Hairy Experience Can Frustrate
Leaf-Infecting Fungi
By Dawn Lyons
Johnson July 25, 1997
Hairy plant leaves could provide an environmentally
friendly defense against crop- damaging fungi like Puccinia recondita,
the culprit behind leaf rust that costs wheat and rye growers millions of
dollars in crop losses each year.
By examining leaf surfaces under a scanning electron microscope,
scientists with USDAs Agricultural Research Service were able to see how
hair-like structures on leaf surfaces entangle and trap fungal spores that land
and try to take hold.
When a spore settles on the leaf surface, the scientists say, it
germinates and sends out a root-like structure called an infection
tube in search of stomates--small pores on the surface of the plant that
allow the leaf to take in carbon dioxide from the atmosphere. Carbon dioxide
helps fuel the plants growth.
But when fungal spores land on a plant surface that has a high
number of leaf hairs, the spores can become enmeshed and die before the
infection tube successfully locates a stomate.
Previous research showed disease infestation was reduced up to
27 percent in plants with more leaf hairs. Scientists hope wheat and rye
breeders will use the information to bred hybrids with this characteristic,
which could help growers reduce their use of fungicides and other
disease-killing pesticides.
A longer feature with photograph can be seen on the World Wide
Web at:
http://www.ars.usda.gov/is/AR/archive/jul97/fuzzy0797.htm
Scientific contact: Dave L. Long, ARS Cereal Rust
Laboratory, St. Paul, Minn., phone (612) 625-1284, fax (612) 649-5054,
davidl@puccini.crl.umn.edu. |