Revision of Entrophospora and description of Kuklospora and Intraspora, two new genera in the arbuscular mycorrhizal Glomeromycetes

Five mycorrhizal fungal species of the Glomeromycetes which were organized in the genus Entrophospora are revised. They all form their spores within the hyphal stalk directly beneath or in some distance of a sporiferous saccule formed intercalary or terminally in the mycelium. Based on differences respective similarities in spore morphologies and root infection characteristics only Entrophospora infrequens and Entrophospora baltica remain in this genus. The genus is the type genus for the new family Entrophosporaceae. The other three species are organized in two new genera. Kuklospora gen. nov. with Kuklospora colombiana and Kuklospora kentinensis (formerly Entrophospora colombiana and Entrophospora kentiniensis) is placed into the family of the Acaulosporaceae. Intraspora gen. nov. so far contains only Intraspora schenckii (the former Entrophospora schenckii) and is included into the family of the Archaeosporaceae. The morphological differences between the genera and the distribution of these fungal species in ecosystems are discussed

The Influence of Arbuscular Mycorrhizal Fungi Inoculation on micro-propagated hybrid yam (Dioscorea spp.) growth and root knot nematode (Meloidogyne spp.) suppression

Article Purchased; Published online: 12 October 2016The use of commercial inoculants containing non-indigenous arbuscular mycorrhizal fungi (AMF) is an emerging technology towards improving crop production in Africa. The present study aims at evaluating the influence of two strains of commercial arbuscular mycorrhizal fungi (AMF) products, based on Funneliformis mosseae and Glomus dussii, on yam growth and on root knot nematodes suppression. Using micropropagated plantlets two cultivars each of Dioscorea alata (TDa98-01183 and TDa98-165), and D. rotundata (TDr97-00551 and TDr 745) were inoculated with the F. mosseae and G. dussii products separately, at transplanting into 2L pots, and then inoculated one month later with 500 infective juveniles of Meloidogyne spp. and grown for further seven months in the greenhouse. Results demonstrated that even with low colonization rates (6%), AMF led to improved yam growth, especially for D. alata. When challenged with Meloidogyne spp., AMF inoculation significantly suppressed galling symptoms across the treatments and led to higher tuber yield. This study indicates the potential of AMF to sustainably improve yam quality and productivity, although further screening should be done in order to identify a suitable combination AMF species/strain x cultivar compatibility to optimise the results

Effect of two species of arbuscular mycorrhizal fungi inoculation on development of micro-propagated yam plantlets and suppression of Scutellonema bradys (Tylenchideae)

Using two commercially available arbuscular mycorrhizal fungal (AMF) products, one based on Funneliformis mosseae and the other on Glomus dussii, an experiment was conducted to assess their effect on yam growth and ability to suppress nematode damage in pots. Four yam cultivars (cvs) were used: two Dioscorea alata cvs (TDa98-01183 and TDa98-165), and two Dioscorea rotundata cvs (TDr97- 00551 and TDr 745). Micropropagated yam plantlets were inoculated either with F. mosseae or with G. dussii at the stage of transplanting into 2L pots and - one month later - with 500 vermiform Scutellonema bradys. The plantlets were grown for further six months in the greenhouse at IITA-Ibadan. The results showed that the presence of AMF tended to lead to improved growth of yam, especially D. alata cvs, as compared with the non-arbuscular mycorrhizal control plants. When challenged with the yam nematode S. bradys, plantlets of the two D. alata cultivars pre-inoculated with F. mosseae and cv TDr97-00551 pre-inoculated with G. dussii yielded significantly higher tuber weights compared to non- AMF control plantlets. S. bradys densities on yam plantlets pre-inoculated with AMF were generally suppressed, although no differences were observed in visible damage scores, which remained low or absent across treatments

Phosphorus budget and phosphorus availability in soils under organic and conventional farming

The aim of this work was to assess to which extent organic farming practices would affect the accumulation of total and available phosphorus (P) in a cropped soil in comparison to conventional practices. In order to achieve this, soil samples were taken from a long-term field trial comparing a non-fertilised control (NON), two conventionally cultivated treatments (MIN, CON), and two organically cultivated treatments (ORG, DYN). Soil samples were taken from each treatment at two depths (0-20 and 30-50 cm) before starting the field trial (1977) and at the end of every three crop rotations (1984, 1991 and 1998). They were then analysed for total P (Pt), total inorganic P (Pi), total organic P (Po) and isotopically exchangeable Pi. After 21 years, the average P input-output budget reached -20.9 kg P ha−1 a−1 for NON, -7.8 for DYN, -5.7 for ORG, -5.0 for MIN and +3.8 for CON. Total P, Pi as well as the amount of Pi isotopically exchangeable within 1 minute (E1) were positively correlated to the P budget. Comparison between P budget and Pt in the top- and subsoils of the fertilised treatments suggested a net transfer of P from the 0-20 to the 30-50 cm layers between 13 and 26 kg P ha−1 a−1during the first rotation and between 3 and 12 kg P ha−1 a−1during the second rotation. During the third rotation a net upward movement of P from the subsurface to the topsoil ranging between 3.7 and 10.5 kg P ha−1 a−1was estimated. In the topsoil, E1decreased from an initial value of 12 mg P kg−1 to 11 in CON, 8 in MIN, 6 in ORG, 5 in DYN and 2 in NON after 21 years. In the subsoil, E1 increased from an initial value of 2 mg P kg−1 to 4 in MIN, ORG, DYN and NON and to 6 in CON. These results show that, with the exception of NON, all treatments had still an adequate level of available P after 21 years of trial and that, in this low to moderately P sorbing soil, an equilibrated input-output budget allows to maintain P availability at a constant level. In the organic systems, yields have so far partly been attained at the expense of soil reserves or residual P from earlier fertiliser application

Contrasting effects of cover crops on 'hot spot' arbuscular mycorrhizal fungal communities in organic tomato

Arbuscular mycorrhizal fungal (AMF) communities are fundamental in organic cropping systems where they provide essential agro-ecosystem services, improving soil fertility and sustaining crop production. They are affected by agronomic practices, but still, scanty information is available about the role of specific crops, crop rotations and the use of winter cover crops on the AMF community compositions at the field sites. A field experiment was conducted to elucidate the role of diversified cover crops and AMF inoculation on AMF diversity in organic tomato. Tomato, pre-inoculated at nursery with two AMF isolates, was grown following four cover crop treatments: Indian mustard, hairy vetch, a mixture of seven species and a fallow. Tomato root colonization at flowering was more affected by AMF pre-transplant inoculation than by the cover crop treatments. An enormous species richness was found by morphological spore identification: 58 AMF species belonging to 14 genera, with 46 and 53 species retrieved at the end of cover crop cycle and at tomato harvest, respectively. At both sampling times, AMF spore abundance was highest in hairy vetch, but after tomato harvest, AMF species richness and diversity were lower in hairy vetch than in the cover crop mixture and in the mustard treatments. A higher AMF diversity was found at tomato harvest, compared with the end of the cover crop cycle, independent of the cover crop and pre-transplant AMF inoculation. Our findings suggest that seasonal and environmental factors play a major role on AMF abundance and diversity than short-term agronomic practices, including AMF inoculation. The huge AMF diversity is explained by the field history and the Mediterranean environment, where species characteristic of temperate and sub-tropical climates co-occur

Implementing protocol verification for E-Commerce

This paper presents a survey of the practical application of protocol verification techniques to applications in e­commerce. We concentrate in particular on logic­ based approaches, and review the current state of the art as well as the prospects for realistic deployment of protocol verification techniques in the near future

Progress towards sustainable control of xylella fastidiosa subsp. Pauca in olive groves of salento (apulia, italy)

Xylella fastidiosa subsp. pauca is the causal agent of “olive quick decline syndrome” in Salento (Apulia, Italy). On April 2015, we started interdisciplinary studies to provide a sustainable control strategy for this pathogen that threatens the multi-millennial olive agroecosystem of Salento. Confocal laser scanning microscopy and fluorescence quantification showed that a zinc-copper-citric acid biocomplex—Dentamet® —reached the olive xylem tissue either after the spraying of the canopy or injection into the trunk, demonstrating its effective systemicity. The biocomplex showed in vitro bactericidal activity towards all X. fastidiosa subspecies. A mid-term evaluation of the control strategy performed in some olive groves of Salento indicated that this biocomplex significantly reduced both the symptoms and X. f. subsp. pauca cell concentration within the leaves of the local cultivars Ogliarola salentina and Cellina di Nardò. The treated trees started again to yield. A1 H-NMR metabolomic approach revealed, upon the treatments, a consistent increase in malic acid and γ-aminobutyrate for Ogliarola salentina and Cellina di Nardò trees, respectively. A novel endotherapy technique allowed injection of Dentamet® at low pressure directly into the vascular system of the tree and is currently under study for the promotion of resprouting in severely attacked trees. There are currently more than 700 ha of olive groves in Salento where this strategy is being applied to control X. f. subsp. pauca. These results collectively demonstrate an efficient, simple, low-cost, and environmentally sustainable strategy to control this pathogen in Salento