Immune response to inactivated bacterial vector carrying the recombinant K39 antigen of Leishmania infantum in mice

Objective:To evaluate the immunological response elicited by an inactivated bacterial vector carrying the K39 antigen of Leishmania infantum,and a purified antigen.Methods:Mice were subjected to the following treatments:(1)Purified recombinant K39(rK39)protein at a 20μg dose with complete Freund’s adjuvant;(2)Inactivated Escherichia coli(BL21 DE3)carrying the K39 protein at an equivalent total protein content of 200μg;(3)Inactivated bacteria lacking the K39 protein;(4)Non-immunized control animals.Serological monitoring was performed.All groups were challenged by intraperitoneal injection of 10^(7) Leishmania infantum promastigotes.After euthanasia,the liver and spleen were collected to analyze the levels of TNF,IFN-γ,IL-12,IL-4,and IL-10.Results:Mice immunized with purified rK39 or the inactivated bacterial vector carrying the K39 antigen of Leishmania infantum showed a long-lasting immune response with high levels of polyclonal antibodies specifically recognizing the recombinant proteins.The IgG1 subclass was the predominant immunoglobulin;however,the induction of IgG2a and the profile of cytokines produced were indicative of the induction of a mixed-type response.Conclusions:The inactivated bacterial vector carrying the K39 antigen,as well as the purified antigen can induce a long-lasting immune response in immunized mice,predominantly favouring a Th2 profile response.

Taxonomy and phylogeny of the section Chaetoceros(Chaetocerotaceae,Bacillariophyta),with description of two new species

Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,the delimitations of some species are problematic because of limited morphological information in the classical descriptions.Monoclonal strains of the section Chaetoceros were established,morphological features were studied using light and electron microscopy,and the hypervariable D 1-D 3 region of the nuclear ribosomal large subunit gene was sequenced to address phylogenetic relationships.Fifteen species belonging to the section Chaetoceros were recorded,including two new species,C.hainanensis sp.nov.and C.tridiscus sp.nov.Chaetoceros hainanensis was characterized by straight chains,narrowly lanceolate to hexagonal apertures,sibling setae diverging in nearly right angles,stipule-shaped spines on terminal setae and arrowhead-shaped spines on intercalary setae.C.tridiscus had short straight chains,narrowly lanceolate apertures,arrowhead-shaped spines and circular poroids arranged in a grid pattern on terminal and intercalary setae.The phylogenetic analyses revealed six groups formed by 19 species within the section Chaetoceros,which was found to be monophyletic.The subdivision of the section is still not well understood.The morphological characters within each group varied considerably and molecular information on more species are needed to enrich the phylogenetic profiling.

Overexpression of wild-type HRAS drives non-alcoholic steatohepatitis to hepatocellular carcinoma in mice

Hepatocellular carcinoma(HCC),a prevalent solid carcinoma of significant concern,is an aggressive and often fatal disease with increasing global incidence rates and poor therapeutic outcomes.The etiology and pathological progression of non-alcoholic steatohepatitis(NASH)-related HCC is multifactorial and multistage.However,no single animal model can accurately mimic the full NASH-related HCC pathological progression,posing considerable challenges to transition and mechanistic studies.Herein,a novel conditional inducible wild-type human HRAS overexpressed mouse model(HRAS-HCC)was established,demonstrating 100%morbidity and mortality within approximately one month under normal dietary and lifestyle conditions.Advanced symptoms of HCC such as ascites,thrombus,internal hemorrhage,jaundice,and lung metastasis were successfully replicated in mice.In-depth pathological features of NASH-related HCC were demonstrated by pathological staining,biochemical analyses,and typical marker gene detections.Combined murine anti-PD-1 and sorafenib treatment effectively prolonged mouse survival,further confirming the accuracy and reliability of the model.Based on protein-protein interaction(PPI)network and RNA sequencing analyses,we speculated that overexpression of HRAS may initiate the THBS1-COL4A3 axis to induce NASH with severe fibrosis,with subsequent progression to HCC.Collectively,our study successfully duplicated natural sequential progression in a single murine model over a very short period,providing an accurate and reliable preclinical tool for therapeutic evaluations targeting the NASH to HCC continuum.

Soil Physico-Chemical Properties and Different Altitudes Affect Arbuscular Mycorrhizal Fungi Abundance and Colonization in Cacao Plantations of Cameroon

This study aims to investigate the abundance of AMF according to soil properties and altitudes in different cacao plantations of Cameroon. Physico-chemical analyses were made on soil samples collected from three agro-ecological zones. Soil samples were also used to evaluate directly the AMF abundance following the various altitudes and after trapping by sorghum plant. The results showed that soil properties, AMF spore abundances and colonization fluctuated significantly at different altitudes. The most represented texture was sandy loam. The bimodal zone presented a homogeneous texture (sandy loam) in all its localities. Cacao soil chemical characteristics showed that, the highest nitrogen rate (0.47%;p 0.05, Scott-Knott test) was recorded at Melong in a monomodal zone while Tonga in the Western highlands displayed the lowest rate (0.13%). Soil P concentration was significantly high in monomodal zones (Mbanga and Melong). Soil pH level indicated that the soil from Tonga in the Western highlands was neutral (pH = 6.67), and soils of other localities under study were acidic with the lowest (4.75) pH level recorded at Melong in a monomodal zone. In soil samples, the highest spore density (1.03 spores/g soil) was observed at Ntui in Bimodal zone, while the lowest spore density (0.26 spores/g soil) was observed at Bafang in the Western highlands. Root colonization showed that the sample from Bokito in a bimodal zone displayed the best frequency of mycorrhization (86.11%) while the sample from Bafang in the Western highlands recorded the lowest (27.11%). The PCA analysis highlighted that available phosphorus, pH and altitude all strongly correlated with AMF root colonization ability and can be used as a predictor of AMF colonization ability in cacao rhizosphere.

Physico-Chemical and Nutritional Properties of a Food Broth Based on Nere (Parkia biglobosa)

Purpose: Diet and eating habits are major risk factors for the health and the development of disease, such as, for example, metabolic disorder leading to cardiovascular pathology and cancer, decreased immunity exposing to infections. This study of the physico-chemical and nutritional properties of a soumara-based food broth was carried out with the aim of promoting the consumption of organic broth made from nere seeds (soumara). That is to alleviate certain metabolic diseases, which is a matter of food safety, and also to limit the risk for the health about the consumption of some cooking stocks on the market. Methods: Several natural ingredients such as nere seeds (soumara), ginger, black pepper, parsley and garlic were used to create a nere-based stock. All these ingredients were freeze-dried and the powder obtained was used to make the broth, regarding their physical and chemical properties. Results: The broth had a good protein content of 17.41 ± 0.367 g/100g, a lipid content of 16.80 ± 0.08 g/100g and a fiber content of 8.66 ± 0.04 g/100g. In terms of nutritional values, the broth showed good levels of calcium 184.21 ± 0.09 mg/100g, potassium 50.04 ± 1.45 mg/100g and iron and zinc. In terms of antioxidant activity, the broth also showed good antioxidant activity. Conclusion: Regarding the properties of our food broth, whose composition is based on natural ingredients, could be recommended for consumption and, its properties, could play an important role in preventing and combating certain metabolic diseases.

Elucidating the role of SlXTH5 in tomato fruit softening

Fruit softening in tomato(Solanum lycopersicum)is closely associated with cell wall disassembly,which is brought about through the action of a range of cell wall structure-related enzymes and other proteins such as expansins.Xyloglucan endotransglucosylase/hydrolase(XTH)(EC 2.4.1.207 and/or EC 3.2.1.151)has been proposed to be key player involved in xyloglucan metabolism.SlXTH5 showed the highest expression level among all SlXTHs during tomato ripening.In this study,the role of SlXTH5 involved in tomato softening was investigated in CRISPR-based knockout mutants of SlXTH5.Loss-of-function of SlXTH5 in transgenic tomato lines resulted in slightly firmer fruit pericarp,but significantly decreased their color index compared with azygous wild type(WT)control fruits.Increased paste viscosity was detected in CRISPR mutants,indicating that the activity of SlXTH5 is responsible for maintaining cell wall structural integrity.Immunocytochemistry studies were performed using the monoclonal antibody probe LM25 to examine the localization and distribution of xyloglucan in the pericarp cells of the CRISPR mutant fruits.The data indicated more xyloglucan was retained in the pericarp of CRISPR mutant fruit than in WT control fruit.This study revealed the link between SlXTH5 and xyloglucan metabolism and indicated the potential of manipulating SlXTH5 to regulate fruit softening.

Different routine laboratory tests in assessment of COVID-19: A case-control study

Objective:To identify helpful laboratory paprameters for the diagnosis and prognosis of COVID-19.Methods:An observational retrospective study was conducted to analyze the biological profile of COVID-19 patients hospitalized in the Unit of Pulmonology at Setif hospital between January and December 2021.Patients were divided into two groups:the infection group and the control group with patients admitted for other pathologies.The infected group was further divided according to the course of the disease into non-severe and severe subgroups.Clinical and laboratory parameters and outcomes of admitted patients were collected.Results:The infection group included 293 patients,of whom 237 were in the non-severe subgroup and 56 in the severe subgroup.The control group included 88 patients.The results showed higher white blood cells,neutrophils,blood glucose,urea,creatinine,transaminases,triglycerides,C-reactive protein,lactate dehydrogenase,and lower levels of lymphocyte,monocyte and platelet counts,serum sodium concentration,and albumin.According to ROC curves,urea,alanine aminotransferase,C-reactive protein,and albumin were effective diagnosis indices on admission while neutrophil,lymphocyte,monocyte,glycemia,aspartate aminotransferase,and lactate dehydrogenase were effective during follow-up.Conclusions:Some biological parameters such as neutrophil,lymphocyte,monocyte,glycemia,aspartate aminotransferase,and lactate dehydrogenase are useful for the diagnosis of COVID-19.

Solid-State Cultivation of Edible Oyster Mushrooms, <i>Pleurotus</i>spp. under Laboratory Conditions

Oyster mushrooms of genus Pleurotus are well known as valuable edible mushrooms which are broadly cultivated in the world as well as wildly propagated in forests of the temperate climate zones including Russia. Indoor cultivation conditions adapted for a laboratory with non-specialized facilities were suggested for effective solid-state cultivation and fruit bodies’ production of Pleurotus species. Seven of 9 Pleurotus species of different origin produced fruit bodies successfully. The best fructification was shown for species P. sajor-caju, P. ostreatus, and P. pulmonarius with fruit body yields of 74%, 72%, and 61% by dry substrate weight in the first flushing cycle. Fruit bodies appeared in five to 10-day flushes. “Spawn run” stage was completed within 17 to 24 days, the longest colonization stage (26 days) being for the pink oyster, P. djamor. The cultivation parameters proposed in this study can be employed with ease for laboratory and “home” cultivation of oyster mushrooms. The species and strains’ identification was confirmed by restriction analysis of ITS region of rRNA gene cluster. Molecular barcodes based on restriction enzyme (AluI, and BsuRI) profiles of ITS sequences were shown to be applicable for molecular genotyping of Pleurotus species of different origin.

Effects of N-acetylcysteine on growth,viability and reactive oxygen species levels in small antral follicles cultured in vitro

Objective:To investigate the effects of different concentrations of N-acetylcysteine on follicular growth and morphology,as well as on viability,levels of reactive oxygen species(ROS)and meiotic progression of oocytes from in vitro cultured bovine early antral follicles.Methods:Isolated early antral follicles(about 500μm)were cultured in TCM-199+alone or supplemented with 1.0,5.0 or 25.0 mM N-acetylcysteine at 38.5℃with 5%CO_(2) for 8 days.Follicle diameters were evaluated at day 0,4 and 8 of culture.At the end of culture,the levels of ROS,chromatin configuration and viability(calcein-AM and ethidium homodimer-1 staining)were investigated in the cumulus-oocyte complexes.Comparisons of follicle diameters between treatments were performed.Data on percentages of morphologically normal follicles,growth rates and chromatin configuration in different treatments were compared.Results:An increase in follicular diameters after culture in all treatments was observed,except for follicles cultured with 25.0 mM N-acetylcysteine.Fluorescence microscopy showed that oocytes cultured in all treatments were stained positively with calcein AM,and that 5.0 mM N-acetylcysteine reduced fluorescence for ethidium homodimer-1.Intracellular levels of ROS in oocytes from follicles cultured with 1.0 mM N-acetylcysteine showed a significant reduction compared to other treatments.The presence of N-acetylcysteine in culture medium did not influence the rates of oocyte at the germinal vesicle stage.Conclusions:N-acetylcysteine at concentrations of 1.0 and 5.0 mM reduces ROS levels and staining for ethidium homodimer-1 in in vitro cultured follicles,respectively,while 25.0 mM N-acetylcysteine decreases follicular growth and the percentages of continuously growing follicles.

Creation of cytochrome P450 catalysis depending on a non-natural cofactor for fatty acid hydroxylation

Cytochrome P450 enzymes catalyze diverse oxidative transformations at the expense of reduced nicotinamide adenine dinucleotide phosphate(NADPH),however,their applications remain limited largely because NADPH is cost-prohibitive for biocatalysis at scale yet tightly regulated in host cells.A highly challenging task for P450 catalysis has been to develop an alternative and biocompatible electrondonating system.Here we engineered P450 BM3 to favor reduced nicotinamide cytosine dinucleotide(NCDH)and created non-natural cofactor-dependent P450 catalysis.Two outstanding mutants were identified with over 640-fold NCDH preference improvement and good catalytic efficiencies of over15,000 M^(-1)s^(-1)for the oxidation of the fatty acid probe 12-(para-nitrophenoxy)-dodecanoate.Molecular docking analysis indicated that these mutants bear a compacted cofactor entrance.Upon fusing with an NCD-dependent formate dehydrogenase,fused proteins functioned as NCDH-specific P450catalysts by using formate as the electron donor.Importantly,these mutants and fusions catalyzed NCDH-dependent hydroxylation of fatty acids with similar chain length preference to those by natural P450 BM3 in the presence of NADPH and also similar regioselectivity for subterminal hydroxylation of lauric acid.As P450 BM3 and its variants are catalytically powerful to take diverse substrates and convey different reaction paths,our results offer an exciting opportunity to devise advanced cell factories that convey oxidative biocatalysis with an orthogonal reducing power supply system.

Synthesis of dimeric butenolide catalyzed by various inorganic silver catalysts

This article describes a method for synthesizing butyrolactone dimers using various inorganic silver salt catalysts.The method was successfully applied to alkyl 2-(2-bromopropyl)malonate 1,providing the dimeric butyrolactone 2 when catalyzed by different silver salt catalysts.This synthesis method not only simplifies the original synthetic route,but also cleverly combines with natural product analogs,providing a strategy for the development of natural product polymer analogs in the future.

Influence of Harvest Periods on Cassava (Manihot esculenta Crantz) Agronomic Traits and Physiological Response to Post-Harvest Physiological Deterioration

Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.

In Vitro Evaluation of the Antifungal Activity of Essential Oils of Thymus vulgaris and Cymbopogon citratus on Some Strains of Sclerotinia sclerotiorum, Agent Responsible for White Rot of Beans

The present work was aimed to the study of the antifungal activity of essential oils of two aromatic plants against three strains of Sclerotinia sclerotiorum responsible for white rot of bean. The two essential oils (EO) of the studied plants: Thymus vulgaris (HET) and Cymbopogon citratrus (HEC), used at different concentrations: C1 (0.75 ml/ml), C2 (1.5 ml/ml) and C3 (3 ml/ml) presented significant inhibitory activities on the three tested fungal strains namely Bia 1, Bia 2, and Njo 2. Two control treatments (T-: containing no antifungal substance and T+: synthetic fungicide) were also used. The antifungal activity here is related to the inhibition of mycelial growth especially with high concentrations of essential oils. Thus, against S. sclerotiorum, HET showed the highest activity comparable to that of T+ (100% inhibition) at all concentrations on the Bia 1 and Bia 2 strains and at concentration C3 on the Njo 2 strain compared to that of HEC, which certainly inhibited the mycelial growth of the different strains considerably (with a maximum of 78.15% on the Njo 2 strain) but not completely. According to their sensitivity, the Bia 2 strain showed a higher sensitivity to essential oils than the others while the Njo 2 strain was more aggressive. On the basis of MIC50 and MIC90 obtained on the Njo 2 strain, the HET turns out to be the most efficient with respective lower values of (1.73 and 23.34 ml/ml) against (4.76 and 26.03 ml/ml) for the HEC. These EO could thus be exploited as biodegradable antifungal substances, likely to control white rot of bean.

Evaluation of Glutathione Peroxidase Enzymatic Activity in Seminal Plasma of Patients Treated at the Institute Pasteur in Cote d’Ivoire

Glutathione peroxidase (GPx) is an antioxidant that plays an important role in the maintenance of male fertility. The aim of this study was to compare the profile of enzymatic activity of glutathione peroxidase in the seminal plasma of normozoosperm and those of pathological sperm. Thus, the activity of glutathione peroxidase was determined in the seminal plasma of 20 normozoosperms, 9 azoosperms and 31 oligoasthenoteratozoosperms. It was 37.58 ± 3.14 U/L in normozoosperms, 39.39 ± 2.27 U/L in oligoasthenoteratozoosperms, and 29.77 ± 2.62 U/L in azoosperms. The mean GPx enzyme activity of normozoosperms did not differ significantly from that of oligoasthenoteratozoosperms and azoosperms. In contrast, comparison of enzyme activity between abnormal sperms gave a significant difference. This study showed that glutathione peroxidase enzymatic activity is not related to sperm quality.

Wood anatomical acclimation in the endemic genus Polylepis in Peruvian Andean forests

Polylepis(Queñua)is a dominant woody plant genus in Andean Puna forests that occurs in a wide range of montane habitats and is ecologically diverse in endemism,which may be particularly threatened by climate change.Wood anatomical traits are essential for understanding how plants adjust their ecophysiological requirements and maximize their resilience,resistance,and recovery to extreme climates.Although the effects of extreme climatic conditions in high altitude ecosystems have been studied extensively,our knowledge is relatively limited to quantitative differences in the main xylem tissues.To address this gap,we assessed the acclimation of wood anatomical traits in six Peruvian Andean Polylepis species with different water availability(semi-dry with high moisture and semiarid with dry winters).We selected hydraulic diameter,vessel density,vessel grouping index,solitary vessel index,vulnerability index,mesomorphy index,vessel element length,fiber length,fiber wall thickness,fiber lumen diameter,and total fiber diameter that can provide relevant eco-wood anatomical acclimation to hydric stress.We performed multivariate analysis to determine the leading dimensions of covariation among Polylepis species and climatic factors.Specific wood anatomical traits(vessel grouping index,vulnerability index,and fiber wall thickness)were dissimilar between xeric-and mesic-Polyelpis species.This study demonstrates that wood anatomical traits in Peruvian Andean Polylepis species provides high-resolution and long-term eco-wood anatomical signals on how climate oscillations drive the acclimation processes of fiber and vessel traits.Our findings underscore the significance of xylem hydraulic adjustment to various hydrological environments in Andean puna forests.By evaluating the effects of drought on wood anatomical characteristics and ecological function,we demonstrate the capacity of tree species to adapt and endure climate-related changes,thereby emphasizing their resilience and adaptability.

Turnip mosaic virus pathogenesis and host resistance mechanisms in Brassica

Turnip mosaic virus(TuMV)is a devastating potyvirus pathogen that infects a wide variety of both cultivated and wild Brassicaceae plants.We urgently need more information and understanding of TuMV pathogenesis and the host responses involved in disease development in cruciferous crops.TuMV displays great versatility in viral pathogenesis,especially in its replication and intercellular movement.Moreover,in the coevolutionary arms races between TuMV and its hosts,the virus has evolved to co-opt host factors to facilitate its infection and counter host defense responses.This review mainly focuses on recent advances in understanding the viral factors that contribute to the TuMV infection cycle and the host resistance mechanism in Brassica.Finally,we propose some future research directions on TuMV pathogenesis and control strategies to design durable TuMV-resistant Brassica crops.

Innovation and development of the third-generation hybrid rice technology

The breeding and large-scale application of hybrid rice contribute significantly to the food supply worldwide.Currently,hybrid seed production uses cytoplasmic male sterile(CMS)lines or photoperiod/thermo-sensitive genic male sterile(PTGMS)lines as female parent.Despite huge successes,both systems have intrinsic problems.CMS systems are mainly restricted by the narrow restorer resources that make it difficult to breed superior hybrids,while PTGMS systems are limited by conditional sterility of the male sterile lines that makes the propagation of both PTGMS seeds and hybrid seeds vulnerable to unpredictable climate changes.Recessive nuclear male sterile(NMS)lines insensitive to environmental conditions are widely distributed and are ideal for hybrid rice breeding and production,but the lack of effective ways to propagate the pure NMS lines in a large scale renders it impossible to use them for hybrid rice production.The development of"the third-generation hybrid rice technology"enables efficient propagation of the pure NMS lines in commercial scale.This paper discusses the establishment of"the thirdgeneration hybrid rice technology"and further innovations.This new technology breaks the limitations of CMS and PTGMS systems and will bring a big leap forward in hybrid rice production.

Neuroprotective effects of erythropoietin on neurodegenerative and ischemic brain diseases: the role of erythropoietin receptor

Erythropoietin （Epo） is a fundamental hormone in the regulation of hematopoiesis, and other secondary roles mediated by the binding of the hormone to its specific receptor （EpoR）, which leads to an activation of key signaling pathways that induce an increase in cell differentiation, apoptosis control and neuroprotection. It has been suggested that their ftmction depends on final conformation of glycosylations, related with affinity to the receptor and its half-life. The presence of EpoR has been reported in different tissues including central nervous system, where it has been demonstrated to exert a neuroprotective function against oxidative stress conditions, such as ischemic injury and neurodegenerative diseases. There is also evidence of an increase in EpoR expression in brain cell lysates of Alzheimer＇s patients with respect to healthy patients. These results are related with extensive in vitro experimental data of neuroprotection obtained from cell lines, primary cell cultures and hippocampal slices. Additionally, this data is correlated with in vivo experiments （water maze test） in mouse models of Alzheimer＇s disease where Epo treatment improved cognitive function. These stud- ies support the idea that receptor activation induces a neuroprotective effect in neurodegenerative disorders including dementias, and especially Alzheimer＇s disease. Taken together, available evidence suggests that Epo appears to be a central element for EpoR activation and neuroprotective properties in the central nervous system. In this review, we will describe the mechanisms associated with neuroprotection and its relation with the activation of EpoR in order with identify new targets to develop pharmacological strategies.

Development of herbicide resistance genes and their application in rice

Rice is one of the most important food crops in the world.Weeds seriously affect the rice yield and grain quality.In recent years,there are tremendous progresses in the research and application of herbicideresistant genes in rice worldwide.This article reviews the working mechanisms of six herbicides(glyphosate,glufosinate,acetolactate synthase inhibitor herbicides,acetyl-Co A carboxylase inhibitor herbicides,hydroxyhenylpyruvate dioxygenase(HPPD)inhibitor herbicides and dinitroaniline herbicides),the resistance mutations of the corresponding herbicide-target genes,and the herbicide detoxification mechanisms by non-target genes.Examples are provided on herbicide-resistant rice materials obtained by transformation of exogenous resistance genes,by artificial mutagenesis and mutant screening,and by modifying the target genes through gene editing.This paper also introduces the current application of herbicide-resistant rice,points out problems that may be caused by utilization of herbicide resistant rice and solutions to the problems,and discusses the future prospects for the development of herbicideresistant rice.

Trp_(548)Met mutation of acetolactate synthase in rice confers resistance to a broad spectrum of ALS-inhibiting herbicides

Herbicide resistance in crop plants is valuable for integrated weed management in agriculture. Herbicide resistant rice, in particular, is important to management of weedy rice, a close relative of cultivated rice and a noxious weed prevalent in rice fields that remains challenging to farmers worldwide. Herbicide resistant plants can be obtained through transgenic approach or by mutagenesis of regular plant and screening of mutants with elevated resistance to herbicide. In this study, we conducted ethyl methyl sulfonate mutagenesis(EMS) to elite indica cultivar Huanghuazhan(HHZ) and screened for mutants resistant to imazapic, a herbicide that can inhibit the acetolactate synthase(ALS) in plants. We obtained three mutants of Os ALS gene that have not been reported previously in rice. One of the mutants, with Trp_(548) changed to Met(W_(548)M), was analyzed in more details in this study. This mutation had no negative effect on the plant physiology and morphology as well as rice yield. Compared with the imidazolinone-resistant mutant S_(627)N(Ser_(627) changed to Asn) that has been deployed for Clearfield rice development, W_(548)M mutant showed high levels of resistance to a broad spectrum of five families of ALSinhibiting herbicides, in addition to a higher level of resistance to herbicides of the imidazolinone family.The herbicide-resistance was stably inherited by crossing into other rice lines. Thus, the W_(548)M mutation provides a valuable resource for breeding of herbicide resistant rice and weed management.