|DINH, PHUONG T.Y. - Washington State University|
|ELLING, AXEL - Washington State University|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2014
Publication Date: 9/8/2014
Citation: Dinh, P., Brown, C.R., Elling, A.A. 2014. RNA interference of effector gene Mc16D10L confers resistance against Meloidogyne chitwoodi in Arabidopsis and potato. Phytopathology. 94:1098-1106.
Interpretive Summary: Columbia root-knot nematode is a serious pest of potato in rhe Pacific Northwest. At present the only means to contol the damage it causes is to use soil fumigants. Due to cost and environmental concerns alternative strategies are imperative. Resistance to this soil dweller has been discovered in Mexican wild species and by mostly old-style breeding introduced into oblong russet skin processing potatoes. Another technique is reported here. By gene insertion it is possible to induce the plant to produce a short RNA with sequence that matches a gene expressed by by the nematode. This gene is part of the highly coordinated biochemical communication that occurs between the nematode and the plant. As a result the nematode is ensconced at a feeding site where plant root development is enslaved to the service of the nematode which produces hundreds of eggs. The transgenic plants produced in this study interefered with the normal nematode development and reduced the number of eggs produced by the nematode. This technique has the advantage that any variety can be transformed and express the resistance where other traits unchanged. Traditional breeding is less targeted and more time consuming. Resistance to Columbia Root Knot Nematode can reduce the cost of soil fumigants to the potato industry in Washington State by 20 million dollars
Technical Abstract: Potatoes (Solanum tuberosum) are the most important non-cereal food crop. The Columbia root-knot nematode (Meloidogyne chitwoodi), a quarantine pathogen, is a significant problem in some of the major potato-producing areas worldwide. In spite of great genetic diversity in wild potato species, no commercial potato cultivars with resistance to M. chitwoodi are available to date. Meloidogyne spp. express effector genes in their esophageal glands, from where effector proteins are secreted into plant tissue. Effector genes are essential for the molecular interactions between root-knot nematodes and their host plants. Here a transgenic approach has been used to develop stable transgenic lines of Arabidopsis and potato with resistance against M. chitwoodi. The RNA interference (RNAi) construct pART27(16D10i-2) was introduced into Arabidopsis thaliana and potato cv. Désirée to express double-stranded RNA (dsRNA) complementary to the putative M. chitwoodi effector gene Mc16D10L. Plant-mediated RNAi led to a significant level of resistance against M. chitwoodi in Arabidopsis and potato. In transgenic Arabidopsis lines, the number of M. chitwoodi egg masses and eggs were reduced by up to 57% and 67% compared to empty vector controls, respectively. Similarly, in stable transgenic lines of potato, the number of M. chitwoodi egg masses and eggs were reduced by up to 71% and 63% compared to empty vector controls, respectively. The relative transcript level of Mc16D10L was reduced by up to 76% in M. chitwoodi eggs and infective J2 that developed on transgenic pART27(16D10i-2) potato lines, indicating that the RNAi effect is systemic and expressed in an epigenetic fashon in M. chitwoodi derived from eggs. Produced by nematodes parasitizing transgenic plants.