Nature’s Pharmacy under Siege: Investigating Antibiotic Resistance Pattern in Endophytic Bacteria of Medicinal Plants

Antibiotic resistance poses a significant global health threat, necessitating a thorough understanding of its prevalence in various ecological contexts. Medicinal plants, renowned for their therapeutic properties, host endophytic bacteria that produce bioactive compounds. Understanding antibiotic resistance dynamics in these bacteria is vital for human health and antibiotic efficacy preservation. In this study, we investigated antibiotic resistance profiles in endophytic bacteria from five medicinal plants: Thankuni, Neem, Aparajita, Joba, and Snake plant. We isolated and characterized 113 endophytic bacteria, with varying resistance patterns observed against multiple antibiotics. Notably, 53 strains were multidrug-resistant (MDR), with 14 exhibiting extensive drug resistance (XDR). Thankuni-associated bacteria displayed 44% MDR and 11% XDR, while Neem-associated bacteria showed higher resistance (60% MDR, 13% XDR). Aparajita-associated bacteria had lower resistance (22% MDR, 6% XDR), whereas Joba-associated bacteria exhibited substantial resistance (54% MDR, 14% XDR). Snake plant-associated bacteria showed 7% MDR and 4% XDR. Genus-specific distribution revealed Bacillus (47%), Staphylococcus (21%), and Klebsiella (11%) as major contributors to MDR. Our findings highlight diverse drug resistance patterns among plant-associated bacteria and underscore the complexity of antibiotic resistance dynamics in diverse plant environments. Identification of XDR strains emphasizes the severity of the antibiotic resistance problem, warranting further investigation into contributing factors.

Development of Machine Learning Methods for Accurate Prediction of Plant Disease Resistance

The traditional method of screening plants for disease resistance phenotype is both time-consuming and costly.Genomic selection offers a potential solution to improve efficiency,but accurately predicting plant disease resistance remains a challenge.In this study,we evaluated eight different machine learning(ML)methods,including random forest classification(RFC),support vector classifier(SVC),light gradient boosting machine(lightGBM),random forest classification plus kinship(RFC_K),support vector classification plus kinship(SVC_K),light gradient boosting machine plus kinship(lightGBM_K),deep neural network genomic prediction(DNNGP),and densely connected convolutional networks(DenseNet),for predicting plant disease resistance.Our results demonstrate that the three plus kinship(K)methods developed in this study achieved high prediction accuracy.Specifically,these methods achieved accuracies of up to 95%for rice blast(RB),85%for rice black-streaked dwarf virus(RBSDV),and 85%for rice sheath blight(RSB)when trained and applied to the rice diversity panel I(RDPI).Furthermore,the plus K models performed well in predicting wheat blast(WB)and wheat stripe rust(WSR)diseases,with mean accuracies of up to 90%and 93%,respectively.To assess the generalizability of our models,we applied the trained plus K methods to predict RB disease resistance in an independent population,rice diversity panel II(RDPII).Concurrently,we evaluated the RB resistance of RDPII cultivars using spray inoculation.Comparing the predictions with the spray inoculation results,we found that the accuracy of the plus K methods reached 91%.These findings highlight the effectiveness of the plus K methods(RFC_K,SVC_K,and lightGBM_K)in accurately predicting plant disease resistance for RB,RBSDV,RSB,WB,and WSR.The methods developed in this study not only provide valuable strategies for predicting disease resistance,but also pave the way for using machine learning to streamline genome-based crop breeding.

31 Plant Species against Blood Feeding and Disease Vectors Insects: Beyond Anti-Insect Properties, Unvalued Opportunities and Challenges for Health and Sustainability

Plants with bioactive properties are greatly useful in preventing and controlling blood-sucking and disease-vector invertebrates, particularly in developing countries and low-income communities. Their application is a promising alternative to synthetic compounds whose use remains a health, environmental, and economic challenge. However, many are still unknown and unvalued, while others are becoming ignored and threatened. The main objective of this ethnobotanical study is to identify and characterize indigenous and locally grown plants against blood-sucking and disease-vector insects. Salient opportunities and challenges of using these plants are documented and discussed. Semi-structured interviews, using a prepared questionnaire, were conducted with 228 informants. The consensus index (CI) was calculated to analyze the reliability of the collected information. The identified 31 anti-insect plant species belong to 20 botanical families, four morphological categories, and six habitat types. They can be categorized as insecticidal plants (42% of the total), insect repellent (42% of the total), and both insecticidal and insect repellent (16% of the total). More than 54% of these are still abundant in the study area, while about 35.5% have become rare and difficultly accessible. Based on the numerical importance of related anti-insect plant species, the seven targeted blood-sucking insects range in the following decreasing order: Jiggers (16 species) > Fire Ants (9 species) > Flies (8 plants) > Mosquitoes (4 species) > Fleas (2 species) > Bedbugs (1 species) > lice (0 species). The three most commonly used plants, with the highest confirmation indices, are Tetradenia riparia (ICs = 0.712), Eucalyptus globulus subsp. maidenii (ICs = 0.302), and Solanum aculeastrum (ICs = 0.288). The antimicrobial role of many locally grown anti-insect plants and the multiple other associated valorization possibilities are ignored by most informants. Domesticating, propagating, protecting, and promoting the sustainable use of these plants would be an appropriate route for their conservation and continued availability.

Nitrogen management improves lodging resistance and production in maize(Zea mays L.)at a high plant density

Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant density.We compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.The optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin content.The application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.Internode diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging percentage.In conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.

Defensive Role of Plant Latex on Insect Pests’ Suppression: A Critical Review

Over 350 million years have passed since the documentation of the first interaction between plants and insects. Numerous plant defense qualities and associated counter-adaptive features have developed as a result of these interactions between insects and plants. These characteristics might be either morphological or biological in nature. One of the most significant and useful biochemical characteristics in plants is latex. Latex has a sticky property due to presence of secondary metabolites in it, which aids in entangling or sealing the mouthparts of small insects. These metabolites also chemically interact with the insects interfering with crucial bodily processes. Plant latex has amazing properties that help protect plants from insects and inhibit them in general. It may be possible to control insect pests in a natural, secure, and long-lasting manner by correctly identifying plant latex with strong insecticidal properties and developing formulations of plant latex.

Identification and Evaluation of Insect and Disease Resistance in Transgenic Cry1Ab13-1 and NPR1 Maize

PCR detection,quantitative real-time PCR(q-RTPCR),outdoor insect resistance,and disease resistance identification were carried out for the detection of genetic stability and disease resistance through generations(T2,T3,and T4)in transgenic maize germplasms(S3002 and 349)containing the bivalent genes(insect resistance gene Cry1Ab13-1 and disease resistance gene NPR1)and their corresponding wild type.Results indicated that the target genes Cry1Ab13-1 and NPR1 were successfully transferred into both germplasms through tested generations;q-PCR confirmed the expression of Cry1Ab13-1 and NPR1 genes in roots,stems,and leaves of tested maize plants.In addition,S3002 and 349 bivalent gene-transformed lines exhibited resistance to large leaf spots and corn borer in the field evaluation compared to the wild type.Our study confirmed that Cry1Ab13-1 and NPR1 bivalent genes enhanced the resistance against maize borer and large leaf spot disease and can stably inherit.These findings could be exploited for improving other cultivated maize varieties.

Vacuolar processing enzyme positively modulates plant resistance and cell death in response to Phytophthora parasitica infection

Oomycete, particularly Phytophthora species, causes the most devastating crop diseases, such as potato late blight,and threatens the sustainable crop production worldwide. Our previous studies identified Resistance to Phytophthora parasitica 1(RTP1) as a negative regulator of Arabidopsis resistance to multiple biotrophic pathogens and RTP1 lossof-function plants displayed rapid cell death and reactive oxygen species(ROS) production during early colonization of P. parasitica. In this study, we aim to decipher the mechanism of RTP1-mediated cell death, and identify a member of vaculoar processing enzymes(VPEs), γVPE, playing a role in rtp1-mediated resistance to P. parasitica and cell death occurrence. Our results showed up-regulation of the expression of γVPE as well as increased VPE/caspase 1-like protease activity in P. parasitica-infected rtp1 mutant plants. Besides, we found that the VPE/caspase 1-like protease activity was required for the cell death occurrence in Arabidopsis plants during the infection of P. parasitica as well as rtp1-mediated resistance to P. parasitica. Further pathogenicity assays on either Arabidopsis γvpe mutant plants or leaves of Nicotiana benthamiana with transient overexpression of γVPE demonstrated γVPE could positively affect plant resistance to P. parasitica. Together, our studies suggest that γVPE might function as an important regulator of plant defense and cell death occurrence in response to P. parasitica infection, and VPE/caspase 1-like protease activity is required for rtp1-mediated resistance to P. parasitica.

Evaluation of cotton germplasm for morphological and biochemical host plant UPdates resistance traits against sucking insect pests complex

Background:Sucking insect pests cause severe damage to cotton crop production.The development of insect resistant cotton cultivars is one of the most effective measures in curtailing the yield losses.Considering the role of morphological and biochemical host plant resista nee(HPR)traits in plant defense,12 cotton genotypes/varieties were evaluated for leaf area,leaf glanding,total soluble sugars,total soluble proteins,total phenolics,tannin and total flavonoids against fluctuating populations of whitefly,thrips and jassid under field conditions.Results:The population of these insects fluctuated during the growing seas on and remained above threshold level(whitefly>5,thrips>(8-10)f or jassid>1 per leaf)during late June and early July.Strong and negative association of whitefly(r=-0.825)and jassid(r=-0.929)with seed cotton yield was observed.Mean population of insects were the highest in Glandless-1 followed by NIA-82 and NIA-M30.NIAB-Kiran followed by NI AB-878 and Sadori were the most resistant,with the mean population of 1.41,1.60,1.66(whitefly);2.24,232,2.53(thrips)and 037,0.31,036(jassid),respectively.The resistant variety NIAB-Kiran showed less soluble sugars(8.54 mg.g^(-1)),soluble proteins(27.11 mg.g^(-1))and more phenolic(36.56 mg.g^(-1))and flavonoids(13.10mg.g^(-1))as compared with the susceptible check Glandless-1.Moreover,all insect populations were positively correlated with total soluble sugars and proteins.Whitefly populations exhibited negative response to leaf gossypol glands,total phenolics,tannins and flavonoids.The thrips and jassid populations had a significant and negative correlation with these four biochemical HPR traits.Conclusion:The ide ntified resistant resources and HPR traits can be deployed against sucking in sect pests'complex in future breeding programs of developing insect resistant cotton varieties.

Molecular mechanisms of stress resistance in sorghum: Implications for crop improvement strategies

Abiotic stresses, such as drought, salt, extreme temperatures, and heavy metal pollution, are the main environmental factors that limit crop growth and yield. Sorghum, a C4 grass plant with high photosynthetic efficiency, can grow in adverse environmental conditions due to its excellent stress resistance characteristics. Therefore, unraveling the stress-resistance mechanism of sorghum could provide a theoretical basis for developing and cultivating various stress-resistant crops. This understanding could also help to create a conducive environment for using marginal soil in agriculture and ensuring food security. In this review, we discuss the adaptation mechanisms of sorghum under drought, salinity, temperature, and soil heavy metal stresses, the specific response to stress, the screening of sorghum-resistant germplasm, and the identification and functional analysis of the relevant genes and quantitative trait loci(QTL). In addition, we discuss the application potential of different stress-tolerant sorghum germplasms reported to date and emphasize the feasibility and potential use in developing and promoting highly stress-tolerant sorghum in marginal soil.

Characterization and screening of cotton(Gossypium hirsutum L.)germplasm for leafhopper(Amrasca biguttula biguttula(Ishida))resistance

Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have been hampered by the pest leafhopper.Leafhopper alone has been shown to cause yield losses of up to 40%.In this study,screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant,moderately resistant,sensitive and highly sensitive to leafhoppers.Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance.Based on the screening results,a total of 19 genotypes were resistant to leafhoppers,which was on par with the findings of the check KC 3.The contents of total soluble sugar,total soluble protein,and total free amino acids were significantly positively correlated with the mean grade,whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade.However,based on screening and biochemical analysis,the genotypes KC 2,JR-23,Samaru-26-T,D 4,TCH 1728,RS 253,and B-61-1862 exhibited high resistance to leafhopper.Conclusion According to the findings of this study,choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar,total soluble protein,and free amino acids may aid in the development of resistant genotypes.

Resistance Analysis of the Binary Insect-resistant Transgenic Soybean to Heliothis viriplaca

[Objective] The aim of the research was to analyze the resistance of binary insect-resistant transgenic soybean to Heliothis viriplaca.[Method]In this experiment, resistance analysis of the stabilized binary insect-resistant transgenic soybean to Heliothis viriplaca was conducted in lab and in field conditions.[Result] The results indicated that the leaves of insect-resistant transgenic soybeans T5-150 and T5-195 showed lighter damage than those of non-transgenic soybeans. Meanwhile, the Heliothis viriplaca larvae fed on leaves of these two transgenic soybeans were characterized by less leaf consumption, shortening survival day, slower development and less pupation.[Conclusion]It was concluded that insect-resistance of transgenic soybean to Heliothis viriplaca was increased dramatically and the research provided a reference for selecting binary insect-resistant transgenic soybean to Heliothis viriplaca.

Recent Progress in Elucidating the Structure, Function and Evolution of Disease Resistance Genes in Plants

Plants employ multifaceted mechanisms to fight with numerous pathogens in nature. Resistance （R） genes are the most effective weapons against pathogen invasion since they can specifically recognize the corresponding pathogen effectors or associated protein（s） to activate plant immune responses at the site of infection. Up to date, over 70 R genes have been isolated from various plant species. Most R proteins contain conserved motifs such as nucleotide-binding site （NBS）, leucine-rich repeat （LRR）, Toll-interleukin-1 receptor domain （TIR, homologous to cytoplasmic domains of the Drosophila Toll protein and the manamalian intefleukin-1 receptor）, coiled-coil （CC） or leucine zipper （LZ） structure and protein kinase domain （PK）. Recent results indicate that these domains play significant roles in R protein interactions with effector proteins from pathogens and in activating signal transduction pathways involved in innate immunity. This review highlights an overview of the recent progress in elucidating the structure, function and evolution of the isolated R genes in different plant-pathogen interaction systems.

Insect Resistance of Different Tissues of Transgenic Cotton to Spodoptera exigua(Hbner)

[Objective] The aim was to learn the resistance of different tissues and organs of transgenic cotton to Spodoptera exigua （Hbner）. [Method] Flowers,the 1st,the 3rd,the 6th and the 14th leaves from the top of 33B,GK12 and SGK321 were used to feed S. exigua neonates respectively. Survival larvae and dead ones were counted on the 3rd,the 7th,the 10th,the 16th and the 19th day; meanwhile,the pupae amount was recorded,and the pupae weight was measured at the 24th h after pupation. [Result] The survival curves,pupation rates and pupae weights of S. exigua feeding on different tissues of transgenic cotton were not significantly different from those of S. exigua feeding on the corresponding tissues of conventional cotton; pupation rate of S. exigua feeding on different leaves of the same cotton variety were not significantly different from each other,but all higher than that of S. exigua feeding on the flowers of that cotton; and there were no differences among pupation weights of S. exigua feeding on different leaves or flowers of the same cotton variety. [Conclusion] Transgenic cotton showed weak resistance to S. exigua. Hence,in the transgenic cotton fields,more attention should be paid to occurrence trend of S. exigua and its control.

Effects of Planting Density and Nitrogen Amount on Stalk Lodging-Resistance and Yield of Summer Maize in Sichuan Basin

[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high-yielding cultivation technique.[Method] A widely planted maize cultivar ＇Chengdan 30＇ was used as experimental material to study the effects of planting density and nitrogen amount on the stalk agronomic traits,stalk lodging-resistance mechanical characters,stalk breaking percentage and yield of maize.Experiment was arranged in a two-factor split plot design with three replicates.The planting density was the main factor with three density gradients（4.5×10^4,6.0×10^4 and 7.5×10^4 plants/hm^2） and the nitrogen amount was the second factor with two different levels of nitrogen content（300 and 375 kg/hm^2）.[Result] The stalk lodging-resistance and yield were affected by planting density significantly.The increase of planting density would result in an increase of internode length and decrease of internode diameter,dry matter weight of per unit stalk length,rind penetration strength and breaking resistance of 3rd and 4th basal internodes.When planting density increased from 6.0×10^4 plants/hm2 to 7.5×10^4 plants/hm^2,the stalk breaking percentage in the whole growing season increased by 17.17%,and the yield reduced by 17.58%.The interaction between planting density and nitrogen amount affected the stalk breaking percentage in the whole growing season and yield significantly.The treatment with planting density of 6.0×104 plants/hm^2 and nitrogen amount of 375 kg/hm^2 of pure N was an optimal combination,which may not only control the stalk breaking percentage of whole growing stage effectively,but also could obtain an optimum grain yield.[Conclusion] In Sichuan Basin,the appropriate planting density and nitrogen amount for summer maize were 6.0×10^4 plants/hm^2 and 375 kg/hm^2.

Test of Insect-Resistance of Transgenic Poplar with CpTI Gene

Both non-transgenic hybrid triploid poplars [ (Populus tomentosa×P.bolleana)×P.tomentosa ] and transgenic ones expressing cowpea trypsin inhibitor were cut at the base of the stem to produce auxoblasts, and used as source of leaves for insect feeding trials performed on 3 major insect species of poplar, the forest tent caterpillar ( Malacosoma disstria L.), gypsy moth ( Lymantria dispar L.) and willow moth ( Stilpnotia candida Staudinger). The height and basal diameter of trees were measured by the end of that year (2000). The results indicated that the growth elements of transgenic poplars were not interfered by the incorporation of the CpTI gene. Intriguingly, the height and basal diameter of the clone TG04 were much greater than that of the control. The transgenic foliage consumed by insects induced the increase of larval mortality, and decrease of larval wet weight gain, faecal output, pupal weight and egg deposition. Among them 3 transgenic clones, TG04, TG07 and TG71 received special attention for their outstanding insect resistance compared with other transgenic clones, which showed that the CpTI gene in them was expressed more actively and stably than in others.

Effect of LaCl_3 on Resistance and Absorptive Capacity to Formaldehyde of Indoor Ornamental Plants under Formaldehyde Stress

[Objective] This study aimed to determine the effect of rare earth biological regulator LaCl3 on the absorptive capacity to formaldehyde of four indoor ornamental plants, and to screen out the plant whose absorptive capacity to formaldehyde can be increased most greatly by LaCl3. [Method] Effect of LaCl3 on absorptive capacity to formaldehyde of four indoor ornamental plants was studied through fumigating in laboratory. Simultaneously, the indoor ornamental plant, which could significantly en- hance the degradation capacity of formaldehyde, was screened out to study the physiological and biochemical mechanisms of formaldehyde resistance. [Result] The ability to absorb formaldehyde of four indoor ornamental plants was enhanced by dif- ferent ranges after spraying with LaCl3 at suitable concentrations. The ability to ab- sorb formaldehyde of Hedera nepalensis var. sinensis, Chlorophytum comosum, Scindapsus aureun and Sansevieria trifasciata increased by 15.16%, 4.72%, 19.75% and 7.68%, respectively. In the four indoor ornamental plants, the capacity of S. au- reun to absorb formaldehyde was greatly improved by spraying LaCl3. When S. au- reun was stressed by formaldehyde, its chlorophyll content decreased by 39.87%, membrane permeability, MDA accumulation and POD activity increased by 8.17%, 56.92%, and 11.32%, respectively. However, compared the pre-spraying group with the no-spraying group under formaldehyde stress, chlorophyll content of S. aureun reduced less, membrane permeability and MDA cumulative both increased less, but POD activity increased more. [Conclusion] The formaldehyde absorption capacity of S. aureun was mostly improved after LaCl3 was sprayed.

Seedling and adult plant resistance to leaf rust in 46 Chinese bread wheat landraces and 39 wheat lines with known Lr genes

Wheat leaf rust,caused by Puccinia triticina(Pt),is an important foliar disease that has an important influence on wheat yield.The most economic,safe and effective way to control the disease is growing resistant cultivars.In the present study,a total of 46 wheat landraces and 34 wheat lines with known Lr(leaf rust resistance)genes were inoculated with 16Pt pathotypes for postulating seedling resistance gene(s)in the greenhouse.These cultivars and five wheat differential lines with adult plant resistance(APR)genes(Lr12,Lr22b,Lr34,Lr35 and Lr37)were also evaluated for identification of slow rusting resistance in the field trials in Baoding,Hebei Province of China in the 2014–2015 and 2015–2016 cropping seasons.Furthermore,10 functional molecular markers closely linked to 10 known Lr genes were used to detect all the wheat genotypes.Results showed that most of the landraces were susceptible to most of the Pt pathotypes at seedling stage.Nonetheless,Lr1 was detected only in Hongtangliangmai.The field experimental test of the two environments showed that 38 landraces showed slow rusting resistance.Seven cultivars possessed Lr34 but none of the landraces contained Lr37 and Lr46.Lr genes namely,Lr9,Lr19,Lr24,Lr28,Lr29,Lr47,Lr51 and Lr53 were effective at the whole plant stage.Lr18,Lr36 and Lr45 had lost resistance to part of pathotypes at the seedling stage but showed high resistance at the adult plant stage.Lr34 as a slowing rusting gene showed good resistance in the field.Four race-specific APR genes Lr12,Lr13,Lr35 and Lr37 conferred good resistance in the field experiments.Seven race-specific genes,Lr2b,Lr2c,Lr11,Lr16,Lr26,Lr33 and LrB had lost resistance.The 38 landraces showed slow rusting resistance to wheat leaf rust can be used as resistance resources for wheat resistance breeding in China.

Agrobacterium tumefaciens-mediated transformation of rice with the spider insecticidal gene conferring resistance to leaffolder and striped stem borer

Immature embryos of rice varieties "Xiushui11" and "Chunjiang 11" precultured for 4d were infected and transformed by Agrobacterium tumefaciens strain EHA101/pExT7 (containing the spider insecticidal gene). The resistant cant were transferred onto the differentiation medium and plants were regenerated. The transformation frequency reached 56%-72% measured as numbers of Geneticin (G418)-resistant calli produced and 36%-60% measured as numbers of transgenic plants regenerated, respectively. PCR and Southern blot analysis of transgenic plants confirmed that the T-DNA had been integrated into the rice genome. Insect bioassays using T1 transgenic plants indicated that the mortality of the leaffolder (Cnaphalocrasis medinalis) after 7d of leaf feeding reached 38%-61% and the corrected mortality of the striped stem borer (Chilo suppressalis) after 7d of leaf feeding reached 16%-75%. The insect bioassay results demonstrated that the transgenic plants expressing the spider insecticidal protein conferred enhanced resistance to these pests.

Pathogenesis-related protein genes involved in race-specific allstage resistance and non-race specific high-temperature adultplant resistance to Puccinia striiformis f. sp. tritici in wheat

Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wheat plants activate a w^ae range OT nost nteractions, the expressions of particular pathogenesis-Different types of resistance have been recognized and utilized for developing wheat cultivars for resistance to stripe rust. All-stage resistance can be detected in seedling stage and remains at high levels throughout the plant growth stages. This type of resistance is race-specific and not durable. In contrast, plants with only high-temperature adult-plant （HTAP） resistance are susceptible in seedling stage, but become resistant when plants grow older and the weather becomes warmer. HTAP resistance controlled by a single gene is partial, but usually non-race specific and durable. The objective of this study was to analyze the expression of PR protein genes involved in different types of wheat resistance to stripe rust. The expression levels of 8 PR protein genes （PR1, PRI.2, PR2, PR3, PR4, PR5, PR9 and PRIO） were quantitatively evaluated at 0, 1, 2, 7 and 14 days after inoculation in single resistance gene lines of wheat with all-stage resistance genes YrTrl, Yr76, YrSP and YrExp2 and lines carrying HTAP resistance genes Yr52, Yr59, Yr62 and Yr7B. Races PSTv-4 and PSTv-37 for compatible and incompatible interactions were used in evaluation of PR protein gene expression in wheat lines carrying all-stage resistance genes in the seedling- stage experiment while PSTv-37 was used in the HTAP experiment. Analysis of quantitative real-time polymerase chain reaction （qRT-PCR） revealed that all of the PR protein genes were involved in the different types of resistance controlled by different Yr genes. However, these genes were upregulated at different time points and at different levels during the infection process among the wheat lines with different Yr genes for either all-stage resistance or HTAP resistance. Some of the genes were also induced in compatible interactions, but the levels were almost always higher in the incompatible interaction than in the compatible interaction at the same time point for each Yr gene. These results indicate that both salicylic acid and jasmonate signaling pathways are involved in both race-specific all-stage resistance and non-race specific HTAP resistance. Although expressing at different stages of infection and at different levels, these PR protein genes work in concert for contribution to different types of resistance controlled by different Yr genes.

Enhanced Stem Nematode Resistance of Transgenic Sweetpotato Plants Expressing Oryzacystatin-I Gene

Enhanced stem nematode resistance of transgenic sweetpotato （cv. Lizixiang） was achieved using Oryzacystatin-I （OCI） gene with Agrobacterium tumefaciens-mediated transformation. A. tumefaciens strain EHA105 harbors a binary vector pCAMBIA1301 with OCI gene, gusA gene and hptII gene. Selection culture was conducted using 25 mg L-1 hygromycin. A total of 1 715 plants were produced from the inoculated 1 450 cell aggregates of Lizixiang via somatic embryogenesis. GUS assay and PCR analysis of the putative transgenic plants randomly sampled showed that 90.54% of them were transgenic plants. Transgenic plants exhibited significantly enhanced resistance to stem nematodes compared to the untransformed control plants by the field evaluation with stem nematodes. Stable integration of the OCI gene into the genome of resistant transgenic plants was confirmed by Southern blot analysis, and the copy number of integrated OCI gene ranged from 1 to 4. Transgene overexpression in stem nematode-resistant plants was demonstrated by quantitative real-time PCR analysis. This study provides a way for improving stem nematode resistance in sweetpotato.