|GUO, XIAOLI - University Of Missouri|
|CHRONIS, DEMOSTHENIS - Former ARS Employee|
|DE LA TORRE CUBA, CAROLA - University Of Missouri|
|SMEDA, JOHN - University Of Missouri|
|MITCHUM, MELISSA - University Of Missouri|
Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2014
Publication Date: 1/12/2015
Citation: Guo, X., Chronis, D., De La Torre Cuba, C., Smeda, J., Wang, X., Mitchum, M.G. 2015. Enhanced resistance to soybean cyst nematode Heterodera glycines in transgenic soybean by silencing putative CLE receptors. Plant Biotechnology Journal. DOI: 10.111/pbi.12313.
Interpretive Summary: Soybean cyst nematode (SCN) is the most damaging pathogen of soybean, causing more than $1 billion dollars in yield losses annually in the US. This nematode pathogen secretes into host roots unique effector proteins that mimic plant CLE peptide hormones to promote infection. In this study, we identified genes similar to Arabidopsis CLE receptors including CLV1, CLV2, CRN, and RPK2 in soybean and investigated their role in nematode CLE signaling by biochemical and functional analyses. We found that perception of SCN-secreted CLE peptide through these identified soybean receptors is important for nematode parasitism. Results of this study suggest that targeted disruption of nematode CLE signaling may represent a novel means to engineer nematode resistance in crop plants.
Technical Abstract: CLE peptides are small extracellular proteins important in regulating plant meristematic activity through the CLE-receptor kinase-WOX signaling module. Stem cell pools in the SAM (shoot apical meristem), RAM (root apical meristem), and vascular cambium are tightly controlled by CLE signaling pathways. Interestingly, plant-parasitic cyst nematodes secrete CLE-like effector proteins, which act as ligand mimics of plant CLE peptides and are required for successful nematode parasitism. Recently, we demonstrated that Arabidopsis CLE receptors including CLAVATA1 (CLV1), the CLAVATA2 (CLV2)/CORNYE (CRN) heterodimer receptor complex, and RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2), which transmit the CLV3 signal in the SAM, are also required for perception of beet cyst nematode Heterodera schachtii CLEs. Reduction in nematode infection was observed in clv1, clv2, crn, rpk2 and combined double and triple mutants. In an effort to develop nematode resistance in an agriculturally important crop, orthologs of Arabidopsis receptors including CLV1, CLV2, CRN and RPK2 were identified from soybean, a host for the soybean cyst nematode (SCN) Heterodera glycines. For each of the receptors, there are at least two paralogs in the soybean genome. Localization studies showed that most receptors are expressed in the root, but vary in their level of expression and spatial expression patterns. Expression in nematode-induced feeding cells (syncytia) was also confirmed. In vitro direct binding of the soybean receptors with the H. glycines CLE peptide was analyzed. Knockdown of single and multiple receptors in soybean hairy roots showed enhanced resistance to SCN. Our findings suggest that targeted disruption of nematode CLE signaling may be a potential means to engineer nematode resistance in crop plants.