Submitted to: Experimental Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2010
Publication Date: 7/1/2010
Citation: Ibrahim, H., Alkharouf, N., Meyer, S.L., Sanad, M., El-Din, A., Hussein, E., Matthews, B.F. 2010. Post-transcriptional gene silencing of root knot-nematode in transformed soybean roots. Experimental Parasitology. 127:90-99. Interpretive Summary: Plant parasitic nematodes cause about $100 billion in crop losses annually. Root-knot nematodes are a major pest to many crops. We located four different genes (in soybeans from another plant) that appear to inhibit this nematode when they are found in plants. Using genetic engineering techniques we inserted each gene into soybean roots to see if any of them would keep the nematode from damaging the plant. Two of the genes interfered with root knot nematode development on the soybean plant. The number of galls formed by the nematode was decreased by 90%. With further work, this approach may be a method to help control plant parasitic nematodes, thus saving the farmer millions of dollars in crop loss annually. This information will be used by scientists to develop new soybeans with nematode resistance.
Technical Abstract: Plant-parasitic nematodes cause about $100 billion in crop losses annually. Root-knot nematodes (RKN; Meloidogyne spp.) are sedentary endoparasites, and the genus has been found on more than 3000 host plant species. In this study four different gene constructs were designed to produce RNA interference (RNAi). The RKN genes, L-lactate dehydrogenase, tyrosine phosphatase, mitochondrial stress-70 protein precursor, and ATP synthase beta chain mitochondrial precursor, have high similarity with essential soybean cyst nematode (Heterodera glycines) and Caenorhabditis elegans genes and were identified using BLAST. The DNA constructs were transformed into soybean roots and transformed roots were recognized by the presence of green fluorescent protein. Non-transformed roots were excised and discarded. The transformed roots were challenged with RKN and at different time points root samples were stained to monitor RKN infection inside the RNAi-transformed roots for comparison with control roots. Two constructs, tyrosine phosphatase and mitochondrial stress-70 protein precursor, strongly interfered with the life cycle of RKN and the number of galls formed on roots transformed with RNAi fragments that targeted the RKN tyrosine phosphatase and mitochondrial stress-70 protein precursor genes was greatly reduced by 92% and 94.7%, respectively. The size development and diameter of RKN inside these transformed roots was 3.2 and 4.4 times less than the diameter of RKN found inside the empty vector control. These results indicate that silencing these genes can be a valuable approach for broadening resistance against this plant-parasitic nematode.