Analysis of genes specifically expressed under salt stress in salt-tolerant mutant of rice by using DDRT-PCR technique

Differential display reverse transcription-PCR (DDRT-PCR) technique was used to identify those genes that are expressed differentially between wild type rice variety 77-170 (Oryza Sativa vas Japonica) and its salt-tolerant mutant (M-20) under salt stress. Totally 13 salt-inducible cDNA fragments of 200-600 bp were identified and doned, and were designated as SIGR1 - SIGR13 (salt-induced gene in rice). Northern blot analysis showed that expression of SIGR6 and SIGR8 was salt-inducible in both wild type and mutant, and expression of SIGR12 in M-20 was much higher than that in 77-170 under salt stress. It was also shown that expression of SIGR3, SIGR4, SIGR7, SIGRIO and SIGR13 was salt-inducible, and the genes were highly homologous with Rab1d which was an ABA-inducible gene of rice. The great potential application of DDRT-PCR technique in plant molecular biology research may promote the investigation of expression of salt-induced protein in rice.

Enhanced H^+ transport activity of tonoplast vesicles isolated from roots of salt-tolerant mutant of wheat under NaCl stress

Both enhanced were H^+ transport activities of tonoplast vesicles isolated from roots of the salt-tolerant mutant and wild type of wheat with treatment of NaCI, but the activity of the mutant was significantly higher than that of wild type. H^+ transport activity was indicated as the stable value of fluorescence quenching per mg membrane proteins. The H^+ transport activities dependent on ATP of the mutant and wild type were 1099 and 558 respectively and their activities dependent on PPi were 358 and 228 separately.

Reduced Na^+ and K^+ permeability of K^+ channel in plasma membrane isolated from roots of salt-tolerant mutant of wheat

The Na^+ and K^+ permeability of K^+ channel in plasma membrane, isolated from roots of the salt-tolerant mutant of ,wheat, was lower than that of wild type in 100 mmol/L KCI and NaCI solution. The opening frequency of K^+ channel of the mutant reduced more significantly than that of wild type in two kinds of solution mentioned above. It is assumed that the reduction of opening frequency mainly contributes to the Na^+ and K^+ permeability of K^+ channel of the mutant. The electric conductance of single-channel of the mutant was similar to that of wild type and the main difference between them was exhibited as the opening frequency. Their K^+/Ka^+ selectivity of K^+ channel had no significant difference. The K^+/Na^+ selectivity of the mutant and wild type was 3.35 and 3. 18 respectively.

A novel transcription factor FnMYB4 regulates pigments metabolism of yellow leaf mutants in Fragaria nilgerrensis

The strawberry species Fragaria nilgerrensis Schlechtendal ex J.Gay,renowned for its distinctive white,fragrant peach-like fruits and strong disease resistance,is an exceptional research material.In a previous study,an ethyl methane sulfonate(EMS)mutant library was established for this species,resulting in various yellow leaf mutants.Leaf yellowing materials are not only the ideal materials for basic studies on photosynthesis mechanism,chloroplast development,and molecular regulation of various pigments,but also have important utilization value in ornamental plants breeding.The present study focused on four distinct yellow leaf mutants:mottled yellow leaf(MO),yellow green leaf(YG),light green leaf(LG),and buddha light leaf(BU).The results revealed that the flavonoid content and carotenoid-to-chlorophyll ratio exhibited a significant increase among these mutants,while experiencing a significant decrease in chlorophyll and carotenoid contents compared to the wild type(WT).To clarify the regulatory mechanisms and network relationships underlying these mutants,the RNA-seq and weighted gene coexpression network(WGCNA)analyses were employed.The results showed flavonoid metabolism pathway was enriched both in MO and YG mutants,while the chlorophyll biosynthesis pathway and carotenoid degradation pathway were only enriched in MO and YG mutants,respectively.Subsequently,key structural genes and transcription factors were identified on metabolic pathways of three pigments through correlation analyses and quantitative experiments.Furthermore,a R2R3-MYB transcription factor,FnMYB4,was confirmed to be positively correlated with flavonoid synthesis through transient overexpression,virus-induced gene silencing(VIGS),and RNA interference(RNAi),accompanying by reoccurrence and attenuation of mutant phenotype.Finally,dual-luciferase(LUC)and yeast one-hybrid assays confirmed the binding of FnMYB4 to the FnFLS and FnF3H promoters,indicating that FnMYB4 positively regulates flavonoid synthesis.In addition,correlation analyses suggested that FnMYB4 also might be involved in chlorophyll and carotenoid metabolisms.These findings demonstrated the pivotal regulatory role of FnMYB4 in strawberry leaf coloration.

Detection of ARV-Resistant Mutants in HIV-1-Infected Individuals in a Context of Systematic Switching to an Association Based on Dolutegravir in Abidjan, Côte d’Ivoire

The emergence of antiretroviral resistance mutations represents a major threat to the achievement of national and global goals for the elimination of HIV-1 infection. The global strategy in 2019 in Cte d'Ivoire is a new national policy for the management of people living with HIV with the administration of dolutegravir (DTG)-based fixed-dose combination. The aim of our study was to evaluate HIV-1 resistance to antiretrovirals (ARVs) in infected adult subjects in Cte d’Ivoire in the context of a systematic switch to a DTG-based combination. Between February 2022 and October 2023, a cross-sectional survey with random sampling was conducted in 06 services caring for people living with HIV. A total of 139 participants were included in the study. Adults with a viral load ≥ 1000 copies/mL were tested for HIV-1 ARV resistance mutations. Molecular analyses were performed using protocol of ANRS-MIE (National Agency for Research on AIDS and emerging infectious diseases). The interpretation is performed by HIVGRAD (https://www.hiv-grade.de/cms/grade/). The frequencies of HIV-1 resistance to non-nucleotide reverse transcriptase inhibitors (NNRTIs), nucleotide reverse transcriptase inhibitors (NRTIs), integrase inhibitors (IINTs) and protease inhibitors (PIs) were 82%, 73%, 19% and 11% respectively. The main mutations observed in the different classes were K103N (45%), M184V (64%), E157Q (19%) and L10V/M46I/A71V/I54V (6%) respectively. This study reveals the emergence of resistance to DTG-based fixed-dose combinations, favored by high rates of resistance to NRTIs and NNRTIs. This finding underlines the need for enhanced viral load monitoring and HIV-1 genotyping tests to guide the choice of NRTIs for combination therapy. In addition, monitoring for mutations to second-generation NRTIs is essential, given the scale-up of DTG-based regimens currently underway in Cte d’Ivoire.

An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica

Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional mutation.The random insertional mutant library constructed using this method has become a method of forward genetics for gene cloning.However,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous genes.Many microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries difficult.In this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was identified.This method will facilitate the genetic studies of N.oceanica,which should also be a reference for other microalgal species.

Pichia pastoris composition expressed aerolysin mutant of Aeromonas veronii as an oral vaccine evaluated in zebrafish(Danio rerio)

Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture.In this study,virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target antigen.Pichia pastoris constitutive secretory expression NTaer(GS115-NTaer)was used as a potential safe oral vaccine to evaluate its effectiveness on zebrafish immunity.The result shows that vaccination of GS115-NTaer for four weeks did not affect the growth performance of the host,while eliciting an effective immune protective response.Compared with the control group,the GS115-NTaer could significantly up-regulate the relative expression level of the intestinal tight junction protein 1α(TJP1α)gene,and significantly increased the contents of lysozyme(LYZ),complement C3 and C4 in the gut,indicating that the innate immune response of the fish was activated.The relative gene expression levels of macrophage-expressed gene 1(MPEG1)and T cell receptor(TCR-α)in the gut,and MPEG1,CD4,CD8,TCR-α,GATA3,and T-bet in the spleen were all increased significantly,indicating that the cellular immune response of the fish was activated.Furthermore,the contents of serum IgM and intestinal mucosa IgZ antibodies were significantly increased,which showed that humoral immunity was also activated.Moreover,inoculation with GS115-NTaer significantly changed the structure of gut microbiota.In particular,the relative ratio of(Firmicutes+Fusobacteriota+Bacteroidota)/Proteobacteria was significantly higher than that of the control and GS115 groups.Lastly,the vaccinated fish were challenged with A.veronii,and the relative percent survival of GS115 and the GS115-NTear groups was 14.28%and 33.43%.This improvement of immunity was not only due to the specific immune response but also attributed to the improvement of innate immunity and the gut microbiota which was demonstrated by the germ-free zebrafish model.Collectively,this study provides information on the effectiveness of GS115-NTear as an oral vaccine for the green prevention and control of A.veronii infection in fish aquaculture.

Roles of Mutant TP53 Gene in Cancer Development and Progression

TP53 is a tumor suppressor gene that is mutated in most cancer types and has been extensively studied in cancer research.p53 plays a critical role in regulating the expression of target genes and is involved in key processes such as apoptosis,cell cycle regulation,and genomic stability,earning it the title“guardian of the genome.”Numerous studies have demonstrated p53’s influence on and regulation of autophagy,ferroptosis,the tumor microenvironment,and cell metabolism,all of which contribute to tumor suppression.Alterations in p53,specifically mutant p53(mutp53),not only impair its tumor-suppressing functions but also enhance oncogenic characteristics.Recent data indicate that mutp53 is strongly associated with poor prognosis and advanced cancers,making it an ideal target for the development of novel cancer therapies.This review summarizes the post-translational modifications of p53,the mechanisms of mutp53 accumulation,and its gain-of-function,based on previous findings.Additionally,this review discusses its impact on metabolic homeostasis,ferroptosis,genomic instability,the tumor microenvironment,and cancer stem cells,and highlights recent advancements in mutp53 research.

Decolorization of azo dyes with high salt concentration by salt-tolerant mixed cultures under anaerobic conditions

Because the lack of detailed study of biological decolorization in high salt dye wastewater, it is still difficult to evaluate the biological treatment on high-salinity dye wastewater. The experiments were carried out to study the salt-tolerant bacteria, which is useful in the treatment of high-salinity colored wastewater. Simulated wastewater containing 5-150 g/L salt （NaCI） and 50-2000 mg/L Reactive Brilliant Red K-2BP was treated with three salt-tolerant mixed cultures （CAS, TAS, DSAS）, which were under a gradually acclimated procedure. With the increase of concentrations of salt and dye, the decolorization became low. The abilities of decolorization of dyes wastewater by three mixed cultures （CAS, TAS, DSAS） were studied, CAS and DSAS mixed cultures showed more active for the treatment of high-salinity colored wastewater than TAS mixed cultures. The results suggested that there might be a simple process for the high salt wastewater treatment, which could be incorporated into conventional activated sludge plants.

Generation and analysis of expressed sequence tags from the salt-tolerant eelgrass species, Zostera marina

Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- structed. Single-pass sequencing of the 5＇ ends of 4 081 clones yielded 4 002 high quality expressed sequence tags （ESTs）, which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from 100-1 500 bp. Basic Local Alignment Search Tool （BLASTX） analysis revealed that 1 664 unigenes had significant homology to known genes in the Na- tional Center for Biotechnology Information （NCBI） non-redundant （nr） database （E-value≤5-10）. Among them, the two most abundant genes encoded metallothionein （157 ESTs） and chlorophyll a/b-binding pro- tein （38 ESTs）, accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes （KEGG）, 1 462 unigenes were assigned to 1 161 pathways （E-value≤5-10）. A total of 938 unigenes were assigned Gene Ontology （GO） terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes for metallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z. marina.

A novel salt-tolerant Micrococcus sp. DUT_AHX capable of degrading nitrobenzene

A novel strain of Micrococcus sp.DUT_AHX,which was isolated from the sludge of a nitrobenzene(NB)-manufacturing plant and could utilize NB as the sole carbon source,was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA(rDNA)sequence analysis.It can grow at the temperature up to 40℃or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani(LB)medium.The optimal degradation conditions are as follows:temperature 37℃,pH 7.0,and shaking speed 150 r/min.The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source.Furthermore,the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1,6-dioxygenase activity.The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.

Salt-tolerant mechanism of marine Aspergillus niger cellulase cocktail and improvement of its activity

The cellulase cocktail produced by marine Aspergillus niger exhibits a property of salt-tolerance,which is of great potential in cellulose degradation in high salt environment.In order to explain the mechanism on the salttolerance of the cellulase cocktail produced by marine A.niger,six cellulase components(AnCel6,AnCel7A,AnCel7B,AnEGL,AnBGL1 and AnBGL2)were obtained by directed expression.Studies on their enzymatic properties revealed that oneβ-glucosidase(AnBGL2)and one endoglucanase(AnEGL)exhibited an outstanding salttolerant property,and one cellobiohydrolase(AnCel7B)exhibited a certain salt-tolerant property.Subsequent study revealed that the salt-tolerant An EGL and AnCel7B endowed the cellulase cocktail with stronger salttolerant property,while the salt-tolerant An BGL2 had no positive effect.Moreover,after overexpression of AnCel6,AnCel7A,AnCel7B and AnEGL,the activity of cellulase cocktail increased by 80%,70%,63%and 68%,respectively.However,the activity of cellulase cocktail was not improved after overexpression of AnBGL1 and AnBGL2.After mixed-strain fermentation with cellobiohydrolase recombinants(cel6 a,cel7a and cel7b recombinants)and endoglucanase recombinant(egl recombinant),the the activity of cellulase cocktail increased by 114%,102%and91%,respectively.

Rheological properties of salt-tolerant HPAM solutions with ultrahigh molecular weight

The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields.

High-yield Cultivation Technique of Salt-tolerant Spartina and Rice in Coastal Mudflat

Directing at the characteristics of coastal mudfiat saline and alkaline land, the yield of salt-tolerant Spartina and rice could reach 5 925-8 280 kg/hm^2 by the techniques of land and water resource utilization, farming improvement, construction of matched water system, seed selection and treatment, water direct seeding, seedling raising on seedbed, field transplanting, weeding, nutrient and water management, and disease and pest control, providing a scientific basis for the cultivation of Spartina and Rice in coast mudflat.

Variations in chlorophyll content, stomatal conductance, and photosynthesis in Setaria EMS mutants

Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and high transformation efficiency,has been widely accepted as a model in photosynthesis and drought-tolerance research.The current study characterized Chl content,G_s,and P_n of 48 Setaria mutants induced by ethyl methanesulfonate.A total of 24,34,and 35 mutants had significant variations in Chl content,G_s,and P_n,respectively.Correlation analysis showed a positive correlation between increased G_s and increased P_n,and a weak correlation between decreased Chl b content and decreased P_n was also found.Remarkably,two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1.Seven mutants behaved with significantly decreased G_s but did not decrease P_(n )compared to Yugu 1.The current study thus identified various genetic lines,further exploration of which would be beneficial to elucidate the relationship between Chl content,G_s,and P_n and the mechanism underlying why C_4 species are efficient at photosynthesis and water saving.

Introduction and Selection of Salt-tolerant Wheat in Yellow River Delta

[Objective] This study was to screen a salt-tolerant wheat variety in Dongying, a city in the center of the Yellow River Delta with a large area of coastal saline soil. [Method] Total 9 salt-tolerant, stress-resistant and high-yielding wheat varieties （lines） were introduced, and they were cultivated in the saline soil with total salt content of 3-4 g/kg with Dekang 961 as the control. [Result] The yields of Jinan 18, Yanjian 14 and Shanrong 3 were all significantly higher than that of Dekang 961 （P〈0.05）. These three varieties （lines） all ripen before June 13 with moderate growth period that does not affect the seeding of next-season crop. [Conclusion] Jinan 18, Yanjian 14 and Shanrong 3 are suitable for planting in light and median saline soil in the Yellow River Delta.

Response of Salt-Tolerant Rice Varieties to Biocompost Application in Sodic Soil of Eastern Uttar Pradesh

Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and can be used to reclaim sodic soils. Field experiments were conducted during the wet season of 2011 and 2012 to study the effect of incorporation of biocompost in sodic soil with four treatments: T1—Control, T2—Biocompost at 2 t ha-1, T3—Biocompost at 4 t ha-1 and T4—Biocompost at 6 t ha-1. The two promising salt tolerant rice varieties preferred by farmers, Narendra usar 3 and NDR 359 were used as test crops, which can produce yields ranging between 2-4 t ha-1 in soil having a pH range of 9.2 to 10.5. Among the different doses of biocompost tested, application of biocompost at 6 t ha-1 registered highest yields, enabled by a higher biomass, ear bearing tiller (EBT), and grain fertility in both varieties. Narendra usar 3 was more responsive to treatments even at lower doses of biocompost than NDR 359, but NDR 359 yielded slightly higher than Narendra usar 3 in all treatments. Soil health was also improved evidently on better fertility and low soil pH and EC at harvest. Thus, biocompost can be considered as a commercially viable, environmentally acceptable and practically enforceable option for improving the crop productivity and soil fertility status.

Analysis of nutrient content and assessment of economic value for major salt-tolerant plants in coastal areas:a case study of Dongying City, Shandong Province

Salinization of soil is a worldwide problem concerning resources and ecology,especially serious in coastal areas.Testing of 26 sorts of data or parameters are carried out on leaves of 22 plant species(in 24 plant variety) of existing main salt-tolerant plant of the Yellow River Delta region.Data or parameters include the following ele-ments:contents of K+,Na+,Ca2+,Mg2+ and Cl-,contents of protein,fat,total energy,ash and contents of 17 amino acids.The results show that these tested plants have economic values.For example,according to their uses,they can be divided into edible plants,forage plants,medicine or health plants,and some of them can be used for multipurposes.These plants have played important roles in the sustainable utilization of plant resources in coastal areas.This paper has taken evaluations on the economic uses of salt-tolerant plants and given suggestions for saline soil improvement and resource utilization in coastal areas.Based on the results of investigation and experiments,we suppose that the salt-tolerant plants in coastal areas can be grouped into 9 main groups according to their economic value:pioneer plants for saline land improvement,medicine,edible and forage plants,industry material,forestation,breeding material,energy plants and eco-tourism resources.

Chemical Composition and Ruminal Digestibility of Ceratoides, a Salt-tolerant Perennial Plant,at Different Years

It has been proposed that salt-tolerant plant could be used as a feed resource for ruminants whereby salt would be removed from salinized land (Asian -Aust. J. Anim. Sci. (2002) 15:998 -1001). Ceratoides arborescens (Losinsk.) Tsien et C. G. Ma is known as a drought-and salt-tolerant plant,a kind of shrubs, growing in semi-arid land of Inner Mongolia. Because the covering effect of the perennial plant as a mulch over the soil might be expected, the optimum covering effect would be obtained after the growth period.The perennial plant produces seeds around summer and end its growth thereafter. Nutrient value of the perennial salt-tolerant plant, however,had not been reported in flowering period at different year. It is necessary to know the ruminal degradability of the plants of each growing year in order to determine the regimen to diet for ruminants. The present experiment,therefore,was undertaken to analyze the digestibility and chemical composition of Ceratoides arborescens as feed for ruminants.

Construction of EMS-Induced Peanut Mutant Libraries and Identification of Pod-Related Traits Mutant Lines

Peanut(Arachis hypogaea L.)is an oil and economic crop of vital importance,and peanut pod is the key organ influencing the yield and processing quality.Hence,the Pod-related traits(PRTs)are considered as important agronomic traits in peanut breeding.To broaden the variability of PRTs in current peanut germplasms,three elite peanut cultivars were used to construct Ethyl methane sulfonate(EMS)-induced mutant libraries in this study.The optimal EMS treatment conditions for the three peanut varieties were determined.It was found that the median lethal dose(LD50)of EMS treatment varied greatly among different genotypes.Finally,the EMS-induced peanut mutant libraries were constructed and a total of 124 mutant lines for PRTs were identified and evaluated.Furthermore,“M-8070”,one of the mutant lines for pod constriction,was re-sequenced via high-throughput sequencing technology.The genome-wide variations between“M-8070”and its wild parent“Fuhua 8”(FH 8)were detected.2994 EMS-induced single nucleotide polymorphisms(SNPs)and 1188 insertion-deletions(InDels)between“M-8070”and its wild parent were identified.The predominant SNP mutation type was C/G to T/A transitions,while the predominant InDel mutation type was“1-bp”.We analyzed the distribution of identified mutations and annotated their functions.Most of the mutations(91.68%of the SNPs and 77.69%of the InDels)were located in the intergenic region.72 SNPs were identified in the exonic region,leading to 27 synonymous,43 nonsynonymous and 2 stop-gain variation for gene structure.13 Indels were identified in the exonic region,leading to 4 frame-shift,8 non-frame-shift and 1 stop-gain variations of genes.These mutations may lead to the phenotypic variation of“M-8070”.Our study provided valuable resources for peanut improvement and functional genomic research.