New primers for promising single-copy genes in fungal phylogenetics and systematics

Developing powerful phylogenetic markers is a key concern in fungal phylogenetics. Here we report degenerate primers that amplify the single-copy genes Mcm7 (MS456) and Tsr1 (MS277) across a wide range of Pezizomycotina (Ascomycota). Phylogenetic analyses of 59 taxa belonging to the Eurotiomycetes, Lecanoromycetes, Leotiomycetes, Lichinomycetes and Sordariomycetes, indicate the utility of these loci for fungal phylogenetics at taxonomic levels ranging from genus to class. We also tested the new primers in silico using sequences of Saccharomycotina, Taphrinomycotina and Basidiomycota to predict their potential of amplifying widely across the Fungi. The analyses suggest that the new primers will need no, or only minor sequence modifications to amplify Saccharomycotina, Taphrinomycotina and Basidiomycota

Crescimento, parâmetros biofísicos e aspectos anatômicos de plantas jovens de seringueira inoculadas com fungo micorrízico arbuscular Glomus clarum Growth, biophysical parameters and anatomical aspects of young rubber tree plants inoculated with arbuscular mycorrhizal fungi Glomus clarum

Fungos micorrízicos são reconhecidamente benéficos quando em associação às plantas por favorecerem seu crescimento e desenvolvimento. Apesar de pouco comum para a seringueira, a inoculação artificial de fungos micorrízicos arbusculares (FMAs) tem se mostrado uma alternativa para a redução no uso de fertilizantes e pesticidas nas culturas, bem como para a formação de mudas, visando obtenção de porta-enxertos precoces e bem nutridos. O estudo objetivou avaliar o efeito da inoculação do FMA Glomus clarum no crescimento e características biofísicas e anatômicas de plantas jovens de seringueira. Os tratamentos consistiram de plantas inoculadas com o fungo Glomus clarum adubadas com 50 ppm de fósforo (mic+50P), plantas não inoculadas adubadas com 50 ppm de fósforo (s/mic+50P) e plantas não inoculadas adubadas com 500 ppm de fósforo (s/mic+500P). Constatou-se que as plantas micorrizadas apresentaram altura e diâmetro dos caules, matéria seca da parte aérea, densidade estomática e área foliar, semelhantes às plantas s/mic+500P. Maior acúmulo de matéria seca de raiz, maior taxa de transpiração, menor resistência estomática e menor temperatura foliar foram observadas para as plantas micorrizadas. As análises anatômicas das raízes evidenciam a ocorrência de alterações no tecido vascular, com aumento no número de pólos de xilema das raízes das plantas micorrizadas.<br>Mycorrhizal fungi are beneficial when associated with plants because they favor growth and develop. Although infrequent, artificial inoculation of arbuscular mycorrhizal fungi (AMF) has become an alternative to reduce the use of fertilizers and pesticides in crops, as well as for the formation of seedlings, to obtain precocious and well fed rootstocks. The objective of the study was to evaluate the effect of inoculation of AMF Glomus clarum on growth and biophysical and anatomical characteristics of young rubber trees. The treatments consist of plants inoculated with the fungus Glomus clarum and fertilized with 50 ppm of phosphorus (mic+50P), non-inoculated plants fertilized with 50 ppm of phosphorus (s/mic+50P) and non-inoculated plants fertilized with 500 ppm of phosphorus (s/mic+500P). The mycorrhizal plants showed height and stem diameter, dry matter accumulation of the aerial part, stomatal density and leaf area similar to the plants s/mic+500P. Greater accumulation of dry matter in the roots, higher transpiration rate, less stomatal resistance and lower leaf temperature were reported for the mycorrhizal plants. The anatomical analyses of the roots showed alterations in the vascular tissue, with increase in the number of xylem poles in the mycorrhizal plant roots

Arbuscular mycorrhizal networks: process and functions. A review

International audienceAn unprecedented, rapid change in environmental conditions is being observed, which invariably overrules the adaptive capacity of land plants. These environmental changes mainly originate from anthropogenic activities, which have aggravated air and soil pollution, acid precipitation, soil degradation, salinity, contamination of natural and agro-ecosystems with heavy metals such as cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), global climate change, etc. The restoration of degraded natural habitats using sustainable, low-input cropping systems with the aim of maximizing yields of crop plants is the need of the hour. Thus, incorporation of the natural roles of beneficial microorganisms in maintaining soil fertility and plant productivity is gaining importance and may be an important approach. Symbiotic association of the majority of crop plants with arbuscular mycorrhizal (AM) fungi plays a central role in many microbiological and ecological processes. In mycorrhizal associations, the fungal partner assists its plant host in phosphorus (P) and nitrogen (N) uptake and also some of the relatively immobile trace elements such as zinc (Zn), copper (Cu) and iron (Fe). AM fungi also benefit plants by increasing water uptake, plant resistance and biocontrol of phytopathogens, adaptation to a variety of environmental stresses such as drought, heat, salinity, heavy metal contamination, production of growth hormones and certain enzymes, and even in the uptake of radioactive elements. The establishment of symbiotic association usually involves mutual recognition and a high degree of coordination at the morphological and physiological level, which requires a continuous cellular and molecular dialogue between both the partners. This has led to the identification of the genes, signal transduction pathways and the chemical structures of components relevant to symbiosis; however, scientific knowledge on the physiology and function of these fungi is still limited. This review unfolds our current knowledge on signals and mechanisms in the development of AM symbiosis; the molecular basis of nutrient exchange between AM fungi and host plants; and the role of AM fungi in water uptake, disease protection, alleviation of various abiotic soil stresses and increasing grain production