Effects of hexaconazole application on soil microbes community and nitrogen transformations in paddy soils

Ju, Chao; Xu, Jun; Wu, Xiaohu; Dong, Fengshou; Liu, Xingang; Tian, Chunyan; Zheng, Yongquan

doi:10.1016/j.scitotenv.2017.07.146

Cited by 65 publications

(22 citation statements)

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“…Considering the role of functional genes, we observed a greater reduction in Jiangxi soil than in Beijing soil in the abundance of the 11 nitrogen transfer genes and the 16S rRNA gene after DZ fumigation. Researchers reported that microbes in acidic soil were more sensitive to hexaconazole fungicide than those in alkaline soil ( Ju et al, 2017 ). We observed a temporary inhibition of the functional genes in the Beijing soil and a fast recovery to levels similar to the control, probably because Beijing soils are alkaline and DZ is less persistent in such soils.…”

Section: Discussionmentioning

confidence: 99%

Responses of Nitrogen-Cycling Microorganisms to Dazomet Fumigation

et al. 2018

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The influence of soil fumigation on microorganisms involved in transforming nitrogen remains little understood, despite the use of fumigants for many decades to control soil-borne pathogens and plant-parasitic nematodes. We used real-time PCR (quantitative polymerase chain reaction) and 16S rRNA gene amplicon sequencing techniques to monitor changes in the diversity and community structure of microorganisms associated with nitrogen transfer after the soil was fumigated with dazomet (DZ). We also examined nitrous oxide (N2O) emissions from these microorganisms present in fumigated fluvo-aquic soil and lateritic red soil. Fumigation with DZ significantly reduced the abundance of 16S rRNA and nitrogen cycling functional genes (nifH, AOA amoA, AOB amoA, nxrB, narG, napA, nirK, nirS, cnorB, qnorB, and nosZ). At the same time, N2O production rates increased between 9.9 and 30 times after fumigation. N2O emissions were significantly correlated with NH4+, dissolved amino acids and microbial biomass nitrogen, but uncorrelated with functional gene abundance. Diversity indices showed that DZ temporarily stimulated bacterial diversity as well as caused a significant change in bacterial community composition. For example, DZ significantly decreased populations of N2-fixing bacteria Mesorhizobium and Paenibacillus, nitrifiers Nitrosomonas, and the denitrifiers Bacillus, Pseudomonas, and Paracoccus. The soil microbial community had the ability to recover to similar population levels recorded in unfumigated soils when the inhibitory effects of DZ fumigation were no longer evident. The microbial recovery rate, however, depended on the physicochemical properties of the soil. These results provided useful information for environmental safety assessments of DZ in China, for improving our understanding of the N-cycling pathways in fumigated soils, and for determining the potential responses of different N-cycling groups after fumigation.

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Section: Discussionmentioning

confidence: 99%

Responses of Nitrogen-Cycling Microorganisms to Dazomet Fumigation

et al. 2018

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“…Plant growth-promoting rhizobacteria (PGPR), for example, are a group of free-living bacteria that colonize the rhizosphere and provide benefits to root physiology and growth [ 9 , 10 ]. Fungicides also adversely affect the function and composition of soil enzymes, as well as microbial respiration, biomass production, diversity, and function [ 11 , 12 ]. Among fungicides, hexaconazole (HEXA), for example, has been found to adversely affect the various metabolic activities of plants [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Fungicide-Tolerant Plant Growth-Promoting Rhizobacteria Mitigate Physiological Disruption of White Radish Caused by Fungicides Used in the Field Cultivation

Khan

Shahid

Khan

et al. 2020

IJERPH

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Excessive use of fungicides in agriculture may result in substantial accumulation of active residues in soil, which affect crop health and yield. We investigated the response of Raphanus sativus (white radish) to fungicides in soil and potential beneficial interactions of radish plants with fungicide-tolerant plant growth-promoting rhizobacteria (PGPR). The PGPR were isolated from cabbage and mustard rhizospheres. Morphological and biochemical characteristics measured using standard methods, together with analysis of partial 16S rRNA gene sequences, revealed that fungicide-tolerant PGPR, isolates PS3 and AZ2, were closely related to Pseudomonas spp. These PGPR survived in the presence of high fungicide concentrations i.e., up to 2400 μg mL−1 carbendazim (CBZM) and 3200 μg mL−1 hexaconazole (HEXA). Bacterial isolates produced plant growth stimulants even under fungicide stress, though fungicides induced surface morphological distortion and alteration in membrane permeability of these bacteria, which was proved by a set of microscopic observations. Fungicides considerably affected the germination efficiency, growth, and physiological development of R. sativus, but these effects were relieved when inoculated with PGPR isolates. For instance, CBZM at 1500 mg kg−1 decreased whole dry biomass by 71%, whole plant length by 54%, total chlorophyll by 50%, protein content by 61%, and carotenoid production by 29%. After applying isolate AZ2 for white radish grown in CBZM (10 mg kg−1)-amended soil, it could improve plant growth and development with increased whole plant dry weight (10%), entire plant length (13%) and total chlorophyll content (18%). Similarly, isolate PS3 enhanced plant survival by relieving plant stress with declined biomarkers, i.e., proline (12%), malondialdehyde (3%), ascorbate peroxidase (6.5%), catalase (18%), and glutathione reductase (4%). Application of isolates AZ2 and PS3 could be effective for remediation of fungicide-contaminated soil and for improving the cultivation of radish plants while minimizing inputs of fungicides.

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“…For instance, hexaconazole, a broadspectrum systemic fungicide, is used to manage phytopathogenic fungi 12 on the one hand, while it negatively affects the BNF, ureide levels, N transformation and overall performance of leguminous plants on the other hand. 13,14 Also, it decreases chlorophyll and carotenoid pigment formation by legumes, for example, Phaseolus vulgaris. 15 In yet another study, the fungicide pyrimorph has been found to strongly inhibit the electrontransport reactions of chloroplasts and thus damages the physiological machinery of whole plants.…”

Section: Introductionmentioning

confidence: 99%