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Phytate is considered a poorly available plant P source but proved to be useful for particular soil bacteria strains. In soil-free conditions, it has been shown that bacteria locked up the mineralized phosphorus from phytate whereas bacterial grazers like nematodes were able to deliver P to plants. Here, we aimed to determine if the interactions between phytate-mineralizing bacteria, bacterial grazer nematodes, and mycorrhizal fungi could increase plant P acquisition from phytate in high P-adsorbing soils. Pinus pinaster was grown in a Cambisol supplemented with phytate. Plants, whether associated or not associated with the ectomycorrhizal fungus Hebeloma cylindrosporum, were either inoculated or not inoculated with the phytase-releasing bacteria Bacillus subtilis and the bacterial-feeding nematode Rhabditis sp. After 100 days, the dual inoculation of bacteria and nematodes significantly increased net plant P accumulation. We observed that, on average, mycorrhizal plants accumulated more P in their shoots than non-mycorrhizal plants. However, the highest plant P acquisition efficiency was found when the three soil organisms were present in the P. pinaster rhizosphere. We conclude that, in a highly inorganic P-fixing soil, plant P acquisition from phytate strongly depends on the grazing of phytate-mineralizing bacteria. Our results confirm the importance of the soil microbial loop to improve plant P nutrition from phytate, which should be considered a route to improve the utilization of this source of poorly available P by plants. • In contrast to trees and ectomycorrhizal fungi, bacteria can mineralize phytate. • We used a high P-sorbing cambisol amended with phytate to study plant P acquisition. • We studied bacteria-grazer nematodes-ectomycorrhizal fungi interactions on plant P. • The ectomycorrhizal fungus and bacteria increased plant P use from phytate. • Non mycorrhizal plants depend on bacterial grazing to get P from soil phytate. [ABSTRACT FROM AUTHOR]

• Water deficiency is a crop limiting factors resulting in severe yield reduction. • Arbuscular mycorrhiza increase chicory growth performance in all irrigation rates. • Inoculated chicory plants under drought stress had an enhanced antioxidant activity. • Inoculated chicory plants showed low drought stress by enhancing tolerance mechanisms. Water deficiency is one of the most significant limiting factors resulting in severe crop yield reduction. This study hypothesizes that the inoculation of arbuscular mycorrhiza (AM) minimize the detrimental effects of drought in chicory (Cichorium intybus L.). The objective was to evaluate how AM inoculation affects agro-biochemical traits of chicory under different irrigation rates. Field experiments were conducted in 2017 and 2018 in north of Iran and designed as a factorial combination of three irrigation rates [40, 65 and 90 % of maximum allowable depletion of available soil water (IR1, IR2 and IR3, respectively)], two AM inoculations [inoculated and not inoculated (AM+ and AM−, respectively)] and two chicory ecotypes [Sefid Isfahan and Siyah Shiraz (E1 and E2, respectively)]. Crop growth, pigments and minerals content, carbon exchange rate, transpiration rate and stomatal conductance were evaluated. The data showed that the mycorrhizal colonization increased chicory growth performance by 12.4 %, 16.1 % and 21.0 %, under I1, I2, and I3 water regime, respectively. The mineral content and photosynthesis parameters decreased as irrigation water decreased, irrespective of whether plants were inoculated or not. Similarly, AM+ plants had higher inulin percentage and the mean inulin degree of polymerisation than AM− plant under all of irrigation levels. Furthermore, inoculated chicory plants under drought stress showed an enhanced activity of the antioxidant system, such as superoxide dismutase, peroxidase, ascorbic acid and glutathione, while the accumulation of hydrogen peroxide and the oxidative damage were reduced. The two ecotypes tended to respond similarly to irrigation and AM treatments for all growth and quality parameters measured in the experiment, even if ecotype Siyah Shiraz performed better than ecotype Sefid Isfahan. The improved plant performance and inulin content in the inoculated plants demonstrate that AM has the potential to minimize the detrimental effects of drought stress on chicory under semi-arid conditions. [ABSTRACT FROM AUTHOR]

• Mycorrhiza inoculation along with vermicompost increased significantly saffron traits. • Utilization of bio and organic fertilizers, can provide the feasibility of saffron ecological production. • Utilization Mycorrhiza along with vermicompost can be considered as a movement along the sustainable agriculture. • The interaction of bio and organic fertilizers can increase some of traits of saffron. In order to investigate saffron (Crocus sativus. L) stigma, flower and leaf quantitative and qualitative characteristics under the effect of different vermicompost and mycorrhiza levels, researchers conducted a factorial experiment in the completely randomized design with three replications in the research farm of the agricultural faculty of Shahid Bahonar University of Kerman in 2017–2018. The investigated factors included vermicompost in four levels (0, 8000, 16,000 and 24,000 kg ha-1) and inoculation with mycorrhiza in four levels (0, 7.5, 10 and 15 g for every planting location) (in every planting location two corms with the same weight (7.5 ± 0.5 g) were planted). Results indicated significant effect of vermicompost on the leaf area and dry weight, crocin and picrocrocin in both years. Likewise, leaf dry weight and leaf area were significantly affected by mycorrhiza in both years. The interaction effect of vermicompost fertilizer and mycorrhiza was significant on the traits of leaf components comprising: leaf area in the first year and flower number, chlorophyll 'a', 'b' and total chlorophyll in the second year. Results also indicated that the maximum number of the saffron flower in the first year was obtained from the treatment of 24,000 kg ha-1 vermicompost (3.23 flowers per square meter) and 10 g mycorrhiza fertilizer treatment for every planting location (3.45 flowers per square meter). The maximum number of the saffron flower in the second year was obtained from the treatment of 24,000 kg ha-1 vermicompost (77.25 flowers per square meter) and 10 g mycorrhiza fertilizer treatment for every planting location (84.41 flowers per square meter). Also using 10 g mycorrhiza for every planting location in the second year enhanced the stigmas dry yield by 46.21 % compared with the control. Likewise, 10 g mycorrhiza for every planting location enhanced the dry weight of one-plant leaves by 137.5 % compared with the control. On the same way, the application of 24,000 kg ha-1 enhanced the leaf dry weight by 41.66 % compared with the control. Totally, the mycorrhiza inoculation in the level of 10 g for every planting location along with vermicompost fertilizer application by 24,000 kg ha-1 significantly increased saffron traits especially quantitative characteristics. By using 10 g mycorrhiza for each planting place (5 cm × 5 cm) in the second year, the saffron stigma yield was 3.498 kg per hectare in this treatment, which revealed 46.21 % increase compared with the control. [ABSTRACT FROM AUTHOR]

• Responses of antioxidant enzyme defense system to AMF under DS were studied. • Leaf Fe-SOD, Mn-SOD, Cu/Zn-SOD and CAT activity was increased by AMF under DS. • Leaf PtMn-SOD , PtCAT1 and PtPOD expression was up-regulated by AMF under DS. • AM plants had lower leaf MDA, O 2 − and H 2 O 2 levels under DS. • AM plants had greater capacity on antioxidant enzyme defense systems under DS. A pot experiment was carried out to investigate the responses of leaf antioxidant enzyme defense systems to an arbuscular mycorrhizal fungus (AMF), Funneliformis mosseae , in trifoliate orange (Poncirus trifoliata) seedlings exposed to drought stress (DS). An eight-week soil drought treatment notably decreased root mycorrhizal colonization, root surface area and volume, total plant biomass, leaf relative water content, and leaf chlorophyll a , b , and a + b concentrations, while these variables were significantly greater in mycorrhizal seedlings than in non-mycorrhizal seedlings. There was significantly higher leaf catalase (CAT) activity in AMF-inoculated seedlings versus non-AMF-inoculated seedlings under well-watered (WW) conditions. Under DS, leaf superoxide dismutase (Fe-SOD, Mn-SOD, and Cu/Zn-SOD) and CAT activities were dramatically increased with AMF inoculation. Leaf PtMn-SOD and peroxidase (PtPOD) gene expressions were significantly increased by AMF treatment under WW. Under DS, the relative expression of leaf PtMn-SOD , PtCAT1 , and PtPOD was increased by AMF, while leaf PtFe-SOD and PtCu/Zn-SOD expressions were down-regulated. Such higher antioxidant enzyme activities and corresponding gene expressions in mycorrhizal plants under DS indicated their greater capacity to mitigate the oxidative damage of drought, as evidenced by the lower concentrations of malondialdehyde, superoxide radical, and hydrogen peroxide in AMF-inoculated plants. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) represent an important route for plant carbon (C) inputs into the soil. Nonetheless, the C input via AMF as well as its impact on soil organic matter (SOM) stabilization and C sequestration remains largely unknown. A mycorrhizal wild type progenitor (MYC) and its mycorrhiza defective mutant (reduced mycorrhizal colonization: rmc) of tomato were continuously labeled with 13CO 2 to trace root C inputs into the soil and quantify rhizosphere priming effects (RPE) as affected by AMF symbiosis and N fertilization. Mycorrhizal abundance and 13C incorporation into shoots, roots, soil and CO 2 were measured at 8, 12 and 16 weeks after transplanting. AMF symbiosis decreased the relative C allocation (% of total assimilated C) to roots, in turn increased the net rhizodeposition. Positive RPE was recorded for both MYC and rmc plants, ranging from 16–71% and 25–101% of the unplanted control, respectively. Although net rhizodeposition was higher for MYC than rmc plants 16 weeks after transplanting, the RPE was comparatively lower. This indicated a higher potential for C sequestration by plants colonized with AMF (MYC) because the reduced nutrient availability restricts the activity of free-living decomposers. Although N fertilization decreased the relative C allocation to roots, rhizosphere and bulk soil, it had no effect on the absolute amount of rhizodeposition to the soil. The RPE and N-cycling enzyme activities decreased by N fertilization 8 and 12 weeks after transplanting, suggesting a lower microbial N demand from SOM mining. The positive relationship between enzyme activities involved in C cycling, microbial biomass C and SOM decomposition underlines the microbial activation hypothesis, which explains the RPE. We therefore concluded that AMF symbiosis and N fertilization increase C sequestration in soil not only by increasing root C inputs, but also by lowering native SOM decomposition and RPE. • Arbuscular mycorrhizal fungi (AMF) reduced rhizosphere priming effect (RPE). • N fertilization lowered the magnitude of RPE by decreasing enzymes. • The net rhizodeposition induced by AMF was dependent on N availability. [ABSTRACT FROM AUTHOR]

This issue of Mycological Research News features: Vagaries in interest in natural products by drug discovery companies. The first paper in this issue describes the application of topological analysis to hyphal branching patterns in fungal colonies for the first time. Molecular phylogenetic papers concern the relationships of genera and species of Peronosporaceae, South American Cortinarius species, Amanita spp. genotypes in Australian sclerophyll vegetation, new cryptic species of Albatrellus, Cantharellus and Ophiostoma, and the occurrence of group I introns in Beauveria bassiana. The sterols of field and fungicide resistant Cercospora beticola have been studied, and three novel illudins are described from Coprinopsis episcopalis. An innovative seed-baiting technique to detect different orchid mycorrhizas at the same time has also been devised, and local site variations in fungi on pine needles is documented. The following new scientific names are introduced in this part: Albatrellus citrinus, Cantharellus cascadensis, and Ophiostoma kryptum spp. nov.; and O. crenulatum (syn. Ceratocystiopsis crenulata) comb. nov. [ABSTRACT FROM AUTHOR]

This issue of Mycological Research News features: Kelo trees: a vanishing fungal habitat; Polarized growth in fission yeast; Comparative genomics and functional elements in the yeast genome; When physics meets biology: high-resolution laser-based techiques to study plant–microbe interactions; and an Acknowledgement. The largest molecular phylogenetic fungal tree yet to have been published is presented, based on 1551 sequences; this will be of interest to all concerned with fungal relationships, especially at family and higher levels. Hepatic mycorrhizas are described ultrastructurally and molecularly, and the relationships of the mycobionts determined. The cytology and behaviour of nuclei in tri- and tetraradiate conidia in coelomycetes is examined, and micronuclei are documented for the first time. Confocal laser scanning electron microscopy examines nuclei and ascospore formation using a methodology likely to have wide utility. The conditions affecting the production of the siderophore rhodotorulic acid by Rhodotorula mucilaginosa have been investigated. The poisonous Clitocybe lactea produces phallatoxins, previously only known from Amanita spp., and its relationships are explored by molecular methods. Swainsonine, the cause of locoism in cattle etc. in the USA, is produced by endophytic fungi inside the plants consumed. The enyzmes produced by the lignin-degrading Mycena galopus and responsible for this activity have been investigated and identified. The following new scientific names are introduced in this part: Cornutispora intermedia, C. pittii, and Furcaspora abieticola spp. nov. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizas are ancient symbioses between fungi and plant roots that played a key role in the evolution of vascular land plants and remain a vital component of plant communities today. The mechanisms promoting bidirectional nutrient transfer of phosphates and sugar are beginning to be revealed and transport genes that are specifically expressed in the presence of the fungi have now been identified. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of selected single arbuscular mycorrhiza (AM) species, dual species inoculations and indigenous mycorrhizae (IM) inoculations, using specific growing media (GM), on the growth and nutrient uptake of sour orange (Citrus aurantium L.) seedlings. Five mycorrhiza species and their dual species inoculations, one commercial and one indigenous (multiple species) mycorrhizae were investigated using two growing media, GM1 (andesitic tuff + peat (1:1, V:V)) and GM2 (andesitic tuff + peat + soil (4 + 5+1, V: V:V)), under controlled greenhouse conditions. The experiments were conducted over 12 months. Mycorrhizal inoculation increased certain plant growth parameters such as shoot height, diameter, and shoot and root dry matter. Generally, mycorrhiza species and their dual species inoculations exerted different responses on plant growth. In GM1, Funneliformis mosseae, Rhizophagus clarus and indigenous mycorrhiza (IM) species were the best inoculants to increase citrus growth, root colonization and nutrient uptake; however, in GM2, Fu. mosseae and IM were the best inocula. Fu. mosseae + R. clarus was the most efficient dual species inoculation in GM1, whereas in GM2 the most efficient combination was Fu. mosseae + Fu. caledonium. The beneficial effects of AM fungi and the dual species inoculation with IM was also significant. Citrus seedlings grew much better in GM1 than in GM2. Root colonization was also increased with dual species inoculation and IM. In addition, the plant phosphorus and zinc content increased with mycorrhizal inoculation. Our results reinforce the efficiency of IM and mycorrhizal inoculations as being as effective as exotic AM fungal isolates. Dual species inoculation and IM show promise in the production of healthy seedlings, using several growing media. [ABSTRACT FROM AUTHOR]

Fungi are one of the most important components of forest ecosystems,since they determine to a large extent the fate and transport processes of radionuclides in forests. They play a key role in the mobilization, uptake and translocation of nutrients and are likely to contribute substantially to the long-term retention of radiocesium in organic horizons of forest soil. This paper gives an overview of the role of fungi regarding the transfer and cycling of nutrients and radionuclides, with special emphasis on mycorrhizal symbiosis. Common definitions of transfer factors, soil-fungus and soil-green plant, including their advantages and limitations, are reviewed. Experimental approaches to quantify the bioavailability of radionuclides in soil and potential long-term change are discussed. [ABSTRACT FROM AUTHOR]