Key message
We identified QTLs associated with gummy stem blight resistance in an interspecific F
2:3
Citrullus
population and developed marker assays for selection of the loci in watermelon.
Gummy ...stem blight (GSB), caused by three
Stagonosporopsis
spp., is a devastating fungal disease of watermelon (
Citrullus lanatus
) and other cucurbits that can lead to severe yield losses. Currently, no commercial cultivars with genetic resistance to GSB in the field have been reported. Utilizing GSB-resistant cultivars would reduce yield losses, decrease the high cost of disease control, and diminish hazards resulting from frequent fungicide application. The objective of this study was to identify quantitative trait loci (QTLs) associated with GSB resistance in an F
2:3
interspecific
Citrullus
mapping population (
N
= 178), derived from a cross between Crimson Sweet (
C. lanatus
) and GSB-resistant PI 482276 (
C. amarus
). The population was phenotyped by inoculating seedlings with
Stagonosporopsis citrulli
12178A in the greenhouse in two separate experiments, each with three replications. We identified three QTLs (
ClGSB3.1
,
ClGSB5.1
and
ClGSB7.1
) associated with GSB resistance, explaining between 6.4 and 21.1% of the phenotypic variation. The genes underlying
ClGSB5.1
includes an NBS-LRR gene (
ClCG05G019540
) previously identified as a candidate gene for GSB resistance in watermelon
.
Locus
ClGSB7.1
accounted for the highest phenotypic variation and harbors twenty-two candidate genes associated with disease resistance. Among them is
ClCG07G013230
, encoding an Avr9/Cf-9 rapidly elicited disease resistance protein, which contains a non-synonymous point mutation in the DUF761 domain that was significantly associated with GSB resistance. High throughput markers were developed for selection of
ClGSB5.1
and
ClGSB7.1.
Our findings will facilitate the use of molecular markers for efficient introgression of the resistance loci and development of GSB-resistant watermelon cultivars.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper investigates the prescribed performance fixed-time tracking control problem for a class of second-order nonlinear systems with bounded disturbance and actuator saturation limit. In order ...to facilitate the controller development, we introduce the performance function and output error transformation technique to transform the tracking error dynamics with inequality performance constraints to an equivalent unconstrained error one. Different from the existing work on the guaranteeing prescribed performance control, we incorporate the fixed-time sliding mode surface into the control design procedure to cope with the disturbances and actuator saturation limit. Specifically, a robust adaptive fixed-time tracking controller, which requires no upper bound of the disturbance, is designed to solve the prescribed performance fixed-time tracking control problem. The rigorous mathematical stability proof is given. Finally, numerical simulations for the attitude tracking control are presented to demonstrate the effectiveness and robustness of the proposed controller.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Modern tomatoes have narrow genetic diversity limiting their improvement potential. We present a tomato pan-genome constructed using genome sequences of 725 phylogenetically and geographically ...representative accessions, revealing 4,873 genes absent from the reference genome. Presence/absence variation analyses reveal substantial gene loss and intense negative selection of genes and promoters during tomato domestication and improvement. Lost or negatively selected genes are enriched for important traits, especially disease resistance. We identify a rare allele in the TomLoxC promoter selected against during domestication. Quantitative trait locus mapping and analysis of transgenic plants reveal a role for TomLoxC in apocarotenoid production, which contributes to desirable tomato flavor. In orange-stage fruit, accessions harboring both the rare and common TomLoxC alleles (heterozygotes) have higher TomLoxC expression than those homozygous for either and are resurgent in modern tomatoes. The tomato pan-genome adds depth and completeness to the reference genome, and is useful for future biological discovery and breeding.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The SWEET proteins are a group of sugar transporters that play a role in sugar efflux during a range of biological processes, including stress responses. However, there has been no comprehensive ...analysis of the SWEET family genes in Brassica oleracea (BoSWEET), and the evolutionary pattern, phylogenetic relationship, gene characteristics of BoSWEET genes and their expression patterns under biotic and abiotic stresses remain largely unexplored.
A total of 30 BoSWEET genes were identified and divided into four clades in B. oleracea. Phylogenetic analysis of the BoSWEET proteins indicated that clade II formed first, followed by clade I, clade IV and clade III, successively. Clade III, the newest clade, shows signs of rapid expansion. The Ks values of the orthologous SWEET gene pairs between B. oleracea and Arabidopsis thaliana ranged from 0.30 to 0.45, which estimated that B. oleracea diverged from A. thaliana approximately 10 to 15 million years ago. Prediction of transmembrane regions showed that eight BoSWEET proteins contain one characteristic MtN3_slv domain, twenty-one contain two, and one has four. Quantitative reverse transcription-PCR (qRT-PCR) analysis revealed that five BoSWEET genes from clades III and IV exhibited reduced expression levels under chilling stress. Additionally, the expression levels of six BoSWEET genes were up-regulated in roots of a clubroot-susceptible cabbage cultivar (CS-JF1) at 7 days after inoculation with Plasmodiophora brassicae compared with uninoculated plants, indicating that these genes may play important roles in transporting sugars into sink roots associated with P. brassicae colonization in CS-JF1. Subcellular localization analysis of a subset of BoSWEET proteins indicated that they are localized in the plasma membrane.
This study provides important insights into the evolution of the SWEET gene family in B. oleracea and other species, and represents the first study to characterize phylogenetic relationship, gene structures and expression patterns of the BoSWEET genes. These findings provide new insights into the complex transcriptional regulation of BoSWEET genes, as well as potential candidate BoSWEET genes that promote sugar transport to enhance chilling tolerance and clubroot disease resistance in cabbage.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In agricultural production, carbendazim and other pesticides are used to prevent soybean root rot. However, carbendazim degrades slowly and affects a series of biochemical processes such as soil ...biological nitrogen fixation and soil nutrient activation in the natural environment. This study mainly investigated the effects of Rhizophagus intraradices, Acinetobacter calcoaceticus, and carbendazim on soybean biomass, the incidence of root rot, the total number of bacterial colonies and phosphorus-solubilizing bacteria in rhizosphere soil, and carbendazim residue in soybean grains and rhizosphere soil. The results showed that the arbuscular mycorrhizal fungi (AMF) spore density, AMF infection rate, soybean biomass, nodule number, total bacterial colonies, and phosphorus-solubilizing bacteria colonies in the soybean rhizosphere soil were the highest in the R. intraradices and A. calcoaceticus treatment groups under natural soil conditions. Moreover, the incidence of root rot and carbendazim residue in soybean grains and rhizosphere soil were the lowest in the R. intraradices and A. calcoaceticus treatment group under natural soil conditions. This result indicated that R. intraradices and A. calcoaceticus can effectively reduce carbendazim residue in soybean grains and rhizosphere soil. This study provided theoretical support for the development of microbial fertilizer and microbial degradation of pesticide residues and improved the practical basis for ensuring food safety.
Deep-land resource exploitation is a crucial focus of future scientific and technological development in China. However, with the increasing depth of coal mining, rock burst disasters occur ...frequently, posing significant threats to the safe and efficient mining of coal mines. Therefore, it is of paramount importance to investigate mechanisms of rock burst, develop effective monitoring and warning systems, and explore techniques for pressure relief and shock reduction. This paper begins by summarizing the occurrence mechanisms of rock bursts in coal mines in chronological order and clarifying the interrelationships between these theories. Additionally, the paper presents a comprehensive summary of the mechanisms of rock bursts from a testing perspective, refining the understanding of their generation mechanisms and types. It emphasizes that the material effect and structure effect of coal and rock mass are key influencing factors in rock burst occurrences. Furthermore, the paper compares and analyzes the limitations of existing monitoring and warning by systems for rock bursts by various methods, such as microseismic monitoring, stress monitoring, electromagnetic radiation monitoring, and ground sound monitoring. Based on these findings, a proposed solution is presented: a big data analysis and comprehensive monitoring and early warning system that integrates temporally and spatially relevant precursor information using eigenvectors as weights. Lastly, the paper addresses the challenges faced in China in preventing and controlling rock bursts, including insufficient monitoring accuracy, difficulties in managing complex environments, inadequate optimization of relief and shock reduction schemes, and unsatisfactory support methods. Several suggestions are offered for future rock burst prevention and control efforts. The results of this study can provide valuable references for preventing rock bursts.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The
genus is home to a number of economically and culturally important species. We present the analysis of genotype data generated through genotyping-by-sequencing of the USDA germplasm collections ...of
,
, and
. These collections include a mixture of wild, landrace, and cultivated specimens from all over the world. Roughly 1,500 - 32,000 high-quality single nucleotide polymorphisms (SNPs) were called in each of the collections, which ranged in size from 314 to 829 accessions. Genomic analyses were conducted to characterize the diversity in each of the species. Analysis revealed extensive structure corresponding to a combination of geographical origin and morphotype/market class. Genome-wide associate studies (GWAS) were conducted using both historical and contemporary data. Signals were observed for several traits, but the strongest was for the bush (
) gene in
. Analysis of genomic heritability, together with population structure and GWAS results, was used to demonstrate a close alignment of seed size in
, maturity in
, and plant habit in
with genetic subgroups. These data represent a large, valuable collection of sequenced
that can be used to direct the maintenance of genetic diversity, for developing breeding resources, and to help prioritize whole-genome re-sequencing.
Sporangia of
from pure cultures on agar plates are typically used in lab studies, whereas sporangia from leaflet lesions drive natural infections and epidemics. Multiple assays were performed to ...determine if sporangia from these two sources are equivalent. Sporangia from plate cultures showed much lower rates of indirect germination and produced much less disease in field and moist-chamber tests. This difference in aggressiveness was observed whether the sporangia had been previously incubated at 4°C (to induce indirect germination) or at 21°C (to prevent indirect germination). Furthermore, lesions caused by sporangia from plates produced much less sporulation. RNA-Seq analysis revealed that thousands of the >17,000
genes with a RPKM (reads per kilobase of exon model per million mapped reads) >1 were differentially expressed in sporangia obtained from plate cultures of two independent field isolates compared with sporangia of those isolates from leaflet lesions. Among the significant differentially expressed genes (DEGs), putative RxLR effectors were overrepresented, with almost half of the 355 effectors with RPKM >1 being up- or downregulated. DEGs of both isolates include nine flagellar-associated genes, and all were down-regulated in plate sporangia. Ten elicitin genes were also detected as DEGs in both isolates, and nine (including INF1) were up-regulated in plate sporangia. These results corroborate previous observations that sporangia produced from plates and leaflets sometimes yield different experimental results and suggest hypotheses for potential mechanisms. We caution that use of plate sporangia in assays may not always produce results reflective of natural infections and epidemics.
In China, airports predominantly utilize airport cement concrete pavement, which inevitably undergoes deterioration in service. To uphold pavement durability and functionality, and ensure aircraft ...operational safety, prompt repairs of affected areas are imperative. Therefore, ordinary Portland cement mortars were used as the control group to compare and analyze the bonding performances of two common airport pavement repair materials: modified Portland cement mortars and phosphate cement mortars. Meanwhile, through microscopic experiments, the microscopic characteristics of the interfacial transition zone (ITZ) were studied, and the interface bonding mechanism was analyzed. The research results indicate that the interface bonding strength between phosphate cement mortar and old concrete pavement is the highest. This was because the elements in phosphate cement penetrated the old concrete pavement through hydration reactions, forming van der Waals forces and chemical bonding forces. In addition, the research results indicated that the presence of old concrete pavement made the three repair materials produce similar sidewall effects with the old concrete pavement, leading to a low hydration degree of the repair materials. However, the chemical bonding and penetrating structure of phosphate cement compensated for the weakening effect of the ITZ in the repair materials.
Germplasm collections are a crucial resource to conserve natural genetic diversity and provide a source of novel traits essential for sustained crop improvement. Optimal collection, preservation and ...utilization of these materials depends upon knowledge of the genetic variation present within the collection. Here we use the high-throughput genotyping-by-sequencing (GBS) technology to characterize the United States National Plant Germplasm System (NPGS) collection of cucumber (
L.). The GBS data, derived from 1234 cucumber accessions, provided more than 23 K high-quality single-nucleotide polymorphisms (SNPs) that are well distributed at high density in the genome (~1 SNP/10.6 kb). The SNP markers were used to characterize genetic diversity, population structure, phylogenetic relationships, linkage disequilibrium, and population differentiation of the NPGS cucumber collection. These results, providing detailed genetic analysis of the U.S. cucumber collection, complement NPGS descriptive information regarding geographic origin and phenotypic characterization. We also identified genome regions significantly associated with 13 horticulturally important traits through genome-wide association studies (GWAS). Finally, we developed a molecularly informed, publicly accessible core collection of 395 accessions that represents at least 96% of the genetic variation present in the NPGS. Collectively, the information obtained from the GBS data enabled deep insight into the diversity present and genetic relationships among accessions within the collection, and will provide a valuable resource for genetic analyses, gene discovery, crop improvement, and germplasm preservation.
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