From the classroom to the farm: a lesson plan that promotes smallholder farmers' education and training about plant pathology in the context of climate change.

Climate change represents one of the biggest threats to agricultural productivity around the world. In the tropics, extreme climate and pest and disease outbreaks represent one of the biggest climate change threats to smallholder farmers. Understanding smallholder farmers' educational needs and increasing access to information and awareness of climate change through education and training are key first steps to enhance the adaptive capacity of smallholder farmers. In a primary effort to increase accessible training and education to these communities, we developed a plant pathology lesson plan. The lesson plan introduces basic concepts in plant pathology and disease management using diverse educational activities focused on experiential and collaborative learning. This lesson plan may have implications in enhancing farmers' adaptive capacity and increasing accessible education to underrepresented farming communities around the world.

Communities of endophytic fungi in a Puerto Rican rainforest vary along a gradient of disturbance due to Hurricane Maria.

Increases in the frequency and intensity of hurricanes influence the structure, function, and resilience of Caribbean forests. Trees in such forests harbor diverse fungal endophytes within leaves and roots. Fungal endophytes often are important for plant health and stress responses, but how their communities are impacted by hurricanes is not well known. We measured forest disturbance in Carite State Forest in Puerto Rico ca. 16 months after the passage of Hurricane Maria, a Category 4 storm. In three sites, each comprising three plots representing a local gradient of hurricane disturbance, we evaluated soil chemistry and used culture-free analyses to measure richness, phylogenetic diversity, and composition of endophyte communities in leaves and roots. We found that endophyte richness did not vary significantly among plant families or as a function of soil chemistry. Instead, leaf endophytes peaked in richness and decreased in phylogenetic diversity at intermediate levels of disturbance. Root endophytes did not show such variation, but both leaf- and root endophyte communities differed in species composition as a function of disturbance across the forest. Locations with less disturbance typically hosted distinctive assemblages of foliar endophytes, whereas more disturbed locations had more regionally homogeneous endophyte communities. Together, our results show that changes in endophyte richness and phylogenetic diversity can be detected in aboveground tissues more than a year after major storms. In turn, pervasive shifts in endophyte community composition both aboveground and belowground suggest a subtle and lasting effect of hurricanes that merits further study, potentially contributing to the promotion of spatially heterogeneous endophyte assemblages at a landscape scale in these diverse island forests.

Los aumentos en la frecuencia e intensidad de los huracanes influyen en la estructura, función, y resiliencia de los bosques del Caribe. Los árboles en dichos bosques tienen diversos hongos endófitos dentro de las hojas y raíces. Los hongos endófitos pueden ser importantes para la salud de las plantas y las respuestas a el estrés, pero no se conoce bien cómo los huracanes afectan a sus comunidades. Medimos la perturbación forestal en el Bosque Estatal de Carite en Puerto Rico a 16 meses después del paso del Huracán María (huracán categoría 4). En tres sitios, cada uno de los cuales incluyeron tres parcelas que representan un gradiente local de perturbación debido al huracán, evaluamos la química del suelo y utilizamos análisis libres de cultivos para medir la riqueza, la diversidad filogenética y la composición de las comunidades de endófitos en las hojas y raíces de las plantas. Encontramos que la riqueza de endófitos no varió significativamente entre las familias de plantas o en función de la química del suelo. Los endófitos de hojas alcanzaron su punto máximo en riqueza y disminuyeron en diversidad filogenética en niveles intermedios de perturbación forestal. Los endófitos de raíces no mostraron tal variación, pero ambas comunidades de endófitos difirieron en la composición de especies en función de la perturbación en el bosque. Las ubicaciones con menos perturbaciones generalmente tenían conjuntos distintivos de endófitos foliares, mientras que las ubicaciones más perturbadas tenían comunidades de endófitos regionalmente más homogéneas. Nuestros resultados muestran que los cambios en la riqueza de endófitos y la diversidad filogenética se pueden detectar en los tejidos de las hojas más de un año después de grandes tormentas. A su vez, los cambios generalizados en la composición de la comunidad de endófitos de hojas y raíces sugieren un efecto sutil y duradero de los huracanes que amerita un mayor estudio, lo que podría contribuir a la promoción de ensamblajes de comunidades de endófitos heterogéneas en diversos bosques.

AMPA receptor contribution to methylmercury-mediated alteration of intracellular Ca2+ concentration in human induced pluripotent stem cell motor neurons.

α motor neurons (MNs) are a target of the environmental neurotoxicant methylmercury (MeHg), accumulating MeHg and subsequently degenerating. In mouse spinal cord MN cultures, MeHg increased intracellular Ca2+ [Ca2+]i; the AMPA receptor (AMPAR) antagonist CNQX delayed the increase in [Ca2+]i, implicating the role of AMPARs in this response. Here we used human induced pluripotent stem cell-derived MNs (hiPSC-MNs), to characterize the role of MN AMPARs in MeHg neurotoxicity. Acute exposure to MeHg (0.1, 0.2, 0.5, 1 and 1.5 µM), fura-2 microfluorimetry, and a standard cytotoxicity assay, were used to examine MN regulation of [Ca2+]i, and cytotoxicity, respectively. Contribution of Ca2+-permeable and impermeable AMPARs was compared using either CNQX, or the Ca2+-permeable AMPAR antagonist N-acetyl spermine (NAS). MeHg-induced cytotoxicity was evaluated following a 24 h delay subsequent to 1 h exposure of hiPSC-MNs. MeHg caused a characteristic biphasic increase in [Ca2+]i, the onset of which was concentration-dependent; higher MeHg concentrations hastened onset of both phases. CNQX significantly delayed MeHg's effect on onset time of both phases. In contrast, NAS significantly delayed only the 2nd phase increase in fura-2 fluorescence. Exposure to MeHg for 1 h followed by a 24 h recovery period caused a concentration-dependent incidence of cell death. These results demonstrate for the first time that hiPSC-derived MNs are highly sensitive to effects of MeHg on [Ca2+]i, and cytotoxicity, and that both Ca2+-permeable and impermeable AMPARs contribute the elevations in [Ca2+]i.