Application Of Nicosulfuron Research Articles

Nontarget site-based resistance to nicosulfuron and identification of candidate genes in Cucumis melo L. var. agrestis Naud. via RNA-Seq transcriptome analysis

Herbicide resistance is a worldwide concern for weed control. Cucumis melo L. var. agrestis Naud. (C. melo) is an annual trailing vine weed that is commonly controlled by nicosulfuron, acetolactate synthase (ALS)-inhibiting herbicides. However, long-term use of this herbicide has led to the emergence of resistance and several nicosulfuron resistant populations of C. melo have been found. Here we identified a resistant (R) C. melo population exhibiting 7.31-fold resistance to nicosulfuron compared with a reference sensitive (S) population. ALS gene sequencing of the target site revealed no amino acid substitution in R plants, and no difference in enzyme activity, as shown by ALS activity assays in vitro. ALS gene expression was not significantly different before and after the application of nicosulfuron. Pretreatment with the cytochrome P450 monooxygenase (P450) inhibitor malathion reduced nicosulfuron resistance in the R population. RNA-Seq transcriptome analysis was used to identify candidate genes that may confer metabolic resistance to nicosulfuron. We selected genes with annotations related to detoxification functions. A total of 20 candidate genes (7 P450 genes, 1 glutathione S-transferase (GST) gene, 2 ATP-binding cassette (ABC) transporters, and 10 glycosyltransferase (GT)) were identified; 12 of them (7 P450s, 1 GST, 2 ABC transporters, and 2 GTs) were demonstrated significantly differential expression between R and S by quantitative real-time RT-PCR (qRT–PCR). Our findings revealed that the resistance mechanism in C. melo was nontarget-site based. Our results also provide a valuable resource for studying the molecular mechanisms of weed resistance.

Optimum Time for Safe and Effective Application of Nicosulfuron on Cassava Plot

Optimum Time for Safe and Effective Application of Nicosulfuron on Cassava Plot

Evaluation of the effect of nicosulfuron and bentazone herbicides on growth and yield performance of two maize varieties in Mubi, Nigeria

Abstract. Tizhe TD, Alonge SO, Adekpe DI, Ioortsuun DN. 2023. Evaluation of the effect of nicosulfuron and bentazone herbicides on growth and yield performance of two maize varieties in Mubi, Nigeria. Asian J Agric 7: 122-130. This study aimed to determine the effect of nicosulfuron and bentazone herbicides on the growth and yield performance of maize (Zea mays L.) varieties SAMMAZ 17 and SAMMAZ 37 in Mubi, Nigeria. The study was carried out between 2019 and 2020 wet seasons. Nicosulfuron and bentazone herbicides at 50, 100, 150, and 200 g/ha and 0.5, 1.0, 1.5, and 2.0 kg a.i/ha concentrations, respectively, along with hoe weeded and weedy check controls were applied in the field of the two maize varieties at 3, 5 and 7 Weeks after Sowing (WAS). The maize growth parameters were determined two weeks after treatment at three different times, while the yield parameters were determined using standard procedures. The results showed that nicosulfuron and bentazone had no significant effect on the Crop Growth Rate (CGR), Net Assimilation Rate (NAR), days to 50% silking (except Relative Growth Rate and days to 50% tasselling), and plant height, leaf area index and total biomass of the two maize varieties, when sampled at 2 and 4 (except at 6 weeks) weeks sampling after herbicides application at 3, 5 and 7 WAS. The application at 3 WAS resulted in lower values for virtually all the growth parameters than that at 5 and 7 WAS. The two herbicides, however, significantly affected most of the maize yield parameters. The maize plants on plots treated at 3 WAS had the highest values for all the yield parameters (except kernel depth) than those treated at other periods. The study concluded that the post-emergence application of nicosulfuron and bentazone herbicides had no significant influence on the growth parameters of SAMMAZ 17 and SAMMAZ 37; however, there was a significant effect on the yield parameters.

The Physicochemical Properties and Microbial Populations of Nicosulfuron Treated Soil in Yola, Adamawa State, Nigeria

The use of herbicides in the modern system of farming has really help in boosting crop production, this way meeting up with the ever increasing demand for food by the always increasing human population. However, these herbicides have different mode of actions and effect on soil components; and their continued usage has affected the soil microbial communities and other soil components most of which are the non-target. This study, therefore, was focused on evaluating the physicochemical properties and microbial population of nicosulfuron treated soils of Yola, Adamawa State, Nigeria. The study was carried out in both 2021 and 2022 in the Research Farm of the Department of Plant Science, Modibbo Adama University, Yola. The samples of the soil treated with the different concentrations of nicosulfuron were obtained at 0, 2, 4 and 6 Weeks after Treatment (WAT) at the depth between 0-12 cm. The physicochemical properties and the bacterial and fungal populations of the collected soil samples were determined using standard laboratory procedures. The results revealed that the soils treated with the 50, 100, 150 and 200 g/ha concentrations of nicosulfuron had a comparable values for physicochemical (except percentage moisture content, organic carbon and matter and total nitrogen) properties that include: pH, electrical conductivity, Calcium, magnesium and potassium ions, total exchangeable acidity, total exchangeable base, effective cation exchange capacity, percentage base saturation. On the basis of duration of application, however, the nicosulfuron had significant effect on the physicochemical properties with 6 WAT having the highest values for the physicochemical properties compared to other sampling durations. On the bacterial (except the fungal) population, the nicosulfuron also had a significant effect with the treated soils having the lowest populations of both bacteria and fungi. The study therefore, concluded that the duration of application of nicosulfuron have significant effect on physicochemical properties of soil in Yola. On the bacterial and fungal populations of the soil, nicosulfuron also had significant effect.

Enhanced metabolic ability enabled wild panicgrass (Panicum miliaceum L. var. ruderale kit.) resistance to ALS inhibitor herbicide

Wild panicgrass (Panicum miliaceum L. var. ruderale kit.) is an annual grass weed that primarily occurs in maize fields. Nicosulfuron is a widely used selective herbicide that effectively controls gramineous weeds in maize fields. However, owing to its long-term and extensive application, the control of P. miliaceum has been substantially reduced. The objective of this study was to determine the resistance pattern to ALS inhibitors in P. miliaceum and investigate the underlying resistance mechanisms. These are important for guiding the prevention and eradication of resistant weeds.Whole plant bioassays showed P. miliaceum had evolved high levels of resistance to nicosulfuron and multiple resistance to atrazine and mesotrione. The ALS gene sequence results indicated the absence of mutations in the resistant population. Additionally, there was no significant difference found in the inhibition rate of the ALS enzyme activity (I50) between the resistant and sensitive populations. Following the application of malathion the resistant P. miliaceum population became more sensitive to nicosulfuron. At 96 h after application of nicosulfuron, glutathione-S-transferase activity in the resistant population was significantly higher than that in the susceptible population.The study reveals that the main cause of resistance to ALS inhibitor herbicide in P. miliaceum is likely increased metabolism of herbicides. These findings may assist in devising effective strategies for preventing and eliminating resistant P. miliaceum.

Efficacy of alternative herbicides to glyphosate in the weed control in glyphosate and sulfonylurea-tolerant soybean

It is believed that ALS inhibitor herbicides in combination with ACCase inhibitors can be used as an alternative to glyphosate in weed control in RR2/STS soybeans. In the present study, the efficacy of ALS inhibitor herbicides, in combination with haloxyfop, is evaluated in the control of weeds for post-emergence application (V4) of RR/STS soybeans. The experiment is carried out in the 2017/18 season in Piracicaba, São Paulo (SP), Brazil. The cultivar BMX Garra RR2/STS is used, and the treatments were composed by the application of ALS inhibitor herbicides in association with haloxyfop. The experimental design was a randomized block with four replications. Were evaluated control and dry mass of weeds, symptoms of injury in soybean plants and yield. The data were submitted to analysis of variance and the means of the treatments were compared by the Tukey test. Visual symptoms of injury were observed in soybean plants, mainly for the application of nicosulfuron and nicosulfuron + cloransulam. Soybean yield was higher in all herbicide treatments compared to the control without weeding. Associations between ALS inhibitor herbicides and haloxyfop applied post-emergence (V4) of soybean cultivar BMX Garra RR2/STS were effective in weed control.

Bio-efficacy of nicosulfuron against mixed weed flora in maize and its residual effect on succeeding crops

A field study was conducted during Spring and rainy (Kharif) season of 2017 at N.E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar U.S. Nagar, Uttarakhand, India to evaluate the effective dose of nicosulfuron for weed control in maize while assessing its effect on growth and yield of maize along with its residual effect on succeeding pea and cowpea fodder. Eight treatments were tested which include: post-emergence application (PoE) of nicosulfuron at different doses (30, 36, 42 and 50 g/ha), tembotrione 120 g/ha PoE, pre-emergence application (PE) of atrazine 1000 g/ha, hand weeding twice at 20 and 40 days after seeding (DAS) and weedy check. The weed community during both the seasons in the experimental area consisted of, grassy weeds: Phalaris minor, Eleusine indica, Digitaria sanguinalis, Echinochloa colona and Panicum maximum, broad-leaved weeds (BLW): Trianthema monogyna, Chenopodium album, Phyllanthus niruri, Parthenium hysterophorus and Mallugo stricta and a sedge Cyperus rotundus. Nicosulfuron at 50 g/ha resulted in 50-100% weed control, depending on the weed species. Nicosulfuron at 50 and 42 g/ha were equally effective in increasing grain yield of maize when compared with tembotrione and was found superior over atrazine during both the season. No phytotoxic symptoms on maize and no residual effect on succeeding pea and cowpea fodder crop were observed, at any doses of nicosulfuron. Hence, nicosulfuron at 42 g/ha PoE may be safely used for effective weed management and improved yield of maize.

EFICIENCIA Y RENTABILIDAD DEL CONTROL QUÍMICO DE MALEZAS EN EL CULTIVO MAÍZ

<p>Background: Corn is one of the main crops in Mexico. The crop is affected by different pests such as weeds and high-cost inputs are required for its control. Objective: To determinate the efficiency of five post-emerging herbicides on the control of monocotyledonous and dicotyledonous weeds in a corn crop, as well as to identify the optimal economic herbicide. Methodology: The study was carried out in Cocula, Guerrero, Mexico under irrigation conditions. Treatments were: 1) Nicosulfurón + 2,4-D; 2) Nicosulfurón + atrazine; 3) Nicosulfurón + dicamba; 4) Rimsulfurón + 2,4-D; 5) Rimsulfurón + dicamba; 6) Rimsulfurón + atrazine and 7) Treatment without application. Sampling was performed 7, 15, 30 and 60 days after application. The variables evaluated were, weed number and control percentage. In addition, an economic analysis was carried out, depending on the grain yield obtained. Results: Application of nicosulfuron and rimsulfuron in mixture with 2,4-D, dicamba and atrazine archived control levels than or equal to 90% for 30 days on Sorghum halepense and Panicum reptans weeds. For Melampodium divaricatum and Argythamnia neomexicana nicosulfuron + dicamba and rimsulfuron + atrazina herbicides-controlled weeds for 30 days. Kallstroemia maxima weed, was controlled by 100% with the application of nicosulfuron + dicamba. As for the financial analysis, the greatest economic benefit was with the mixture of rimsulfuron with atrazine and 2,4-D. Implications: The mixture of rimsulfuron + 2,4-D is efficient on the weed control in corn crop, in addition to being the most economical. Conclusion: The application of nicosulfuron and rimsulfurn achieves the best control over monocotyledons and dicotyledons, the greater control was observed with the nicosulfuron +dicamba application, however, the rimsulfuron application with atrazine and 2,4-D generated the best profitability.</p>

Effect of nicosulfuron on chlorophyll content of marandu-grass cultivated in crop-forest-livestock integration systems

The aim of this work was to study the effect of sub-doses of herbicide nicosulfuron on the levels of chlorophyll and growth of marandu-grass in an forest-livestock integration system. The treatments consisted of eucalyptus consortium with sorghum (BRS 655 hybrid) and forage Urochloa brizantha cv. Marandu (marandu-grass) at 12×2 and 12×3 m spacings in agroforestry systems, in addition to sorghum + marandu-grass and marandu-grass in monoculture. The doses of nicosulfuron applied at the marandu-grass were 0, 15 and 30 g ha-1. At 30 and 120 days after the application of nicosulfuron, chlorophyll a and chlorophyll b were measured usinf a portable chlorophyll meter, with six measurements per plant. Afterwards, the total chlorophyll content and chlorophyll a/b were calculated. We also measured the mass of the total dry matter of marandu-grass and growth rate of the culture. Marandu-grass plants cultivated in monoculture showed higher quantities of chlorophyll and the highest growth rates. The levels of chlorophyll a, b and chlorophyll a/b and the growth rate of marandu grass were similar between systems integrated with eucalyptus (12x2 and 12x3 m). The increase of herbicide dose negatively influenced on chlorophyll content in marandu-grass in all treatments evaluated. The use of nicosulfuron in doses of 25 and 50 g L-1 reduced the growth rate of marandu grass only when grown in monoculture

Effect of Post-Emergence Application of Nicosulfuron in Mixture with Atrazine for Weed Control in Sweet Sorghum

The objective of this work was to evaluate if different rate of a nicosulfuron and atrazine mixture applied post-emergence to effectively control weeds in sweet sorghum without interfering in the initial growth and gas exchanges of the crop. The genotypes BRS 506, BRS 511, and SF 15 were subjected to weed management with atrazine (2500 g a.i. ha−1) mixed with six different doses of nicosulfuron (10, 20, 30, 40, 50, 60 g a.i. ha−1). The herbicide mixtures were applied 12 days after sowing. At 7, 14, 21, and 28 days after application (DAA), phytotoxicity evaluations were performed in sorghum genotypes and weed control efficiency was evaluated. Initial growth (plant height, stalk diameter, leaf area, and number of leaves), gas exchanges, and relative chlorophyll index (a and b) were determined 7 DAA. The production of total fresh biomass, total soluble solids and ethanol yield were carried out at the end of the culture cycle. The mixture with doses higher than 40 g a.i. ha−1 of nicosulfuron with atrazine caused greater phytotoxicity in sweet sorghum and better weed control. Gradual increase in nicosulfuron reduced photosynthesis, transpiration, and initial growth of sorghum crop. The weed control did not interfere with production of fresh biomass, total soluble solids content and ethanol production, but showed different response in tested genotypes (BRS 511 > BRS 506 > SF 15). Thus, within the dose range evaluated, the mixture of 30 g a.i. ha−1 of nicosulfuron with atrazine was found effective in controlling weeds in sweet sorghum plantations without causing significant damage to the crop.

English

A two-year investigation into the effects of weed management practices, sowing dates and maize varieties was made in a Striga endemic field at Minna, Nigeria. The treatment was a factorial combination of variety (SAMMAZ 15, 17, 37, 40 and SUWAN-1-SR-Y), weed management practices (weedy check, two hoe weeding (HW) at 3 + 6 weeks after sowing (WAS), pre-emergence (PE) Atrazine at 2.4 kg a.i ha-1 + 1 HW at 6 WAS and PE Atrazine at 2.4 kg ha-1 + post-emergence (POE) Nicosulfuron at 0.06 kg ha-1 at 6 WAS) and sowing dates: early (28th May), mid-season  (18th June) and late-season (9th July) in 2018 and early-season (26th May), mid-season (16th June) and late-season  (7th July) in 2019 laid in a split plot arranged in a randomized complete block with three replications. Maize variety and weed management practices were combined as the main plot and sowing dates constituted the subplot. Delayed Striga shoot emergence and reduced shoot density were observed in SAMMAZ 15 and 40 and higher grain yield with SAMMAZ 17 in 2018 and 2019. Application of Atrazine plus Nicosulfuron significantly delayed Striga shoot emergence, reduced shoot density and higher maize grain yield in both years. Sowing in May significantly delayed Striga shoot emergence and reduced shoot density in both years. Sowing in June significantly increased maize grain yield in 2018 and 2019. These results suggest that SAMMAZ 15 and 40 in combination with PE Atrazine at 2.4 kg a.i ha-1 and POE Nicosulfuron at 0.06 kg a.i ha-1 and sowing in May effectively reduced Striga infestation. SAMMAZ 17 in combination with PE Atrazine at 2.4 kg a.i ha-1 and POE Nicosulfuron at 0.06 kg a.i ha-1 and sowing in June increased maize grain yield. Key words: Maize variety, sowing date, Striga, weed management. &nbsp

Control of Italian ryegrass and Alexandergrass in corn using different corn sowing date, pre- and post-emergent herbicides

Glyphosate-resistant (GR) Italian ryegrass (LOLMU) and Alexandergrass (URPLA) are troublesome weeds in corn cropping systems in Southern Brazil. The emergence pattern of those weeds is not uniform and may change according to the season’s environmental characteristics. Also, herbicide resistance has been diminishing the success of the weed control programs. The objectives of this study were to evaluate the influence of corn-sowing date on LOLMU and URPLA densities and their control provided by pre- and post-emergent herbicides. Field trials were conducted in two crop seasons in Southern Brazil consisting of three corn sowing date (August, September, and October) and the application of atrazine + S-metolachlor (residual) in corn pre-emergence in different post-emergence weed control programs with glyphosate, ammonium-glufosinate, nicosulfuron, and atrazine. The results indicated that the sowing date had a significant influence on LOLMU and URPLA densities. Corn sown in the earliest period was exposed to a higher LOLMU density, whereas corn sown in the latest period had a higher density of URPLA. Also, the application of residual herbicide at corn pre-emergence reduced both weed species densities and decreased the pressure for the control of glyphosate-resistant LOLMU for the post-emergence herbicides. The use of residual herbicides in corn pre-emergence is an efficient strategy to be considered in the LOLMU and URPLA control programs, followed by post-emergence application of glyphosate, ammonium-glufosinate, atrazine, and nicosulfuron.

Biostimulatory and carbon sequestration potentials of neem seed-based fertilizer formulation in nicosulfuron contaminated soil

Neem seed cake has been reported to make nutrients available to support good growth of crops and increase yield. This ease of nutrient release is also required in a potential bio-stimulant. This study assessed the potentials of a neem seed-based fertilizer formulation as a bio-stimulant to aid continued nutrient mineralization from an organic source in contaminated soil samples. Neem seed-based organomineral formulation was added to soil samples contaminated with two field rates (40 and 60 mg.a. i ha-1) of nicosulfuron herbicide to assess their separate and interaction effects on soil microbial activity in the laboratory. The treated samples were incubated for 8 weeks, and soil microbial activity was monitored in dynamics for the period of incubation. Data on soil basal respiration, soil organic carbon, and soil carbon mineralization quotient (qM) were collected on weekly basis for the 8 weeks. Application of nicosulfuron alone regardless of rate repressed soil basal respiration; hence carbon mineralization in the early weeks of the incubation period, but these parameters were stimulated after the 5th week of incubation. Addition of the neem formulation on the other hand caused consistent significant stimulation from the beginning to the end of incubation. Results further showed that combining nicosulfuron and the neem formulation raised soil basal respiration significantly above what individual factor contributed. It was therefore concluded that although the individual factor was found to increase CO2-C compared to the control at the end of incubation, the interaction of the two inputs raised CO2-C even higher. This is an indication that the neem seed cake formulation has the potentials to cushion the adverse effects of nicosulfuron contamination on the soil microbial community.

Integrated crop–forage–forestry for sustainable agricultural systems: productive performance

The objective of this study was to evaluate the effects of different crop arrangements and weed management in integrated crop–forage–forestry systems on weed incidence, yield of maize and forage grass, quality of total harvested and tree development. The experiment was analyzed as split-plot and as randomized complete block design. Whole plots were crop arrangements containing maize, Marandu palisadegrass, Basilisk signalgrass, Piata palisadegrass, eucalyptus and acacia, and subplots were the weed management (1.5 kg ha−1 of atrazine and 1.5 kg ha−1 of atrazine + 0.006 kg ha−1 of nicosulfuron). Planting was done under no-tillage system and herbicides were applied 22 days after maize emergence. The weeds incidence was not affected by treatments. Applying the mixture of atrazine and nicosulfuron reduced the grasses yield. However, the total dry mass harvested was not affected. The average yield of whole-plant corn in the intercropping systems was 12.9 t ha−1 of dry mass. The simultaneous establishment of the integrated crop–forage–forestry systems does not reduce the productivity and quality of whole-plant corn nor the production of the tree component at the first cultivation year. Despite the reduced grasses yield, the application of nicosulfuron and atrazine does not improve the production and quality of whole-plant corn in relation to the application of atrazine alone.

Suppression of Annual Ryegrass in Corn with Nicosulfuron

AbstractField studies were conducted to determine the possible rate and timing of nicosulfuron to suppress annual ryegrass (ARG) seeded as a cover crop at the time of corn planting without affecting corn performance near Ridgetown, ON, Canada, in 2016 and 2017. Nicosulfuron was applied at rates from 0.8 to 50 g ai ha–1when the ARG was at the two- to three- or four- to five-leaf stages, or approximately 3 or 4 wk after emergence of both corn and ARG. There were no differences between the two application timings in grain yield responses or ARG suppression. As the rate of nicosulfuron increased from 0.8 to 50 g ai ha–1, ARG was suppressed 6% to 76% and 5% to 96%, at 1 and 4 wk after application (WAA), respectively. At 4 WAA, ARG biomass decreased from 29 to 1 g m–2as the rate of nicosulfuron increased from 0.8 to 50 g ai ha–1, compared to 36 g m–2in the untreated control. Where nicosulfuron was not applied to ARG, grain corn yield was reduced by 6% compared to the ARG-free control; similar effects on corn yield were observed with nicosulfuron at the lowest rate applied at 0.8 g ai ha–1. Grain corn yield was reduced by 2.5% with the application of nicosulfuron at 25 g ai ha–1(label rate for corn) compared to no ARG control, but this was not statistically significant. This study identified rates of nicosulfuron that suppressed ARG when emerged approximately the same day as corn, but there was evidence that grain corn yields were lowered because of interference, possibly during the critical weed control period. Based on this study, an ARG cover crop should not be seeded at the same time as corn unless one is willing to accept a risk for corn grain yield losses for the sake of the cover crop.

Effects of nicosulfuron on biological production of weedy sunflower (Helianthus annuus)

Field experiments were conducted to quantify the effects of nicosulfuron on biological production of weedy sunflower (Helianthus annuus). Plants of this weed species were sown in plots sized 5x4.2 m with inter-row spacing of 24 cm, and 70 cm distance between rows. Plants with two pairs of developed leaves were treated with nicosulfuron using the next rates: 0, 10, 20, 40, 60 and 80 g a.i. ha-1. Vegetative parameters (plant height, fresh weight and leaf area) were recorded five times during vegetation, including the first measurement just before herbicide application and four measurements at intervals of about two weeks. Head and seed production (number of heads per plant, head weight, head diameter, weight of seeds per head, weight of seeds per plant, number of seeds per plant) were determined after seed maturity. The application of nicosulfuron caused growth reduction of weedy sunflower in comparison with the control. All application rates of this herbicide reduced vegetative (height, fresh weight, leaf area) and some generative (number of heads per plant, weight of seeds per plant, number of seeds per plant) parameters, which decreased with increasing rates of nicosulfuron. Effects on the remaining generative test parameters (head weight, head diameter, weight of seeds per head) were not analogous to the effects on other parameters.

Rates of Nicosulfuron Applied in Glyphosate-Tolerant and Sulfonylurea-Tolerant Soybean

ABSTRACT: STS cultivars tolerate up to four times higher rates of chlorimuron than those recommended for non-tolerant cultivars, without significant damage. However, few studies position the selectivity of nicosulfuron in STS cultivars. The aim of this study was to assess the selectivity of rates of the herbicide nicosulfuron applied in the post-emergence (V4) of RR/STS soybean. The experiments were conducted in the 2015/16 and 2016/17 seasons in Piracicaba, SP. In the 2016/17 season, the experiment was also conducted in Palotina, PR. Treatments consisted of six rates of the herbicide nicosulfuron (0, 50, 100, 150, 200, and 250 g a.i. ha-1). The experimental design was a randomized block design with four replications. The symptoms of injury were assessed at 7, 14, 21, and 28 days after application, as well as the assessment of variables related to the agronomic performance (plant height, number of pods per plant, yield, and one thousand-grain weight). The data were submitted to regression analysis (p<0.05). The estimated rates reduced yield by 5% in relation to the rate 0 and were between 57.79 and 68.37 g a.i. ha-1. In general, the RR/STS soybean is tolerant to the application of nicosulfuron up to 57.79 g a.i. ha-1 when considering the estimated rates. Therefore, the RR/STS soybean is tolerant to the application of nicosulfuron up to 50 g a.i. ha-1, according to the applied rates.

Ispitivanje mikrobnog diverziteta zemljišta tretiranog nikosulfuronom

Nicosulfuron belongs to the sulfonylurea pesticides, which are widely used for weeds control. Except of benefits in plant production, long-term application of nicosulfuron may have toxic effect for living organisms, including microorganisms. The aim of this paper was to determined impact of nicosulfuron on microbial diversity of soil. Sampling of soil (0-20 and 20-40 cm) treated with nicosulfuron at village Trenica (Novi Travnik municipality, Bosnia and Herzegovina) was performed in autumn 2017. Determination of microbial diversity (total number of bacteria, ammonification bacteria, fungi and actinomycetes) was performed using standard methodology, whilst nicosulfuron-tolerant bacteria were isolated using enrichment method. Soil without nicosulfuron application was used as a control. The results showed that bacteria were most abundant microbial population. In all experiments, reduction of microbial diversity in nicosulfuron-treated soil compared to untreated was observed. This reduction was most expressed in fungal number, which is reduced from 38 to 60% compared to control. Several nicosulfuron-tolerant isolates were isolated by enrichment method. By microscopic observation and using API test kits and APIWEB database, isolates 17cs, and 22wl and 5 wl were identified as Pseudomonas fluorescens, and Bacillus subtilis, respectively. These bacterial isolates could be applied in remediation of environments polluted by nicosulfuron.

Soil Microbial Community Response to Compost Addition to Nicosulfuron Contaminated Soil

The toxicity of nicosulfuron to none target organisms is its downside, which has generated concerns about the herbicide in spite of its high herbicidal activity. Practices that would facilitate accelerated degradation of this herbicide will certainly be complementary to its use. A completely randomized design laboratory incubation experiment was carried out to examine the potentials of organic and mineral fertilizers to stimulate microbial activities in soil under the influence of the nicosulfuron herbicide. Soil contaminated with the field rate of nicosulfuron was separately amended with compost and NPK mineral fertilizer, and the treated samples were incubated for 56 days at room temperature. Soil microbial activity and microbial biomass C were measured in dynamics for the period of incubation. Eco-physiological quotients were also computed at the end of incubation to determine responses of soil microbes at the community level to the treatments. Application of nicosulfuron alone was found to repress both microbial biomass and microbial activity. Addition of fertilizer however caused these parameters to increase especially during the first 28 days after treatment application. The microbial metabolic quotient was raised by the soil amendments shortly after application with the exemption of NPK treated soil. However, only the soil samples in which compost was present lowered qCO2 at the termination of the experiment. NIC-COMP and NIC-NPK respectively raised and lowered the soil carbon mineralization quotient (qM) measured at the end of incubation. The soil microbial community was also found to be positively affected by the addition of fertilizers as indicated by the Cmic: Corg ratio and the microbial biomass change rate quotient (qC). It was therefore concluded that though the nicosulfuron herbicide at the field recommended rate has potentials to negatively affect the soil microbial community, application of organic fertilizer may help the soil to regain its microbial competence through enhanced degradation engendered by biostimulation of native microorganisms.

Genomic and transcriptomic insights into cytochrome P450 monooxygenase genes involved in nicosulfuron tolerance in maize (Zea mays L.)

Postemergence application of nicosulfuron for weed control in maize fields can cause great damage to certain maize inbred lines and hybrids. Two maize genotypes, tolerant inbred (HBR) and sensitive inbred (HBS), were found to significantly differ in their phenotypic responses to nicosulfuron, with the EC50 (50% effective concentration) values differed statistically (763.6 and 5.9 g a.i. ha–1, respectively). Pre-treatment with malathion, a known cytochrome P450 inhibitor, increased nicosulfuron injury in both HBR and HBS. Our results support the hypothesis that nicosulfuron selectivity in maize is associated with cytochrome P450 metabolism. Further analysis of the maize genome resulted in the identification of 314 full length cytochrome P450 monooxygenase (CYP) genes. These genes were classified into 2 types, 10 clans and 44 families. The CYP71 clan was represented by all A-type genes (168) belonging to 17 families. Nine clans possessed 27 families containing 146 non-A-type genes. The consensus sequences of the heme-binding regions of A-type and non-A-type CYP proteins are ‘PFGXGRRXCPG’ and ‘FXXGPRXCXG’, respectively. Illumina transcriptome sequence results showed that there were 53 differentially expressed CYP genes on the basis of high variation in expression between HBS and HBR, nicosulfuron-treated and untreated samples. These genes may contribute to nicosulfuron tolerance in maize. A hierarchical clustering analysis obtained four main clusters named C1 to C4 in which 4, 15, 21, and 13 CYP genes were found in each respective cluster. The expression patterns of some CYP genes were confirmed by RT-qPCR analysis. The research will improve our understanding of the function of maize cytochrome P450 in herbicide metabolism.