|Khan, Rana - UNIVERSITY OF MARYLAND|
|Alkharouf, Nadim - GEORGE MASON UNIVERSITY|
|Knap, Halina - CLEMSON UNIV. CLEMSON, SC|
|Chouikha, Imed - GEORGE MASON UNIVERSITY|
|Greffenstette, John - GEORGE MASON UNIVERSITY|
Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 2004
Publication Date: September 1, 2004
Citation: Khan, R., Alkharouf, N., Beard, H.S., Knap, H., Meyer, S.L., Chouikha, I., Greffenstette, J., Matthews, B.F. 2004. Resistance mechanisms in soybean: gene expression profile at an early stage of soybean cyst nematode invasion. J. Nematol. 36: 241-248. Interpretive Summary: The soybean cyst nematode (SCN) is the major pest of soybean causing an estimated $1.5 billion in damage throughout the US each year, more than all other soybean pests combined. Several soybean genes play important roles determining resistance to SCN. The amount of resistance displayed by soybean depends upon the resistance genes in the soybean and the race of SCN. The expression of approximately 1,500 soybean genes was monitored using "microarray technology" to identify genes involved in the response of soybean to SCN. An SCN-resistant and an SCN-susceptible soybean were examined before infection and two days after infection by SCN race 3. A number of genes were expressed at least 2-fold higher levels in the presence of SCN as compared to in the absence of SCN. Some of these genes are known to be involved in cell wall synthesis and maintenance; others are involved in the defense response of plants to other pests and pathogens. Some of the genes have unknown function. This report is of interest to scientists working on the plant defense response and on plant-microbe interactions. These results provide insights into the mechanisms used by soybean to respond to SCN attack.
Technical Abstract: The soybean cyst nematode (SCN) is the major pest of soybean causing an estimated $1.5 billion in damage throughout the US each year, more than all other soybean pests combined. The defense response of soybean to SCN is a multigenic trait and varies depending upon the genotypes of soybean and SCN. The expression of approximately 1,500 soybean genes was monitored using microarrays to identify genes involved in the response of soybean to SCN. RNA was harvested from roots of soybean cv. Peking resistant to SCN race 3 and cv. Kent susceptible to SCN race3, either two days after infection by SCN race 3 or not infected. Microarrays were produced that display PCR amplified cDNA inserts from approximately 1500 root-specific genes. These genes are derived from cDNA libraries made from root tissue of resistant soybean cultivars infected or not infected by SCN. The arrays were hybridized with probes derived from root mRNA of Peking (resistant) or Kent (susceptible) cultivars. The number of genes that were at least 2-fold induced in the presence of SCN was higher in the resistant cultivar as compared to the susceptible cultivar. Among the genes induced specifically in the resistant soybean variety are defense-related genes, potential regulatory factors, and transcription factors. This report is of interest to scientist working on the plant defense response and on plant-microbe interactions. These results provide some insights into the mechanisms used by soybean to respond to SCN attack.