Location: Soybean Genomics and Improvement
Title: Overexpression of four Arabidopsis thaliana NHLgenes in soybean (Glycine max) roots and their effect over resistance to the soybean cyst nematode (Heterodera glycines) Authors
Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 4, 2014
Publication Date: February 8, 2014
Citation: Maldonado, A., Macdonald, M.H., Brewer, E.P., Beard, H.S., Youssef, R.M., Matthews, B.F. 2014. Overexpression of four Arabidopsis thaliana NHLgenes in soybean (Glycine max) roots and their effect over resistance to the soybean cyst nematode (Heterodera glycines). Physiological and Molecular Plant Pathology. 86:1-10. Interpretive Summary: Glycine max is one of the most important cash-crops in the US. Major losses in soybean production are reported annually due to the attack of the soybean cyst nematode (Heterodera glycines). Since chemical control is neither environmental nor economically viable, efforts have been focused on enhancing the plants defense system. Plants have developed mechanisms to identify and react to pathogen attack. Basal defenses are activated by resistance (R) proteins. The Arabidopsis NON-RACE-SPECIFIC DISEASE RESISTANCE 1, NDR1 protein shows some sequence similarity to the tobacco HAIRPIN INDUCED GENE 1 (HIN1), is localized to the plasma membrane, and usually interacts with CC-NB-LRR R proteins to mediate defense signaling. Forty five NDR1/HIN1-LIKE (NHL) genes have been found in Arabidopsis. NHL1 is most similar to NDR1, and NHL8 is an E3 ubiquitin ligase, Ariadne ring zinc finger protein. We overexpressed several AtNHL genes in soybean roots to determine if they could confer resistance to H. glycines. AtNHL1 and AtNHL8 significantly decreased the number of mature females to 50 and 46% of the number found in control roots. Relative expression analysis showed they induced the expression of marker genes for jasmonic acid (PR3 and OSM, encoding chitinase B and an osmotin, respectively) and ethylene (EBF, ERF1, and ERS2, encoding the EIN3-binding F box protein, the ethylene response factor 1, and the ethylene response sensor 2, respectively).
Technical Abstract: In the US, the soybean cyst nematode (SCN) is the most destructive pathogen of soybean. Currently grown soybean varieties are not resistant to all field populations of SCN. We genetically engineered soybean roots so they expressed genes from the model plant, Arabidopsis. When the Arabidopsis genes, NHL1 and NHL8, were overexpressed in soybean roots, the genes reduced the number of cysts formed by SCN 50 and 46%, respectively, as compared to control values. These results are important, because these two genes confer partial resistance to SCN and may be useful in the future to SCN.