Broad-spectrum Resistance Research Articles

Transcription-Aided Selection (TAS) for Crop Disease Resistance: Strategy and Evidence

A transcription-aided selection (TAS) strategy is proposed in this paper, which utilizes the positive regulatory roles of genes involved in the plant immunity pathways to screen crops with high disease resistance. Increased evidence has demonstrated that upon pathogen attack, the expression of diverse genes involved in salicylic acid (SA)-mediated SAR are differentially expressed and transcriptionally regulated. The paper discusses the molecular mechanisms of the SA signaling pathway, which plays a central role in plant immunity, and identifies differentially expressed genes (DEGs) that could be targeted for transcriptional detection. We have conducted a series of experiments to test the TAS strategy and found that the level of GmSAGT1 expression is highly correlated with soybean downy mildew (SDM) resistance with a correlation coefficient R2 = 0.7981. Using RT-PCR, we screened 2501 soybean germplasms and selected 26 collections with higher levels of both GmSAGT1 and GmPR1 (Pathogenesis-related proteins1) gene expression. Twenty-three out of the twenty-six lines were inoculated with Peronospora manshurica (Pm) in a greenhouse. Eight showed HR (highly resistant), four were R (resistant), five were MR (moderately resistant), three were S (susceptible), and three were HS (highly susceptible). The correlation coefficient R2 between the TAS result and Pm inoculation results was 0.7035, indicating a satisfactory consistency. The authors anticipate that TAS provides an effective strategy for screening crops with broad-spectrum and long-lasting resistance.

Comprehensive genomic analysis and evaluation of in vivo and in vitro safety of Heyndrickxia coagulans BC99

This study aimed to evaluate the safety profile and beneficial effects of Heyndrickxia coagulans strain BC99 (BC99) for potential use in functional foods and pharmaceuticals. We began with whole genome sequencing of BC99, followed by a comprehensive safety assessment comprising genome analysis, hemolysis, cytotoxicity, antibiotic susceptibility tests, and cell adhesion and tolerance studies, along with acute and subacute oral toxicity studies in animal models. BC99 was isolated from a well-characterized collection originating from the feces of a healthy infant. Our results indicated no hemolytic activity on Columbia blood agar plates and broad antibiotic sensitivity, including to gentamicin, ampicillin, chloramphenicol, ciprofloxacin, and others. Cytotoxicity testing confirmed no adverse effects on HT-29 cells and significant adhesive properties to intestinal epithelial cells. Tolerance tests demonstrated over 90% viability of BC99 under simulated gastrointestinal conditions. In vivo studies in mice and rats confirmed the absence of adverse effects following oral administration. Collectively, these findings support BC99’s robust tolerance to gastrointestinal environments, strong adhesion capabilities, and a broad spectrum of antibiotic resistance, underlining its potential as a safe and effective agent for gut microbiota modulation and host health enhancement.

The ZmCPK39-ZmDi19-ZmPR10 immune module regulates quantitative resistance to multiple foliar diseases in maize.

Gray leaf spot, northern leaf blight and southern leaf blight are three of the most destructive foliar diseases affecting maize (Zea mays L.). Here we identified a gene, ZmCPK39, that encodes a calcium-dependent protein kinase and negatively regulates quantitative resistance to these three diseases. The ZmCPK39 allele in the resistant line displayed significantly lower pathogen-induced gene expression than that in the susceptible line. A marked decrease in ZmCPK39 abundance mitigated the phosphorylation and degradation of the transcription factor ZmDi19. This led to elevated expression of ZmPR10, a gene known to encode an antimicrobial protein, thereby enhancing maize resistance to foliar diseases. Moreover, the F1 hybrid with reduced ZmCPK39 expression favored disease resistance, thereby increasing yield. Hence, the discovery of the ZmCPK39-ZmDi19-ZmPR10 immune module provides insight into the mechanisms underlying broad-spectrum quantitative disease resistance and also offers a new avenue for the genetic control of maize foliar diseases.

Using Marker-Assisted Selection to Develop a Drought-Tolerant Rice Line with Enhanced Resistance to Blast and Brown Planthopper

Rice is a major global staple crop, but rising temperatures and freshwater shortages have made drought one of the most severe abiotic stresses affecting agriculture. Additionally, rice blast disease and brown planthopper infestations significantly impact yields. Therefore, developing water-saving, drought-resistant, high-yielding, and disease-resistant rice varieties is critical for sustainable rice production. The new water-saving and drought-resistant (WDR) rice ‘Huhan 1516’, bred using marker-assisted selection (MAS) and marker-assisted backcrossing (MABC) techniques, addresses these challenges. This variety is highly adaptable to drought-prone and water-scarce regions such as the Yangtze and Huai River basins. With its high yield, drought tolerance, and broad-spectrum resistance to rice blast (conferred by the Pi2 gene) and brown planthopper (BPH), ‘Huhan 1516’ is suitable for various farming systems and environments. Field trials show that this variety outperforms control varieties by 2.2% in yield and exhibits moderate resistance to both rice blast and brown planthopper. ‘Huhan 1516’ has been recognized as a new water-saving and drought-resistant rice variety by the state, and as a released cultivar, it has great potential for market promotion and application.

Comparative analysis of the PAL gene family in nine citruses provides new insights into the stress resistance mechanism of Citrus species

BackgroundThe phenylalanine ammonia-lyase (PAL) gene, a well-studied plant defense gene, is crucial for growth, development, and stress resistance. The PAL gene family has been studied in many plants. Citrus is among the most vital cash crops worldwide. However, the PAL gene family has not been comprehensively studied in most Citrus species, and the biological functions and specific underlying mechanisms are unclear.ResultsWe identified 41 PAL genes from nine Citrus species and revealed different patterns of evolution among the PAL genes in different Citrus species. Gene duplication was found to be a vital mechanism for the expansion of the PAL gene family in citrus. In addition, there was a strong correlation between the ability of PAL genes to respond to stress and their evolutionary duration in citrus. PAL genes with shorter evolutionary times were involved in more multiple stress responses, and these PAL genes with broad-spectrum resistance were all single-copy genes. By further integrating the lignin and flavonoid synthesis pathways in citrus, we observed that PAL genes contribute to the synthesis of lignin and flavonoids, which enhance the physical defense and ROS scavenging ability of citrus plants, thereby helping them withstand stress.ConclusionsThis study provides a comprehensive framework of the PAL gene family in citrus, and we propose a hypothetical model for the stress resistance mechanism in citrus. This study provides a foundation for further investigations into the biological functions of PAL genes in the growth, development, and response to various stresses in citrus.

Marker Assisted Selection in Advanced Backcross Population of Rice Variety, MTU1010 for Bacterial Blight and Blast Resistance

The present study was aimed for identification of the bacterial blight and blast resistant lines in the advanced back cross population of MTU-1010 using marker assisted foreground selection and also for evaluation of agro-morphological characters. The M-16-59 introgressed line (derived from an intercrossing of BC2F1 plants of MTU-1010 x GPP2 and MTU-1010 x NLR 145) is developed under ongoing DBTDBSRR subproject -IV possessing Xa21, xa13, Pi1 and Pi54 resistance genes having broad spectrum resistance to bacterial blight and blast is used as a donor parent and MTU-1010 was used as a recurrent parent for the back cross. Before attempting the backcross both the parents were verified for the target genes along with the original donors GPP2 and NLR 145 using gene specific/linked molecular markers viz., xa13-promo for xa13 gene, pTA248 for Xa21 gene, RM 224 for Pi1 and Pi54 MAS for Pi54. under the F1 generation (equivalent to BC3F1 because two backcrosses were completed earlier), 120 plants were screened, and 16 plants were confirmed for xa13, Xa21, Pi1, and Pi54 genes under heterozygous conditions. These confirmed plants were assessed for agro-morphological characteristics such as yield, grain features, and plant type. The results showed that the confirmed heterozygous plants were comparable to MTU-1010 and passed to the next round of selection and evaluation. The BC1F1-198th plant (96.8%) was selfed to produce BC1F2 population. Twenty five plants were advanced to BC1F3 generation based on BB resistance and above other phenotypic characters. The selected BC1F3 progenies were screened for blast and BB resistance. Four BC1F3 progenies with four target genes (xa13xa13Xa21Xa21Pi54Pi54Pi1Pi1) showed very high level of resistance to both the diseases. BC1F2-198-52nd line found similar to MTU1010 with respect to yield and yield related characters besides showing resistance to both BB and blast.Improved lines of MTU1010 can be advanced for multi-location testing under All India Coordinated Rice Improvement Project (AICRIP) for their evaluation and possible release for the benefit of rice farmers.

Antimicrobial Potential of Scorpion-Venom-Derived Peptides

The frequent and irrational use of antibiotics by humans has led to the escalating rise of antimicrobial resistance (AMR) with a high rate of morbidity-mortality worldwide, which poses a challenge to the development of effective treatments. A large number of host defense peptides from different organisms have gained interest due to their broad antibacterial spectrum, rapid action, and low target resistance, implying that these natural sources might be a new alternative to antimicrobial drugs. As important effectors of prey capture, defense against other animal attacks, and competitor deterrence, scorpion venoms have been developed as important candidate sources for modern drug development. With the rapid progress of bioanalytical and high throughput sequencing techniques, more and more scorpion-venom-derived peptides, including disulfide-bridged peptides (DBPs) and non-disulfide-bridged peptides (NDBPs), have been recently identified as having massive pharmacological activities in channelopathies, pathogen infections, and cancer treatments. In this review, we summarize the molecular diversity and corresponding structural classification of scorpion venom peptides with antibacterial, antifungal, and/or antiparasitic activity. We also aim to improve the understanding of the underlying mechanisms by which scorpion-venom-derived peptides exert these antimicrobial functions, and finally highlight their key aspects and prospects for antimicrobial therapeutic or pharmaceutical application.

Exploring the molecular mechanisms of rice blast resistance and advances in breeding for disease tolerance.

Rice blast, caused by the fungus Magnaporthe oryzae (syn. Pyricularia oryzae), is a major problem in rice cultivation and ranks among the most severe fungal diseases. Cloning and identifying resistance genes in rice, coupled with a comprehensive examination of the interaction between M. oryzae and rice, may provide insights into the mechanisms of rice disease resistance and facilitate the creation of new rice varieties with improved germplasm. These efforts are essential for protecting food security. This review examines the discovery of genes that confer resistance or susceptiblity to M. oryzae in rice over the last decade. It also discusses how knowledge of molecular mechanisms has been used in rice breeding and outlines key strategies for creating rice varieties resistant to this disease. The strategies discussed include gene pyramiding, molecular design breeding, editing susceptibility genes, and increasing expression of resistance genes through pathogen challenge. We address the prospects and challenges in breeding for rice blast resistance, emphasizing the need to fully exploit germplasm resources, employ cutting-edge methods to identify new resistance genes, and develop innovative breeding cultivars. Additionally, we underscore the importance of understanding the molecular basis of rice blast resistance and developing novel cultivars with broad-spectrum disease resistance.

Gene co-expression analysis reveals conserved and distinct gene networks between resistant and susceptible Lens ervoides challenged by hemibiotrophic and necrotrophic pathogens

As field crops are likely to be challenged by multiple pathogens during their development, the investigation of broad-spectrum resistance in the host is of great interest for crop genetic enhancement. In this study, we attempted to address this question by adopting a weighed gene co-expression approach to study the temporal transcriptome dynamics of resistant and susceptible recombinant inbred lines (RILs) derived from an intraspecific Len ervoides cross during the infection process with either the necrotrophic pathogens Ascochyta lentis or Stemphylium botryosum, or the hemibiotrophic pathogen Colletotrichum lentis. By comparing networks of resistant and susceptible RILs, seven network module pairs were found to possess high correlation coefficients (R > 0.70) and large number of overlapping genes (n > 100). The conserved co-regulation of genes in these network module pairs were involved in plant cell wall synthesis, cell division, cytoskeleton organization, and protein ubiquitin related processes and appeared to be common disease responses against these pathogens. On the other hand, we also identified eight modules with low correlation between resistance and susceptibility networks. Among those, a stronger gene co-expression in R-genes and small RNA processes in the resistant hosts may be enhancing L. ervoides resistance against A. lentis, C. lentis, and S. botryosum, whereas the higher level of synergistic regulation in the synthesis of arginine and glutamine and phospholipid and glycerophospholipids in the susceptible hosts may contribute to increased susceptibility in L. ervoides.

Potato β-aminobutyric acid receptor IBI1 manipulates VOZ1 and VOZ2 transcription factor activity to promote disease resistance.

Upon infection with non-pathogenic microorganisms or treatment with natural or synthetic compounds, plants exhibit a more rapid and potent response to both biotic and abiotic stresses. However, the molecular mechanisms behind this phenomenon, known as defense priming, are poorly understood. β-aminobutyric acid (BABA) is an endogenous stress metabolite that enhances plant tolerance to various abiotic stresses and primes plant defense responses, providing the ability to resist a variety of pathogens (broad-spectrum resistance). In this study, we identified an aspartyl-tRNA synthetase (AspRS), StIBI1 (named after Arabidopsis IMPAIRED IN BABA-INDUCED IMMUNITY 1; IBI1), as a BABA receptor in Solanum tuberosum. We elucidated the regulatory mechanisms by which StIBI1 interacts with two NAC (NAM, ATAF1, 2, and CUC2) transcription factors (TFs), StVOZ1 and StVOZ2 (VASCULAR PLANT ONE ZINC FINGER, VOZ), to activate BABA-induced resistance (BABA-IR). StVOZ1 represses, whereas StVOZ2 promotes, immunity to the late blight pathogen Phytophthora infestans. Interestingly, BABA and StIBI1 influence StVOZ1- and StVOZ2-mediated immunity. StIBI1 interacts with StVOZ1 and StVOZ2 in the cytoplasm, reducing the nuclear accumulation of StVOZ1 and promoting the nuclear accumulation of StVOZ2. Our findings indicate that StVOZ1 and StVOZ2 finely regulate potato resistance to late blight through distinct signaling pathways. In summary, our study provides insights into the interaction between the potato BABA receptor StIBI1 and the TFs StVOZ1 and StVOZ2, which affects StVOZ1 and StVOZ2stability and nuclear accumulation to regulate late blight resistance during BABA-IR. This research advances our understanding of the primary mechanisms of BABA-IR in potato and contributes to a theoretical basis for the prevention and control of potato late blight using BABA-IR.

Assessment of Antimicrobial Resistance and Susceptibility Pattern of UTI-causing Microorganisms in Southern Punjab, Pakistan

Background: Bacterial resistance against antibiotics has become a global challenge and measures are needed to stop this. The aim of this study is to highlight this problem and to determine the antibiotic susceptibility pattern of organisms in Southern Punjab, Pakistan. Method: This descriptive cross-sectional study was conducted in Sheikh Zayed Medical Hospital, Rahim Yar Khan. The urine samples obtained from 4 different wards were sent for culture and sensitivity analysis. 9 antibiotics (Nitrofurantoin, Fosfomycin, Ciprofloxacin, Ceftriaxone, Trimethoprim-Sulfamethoxazole, Norfloxacin, Linezolid, Amoxicillin, and Imipenem) were tested against 5 isolated strains of uropathogens using Kirby Bauer disk diffusion test. The sensitivity reports were obtained, and data points were entered into a spreadsheet and analysed using SPSS. Results: Out of 101 samples of uropathogens that showed positive growths (42.08%), 53 (52.4%) were from male patients and 48 (47.5%) positive growths were from females. Escherichia Coli had the highest positive growths (58%) followed by Pseudomonas (19%) Klebsiella (13%), Staphylococcus Aureus (7%) and Coagulase-negative staphylococci (3%). Imipenem was the most sensitive drug whereas the highest resistance by organisms was developed against TMP-SMX. No significant association(p>0.05) was found between any of the anti-microbial drugs and Escherichia coli, gram-positive uropathogens, and gram negative uropathogens. Conclusion: The high increasing rate of broad-spectrum antibiotics resistance suggests that diagnostic and culture tests should be encouraged in hospitals. Based on these test results, appropriate antibiotics should be prescribed. The limitations include the inability to distinguish between nosocomial and community-acquired urinary tract infections and also did not consider other demographic factors like age.

Pathotype determination of sorghum anthracnose (Colletotrichum sublineola) isolates from Ethiopia using sorghum differentials.

Sorghum anthracnose, caused by Colletotrichum sublineola, is the most destructive disease of sorghum, which causes up to 80% grain yield loss in susceptible varieties. The use of resistance varieties is an effective, durable, and eco-friendly strategy for anthracnose control. Knowledge of the phenotypic and genetic variation in C. sublineola is vital for designing appropriate anthracnose management strategies. The present study examined the morphology and virulence of 25 C. sublineola isolates recovered from various sorghum-producing regions of Ethiopia against 18 known sorghum anthracnose differentials, 6 Ethiopian sorghum landraces, and a variety of Bonsa. Analysis of variance (ANOVA) revealed significant differences among sorghum genotypes, C. sublineola isolates, and their interactions. There was a significant difference between the isolates in virulence, with each isolate exhibiting virulence in 8-72% of the sorghum genotypes tested. Among the 25 tested isolates, the top four most virulent isolates were from Pawe, suggesting that this area is suitable for pathogen diversity studies and host plant resistance screening. The sorghum genotypes IS_18760, Brandes, and Bonsa showed resistance to all tested isolates. Consequently, they may provide potential sources of resistance genes for sorghum breeding programs to develop cultivars resistant to different C. sublineola pathotypes. However, the resistant check SC748-5 was susceptible to isolates NK73_F37, while another resistant check SC112-14 was susceptible to isolates PW123_F47 and PW122_F47. Cluster analysis grouped 22 isolates into seven clusters based on their morphological characters, whereas 24 pathotypes were identified among 25 isolates that were tested on 25 sorghum genotypes. Hence, this study revealed high variation in C. sublineola in Ethiopia suggesting the need for broad-spectrum resistance to control the disease. Sorghum genotypes resistant to various C. sublineola isolates were identified in this study, which can be used in sorghum breeding programs aiming to develop resistant cultivars to anthracnose. Highly virulent C. sublineola isolates were also identified which could be used in sorghum germplasm resistance screening. The report is the first to show the existence of C. sublineola pathotypes in Ethiopia.

Overexpressing CsSABP2 enhances tolerance to Huanglongbing and citrus canker in C. sinensis.

Huanglongbing (HLB) and citrus canker, arising from Candidatus Liberibacter asiaticus (CaLas) and Xanthomonas citri pv. Citri (Xcc), respectively, have been imposing tremendous losses to the global citrus industry. Systemic acquired resistance (SAR) has been shown to be crucial for priming defense against pathogen in citrus. Salicylic acid (SA) binding protein 2 (SABP2), which is responsible for converting methyl salicylate (MeSA) to SA, is essential for full SAR establishment. Here, we characterized the functions of four citrus SABP2 genes (CsSABP2-1, CsSABP2-1V18A , CsSABP2-2 and CsSABP2-3) against HLB and citrus canker. In vitro enzymatic assay revealed that all four proteins had MeSA esterase activities, and CsSABP2-1 and CsSABP2-1V18A has the strongest activity. Their activities were inhibited by SA except for CsSABP2-1V18A. Four genes controlled by a strong promoter 35S were induced into Wanjincheng orange (Citrus sinensis Osbeck) to generate transgenic plants overexpressing CsSABP2. Overexpressing CsSABP2 increased SA and MeSA content and CsSABP2-1V18A had the strongest action on SA. Resistance evaluation demonstrated that only CsSABP2-1V18A had significantly enhanced tolerance to HLB, although all four CsSABP2s had increased tolerance to citrus canker. The data suggested the amino acid Val-18 in the active site of CsSABP2 plays a key role in protein function. Our study emphasized that balancing the levels of SA and MeSA is crucial for regulating SAR and conferring broad-spectrum resistance to HLB and citrus canker. This finding offers valuable insights for enhancing resistance through SAR engineering.

Structural insights into alterations in the substrate spectrum of serine-β-lactamase OXA-10 from Pseudomonas aeruginosa by single amino acid substitutions

ABSTRACT The extensive use of β-lactam antibiotics has led to significant resistance, primarily due to hydrolysis by β-lactamases. OXA class D β-lactamases can hydrolyze a wide range of β-lactam antibiotics, rendering many treatments ineffective. We investigated the effects of single amino acid substitutions in OXA-10 on its substrate spectrum. Broad-spectrum variants with point mutations were searched and biochemically verified. Three key residues, G157D, A124T, and N73S, were confirmed in the variants, and their crystal structures were determined. Based on an enzyme kinetics study, the hydrolytic activity against broad-spectrum cephalosporins, particularly ceftazidime, was significantly enhanced by the G157D mutation in loop 2. The A124T or N73S mutation close to loop 2 also resulted in higher ceftazidime activity. All structures of variants with point mutations in loop 2 or nearby exhibited increased loop 2 flexibility, which facilitated the binding of ceftazidime. These results highlight the effect of a single amino acid substitution in OXA-10 on broad-spectrum drug resistance. Structure–activity relationship studies will help us understand the drug resistance spectrum of β-lactamases, enhance the effectiveness of existing β-lactam antibiotics, and develop new drugs.

CRISPR/Cas-Mediated Gene Editing in Plant Immunity and Its Potential for the Future Development of Fungal, Oomycete, and Bacterial Pathogen-Resistant Pulse Crops.

Pulses provide myriad health benefits and are advantageous in an environmental context as a result of their leguminous nature. However, phytopathogenic fungi, oomycetes and bacteria pose a substantial threat to pulse production, at times leading to crop failure. Unfortunately, existing disease management strategies often provide insufficient control, and there is a clear need for the development of new pulse cultivars with durable and broad-spectrum disease resistance. CRISPR/Cas-mediated gene editing has proven its potential for rapidly enhancing disease resistance in many plant species. However, this tool has only very recently been applied in pulse species, and never in the context of plant immunity. In this review, we examine the recent successful utilization of this technology in pulse species for proof-of-concept or the improvement of other traits. In addition, we consider various genes that have been edited in other plant species to reduce susceptibility to pathogens, and discuss current knowledge regarding their roles in pulses. Given the functional conservation of the selected genes across diverse plant species, there is a high likelihood that their editing would elicit similar effects in non-oilseed grain legumes, thus providing a suite of potential targets for CRISPR/Cas-mediated gene editing to promote pulse crop productivity in coming years.

Marker Assisted Selection (MAS) and It's Application in Vegetable Crop Improvement

Vegetable crop breeding has changed dramatically since the early 1980s due to technological breakthroughs, especially high-throughput sequencing and molecular marker technologies, which have made it possible to sequence many plant genomes, create dense genetic maps, and identify important genes and QTLs linked to traits like yield and disease resistance. ..These instruments have expedited genetic research and breeding programs in crops including tomato, pepper, eggplant, and cucumber, establishing marker-assisted selection (MAS) as a crucial component of contemporary breeding. The use of these technologies has improved crop characteristics significantly and is still influencing the development of vegetable crops in the future. .. For instance, in the majority of private and public tomato breeding projects, major-gene disease resistance traits like verticillium wilt and anthracnose are selected for using PCR-based markers such as SCAR and CAPS.Bs5 and Bs6 have broad-spectrum resistance against Xanthomonas spp. against chilli leaf spot thanks to marker-assisted gene pyramiding. Major QTLs associated to SSR marker CAMS451 on chromosome 1 (from Capsicum accession LS2341) and marker ID10-194305124 on chromosome 10 (from C. annuum BVRC1) have been mapped for resistance to Ralstonia bacterial wilt.Constantly searching crop germplasm for new resistance genes or alleles is essential to diversify the gene pool and stop resistance from breaking down. By using marker-assisted selection (MAS), it is possible to combine genes for resistance to different pathogens or several sources of resistance to the same pathogen to create novel cultivars.

Research Progress of Bacillus subtilis in Wheat Growth Promotion and Disease Control

Wheat is one of the main food crops in the world, and its output is related to the world food security. In recent years, with the change of climate conditions and the overuse of chemical pesticides, the growing environment of wheat is facing severe challenges, and wheat diseases occur frequently, which seriously affects the growth and yield of wheat. As a new type of green growth promotion and control measures, biological control provides a more sustainable and environmentally friendly way for crops to cope with the challenges of the growing environment. Bacillus subtilis is a kind of PGPR widely found in plant rhizosphere soil. It has strong broad-spectrum antibacterial activity and resistance to stress. In this paper, the mechanism of Bacillus subtilis in promoting wheat growth and the control principle and effect of pathogenic bacteria in wheat were reviewed, and the existing problems were analyzed and prospected in order to provide reference for the application of Bacillus subtilis in agricultural field.

Improvement of Quality and Disease Resistance for a Heavy-Panicle Hybrid Restorer Line, R600, in Rice (Oryza sativa L.) by Gene Pyramiding Breeding.

The utilization of heavy-panicle hybrid rice exemplifies the successful integration of architectural enhancement and heterosis, which has been widely adopted in the southwest rice-producing area of China. Iterative improvement in disease resistance and grain quality of heavy-panicle hybrid rice varieties is crucial to promote their sustainable utilization. Here, we performed a molecular design breeding strategy to introgress beneficial alleles of broad-spectrum disease resistance and grain quality into a heavy-panicle hybrid backbone restorer line Shuhui 600 (R600). We successfully developed introgression lines through marker-assisted selection to pyramid major genes (Wxb + ALKA-GC + Pigm + Xa23) derived from three parents (Huanghuazhan, I135, I488), which significantly enhance grain quality and confer resistance to rice blast and bacterial blight (BB). The improved parental R600 line (iR600) exhibited superior grain quality and elevated disease resistance while maintaining the heavy-panicle architecture and high-yield capacity of R600. Moreover, the iR600 was crossed with male sterility line 608A to obtain a new heavy-panicle hybrid rice variety with excellent eating and cooking quality (ECQ) and high yield potential. This study presents an effective breeding strategy for rice breeders to expedite the improvement of grain quality and disease resistance in heavy-panicle hybrid rice.

Overexpression of plant chitin receptors in wheat confers broad-spectrum resistance to fungal diseases.

Wheat (Triticum aestivum L.) is a globally staple crop vulnerable to various fungal diseases, significantly impacting its yield. Plant cell surface receptors play a crucial role in recognizing pathogen-associated molecular patterns (PAMPs) and activating PAMP-triggered immunity, boosting resistance against a wide range of plant diseases. Although the role of plant chitin receptor CERK1 in immune recognition and defense has been established in Arabidopsis and rice, its function and potential agricultural applications in enhancing resistance to crop diseases remain largely unexplored. Here, we identify and characterize TaCERK1 in Triticeae crop wheat, uncovering its involvement in chitin recognition, immune regulation, and resistance to fungal diseases. By a comparative analysis of CERK1 homologs in Arabidopsis and monocot crops, we demonstrate that AtCERK1 in Arabidopsis elicits the most robust immune response. Moreover, we show that overexpressing TaCERK1 and AtCERK1 in wheat confers resistance to multiple fungal diseases, including Fusarium head blight, stripe rust, and powdery mildew. Notably, transgenic wheat lines with moderately expressed AtCERK1 display superior disease resistance and heightened immune responses without adversely affecting growth and yield, compared to TaCERK1 overexpression transgenics. Our findings highlight the significance of plant chitin receptors across diverse plant species and suggest potential strategies for bolstering crop resistance against broad-spectrum diseases in agricultural production through the utilization of plant immune receptors.

The Effects of Bacillus subtilis Expressing a Plant Elicitor Peptide on Nematode Infection on Soybean.

There is a pressing need to develop alternative management strategies for the soybean cyst nematode (Heterodera glycines), the most costly pathogen to soybeans. Plant elicitor peptides (PEPs), which are produced by plants in response to stress and stimulate broad-spectrum disease resistance, were previously shown to reduce soybean cyst nematode infection on soybeans when applied as a seed treatment. Here, we introduce an alternative method to deliver PEPs to soybean using a common plant growth-promoting rhizobacterium, Bacillus subtilis, as a bacterial expression system. Similar to the empty vector control, B. subtilis engineered to express a PEP from soybean (GmPEP3) was able to colonize soybean roots and persisted on roots more than a month after treatment. Compared with water or the empty vector control, plants that received a seed treatment with B. subtilis expressing GmPEP3 (B.+GmPEP3) were significantly taller early in vegetative growth (V1 stage) and had lower chlorophyll content in the reproductive stage (R3/R4); these results suggest that GmPEP3 may hasten growth and subsequent senescence. When plants were inoculated with soybean cyst nematode at the V1 stage, those pretreated with B.+GmPEP3 supported significantly fewer nematode eggs at the reproductive stage (R3/R4) than plants treated with water or the empty vector. The effects of B.+GmPEP3 on nematode infection and plant growth appeared to be due primarily to the peptide itself because no significant differences were observed between plants treated with water or with B. subtilis expressing the empty vector. These results indicate the ability of B. subtilis to deliver defense activators for nematode management on soybean.