Trait-based approaches in arbuscular mycorrhizal fungi need to distinguish between response and effect traits

Mycologists usually borrow models or theoretical frameworks from other ecological disciplines to test them in fungal ecology. For example, using models from plant and animal ecology, some attempts intended to classify fungi according to life-history strategies, or functional groups and guilds. In this way, species composition in a community is simplified to a few groups or guilds of species sharing similar traits from which we can make some predictions about nature functioning. Importantly, theseclassifications could be based on “response” traits to environmental changes or “effect” traits on ecosystem processes, and classifications based on response traits could differ from those based on effect traits.Fil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Trait-based approaches in arbuscular mycorrhizal fungi need to distinguish between response and effect traits

Mycologists usually borrow models or theoretical frameworks from other ecological disciplines to test them in fungal ecology. For example, using models from plant and animal ecology, some attempts intended to classify fungi according to life-history strategies, or functional groups and guilds. In this way, species composition in a community is simplified to a few groups or guilds of species sharing similar traits from which we can make some predictions about nature functioning. Importantly, theseclassifications could be based on “response” traits to environmental changes or “effect” traits on ecosystem processes, and classifications based on response traits could differ from those based on effect traits.Fil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Produção de árvore neotropical: percepções sobre a germinação, crescimento e plantio de Maytenus boaria

Knowledge about tree production practices is essential to support forestrestoration projects, but is still lacking for many tree species. Maytenus boaria is a neotropical tree distributed across the temperate and subtropical South American mountains. In central Argentina, it is mainly restricted to the most preserved forest remnants. Attempts to plant this species have had little success due to difficulties in seedling production and low seedlingsurvival. We set up four trials aiming to identify the constraints of seedling production and outplanting. Under greenhouse conditions, we evaluated (i) pre?germination treatments and (ii) seedling response to inoculation with arbuscular mycorrhizal fungi (AMF). In the field, we planted M. boaria saplings as well as saplings of the most abundant tree in our study site and recorded (iii) survival and height for 10 years. Finally, (iv) we quantified natural recruitmentin an attempt to determine M. boaria regeneration niche. Germination varied from 13.1 to 29.2% among treatments. Depulped seeds stratified at 5 oC showed the highest germination (29.2%). Shoot phosphorus concentration in AMF-treated seedlings was significantly higher (45%) than in non-inoculated seedlings. Survival of M. boaria saplings was similar to that of the most abundant tree in our study site, but their lower height suggested limited growth.We recorded low abundance of M. boaria seedlings in the field; therefore, we were unable to identify the characteristics of its regeneration niche. Reforestation activities should include seed depulping and stratification at 5 oC to improve germination. The capacity of AMF to enhance nutrition should be evaluated under field conditions.Conhecimento sobre as práticas de produção da árvore é essencial para apoiar projetos de restauração florestal, mas é ainda insuficiente para muitas espécies arbóreas. Maytenus boaria é uma árvore neotropical distribuída pelas montanhas temperadas e subtropicais da América do Sul. No centro da Argentina, é majoritariamente restrita nos remanescentes de floresta mais preservados. Tentativas de plantar esta espécie tiveram pouco sucesso devido às dificuldades de produção de mudas e baixa sobrevivência das plântulas. Montamos quatro ensaios com o objetivo de identificar as restrições à produção de mudas e plantio de campo. Sob condições de estufa, avaliamos os tratamentos de (i) pré-germinação e (ii) resposta das plântulas à inoculação com fungos micorrízicos arbusculares (FMA). No campo, nós plantadas mudas de M. boaria, bem como mudas da árvore mais abundante em nosso local de estudo, e avaliamos a (iii) sobrevivência e altura por 10 anos. Finalmente, (iv) nós quantificamos o recrutamento natural em tentativa de determinar o nicho de regeneração da M. boaria. A germinação variou de 13,1 a 29,2% entre os tratamentos. Sementes sem a polpa estratificadas a 5 °C obtiveram a maior germinação (29,2%). Concentração de fósforo na parte aérea das mudas tratadas com FMA foi significativamente maior (45%) do que em mudas não inoculadas. Sobrevivência das mudas de M. boaria foi semelhante ao da árvore mais abundante em nosso local de estudo, mas sua baixa altura sugeriu crescimento limitado. Nós gravamos baixa abundância de plântulas de M. boaria no campo, portanto, não fomos capazes de identificar as características do seu nicho de regeneração. Atividades de reflorestamento devem incluir a retirada da polpa das sementes e estratificação a 5 °C para melhorar a germinação. A capacidade de FMA para melhorar a nutrição deve ser avaliada em condições de campo.Fil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Soteras, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cofré, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Ibarra, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Torres, Romina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Renison, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

Effect of the entomopathogenic nematode-bacterial symbiont complex on Meloidogyne hapla and Nacobbus aberrans in short-term greenhouse trials

Meloidogyne hapla and Nacobbus aberrans are plant-parasitic nematodes that form galls in the roots of infected plants and cause important economic losses. Entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis infect and kill insects via toxins produced by their symbiotic bacteria. EPNs have shown to have an antagonistic effect on different plant-parasitic nematode species in field and greenhouse trials. The aim of the present work was to evaluate, in tomato plants in greenhouse, the effect of the application of three Argentine EPN isolates, their symbiotic bacteria and cell-free supernatants, on a population of M. hapla and two populations of N. aberrans. Sixty days after inoculation, the number of galls and egg masses, the nematode reproduction factor (RF) and plant biomass were calculated. With a few exceptions, biomass was not affected by the different treatments. None of the plant-parasitic nematode populations was reduced by infective juvenile inoculation of the different EPN isolates. Bacterial action differed among populations; M. hapla was the most susceptible one, with a significant reduction in the number of galls, egg masses and RF caused by the application of the three bacterial strains. The most significant effect was produced by the cell-free supernatants on nematode RF, with reductions of 62–90%, caused by bacterial metabolites. The different inoculation alternatives of the EPN-bacterial symbiont complex tested in the present work (infective juveniles, bacteria and cell-free supernatant) are compared for the first time for plant-parasitic nematode species.Fil: Caccia, Milena Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Rondan Dueñas, Juan. Pabellón CEPROCOR. Laboratorio de Biología Molecular; ArgentinaFil: Doucet, Marcelo Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Lax, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Use of the arbuscular mycorrhizal fungus <i>Glomus intraradices</i> as biological control agent of the nematode <i>Nacobbus aberrans</i> parasitizing tomato

The plant-parasitic nematode Nacobbus aberrans is an endoparasite that induces gall formation in the roots and causes severe losses to diverse crops. Some populations of this nematode show preference for certain hosts, revealing the existence of "races/groups" with different behaviour and making nematode management difficult. A possible biological control alternative to reduce the damage caused by this species may be the use of arbuscular mycorrhizal fungi (AMF). In the present work, the effect of Glomus intraradices on tomato plants inoculated with the nematode at transplanting and three weeks later was tested. At 60 days, the following parameters were estimated: percentage of AMF colonization, root and aerial dry weight, number of galls and egg masses, and reproduction factor (RF=final population/initial population) of N. aberrans. AMF colonization was higher in the presence of the nematode. The use of AMF favoured tomato biomass and reduced the number of galls and RF on the plants inoculated with the nematode at transplanting.Facultad de Ciencias Naturales y MuseoInstituto de Botánica "Dr. Carlos Spegazzini

Mycorrhizas reduce tomato root penetration by false root-knot nematode <i>Nacobbus aberrans</i>

Arbuscular mycorrhizal fungi (AMF) are considered as a possible alternative for the biological control of plantparasitic nematodes. The false root-knot nematode Nacobbus aberrans is an endoparasite that induces the formation of galls in plant roots and causes severe damage to crops of economic importance. The purpose of the study was to evaluate the effect of the individual and combined application of two AMF species (Rhizophagus intraradices and Funneliformis mosseae) on the tomato root penetration of N. aberrans second-stage juveniles (J2). Forty-five days after the application of AMF, 300 J2 were inoculated per plant. Tomato roots were analyzed after 4, 8 and 12 days in order to quantify the nematodes that had invaded them. Plants inoculated with AMF presented a lower number of juveniles within the roots compared with non-mycorrhizal plants. No significant differences were observed between the individual and combined application of AMF regarding the number of nematode juveniles. The use of R. intraradices and F. mosseae (both individually and combined) reduced the entry of nematodes in tomato roots. The antagonistic effect of AMF on the invasion of N. aberrans J2 is reported for the first time.Instituto de Botánica "Dr. Carlos Spegazzini

Efecto de hongos micorrícico arbusculares (Glomeromycota) sobre el nematodo fitófago Nacobbus aberrans (nematoda) en plantas de importancia agrícola

Nacobbus aberrans es un nematodo endoparásito sedentario que induce alteracioneshistológicas en la raíz de la planta y produce severos daños en cultivos de relevanciaagrícola. Los hongos micorrícico arbusculares (HMA) establecen una relación simbióticacon la mayoría de las especies vegetales a través de una comunicación química mediada porcomponentes de los exudados radicales; entre ellos, la hormona vegetal estrigolactona (EL)juega un rol importante. Los HMA favorecen la tolerancia del hospedador ante distintosfactores de estrés y el ataque de patógenos del suelo, tales como, los nematodos fitófagos.En la búsqueda de métodos para el manejo de N. aberrans, el uso de HMA es una opciónprometedora para minimizar los daños inducidos por esta plaga. Hasta el momento, lainformación sobre su interacción con HMA es limitada. El objetivo de este trabajo fueevaluar la utilización de HMA como una alternativa de control biológico de N. aberrans envegetales de importancia agrícola y estudiar posibles mecanismos involucrados en esarelación. Por un lado, se examinó el efecto de la inoculación individual y combinada de dosespecies de HMA (Rhizophagus intraradices y Funneliformis mosseae) sobre el parásito entomate (Solanum lycopersicum) y pimiento (Capsicum annuum). A los 60 días, se midió eldesarrollo vegetal (biomasa total, largo aéreo y radical), el porcentaje de colonizaciónmicorrícica arbuscular (% CMA) y variables del nematodo [número de agallas, masas dehuevos y factor de reproducción (FR)]. Por otro lado, se analizó cómo la micorrizaciónprevia (singular y dual) de tomate afectó el nivel de penetración de juveniles del nematodoen los sistemas radicales. El largo aéreo no mostró diferencias entre tratamientos mientrasque la longitud radical disminuyó frente al ataque de N. aberrans, incluso en raícesmicorrizadas. En plantas infectadas, el principal beneficio sobre la biomasa se obtuvo alcombinar los HMA. En los dos hospedadores, el % CMA fue mayor en presencia delnematodo mientras que el número de agallas, masas de huevos, FR y el nivel depenetración (en el caso de la experiencia con tomate) disminuyeron independientemente dela modalidad de empleo de HMA. Por otro lado, se cuantificó y midió la expresión génicarelativa de EL en la interacción nematodo-HMA-tomate, poniendo en evidencia que fuesignificativamente superior en plantas pre-micorrizadas e inoculadas con N. aberrans.Además, se observó que al aplicar dos densidades iniciales diferentes del nematodo, seincrementó la producción de EL mientras que la expresión génica fue mayor solo frente al12inóculo más alto. Los resultados de este trabajo muestran que la utilización individual ycombinada de los HMA tuvo acción similar sobre la población del parásito; sin embargo,inocularlos de manera conjunta favoreció el crecimiento vegetal. Por otro lado, se pone enevidencia que uno de los posibles mecanismos involucrados en la interacción nematodo-HMA-planta sería la producción de EL. Debido al efecto antagónico de los HMA sobre N.aberrans, es importante profundizar sobre el uso combinado de diferentes especies dehongos como agentes de control biológico en plantas de importancia agrícola para el país.Fil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

The global invader Ligustrum lucidum accumulates beneficial arbuscular mycorrhizal fungi in a novel range

Alien invasive trees may expand and form monospecific forests by enhancing mutualism with arbuscular mycorrhizal fungi (AMF) and/or preventing the establishment of other plants through accumulation of antagonists for native plants. The success of invasive plants also has been associated with their higher phenotypic plasticity. Here we tested these mechanisms by studying the global invasive tree Ligustrum lucidum (hereafter Ligustrum) and the dominant native tree of the Chaquean montane forest (central Argentina) Lithraea molleoides (hereafter Lithraea). We experimentally addressed the effects of soil biota from Ligustrum monospecific forest stands and native montane forests on growth, biomass allocation, and nutrition of alien Ligustrum and native Lithraea. Soil biota was recovered from the rooting zone of adult trees of both species in each forest type. We found that arbuscule colonization in Ligustrum roots was significantly higher in seedlings grown with AMF communities from monospecific invaded forests in comparison to native soils. Mycorrhizal colonization in Lithraea roots did not differed between forest types. Soil biota from the rooting zone of the native Lithraea had no major effects on both itself and the invasive Ligustrum. Instead, AMF from Ligustrum rooting zone almost tripled and doubled P nutrition of the alien and the native compared with non-AMF treatments, respectively. Besides, antagonistic effects of soil biota were not observed. Lithraea root mass fraction (root mass/total plant mass, RMF) was not affected by forest type nor by soil treatment but Ligustrum RMF was affected by both factors. In particular, RMF decreased when seedlings grew with AMF from its rooting zone. The observed positive plant–soil feedback and the phenotypic plasticity of Ligustrum could explain, at least in part, the high invasiveness and the formation of monospecific forest stands by this global invader.Fil: Borda, Valentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Longo, Maria Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Marro, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Are strigolactones a key in plant–parasitic nematodes interactions? An intriguing question

Plant parasitic nematodes (PPNs) are among the most important pests in agriculture. Chemical inputs are widely used for their control; however, the negative impact of these agrochemicals on environmental and human health is a current concern. Biological control and interventions on rhizosphere signaling are promising ecofriendly alternatives for managing these pests in the field. Nevertheless, the molecular mechanisms involved in plant-PPN interaction need to be unraveled in order to develop appropriate management strategies. Strigolactones (SLs) are phytohormones that are exuded from roots, acting as signaling molecules in the rhizosphere. They are important cues in the establishment of arbuscular mycorrhizal and Rhizobium-legume symbioses. Recently, it has been shown that SLs can also affect the interaction between plants and certain PPN species; however, data are scarce and ambiguous. Some studies propose that SLs positively regulate PPN species performance acting as attractants to roots, or by inhibiting plant defense responses. On the contrary, other studies suggest that SLs could negatively regulate PPN performance by reducing abscisic acid, or by promoting plant interactions with beneficial soil microorganisms. In the present Opinion paper, we discuss these controversial results and propose future research challenges to develop new management strategies against these harmful PPN species.Fil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Caccia, Milena Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: López-Ráez, Juan Antonio. Estación Experimental del Zaidín; España. Consejo Superior de Investigaciones Científicas; Españ