Consistency of response to arbuscular mycorrhizal (AM) inoculation is required for efficient use of AM fungi in plant production. Here, we found that the response triggered in plants by an AM strain depends on the properties of the soil where it is introduced. Two data sets from 130 different experiments assessing the outcome of a total of 548 replicated single inoculation trials conducted either in soils with a history of (1) high input agriculture (HIA; 343 replicated trials) or (2) in more pristine soils from coffee plantations (CA; 205 replicated trials) were examined. Plant response to inoculation with different AM strains in CA soils planted with coffee was related to soil properties associated with soil types. The strains Glomus fasciculatum-like and Glomus etunicatum-like were particularly performant in soil relatively rich in nutrients and organic matter. Paraglomus occultum and Glomus mosseae-like performed best in relatively poor soils, and G. mosseae and Glomus manihotis did best in soils of medium fertility. Acaulospora scrobiculata, Diversispora spurca, G. mosseae-like, G. mosseae and P. occultum stimulated coffee growth best in Chromic, Eutric Alluvial Cambisol, G. fasciculatum-like and G. etunicatum-like in Calcaric Cambisol and G. manihotis, in Chromic, Eutric Cambisols. Acaulospora scrobiculata and Diversispora spurca strains performed best in Chromic Alisols and Rodic Ferralsols. There was no significant relationship between plant response to AM fungal strains and soil properties in the HIA soil data set, may be due to variation induced by the use of different host plant species and to modification of soil properties by a history of intensive production. Consideration of the performance of AM fungal strains in target soil environments may well be the key for efficient management of the AM symbiosis in plant production.

Asteraceae family shows a great diversity in Cuba and presents threatened taxons in high number. Pinar del Río has 19 threatened species belonging to this family and three of them are characteristic of a sandy (quartzitic) soil at the Reserva Florística Manejada San Ubaldo-Sabanalamar (Floristic Reserve San Ubaldo-Sabanalamar). The arbuscular mycorrhizal status and colonization rate in Aster grisebachii, Erigeron bellidiastroides, Erigeron cuneifolius, Pectis juniperina and Sachsia polycephala (Asteraceae) from this Reserve was determined in October 2009 and April 2010, during hydrologic rainy and dry period, respectively. All species were mycotrophic in both periods with a high percentage of colonization rates, between 66 and 100% in rainy period and between 84 and 100% in dry period. Vesicles, arbuscules, spores, hyphal and arbuscular coils of arbuscular mycorrhizae were observed. Paris -type and Arum -type morphologies (both) were observed indistinctly in all the species, and Intermediate type was observed only in Aster grisebachii and Erigeron bellidiastroides , which could be a hint that these species are colonized by more than one fungal species, and therefore enhancing the relevance of fungal identity as a considerable character in the morphology association. Also, septate hyphae and microsclerotium of dark septate endophytes were identifyed inside the roots of all the species. Resumen: La familia Asteraceae muestra una gran diversidad en Cuba y presenta un elevado número de taxones amenazados. Pinar del Río cuenta con 19 especies amenazadas pertenecientes a esta familia, de las cuales tres son características de los suelos arenosos cuarcíticos de la Reserva Florística Manejada San Ubaldo-Sabanalamar. Se determinó el estatus micorrízico arbuscular y la tasa de colonización de Aster grisebachii, Erigeron bellidiastroides, Erigeron cuneifolius ,Pectis juniperina y Sachsia polycephala (Asteraceae) presentes en esta Reserva, en octubre del 2009 y abril del 2010, durante los períodos hidrológicos húmedo y seco, respectivamente. Todas las especies estaban micorrizadas en ambos períodos con elevados porcentaje de colonización micorrízica, entre 66 y 100% en el período lluvioso y entre 84 y 100% en el período seco. Se identificaron vesículas, arbúsculos, esporas, enrollados hifales y arbusculares característicos de las micorrizas arbusculares. Los tipos morfológicos Paris y Arum (ambos) fueron observados indistintamente en todas las especies, y el tipo Intermedio solo se observó en Aster grisebachii y Erigeron bellidiastroides, lo cual sugiere la colonización de estas especies por más de una especie fúngica y con ello la importancia de la identidad fúngica en la determinación de la morfología de la asociación. Se identificaron además, hifas septadas y microesclerosios de endófitos oscuros septados en el interior de las raíces de todas las especies estudiadas.

A new ornamented species of the Glomeromycetes found in Pinar del Rio and Moa, western and east Cuba, respectively, is proposed here as Glomus crenatum. The fungus differs from previously described species by the darkly pigmented spore walls that possess a hemispherical dome-like surface ornamentation.

No abstract

Glomus trufemii, which forms large aggregates (≤ 850 × 1200 μm) in the rhizosphere of a herbaceous plant community in NE Brazilian sand dunes, is described as new. Its subglobose glomerospores measuring 72–92 × 79–105 μm have two spore wall layers: an evanescent hyaline 0.3–0.8 μm thick outer layer and a laminate orange brown to dark red brown 7.4–15.5 μm thick inner layer. The pigmentation of the subtending hypha is similar but often much lighter than that of the laminate spore wall layer. The spore size and color, spore wall structure, and features of the spore base and subtending hyphae separate this species from similar yellow-brown to brown spored species like G. badium, G. glomerulatum, and G. brohultii.