Crop Biotech Update

Corn Defenses for Improved Pest Resistance

January 6, 2012

New discoveries on how corn defend itself from pathogens have been recently reported in the journals Plant Physiology and The Proceedings of the National Academy of Sciences.

Authors of papers from the USDA Agricultural Research Service in Gainesville and University of Florida found defensive compounds known as zealexins and kauralexins to rapidly accumulate at fungal infection sites, impeding the microbes' continued spread. Another protein signal was discovered in corn called ZmPep1, which alerts the plant to fungal intruders and helps mobilize a timely counterattack.

In laboratory experiments, kauralexin class of phytoalexins inhibited the growth of anthracnose stalk rot (Colletotrichum graminicola) by 90 percent, while zealexins inhibited the growth of the aflatoxin-producing fungus Aspergillus flavus by 80 percent. These findings are important in reducing the yield loss and fungal-derived toxin contamination issues for U.S. corn farmers.

For more details, view http://www.ars.usda.gov/News/docs.htm?docid=1261