This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Windstam, S.
Right arrow Articles by Nelson, E. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Windstam, S.
Right arrow Articles by Nelson, E. B.
Agricola
Right arrow Articles by Windstam, S.
Right arrow Articles by Nelson, E. B.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, July 2008, p. 4292-4299, Vol. 74, No. 14
0099-2240/08/$08.00+0     doi:10.1128/AEM.00264-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Temporal Release of Fatty Acids and Sugars in the Spermosphere: Impacts on Enterobacter cloacae-Induced Biological Control{triangledown}

Sofia Windstam{dagger} and Eric B. Nelson*

Cornell University, Department of Plant Pathology and Plant-Microbe Biology, 334 Plant Science Building, Ithaca, New York 14853

Received 30 January 2008/ Accepted 21 May 2008

The aim of this study was to determine the temporal release of fatty acids and sugars from corn and cucumber seeds during the early stages of seed germination in order to establish whether sugars found in exudate can prevent exudate fatty acid degradation by Enterobacter cloacae. Both saturated (long-chain saturated fatty acids [LCSFA]) and unsaturated (long-chain unsaturated fatty acids [LCUFA]) fatty acids were detected in corn and cucumber seed exudates within 15 min after seed sowing. LCSFA and LCUFA were released at a rate of 26.1 and 6.44 ng/min/seed by corn and cucumber seeds, respectively. The unsaturated portion of the total fatty acid pool from both plant species contained primarily oleic and linoleic acids, and these fatty acids were released at a combined rate of 6.6 and 0.67 ng/min/seed from corn and cucumber, respectively. In the absence of seed exudate sugars, E. cloacae degraded linoleic acid at rates of 29 to 39 ng/min, exceeding the rate of total fatty acid release from seeds. Sugars constituted a significant percentage of corn seed exudate, accounting for 41% of the total dry seed weight. Only 5% of cucumber seed exudate was comprised of sugars. Glucose, fructose, and sucrose were the most abundant sugars present in seed exudate from both plant species. Corn seeds released a total of 137 µg/seed of these three sugars within 30 min of sowing, whereas cucumber seeds released 0.83 µg/seed within the same time frame. Levels of glucose, fructose, and sucrose found in corn seed exudate (90 to 342 µg) reduced the rate of linoleic acid degradation by E. cloacae to 7.5 to 8.8 ng/min in the presence of either sugar, leaving sufficient concentrations of linoleic acid to activate Pythium ultimum sporangia Our results demonstrate that elevated levels of sugars in the corn spermosphere can prevent the degradation of LCUFA by E. cloacae, leading to its failure to suppress P. ultimum sporangial activation, germination, and subsequent disease development.

* Corresponding author. Mailing address: Cornell University, Department of Plant Pathology, 334 Plant Science Building, Ithaca, NY 14853. Phone: (607) 255-7841. Fax: (607) 254-6448. E-mail: ebn1{at}cornell.edu

{triangledown} Published ahead of print on 30 May 2008.

{dagger} Present address: Michigan State University, Department of Plant Pathology, 140 Plant Biology Building, East Lansing, MI 48824.

Applied and Environmental Microbiology, July 2008, p. 4292-4299, Vol. 74, No. 14
0099-2240/08/$08.00+0     doi:10.1128/AEM.00264-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Windstam, S., Nelson, E. B. (2008). Differential Interference with Pythium ultimum Sporangial Activation and Germination by Enterobacter cloacae in the Corn and Cucumber Spermospheres. Appl. Environ. Microbiol. 74: 4285-4291 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»