The uptake mechanism, translocation, and subcellular distribution of azoxystrobin (5 mg kg–1) in wheat plants was investigated under laboratory conditions. The wheat–water system reached equilibrium after 96 h. Azoxystrobin concentrations in roots were much higher than those in stems and leaves under different exposure times. Azoxystrobin uptake by roots was highly linear at different exposure concentrations, while the bioconcentration factors and translocation factors were independent of the exposed concentration at the equilibrium state. Dead roots adsorbed a larger amount of azoxystrobin than fresh roots, which was measured at different concentrations. Azoxystrobin preferentially accumulated in organelles, and the highest distribution proportion was detected in the soluble cell fractions. This study elucidated that the passive transport and apoplastic pathway dominated the uptake of azoxystrobin by wheat roots. Azoxystrobin primarily accumulated in roots and could be acropetally translocated, but its translocation capacity from roots to stems was limited. Additionally, the uptake and distribution of azoxystrobin by wheat plants could be predicted well by a partition-limited model.

Broomrapes (Orobanche spp.) are parasitic weeds that cause significant losses of crop yield. Experiments were conducted to investigate the seed response to the artificial germination stimulant GR 24 in three species of Orobanche subjected to preconditioning under various temperatures, water potentials and with plant growth regulators. The highest germination percentages were observed in Orobanche ramosa, Orobanche aegyptiaca and Orobanche minor seeds conditioned at 18°C for 7 days followed by germination stimulation at 18°C. With the increase of the conditioning period (7, 14, 21 and 28 days), the germination percentage of O. ramosa and O. aegyptiaca progressively decreased. When conditioned at )2 MPa, the germination percentage was lower than at 0 and )1 MPa, especially at 13 and 28°C. Orobanche minor seeds could retain relatively high germination if conditioned at 18, 23 or 28°C, even after significantly extended conditioning periods (up to 84 days). GA 3 (30-100 mg L )1 ), norflurazon and fluridone (10-100 mg L )1 ), and brassinolide (0.5-1.0 mg L )1 ) increased seed germination, while 0.01 mg L )1 uniconazole significantly reduced germination rates of all three Orobanche spp. The promotional effects of GA 3 and norflurazon and the inhibitory effect of uniconazole were evident, even when they were treated for 3 days. Germination of Orobanche seeds was much lower when the unconditioned seeds were directly exposed to GR 24 at 10 )6 M. This early GR 24 -induced inhibition was however alleviated or even eliminated by the inclusion of GA 3 or norflurazon (10-50 mg L )1 ) in the conditioning medium. On the contrary, the inclusion of uniconazole increased the inhibitory effect of GR 24 , particularly in the case of O. ramosa.

No abstract

Triazole resistance in Aspergillus fumigatus is a growing public health concern. In addition to its emergence in the therapy of invasive aspergillosis by triazole medicines, it has been frequently detected in agricultural fields all over the world. Here, we explore the potential link between residues of azole fungicides with similar chemical structure to triazole medicines in soil and the emergence of resistant A. fumigatus (RAF) through 855 500 km2 monitoring survey in Eastern China covering 6 provinces. In total, 67.3%, 15.2%, 12.3%, 2.9%, 1.5%, 0.4%, and 0.3% of the soil samples contained these five fungicides (tebuconazole, difenoconazole, propiconazole, hexaconazole, and prochloraz) of 0–100, 100–200, 200–400, 400–600, 600–800, 800–1000, and >1000 ng/g, respectively. The fractions of samples containing RAF isolates were 2.4%, 5.2%, 6.4%, 7.7%, 7.4%, 14.3%, and 20.0% of the samples with total azole fungicide residues of 0–100, 100–200, 200–400, 400–600, 600–800, 800–1000, and >1000 ng/g, respectively. We find that the prevalence of RAFs is positively (P < 0.0001) correlated with residual levels of azole fungicides in soils. Our results suggest that the use of azole fungicides in agriculture should be minimized and the intervals between treatments expanded to reduce the selective pressure toward the development of resistance in A. fumigatus in agricultural fields.

No abstract

A total of 191 soil samples from Hangzhou, China, were submitted to detect non-wild-type (non-WT) Aspergillus fumigatus and its associated mechanisms. There were 2 (4.7%), 13 (12.4%), and 31 (23.1%) isolates identified as non-WT in 2014, 2016, and 2018, respectively. The resistant mutations of TR34/L98H, TR46/Y121F/T289A, and TR34/L98H/S297T/F495I were found in 3, 5, and 5 non-WT isolates. The G448S mutation, previously only found in clinical settings, was detected in A. fumigatus from soil samples.

No abstract

Aims:  This paper investigates a selection‐based acclimation strategy for improving the performance and stability of aerobic granules at a high chloroanilines loading. Methods and Results:  The experiments were conducted in a sequencing airlift bioreactor (SABR) to develop aerobic granules fed with chloroanilines (ClA). The evolution of aerobic granulation was monitored using image analysis and scanning electron microscopy, and PCR–DGGE analysis of microbial community was performed. The sludge granulation was apparently developed by decreased settling time and gradual increased ClA loading to 0·8 kg m−3 day−1. A steady‐state performance of the granular SABR was reached at last, as evidenced by biomass concentration of 6·3 g l−1 and constant ClA removal efficiency of 99·9%. The mature granules had a mean size of 1·55 mm, minimal settling velocity of 68·4 m h−1, specific ClA degradation rate of 0·181 g gVSS−1 day−1. Phylogenetic analysis of aerobic ClA‐degrading granules confirmed the dominance of β‐, γ‐Proteobacteria and Flavobacteria. Conclusions:  The chosen operating strategy involving step increase in ClA loading and enhancement of major selection pressures was successful in cultivating the aerobic ClA‐degrading granules. Significance and Impact of the Study:  This research could be helpful for improving the stability of aerobic granules via optimizing operating conditions and developing economic feasible full‐scale granular bioreactor.