ABSTRACT
ABSTRACT Perennial ryegrass is one of the most important food sources in animal production. However, several pests affect this crop, and one of the primary control strategies is the symbiotic relationships between ryegrass endophyte fungi. This fungus produces alkaloids that exhibit toxic activity against arthropods. Furthermore, the effect of fungi may extend to higher trophic levels, including predators (spiders and/or insects), decreasing their abundance and diversity. Given the importance of spiders and insects as predators, whether the symbiotic interaction between perennial ryegrass and endophyte fungus reduces the abundance and diversity of predators pose an important question. To address this question, natural enemies in perennial ryegrass were collected and analyzed over a year, and the percentage of endophyte fungus was evaluated by the presence of hyphae from two ryegrass cultivars, Jumbo (E-) and Alto AR1 (E+). We observed an 80% endophyte infection rate for (E+) and 0% for (E-). Moreover, 222 individual spiders corresponding to 10 families were identified in both perennial ryegrasses, including 209 individuals for (E-) and 13 for (E+). The most abundant spider family was Lycosidae, representing 71.17% of the total spiders. In addition, 65 insects were collected, corresponding to 6 families, with Carabidae being the most abundant. Furthermore, the Simpson index indicated the dominance of the family Lycosidae. Overall, spider and insect abundance and diversity were reduced in (E+), suggesting a negative effect of the endophyte on predator populations.
ABSTRACT
Volatiles compounds are involved in defensive induction against insects, playing an important role in insect-plant interaction being induced by response to mechanical damage. However, they could decrease according to the domestication degree in cultivated plants. Currently, it has been established that secondary metabolites are reduced due to the domestication process in murtilla. Hence, the follow question emerges: Are volatile organic compounds induced by mechanical damage reduced in cultivated murtilla plants in relation to wild plants? Two cultivated ecotypes and their respective wild counterparts were sampled. Volatiles compounds were obtained using Porapak-Q columns and analyzed by gas chromatography. Results showed that compounds as 2-hexanone, α-pinene, 2-thujene, 3-thujene and 1,8- cineole were more abundant in wild plants exposed to a mechanical damage than cultivated plants. Hence, these compounds have been associated to induced defense, these results suggest that domestication reduced the induction of defensive volatiles in cultivated murtilla in response to mechanical damage.
Los compuestos volaÌtiles estaÌn implicados en la defensa inducida contra insectos, desempenÌando un papel importante en esta interaccioÌn. Sin embargo, estos compuestos podriÌan disminuir seguÌn el grado de domesticacioÌn. Actualmente, se ha reportado que algunos metabolitos secundarios son reducidos en plantas de murtilla domesticadas. Por lo tanto, surge la siguiente pregunta de investigacioÌn: ¿Los compuestos orgaÌnicos volaÌtiles inducidos por el danÌo mecaÌnico son reducidos en plantas cultivadas de murtilla en comparacioÌn con plantas silvestres? Para dos ecotipos cultivados y sus respectivas contrapartes silvestres, los compuestos volaÌtiles fueron capturados usando columnas de Porapak-Q y las muestras analizadas por cromatografiÌa gaseosa. Los resultados mostraron que compuestos tales como 2- hexanona, α-pineno, 2-tujeno, 3-tujeno y 1,8-cineol fueron maÌs abundantes en plantas silvestres expuestas a danÌo mecaÌnico que en cultivadas. Debido a que estos compuestos se han asociado a defensa inducida, estos resultados sugieren que la domesticacioÌn reduce la induccioÌn de volaÌtiles en plantas cultivadas sometidas a danÌo mecaÌnico.
Subject(s)
Animals , Oils, Volatile/metabolism , Myrtaceae/metabolism , Myrtaceae/microbiology , Domestication , Insecta/physiology , Sesquiterpenes/analysis , Sesquiterpenes/metabolism , Oils, Volatile/chemistry , Myrtaceae/chemistry , Monoterpenes/analysis , Monoterpenes/metabolism , Wilderness , Larva/physiology , Gas Chromatography-Mass SpectrometryABSTRACT
Red clover (Trifolium pratense L.) is a perennial plant widely used as a forage resource for several animals. This plant is the exclusive host of Hylastinus obscurus (Marsham) which causes irreparable damages to the root system affecting their persistence. It has been reported that the presence of the isoflavonoid formononetin in roots of red clover could act as an antifeedant on H. obscurus. There are not studies related to the formononetin content in red clover roots to the antifeedant effect elicited by experimental lines and cultivar of red clover. Six red clover genotypes were investigated in both formononetin content and their respective antifeedant action. The results showed to Sabtoron High and Superqueli-INIA with both the highest formononetin content in red clover roots and antifeedant effect, allowing to suggest that this secondary metabolites could be used as a chemical factor for red clover plants. Moreover, a rapid methodology for searching red clover genotypes with high formononetin content is reported.
El treÌbol rosado (Trifolium pratense L.) es una planta perenne ampliamente utilizada como fuente de forraje de variados animales. Esta planta es el exclusivo hospedero de Hylastinus obscurus (Marsham) el cual causa irreparables danÌos al sistema radical afectando seriamente su persistencia. Se ha reportado que la presencia del isoflavonoide formononetina en raiÌces del treÌbol rosado podriÌa actuar como antialimentario sobre H. obscurus. Actualmente no existen estudios que relacionen el contenido de formononetina en raiÌces de treÌbol rosado con el efecto antialimentario elicitado por liÌneas experimentales y cultivares de treÌbol rosado. Seis genotipos de esta leguminosa fueron evaluados en cuanto a su contenido de formononetina y actividad antialimentaria. Los resultados mostraron que los cultivares Sabtoron High y Superqueli-INIA presentaron altos niveles de formononetina en sus raiÌces y efecto antialimentario sobre H. obscurus, lo que permite sugerir que este metabolito secundario podriÌa ser usado como factor quiÌmico para incrementar la persistencia de plantas de treÌbol rosado. AdemaÌs, se informa una metodologiÌa raÌpida para la buÌsqueda de genotipos con altos contenidos de formononetina.