Metagenetics of fairy rings reveals complex and variable soil fungal communities

Although fairy rings are widely observed, little is known about the community processes associated with them. Here, we studied fairy rings in a natural grassland in northern Mongolia by sampling soils outside (future stage), directly under (present stage), and within (past stage) the rings, to represent different time stages during the expansion of fairy rings. Soil DNA was extracted for amplicon sequencing of the fungal ITS1 region. The present stage had reduced fungal diversity and different fungal communities toward the other stages. Most strikingly, there was an increase in the pathogenic fungus Gibberella baccata in the present stage of most rings and the saprotrophic fairy ring fungus Lepista luscina in several. However, no mushrooms of Lepista had been recorded from any of these rings during several years of observation. Known fairy ring fungi were not found in the present stage of every ring, even in some known rings to have previously displayed mushrooms of such species. It is possible that these fungi occurred or were more abundant at the unsampled leading edge of the ring. The increase in G. baccata is intriguing, but its importance, if any, is unclear. It is also unclear whether consortia of fungi or other microbes might be present in these rings. The absence or low abundance of the previously reported fairy ring fungal species suggests that their presence is transient, with rapid replacement by other fungi. No differences in soil parameters were found between the fairy ring stages, except for aluminum. There is a need for broader sampling, including analysis of non-fungal biota, to understand the functional diversity of fairy ring fungi and the consequences for plant communities.     

Effect of lameness (hoof disorders) on productivity of Karan Fries crossbred cows

In present study production performance of 96 lame cows was compared with 67 healthy cows. No significant effect of parity and year of calving on milk yield were observed but the effect of season of calving was significant (P < 0.01). Effect of lameness on milk yield at the second, third and fourth months and 305 days was highly significant (P < 0.01), and was also significant (P < 0.05) on lactation yield of the fifth and tenth months. The effect of lameness on monthly and 305‐day milk yield was significant (P < 0.01) only for those cows diagnosed lame before calving and during the first month of lactation. The differences in mean monthly yield were highly significant (P < 0.01) at the second, third and fourth months; and significant (P < 0.05) in the first and fifth months. The loss in the first lactation month of cows which were diagnosed as lame in the second month, was found to be significant (P < 0.05). Thus the yield of the month previous to the diagnosis (sub‐clinical stage) was also affected. A significant (P < 0.01) total loss of 498.95 kg of milk yield was observed during a period of 305 days.     

土壤碳氮对多年生能源草、覆盖作物和氮施肥的响应

Cover crop and nitrogen(N) fertilization may maintain soil organic matter under bioenergy perennial grass where removal of aboveground biomass for feedstock to produce cellulosic ethanol can reduce soil quality. We evaluated the effects of cover crops and N fertilization rates on soil organic carbon(C)(SOC), total N(STN), ammonium N(NH_4-N), and nitrate N(NO_3-N) contents at the0–5, 5–15, and 15–30 cm depths under perennial bioenergy grass from 2010 to 2014 in the southeastern USA. Treatments included unbalanced combinations of perennial bioenergy grass, energy cane(Saccharum spontaneum L.) or elephant grass(Pennisetum purpureum Schumach.), cover crop, crimson clover(Trifolium incarnatum L.), and N fertilization rates(0, 100, and 200 kg N ha~(-1)). Cover crop biomass and C and N contents were greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1) than in the treatment of energy cane and elephant grass. The SOC and STN contents at 0–5 and 5–15 cm were 9%–20% greater in the treatments of elephant grass with cover crop and with or without 100 kg N ha~(-1)than in most of the other treatments. The soil NO_3-N content at 0–5 cm was 31%–45% greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1)than in most of the other treatments.The SOC sequestration increased from 0.1 to 1.0 Mg C ha~(-1)year~(-1)and the STN sequestration from 0.03 to 0.11 Mg N ha~(-1)year~(-1)from 2010 to 2014 for various treatments and depths. In contrast, the soil NH_4-N and NO_3-N contents varied among treatments,depths, and years. Soil C and N storages can be enriched and residual NO_3-N content can be reduced by using elephant grass with cover crop and with or without N fertilization at a moderate rate.     

Properties of soil kaolinites from south-western Australia

The clay fraction of soils from south-western Australia is dominated by kaolinite. These soil kaolinites give broad basal reflections (median value for WHH 001 =0.41° 2θ) and have poorly ordered structures. The median value of the Hughes & Brown crystallinity index for 35 soil kaolinites is 5.4 compared to 42.0 for mineral standard kaolinites. The median values for surface area and cation exchange capacity of soil kaolinites are 35 m² g⁻¹ and 56.7 mmol_c kg⁻¹, respectively, compared to 10 m² g⁻¹ and 4.8 mmol_c kg- ^l for standard kaolinites. The dehydroxylation temperature of soil kaolinites is about 50 K lower than for standard kaolinites and decreases with increasing Fe content. Soil kaolinite crystals are much smaller (c. 0.10 pm) and are irregular subrounded to rounded plates in comparison to the larger (c. 0.28 pm), perfectly hexagonal euhedral plates of Georgia kaolinite. Analytical electron microscopy of single soil kaolinite crystals indicates that the Fe content varies with an average value of c. 2.5% Fe,₂O₃. X-ray diffraction line broadening data indicate that crystal size decreases as the Fe content increases. Crystal order also decreases with increasing Fe content. The P sorption maximum of soil kaolinite ranges from 486–654 μg P g^−l and is thus about six times larger than for the clay fraction of Georgia kaolinite.     

Effect of powdery mildew (Erysiphe pisi) on nodulation and nitrogenase activity in pea (Pisum sativum)

The effects of powdery mildew ( Erysiphe pisi) disease of pea (Pisum sativum) on the number and size of root nodules and on nitrogenase activity were investigated in pea plants grown in pots and in the field. There were significant reductions in nodulation and in the size of root nodules as well as in nitrogenase activity in infected plants.     

Natural infection of cucumber mosaic virus on Dianthus barbatus in India

Cucumber mosaic virus (serologically closely related to strains CMV-C and CMV-D) is reported for the first time as a natural infection of Dianthus barbatus causing leaf crinkle and stunting of plants. It was mechanically transmitted to healthy D. barbatus and Vaccaria pyramidata (Caryophyllaceae) and to other herbaceous test plants, and was also aphid-transmissible from D. barbatus to D. barbatus. A convenient host for multiplication and purification of the virus was Nicotiana rustica. The presence of CMV was confirmed in D. barbatus and also in V. pyramidata by Western immunoblotting, but the concentration was too low in both the hosts to detect the virus by agar double diffusion tests.     

Comparison between ELISA and bio tin-la belled probes from cloned cDNA of potato virus X for the detection of virus in crude tuber extracts

Diseases caused by potato virus X (PVX) are of significant agronomic importance, and early detection is vital. Biotinylated DNA probes were prepared by random-primed labelling from cDNA inserts and used for the detection of PVX in crude extracts of infected tubers. The minimum detection level in these extracts is in the order of femtograms of PVX RNA. Comparison with ELISA showed that the hybridization method is 100–250 times more sensitive. Probes prepared by this method are highly specific for target RNA even in crude tuber extracts.     

Genes for race-specific resistance to yellow rust (Puccinia striiformis) in Indian wheat cultivars

Seedlings of Indian wheat cultivars (Kalyansona, Sonalika, WL711 and eight others released commercially) were tested with 13 British and four alien races of Puccinia striiformis. The data indicated the probable presence of the resistance gene Yr2 in the three cultivars named above and in six of the others. Reactions of the remaining two cultivars, PWB12 and WL2265, were consistent with the presence of the gene 177. The presence of Yr2 in Kalyansona, Sonalika and WL711 was supported by evidence from crosses between them and with Heines VII, which is known to carry Yr2. In crosses of Sonalika with a susceptible cultivar, Kharchia Local and also with WL711, tests of F1, F2 and F3 generations indicated that, in addition to Yr2 , Sonalika possesses at least two other genes. Both these genes were difficult to detect but the F3 data supported the hypothesis that there is a single partially recessive gene giving resistance to alien race 6E16 and a different, possibly complementary, gene system effective against another alien race, 39E134. The presence of resistance in addition to Yr2 was also detected in WL711 and HD2329.     

Effect of maternal ketoacidosis on the ovine fetus

Ketoacidosis during pregnancy carries significant risk of intrauterine fetal demise, but little is known about the impact of ketoacids on the ovine fetus. We report a case series of maternal ketoacidosis in ewes. Maternal ketoacidosis may result in biochemical and acid-base fetal abnormalities associated with changes in feto-placental unit perfusion.