RESUMEN
KEY MESSAGE: Functional characterization of the Columbia root-knot nematode resistance gene R Mc1 ( blb ) in potato revealed the R gene-mediated resistance is dependent on a hypersensitive response and involves calcium. The resistance (R) gene R Mc1(blb) confers resistance against the plant-parasitic nematode, Meloidogyne chitwoodi. Avirulent and virulent nematodes were used to functionally characterize the R Mc1(blb)-mediated resistance mechanism in potato (Solanum tuberosum). Histological observations indicated a hypersensitive response (HR) occurred during avirulent nematode infection. This was confirmed by quantifying reactive oxygen species activity in response to avirulent and virulent M. chitwoodi. To gain an insight into the signal transduction pathways mediating the R Mc1(blb)-induced HR, chemical inhibitors were utilized. Inhibiting Ca(2+) channels caused a significant reduction in electrolyte leakage, an indicator of cell death. Labeling with a Ca(2+)-sensitive dye revealed high Ca(2+) levels in the root cells surrounding avirulent nematodes. Furthermore, the calcium-dependent protein kinase (CDPK), StCDPK4 had a higher transcript level in R Mc1(blb) potato roots infected with avirulent nematodes in comparison to roots infected with virulent M. chitwoodi. The results of this study indicate Ca(2+) plays a role in the R Mc1(blb)-mediated resistance against M. chitwoodi in potato.
Asunto(s)
Calcio/inmunología , Resistencia a la Enfermedad/inmunología , Genes de Plantas/inmunología , Enfermedades de las Plantas/inmunología , Solanum tuberosum/inmunología , Tylenchoidea/inmunología , Animales , Calcio/metabolismo , Bloqueadores de los Canales de Calcio/farmacología , Resistencia a la Enfermedad/genética , Electrólitos/metabolismo , Regulación de la Expresión Génica de las Plantas/inmunología , Genes de Plantas/genética , Interacciones Huésped-Parásitos/inmunología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/parasitología , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/inmunología , Raíces de Plantas/parasitología , Proteínas Quinasas/genética , Proteínas Quinasas/inmunología , Proteínas Quinasas/metabolismo , Especies Reactivas de Oxígeno/inmunología , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Transducción de Señal/inmunología , Solanum tuberosum/genética , Solanum tuberosum/parasitología , Tylenchoidea/patogenicidad , Tylenchoidea/fisiología , Virulencia/inmunologíaRESUMEN
⢠Plant-parasitic cyst nematodes form a feeding site, termed a syncytium, through which the nematode obtains nutrients from the host plant to support nematode development. The structural features of cell walls of syncytial cells have yet to be elucidated. ⢠Monoclonal antibodies to defined glycans and a cellulose-binding module were used to determine the cell wall architectures of syncytial and surrounding cells in the roots of Arabidopsis thaliana infected with the cyst nematode Heterodera schachtii. ⢠Fluorescence imaging revealed that the cell walls of syncytia contain cellulose and the hemicelluloses xyloglucan and heteromannan. Heavily methyl-esterified pectic homogalacturonan and arabinan are abundant in syncytial cell walls; galactan could not be detected. This is suggestive of highly flexible syncytial cell walls. ⢠This work provides important information on the structural architecture of the cell walls of this novel cell type and reveals factors that enable the feeding site to perform its functional requirements to support nematode development.