The false root-knot nematode Nacobbus aberrans modifies the level of phenylpropanoid compounds during infection of chilli pepper

[SPA] En este trabajo, algunos metabolitos fenilpropanoide en plantas de chile CM334 infectadas por el nemátodo falso agallador Nacobbus aberrans fueron determinados. Las raíces fueron químicamente analizadas para su contenido de lignina y perfil de fenilpropanoides mediante un ensayo cuantitativo de lignina y HPLC-ESI/MS. El efecto in vitro de flavonoides en larvas juveniles (J2) de N. aberrans y Meloidogyne incognita también fue probado. El contenido de lignina fue similar en todos los tratamientos, excepto cuando M. incognita estuvo involucrado (P<0.05). Ácidos fenólicos (hidroxibenzoico –pHBA-, gálico, caféico, siríngico, ferúlico, vanílico y clorogénico) y el flavonoid quercetin-3-rutinósido fueron encontrados en el sistema radical. La concentración de los ácidos pHBA, ferúlico y clorogénico fue menor en las plantas inoculadas en comparación con el control (P<0.05) en cualquier tiempo de muestreo. El compuesto quercetin-3-rutinósido tuvo un efecto nematicida en larvas de N. aberrans, mientras que éste solamente tuvo un efecto nematostático en M. incognita. Estos resultados indican que N. aberrans modifica el nivel de compuestos fenilpropanoides durante la infección de chile. [ENG] In this work, some phenylpropanoid metabolites in CM334 chilli pepper plants infected by the false root-knot nematode Nacobbus aberrans were determined. Roots were chemically analyzed for their lignin content and phenylpropanoid profile by quantitative lignin assay and HPLC-ESI/MS. The in vitro effect of flavonoids on second-stage juveniles (J2) of N. aberrans and Meloidogyne incognita was also tested. The lignin content was similar in all treatments excepting when M. incognita was involved (P<0.05). Phenolic acids (Hidroxibenzoic -pHBA-, gallic, caffeic, syringic, ferulic, vanillic and chlorogenic) and the flavonoid quercetin-3-O-rutinoside were found in the root system. Concentration of pHBA, ferulic and chlorogenic acids was lower in inoculated plants than in the control (P<0.05) at any sampling date. Quercetin-3-O-rutinoside had a nematocidal effect on J2 of N. aberrans, whereas it only had a nemastatic effect on M. incognita. These results indicate that N. aberrans modifies the level of phenylpropanoid compounds during the infection of chilli pepper.Our thanks go to Dirección General Académica of Universidad Autónoma Chapingo for the financial support for participate in WiA2016. Thanks are due to CONACYT for financial support of the Research Project 46331-Z

Changes in the phenylpropanoid metabolism induced by Nacobbus aberrans in chilli pepper CM334 resitant to Phytophthora capsici

[SPA] La línea endogámica de chile Criollo de Morelos 334 (CM334I es resistente a Phytophthora capsici Leonian, pero Nacobbus aberrans Thorne and Allen, 1944 podría romper su resistencia en plantas previamente infectadas por el nemátodo. Éste fenómeno es conocido como “ruptura de la resistencia”. La resistencia de las plantas de chile CM334 ha sido asociada con la ruta de los fenilpropanoides. Tanto los ácidos fenólicos como los flavonoides son metabolitos sintetizados a través de esa ruta metabólica y juegan importantes funciones en la interacción planta-patógeno. El objetivo de esta tesis doctoral será determinar qué cambios son inducidos por N. aberrans en la ruta fenilpropanoide que podrían convertir al tejido resistente en un substrato favorable para el establecimiento de P. capscici. Los cambios inducidos por N. aberrans en la actividad de la L-fenil alanina amonio liasa, el contenido total de fenoles solubles totales, el establecimiento de un perfil y la caracterización de ácidos fenólicos solubles y flavonoides, el efecto tóxico de los flavonoides de la raíz en nemátodos y el contenido de lignina en plantas de chile CM334 podrían ser asociados a esta ruptura de la resistencia a P. capscici en chile CM334. [ENG] The inbred chilli line Criollo de Morelos 334 (CM334) is resistant to Phytophthora capsici Leonian, but Nacobbus aberrans Thorne and Allen, 1944 could break down resistance of plants previously infected by this nematode. This phenomenon is known as “resistance breakdown”. The resistance of CM334 chilli pepper plant has been associated to the phenylpropanoid pathway. Both phenolic acids and flavonoids metabolites are synthesized in this metabolic pathway and play an important role in the plant-pathogen interaction. The goal of this PhD project will be to determine which changes are induced by N. aberrans in the phenylperopanoid pathway that could turn the resistant plant tissues into a favourable sub-stratum for the establishment of P. capscici. Changes induced by N. aberrans on L-phenylalanine ammonia-lyase (PAL) activity, total soluble phenols content, the profiling and characterization of soluble phenolic acids and flavonoids, the toxic effect of root flavonoids on nematodes and the lignin content of CM334 chilli pepper plants may be associated to the breakdown of resistance to P. capscici in CM334 chilli pepper.We would like to thank the Structural Research Laboratory (SRL) at the Department of Chemistry of University of Warsaw for using HPLC–MS. SRL has been established with financial support from European Regional Development Found in the Sectorial Operational Programme “Improvement of the competitiveness of Enterprises, years 2004–2005” project no: WPK_1/1.4.3./1/2004/72/72/165/2005/U. The first author thanks Dirección General Académica of Universidad Autónoma Chapingo for the financial support to participate in WiA15

Modification in the phenylpropanoid metabolism induced by the false root-knot nematode Nacobbus aberrans in chilli pepper CM334

[SPA] La resistencia del genotipo de chile CM334 contra las tres especies de nematodos agalladores y al oomiceto Phytophthora capsici ha sido asociada con la ruta fenilpropanoide del metabolismo secundario. Sin embargo, el nemátodo falso agallador de raíz Nacobbus aberrans podría inducir cambios en esta ruta. La actividad de la enzima L-fenil alanina amonio liasa (PAL) y el contenido de fenoles solubles totales (FST) fueron determinados en plantas de CM334 inoculadas con N. aberrans, P. capsici o con ambos patógenos. El perfilado de compuestos fenilpropanoide fue analizado mediante HPL-ESI/MS. Los valores más altos de la actividad de PAL y contenido de FST fueron registrados en plantas inoculadas únicamente con P. capsici, mientras aquellas plantas inoculadas con N. aberrans solo o en combinación con P. capsici mostraron los niveles más bajos (P<0.05). Ácidos fenólicos (p-HBA, gálico, caféico, siríngico, sinápico, ferúlico, vanílico, p-coumárico y clorogénico) y flavonoides (rutina, apigenina y luteolina) fueron encontrados en el follaje. El ácido clorogénico y la leutolina fueron los compuestos fenilpropanoides en mayor cantidad en CM334. La concentración de los ácidos p-HBA, clorogénico y los flavonoides fue más baja en las plantas inoculadas con N. aberrans que en el control (P<0.05) en cualquier tiempo de muestreo. N. aberrans indujo modificaciones en el metabolism fenilpropanoide. [ENG] Resistance in the genotype of chilli pepper CM334 against the three major species of root-knot nematodes and the oomycete Phytophthora capsici has been associated with the phenylpropanoid pathway of secondary metabolism. However, the false root-knot nematode Nacobbus aberrans could induces changes in this pathway. In this work, L-phenylalanine ammonia-lyase (PAL) activity and the content of total soluble phenols (TSP) were determined in foliage of CM334 plants inoculated with N. aberrans, P. capsici or both pathogens. Besides, the phenylpropanoid profile was analyzed by HPLC-ESI/MS. The highest values of PAL activity and content of TSP were registered in plants inoculated only with P. capsici, while those plants inoculated with N. aberrans alone or in combination with P. capsici showed the lowest level (P<0.05). Phenolic acids (p-HBA, gallic, caffeic, syringic, sinapic, ferulic, vanillic, p-coumaric and chlorogenic) and flavonoids (rutin, apigenin and luteolin) were found in foliage. Chlorogenic acid and luteolin were the phenylpropanoid compounds in highest quantity in CM334. Concentration of p-hidroxy benzoic and chlorogenic acids and flavonoids was lower in plants inoculated with N. aberrans than in the control (P<0.05) at any sampling date. These results confirm that N. aberrans induced modifications in phenylpropanoid metabolism.Our thanks go to Dirección General Académica of Universidad Autónoma Chapingo for the financial support for participate in WiA17. We also appreciate at the Structural Research Laboratory (University of Warsaw, Poland) for using HPLC-ESI-MS

Performance of Dual-Purpose Cows on a Native Pasture-\u3ci\u3eArachis pintoi\u3c/i\u3e Association in the Humid Tropics of Mexico

Native grasslands (NG) are the main feed supply of dual-purpose (DP) cows of the Mexican humid tropics. NG comprise about 85% of Paspalum, Axonopus and Cynodon species, about 5% of native legumes, mainly of Desmodium, and the remaining 10% are narrow and broad leafed weeds. Arachis pintoi (AP) is a persistent grazing tolerant tropical legume. In association with sown grasses, it has improved dry matter (DM) yield, nutritive quality of forage, and milk yield up to 9 kg/cow/day (González et al., 1996). The objective was to determine if productive performance of DP cows could be improved by the introduction of AP into NG grassland