|Ben Chouikha, Imed|
|Macdonald, Margaret - Peggy|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2006
Publication Date: 3/11/2006
Citation: Alkharouf, N., Ben Chouikha, I., Beard, H.S., Macdonald, M.H., Meyer, S.L., Knap, H.T. 2006. Expression of soybean genes during invasion of susceptible roots by the soybean cyst nematode.. Molecular Plant-Microbe Interactions. 224:838-852. Interpretive Summary: The soybean cyst nematode is the major pest of soybean and causes an estimated one billion dollars of damage each year in the United States. We monitored changes in gene expression over an 8-day period in roots of soybean that were susceptible to attack by the soybean cyst nematode (SCN), Heterodera glycines, using state-of-the-art DNA technologies. We identified several genes that may be useful to broaden resistance of soybean to the soybean cyst nematode. This information is of interest to scientists developing new methods for broadening plant resistance to pests and pathogens.
Technical Abstract: Changes in gene expression in roots of soybean, cv. Kent, susceptible to attack by the soybean cyst nematode (SCN), Heterodera glycines, were monitored using microarrays containing over 6,000 cDNA inserts. We divided the seven time points into early (6, 12 and 24 hours), mid (2 and 4 days) and late (6 and 8 days) time intervals, and compared statistically induced and suppressed genes in each (at least .5 fold induced or suppressed and p <= 0.05). Genes induced at the early time points included genes induced by jasmonic acid (PR-6 and SAM-22), genes involved in secondary product and cell wall metabolism, and proteinase inhibitors. At the mid-time points, trehalose-6-phosphate synthase was induced, perhaps indicating the nematodes' successful utilization of the plants cellular apparatus to provide nutrients for nematode development. There was an increase in energy-related genes during the mid and late time points, while proteinase inhibitors were unchanged at these two time intervals. Key defense genes induced by salicylic acid (SA), such as PR-1a and NPR1, were unchanged in Kent, whereas a WRKY transcription factor, believed to suppress PR-1 genes, was statistically induced at all time points. Our results suggest that a number of changes in gene expression occur in the susceptible root of soybean upon invasion by SCN, however we do not see evidence for strong induction of the SA signaling pathway.