Innate promiscuity of the CYP706 family of P450 enzymes provides a suitable context for the evolution of dinitroaniline resistance in weed.

Increased metabolism is one of the main causes for evolution of herbicide resistance in weeds, a major challenge for sustainable food production. The molecular drivers of this evolution are poorly understood. We tested here the hypothesis that a suitable context for the emergence of herbicide resistance could be provided by plant enzymes with high innate promiscuity with regard to their natural substrates. A selection of yeast-expressed plant cytochrome P450 enzymes with well documented narrow to broad promiscuity when metabolizing natural substrates was tested for herbicide metabolism competence. The positive candidate was assayed for capacity to confer herbicide tolerance in Arabidopsis thaliana. Our data demonstrate that Arabidopsis thaliana CYP706A3, with the most promiscuous activity on monoterpenes and sesquiterpenes for flower defence, can also oxidize plant microtubule assembly inhibitors, dinitroanilines. Ectopic overexpression of CYP706A3 confers dinitroaniline resistance. We show, in addition, that the capacity to metabolize dinitroanilines is shared by other members of the CYP706 family from plants as diverse as eucalyptus and cedar. Supported by three-dimensional (3D) modelling of CYP706A3, the properties of enzyme active site and substrate access channel are discussed together with the shared physicochemical properties of the natural and exogenous substrates to explain herbicide metabolism.

Determination of Two Sulfonylurea Herbicides Residues in Soil Environment Using HPLC and Phytotoxicity of These Herbicides by Lentil Bioassay.

A HPLC-UV detection system was used for determination of sulfosulfuron and tribenuron methyl residues from soils. The soils were fortified with sulfosulfuron and tribenuron methyl at rates of 26 and 15 g a.i. ha-1 respectively and samples were taken randomly on 0 (2 h), 1, 2, 4, 10, 20, 40, 60, 90 and 120 days after treatment. The final extracts were prepared for analysis by HPLC. The results showed that degradation of both herbicides in the silty loam soil was faster than sandy loam soil. Half-life of sulfosulfuron was ranged from 5.37 to 10.82 days however this value for tribenuron methyl was ranged from 3.23 to 5.72 days on different soils. The residue of both herbicides at 120 days after application in wheat field had no toxicitic effect on lentil. It was concluded that HPLC analysis procedure was an appropriate method for determination of these herbicides from soils.

Evaluation of techniques to break seed dormancy in Redroot pigweed (Amaranthus retroflexus).

By identifying the factors that initiate seed dormancy release, we can reliably predict whether a seed will remain dormant within or exit the seed bank and become a seedling. With regard to annual weed species, assessing which factors efficiently break seed dormancy is critical for estimating the number of weed seeds that will develop into problematic weeds. To better understand dormancy breaking in Redroot pigweed (Amaranthus retroflexus), dormant seeds were treated with cold stratification (4°C for 30 days), application of gibberellic acid (at 500, 1000, 1500, and 2000 parts per million), ultrasound (for 10, 20, 30, and 40 min), soaking in hot water (90°C for 3, 5, 7, and 10 min), and 98% sulfuric acid (for 1, 2, and 3 min). The results showed that Redroot pigweed seed dormancy was effectively broken by cold stratification, gibberellic acid, and ultrasound. Short treatments with hot water had minimal effect while longer times or treatment with sulfuric acid stopped seed germination. In addition to germination percentage, germination rate, plumule length, radicle length, seedling length, seedling dry weight, and seed vigor index were also measured; similarly, application of gibberellic acid had the most significant effect on these parameters. The results of this study add to our knowledge of what processes effectively or ineffectively break Redroot pigweed seed dormancy and promote growth.

Green synthesis of spermine coated iron nanoparticles and its effect on biochemical properties of Rosmarinus officinalis.

In this study, aqueous spinach extract was used for the green synthesis of iron nanoparticles. The surface of iron oxide nanoparticles was coated with spermine. The physicochemical properties of nanoparticles were investigated using UV-Vis, TGA, FTIR, VSM, TEM, and DLS. The results showed that the nanoparticles had a spherical structure. The surface charge of the Fe3O4-NPs increased from -3.2 to 18.42 (mV) after Fe3O4 coating by spermine. In order to investigate the effect of nanoparticles on physicochemical properties of rosemary under drought stress conditions, an experiment was carried out in a completely randomized design. The results showed that the amount of antioxidant enzymes and secondary metabolites increased significantly under drought stress. Moreover, the use of spermine-coated iron nanoparticles can be useful in increasing resistance to drought stress in plants by increasing the activity of some antioxidant enzymes and secondary metabolites. The biocompatibility of Nanoparticles in cell suspension was investigated. the ability of Fe3O4-SM NPs to interact with DNA and protect it against DNaseI and ultrasonic waves using agarose gel electrophoresis was studied. The ability of Fe3O4-SM to neutralize the negative charge of DNA and protect it against DNaseΙ and ultrasonic waves was confirmed using an agarose gel electrophoresis assay.

Design and synthesis of multi-targeted nanoparticles for gene delivery to breast cancer tissues.

Biocompatibility of nanoparticles is the most essential factor in their use in clinical applications. In this study, hyperbranched spermine (HS), hyperbranched spermine-polyethylene glycol-folic acid (HSPF), and hyperbranched spermine-polyethylene glycol-glucose (HSPG) were synthesized for DNA protection and gene delivery to breast cancer cells. The synthesis of HSPG and HSPF was confirmed using proton nuclear magnetic resonance (H-NMR), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) spectroscopy. The HS/DNA, HSPF/DNA, HSPG/DNA, and hyperbranched spermine-polyethylene glycol-folic acid/glucose/DNA (HSPFG/DNA) nanoparticles were prepared by combining different concentrations of HS, HSPF, and HSPG with the same amount of DNA. The ability of HS, HSPF, and HSPG to interact with DNA and protect it against plasm digestion was evaluated using agarose gel. Moreover, in vivo and in vitro biocompatibility of HSPF/DNA, HSPG/DNA, and HSPFG/DNA was investigated using MTT assay and calculating weight change and survival ratio of BALB/c mice, respectively. The results of agarose gel electrophoresis showed that HS, HSPF, and HSPG have the high ability to neutralize the negative charge of DNA and protect it against plasma degradation. The results of in vivo cytotoxicity assay revealed that the HSPF/DNA, HSPG/DNA, and HSPFG/DNA nanoparticles have good biocompatibility on female BALB/c mice. In vitro and in vivo transfection assays revealed that functionalization of the surface of HS using polyethylene glycol-folic acid (HSPF) and polyethylene glycol-glucose (HSPG) significantly increases gene delivery efficiency in vitro and in vivo. These results also showed that gene transfer using both HSPF and HSPG copolymers increases gene transfer efficiency compared to when only one of them is used. The HSPFG/DNA nanoparticles have a high potential for use in therapeutic applications because of their excellent biocompatibility and high gene transfer efficiency to breast cancer tissue.

Genetic variation of Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) suggests multiple independent introductions into Iran.

Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) are weedy plants that cause severe ecological and economic damage. In this study, we collected DNA from three different countries and assessed genetic diversity using inter-simple sequence repeat (ISSR) markers. Our analysis shows both weed species have low genetic diversity within a population and high genetic diversity among populations, as well as a low value of gene flow among the populations. UPGMA clustering and principal coordinate analysis indicate four distinct groups for A. retroflexus L. and C. album L. exist. We detected significant isolation-by-distance for A. retroflexus L. and no significant correlation for C.album L. These conclusions are based data from 13 ISSR primers where the average percentage of polymorphism produced was 98.46% for A. retroflexus L. and 74.81% for C. album L.These data suggest that each population was independently introduced to the location from which it was sampled and these noxious weeds come armed with considerable genetic variability giving them the opportunity to manifest myriad traits that could be used to avoid management practices. Our results, albeit not definitive about this issue, do not support the native status of C. album L. in Iran.

The Survival Response of Earthworm (Eisenia fetida L.) to Individual and Binary Mixtures of Herbicides.

Frequent use of herbicides may impose a risk on non-target species. The objective was to test the combined toxic effect of binary herbicide mixtures­metribuzin:halosulfuron and metribuzin:flumioxazin­on non-target earthworms in two test systems: filter paper and a soil toxicity test system. The joint action experiments were independently run twice to substantiate the findings. The most potent individual herbicide was metribuzin, with a 50% lethal concentration (LC50) of 17.17 µg ai. cm−2 at 48 h in the filter paper test. The toxicity of the individual herbicides on the filter paper test was ranked as metribuzin>halosulfuron>flumioxazin. In the soil test, metribuzin and halosulfuron had high toxicity with an LC50 of 8.48 and 10.08 mg ai. kg−1, respectively, on day 14. Thus, the individual herbicide ranking did not change between the filter paper and artificial soil tests. The herbicide's mixed effect in both test systems showed a consistent antagonistic effect relative to a Concentration Addition reference model. It indicates that the mixtures retracted the herbicide's action in the earthworms.

The Response of Iranian Melon (Cucumis melo L.) Accessions to 2,4-D Drift.

One of the most widely used auxinic herbicides in southern Iran's cereal crop fields is 2,4-D; however, the concurrent growing season of off-season melons in this region potentially leads to herbicide drift from cereal fields to the melon fields. To study the response of some Iranian wild melon accessions to three simulated drift rates of 2,4-D, including 112.1, 11.2, and 3.7 g ae ha-1, a field experiment was conducted during 2019 and 2020 growing seasons. It was found that by increasing the herbicide rate from 3.7 to 112.1 g ae ha-1, the level of visual injury increased in all accessions. However, significant variation in herbicide tolerance was observed among different melon accessions. The MEL-R1 was the most tolerant accession with only 20% injury, while MEL-D8 displayed very high injury rate (ca. 90%) as assessed at 6 weeks after treatment during 2019. The accession MEL-S3 was the most tolerant to 2,4-D drift rates (20% injury) at 6 weeks after treatment during 2020. There was no significant difference between the accessions MEL-R1 and MEL-S3 in terms of their response to 2,4-D treatment during both years of the study, as these accessions fully recovered from injury over 6 weeks after herbicide treatment. In addition, only these two accessions were able to produce yield after the application of 2,4-D at the highest rate tested (112.1 g ae ha-1). Therefore, the melon accessions MEL-R1 and MEL-S3 could be recommended for cultivation and even for breeding programs in order to develop 2,4-D-tolerant commercial cultivars in regions where this herbicide is commonly used in cereal crop production adjacent to the melon fields.

Sesamol-based terpenoids as promising bio-sourced crop protection compounds against the wheat pathogen Zymoseptoria tritici.

BACKGROUND: Research into environmentally friendly alternatives to conventional plant protection products, to promote sustainable agriculture and healthy food, is strongly encouraged. RESULTS: In this context, 20 naturally occurring terpenoids and phenolic compounds were selected and evaluated in vitro as crop protection compounds against Zymoseptoria tritici, the causal agent of Septoria tritici blotch of wheat. After selection of the most active compounds, some hemisynthetic modifications were conducted to modify their lipophilicity. These modifications led to the discovery of sesamol esters as promising antifungal agents, with IC50 around 10 µg/mL and a total absence of cytotoxicity against human cells. CONCLUSION: These sesamol-based derivatives should be selected for further evaluations in planta to validate their use as wheat crop protection agents. Moreover, the importance of a balanced hydrophily/lipophilicity ratio should be further studied. © 2021 Society of Chemical Industry.

Redroot Pigweed (Amaranthus retroflexus L.) and Lamb's Quarters (Chenopodium album L.) Populations Exhibit a High Degree of Morphological and Biochemical Diversity.

Amaranthus retroflexus L. and Chenopodium album L. are noxious weeds that have a cosmopolitan distribution. These species successfully invade and are adapted to a wide variety of diverse climates. In this paper, we evaluated the morphology and biochemistry of 16 populations of A. retroflexus L. and 17 populations of C. album L. Seeds from populations collected from Spain, France, and Iran were grown together at the experimental field of the agriculture research of University of Mohaghegh Ardabili, and a suite of morphological traits and biochemical traits were assessed. Among the populations of A. retroflexus L. and of C. album L. were observed significant differences for all the measured traits. The number of branches (BN) for A. retroflexus L. (12.22) and inflorescence length (FL; 14.34) for C. album L. were the two characteristics that exhibited the maximum coefficient of variation. Principal component analysis of these data identified four principal components for each species that explained 83.54 (A. retroflexus L.) and 88.98 (C. album L.) of the total variation. A dendrogram based on unweighted neighbor-joining method clustered all the A. retroflexus L. and C. album L. into two main clusters and four sub-clusters. Canonical correlation analysis (CCA) was used to evaluate relationships between climate classification of origin and traits. Similarly, the measured characteristics did not group along Köppen climate classification. Both analyses support the conclusion that A. retroflexus L. and C. album L. exhibit high levels of diversity despite similar environmental histories. Both species also exhibit a high diversity of the measured biochemical compounds indicating that they exhibit different metabolic profiles even when grown concurrently and sympatrically. Several of the biochemical constituents identified in our study could serve as effective indices for indirect selection of stresses resistance/tolerance of A. retroflexus L. and C. album L. The diversity of the morphological and biochemical traits observed among these populations illustrates how the unique selection pressures faced by each population can alter the biology of these plants. This understanding provides new insights to how these invasive plant species successfully colonize diverse ecosystems and suggests methods for their management under novel and changing environmental conditions.

Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album).

Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore, techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35 kH were applied for 0 (control), 5, 10, 15, and 30 min using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared with the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 min and seedling length (40%) at 30 min compared with the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 min had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient nondestructive method to break seed dormancy in common lambsquarters.