Systemic infection of stalks and ears of corn hybrids
by <Emphasis Type="Italic">Aspergillus parasiticus</Emphasis> |
| |
Authors: | Gary L Windham William P Williams |
| |
Institution: | (1) USDA-ARS, Corn Host Plant Resistance Research Unit, P. O. Box 5367, Mississippi State, MS 39762, USA |
| |
Abstract: | This study was conducted to explore systemic infection by the Aspergillus flavus group into corn ears via the stalk. An A. parasiticus mutant which produces norsolorinic (NOR) acid (a visible orange intermediate of the aflatoxin biosynthetic pathway) was used
in field studies to monitor systemic infection of corn stalk and ear tissues. Corn hybrids resistant and susceptible to aflatoxin
contamination were grown in the field and inoculated prior to tasseling by inserting A. parasiticus infested toothpicks into stalks between the 5th and 6th node below the lowest ear shoot. Beginning 2 weeks after inoculation,
systemic infection by the NOR mutant was assessed weekly by collecting ear shank tissue and stalk tissue from the nodes between
the infection sites and the developing ears. Ears were collected at the end of the growing season to determine the level of
kernel infection by the NOR mutant. In two separate studies, the A. parasiticus NOR mutant was isolated from stalk tissues at all of node positions and ear shank tissue from several susceptible corn hybrid
plants at the first harvest date 2 weeks after inoculation. The NOR mutant was also isolated from stalk and ear tissue of
a resistant hybrid. The NOR mutant was only isolated from kernels of susceptible hybrids in 2003 and 2004. Infection rates
of kernels in infected ears were very low (<1%). In 2005, the fungus was found in only one kernel from an ear of the resistant
hybrid. The NOR mutant was not isolated from stalks, ears, or kernels from control (uninoculated) plants grown in the plots
with inoculated plants. Although infection levels of corn kernels were low, systemic movement of the A. parasiticus up the stalk appears to be another possible route to infection of developing corn ears. |
| |
Keywords: | Aspergillus parasiticus Corn Maize Systemic infection Zea mays |
本文献已被 PubMed SpringerLink 等数据库收录! |
|