cross-kingdom RNA interference, some pathogens and plants exchange sRNAs during their interactions with each other. Small RNAs are molecules that regulate biological processes by interfering with gene expression. While pathogens deliver sRNAs into plant cells to suppress host immunity, plants transfer their sRNAs into pathogens to inhibit their ability to cause infection. Until now, it remained unknown how small RNAs move across the cellular boundaries between hosts and pathogens.

Jin's team found that during infection with Botrytis cinerea, plant cells package sRNAs inside bubble-like sacs, called exosomes, which are sent out of the plant cells and accumulate near the site of infection. These 'battling bubbles' are taken up by the fungal cells efficiently. The transferred host sRNAs inhibit the expression of fungal genes needed to cause the disease. The research was performed using Arabidopsis thaliana, a small flowering plant widely used as a model species because it is easy to grow and study.

"The discovery of the role of exosomes in cross-kingdom RNA interference will help us develop effective delivery methods to target plant pathogens with artificial sRNAs, with the goal of controlling plant diseases in crops, said Jin, who holds the Cy Mouradick Endowed Chair at UCR and is a member of the university's Institute for Integrative Genome Biology.

Jin said her group is also characterizing the pathogen targets of the protective sRNAs transferred from the plant to help identify new genes involved in pathogen virulence.
-end-
The paper is titled "Plants secrete extracellular vesicles to deliver small RNAs into a fungal pathogen to silence its virulence genes." In addition to Jin, contributors from UCR include Qiang Cai, a postdoctoral researcher in Jin's group and first author on the paper; Lulu Qiao; Ming Wang; Baoye He; and Jared Palmquist. Feng-Mao Lin and Bryan Hsien-Da Huang from National Chiao Tung University in Taiwan also contributed.

University of California - Riverside

Related Fungus Articles from Brightsurf:

International screening of the effects of a pathogenic fungus
The pathogenic fungus Candida auris, which first surfaced in 2009, is proving challenging to control.

Research breakthrough in fight against chytrid fungus
For frogs dying of the invasive chytridiomycosis disease, the leading cause of amphibian deaths worldwide, the genes responsible for protecting them may actually be leading to their demise, according to a new study published today in the journal Molecular Ecology by University of Central Florida and the Smithsonian Conservation Biology Institute (SCBI) researchers.

Researchers look to fungus to shed light on cancer
A team of Florida State University researchers from the Department of Chemistry and Biochemistry found that a natural product from the fungus Fusicoccum amygdali stabilizes a family of proteins in the cell that mediate important signaling pathways involved in the pathology of cancer and neurological diseases.

The invisibility cloak of a fungus
The human immune system can easily recognize fungi because their cells are surrounded by a solid cell wall of chitin and other complex sugars.

Taming the wild cheese fungus
The flavors of fermented foods are heavily shaped by the fungi that grow on them, but the evolutionary origins of those fungi aren't well understood.

Candida auris is a new drug-resistant fungus emerging globally and in the US early detection is key to controlling spread of deadly drug-resistant fungus
Early identification of Candida auris, a potentially deadly fungus that causes bloodstream and intra-abdominal infections, is the key to controlling its spread.

Genetic blueprint for extraordinary wood-munching fungus
The first time someone took note of Coniochaeta pulveracea was more than two hundred years ago, when the South African-born mycologist Dr Christiaan Hendrik Persoon mentioned it in his 1797 book on the classification of fungi.

How a fungus can cripple the immune system
An international research team led by Professor Oliver Werz of Friedrich Schiller University, Jena, has now discovered how the fungus knocks out the immune defenses, enabling a potentially fatal fungal infection to develop.

North American checklist identifies the fungus among us
Some fungi are smelly and coated in mucus. Others have gills that glow in the dark.

Tropical frogs found to coexist with deadly fungus
In 2004, the frogs of El Copé, Panama, began dying by the thousands.

Read More: Fungus News and Fungus Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.