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1.
Hortic Res ; 11(9): uhae199, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39263630

ABSTRACT

It is well known that if a fruit is harvested extremely early its development and function are interrupted, and it may never attain full maturity and optimal quality. Reports revealing insights regarding the alterations of maturation, ripening and postharvest quality in very early picked fruits are rare. We examined the effects of early harvesting on tomatoes by characterizing different accessions at the molecular, physiological, and biochemical levels. We found that even very early-harvested fruits could achieve postharvest maturation and ripening though with some defects in pigment and cuticle formation, and seeds from very early-harvested fruits could still germinate and develop as normal and healthy plants. One critical regulator of tomato cuticle integrity, SlCER1-2, was shown to contribute to cuticle defects in very early-harvested fruits. Very early fruit harvest still allowing ripening and seed development indicate that the genetic and physiological programs of later maturation and ripening are set into motion early in fruit development and are not dependent on complete fruit expansion nor attachment to the plant.

2.
Int J Mol Sci ; 25(17)2024 Aug 28.
Article in English | MEDLINE | ID: mdl-39273254

ABSTRACT

The fruit surface is a critical first line of defense against environmental stress. Overlaying the fruit epidermis is the cuticle, comprising a matrix of cutin monomers and waxes that provides protection and mechanical support throughout development. The epidermal layer of the cucumber (Cucumis sativus L.) fruit also contains prominent lipid droplets, which have recently been recognized as dynamic organelles involved in lipid storage and metabolism, stress response, and the accumulation of specialized metabolites. Our objective was to genetically characterize natural variations for traits associated with the cuticle and lipid droplets in cucumber fruit. Phenotypic characterization and genome-wide association studies (GWAS) were performed using a resequenced cucumber core collection accounting for >96% of the allelic diversity present in the U.S. National Plant Germplasm System collection. The collection was grown in the field, and fruit were harvested at 16-20 days post-anthesis, an age when the cuticle thickness and the number and size of lipid droplets have stabilized. Fresh fruit tissue sections were prepared to measure cuticle thickness and lipid droplet size and number. The collection showed extensive variation for the measured traits. GWAS identified several QTLs corresponding with genes previously implicated in cuticle or lipid biosynthesis, including the transcription factor SHINE1/WIN1, as well as suggesting new candidate genes, including a potential lipid-transfer domain containing protein found in association with isolated lipid droplets.


Subject(s)
Cucumis sativus , Fruit , Genome-Wide Association Study , Lipid Droplets , Quantitative Trait Loci , Cucumis sativus/genetics , Cucumis sativus/metabolism , Cucumis sativus/growth & development , Fruit/genetics , Fruit/metabolism , Lipid Droplets/metabolism , Phenotype , Polymorphism, Single Nucleotide , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Epidermis/genetics , Plant Epidermis/metabolism
3.
DNA Res ; 2024 Aug 26.
Article in English | MEDLINE | ID: mdl-39185728

ABSTRACT

Wild Malus species flourished in North America long before Europeans introduced domesticated apples. Malus coronaria and M. ioensis are native to the mid-western and eastern USA, while M. angustifolia and M. fusca grow in the southeast and west, respectively. They offer disease resistance, climate and soil adaptability, and horticultural traits for apple breeding. However, their utilization remains limited due to insufficient genomic resources and specific genetics. We report high-quality phased chromosome-scale assemblies of M. coronaria and M. ioensis, generated using long-read and conformation capture sequencing. Phylogenetic and synteny analysis indicated high relatedness between these two genomes and previously-published genome of M. angustifolia, and lower relatedness with M. fusca. Gene family-based pangenome of North American Malus identified 60,211 orthogroups containing 340,087 genes. Genes involved in basic cellular and metabolic processes, growth, and development were core to the existence of these species, whereas genes involved in secondary metabolism, stress response, and interactions with other organisms were accessory and are likely associated with adaptation to specific environments. Structural variation hotspots were mostly overlapping with high gene density. This study offers novel native North American Malus genome resources that can be used to identify genes for apple breeding and understand their evolution and adaptation.

4.
Sci Adv ; 10(31): eadp6436, 2024 Aug 02.
Article in English | MEDLINE | ID: mdl-39083610

ABSTRACT

Host range specificity is a prominent feature of the legume-rhizobial symbiosis. Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species that engage in root nodule symbiosis with legume plants of the Medicago genus, but certain Medicago species exhibit selectivity in their interactions with the two rhizobial species. We have identified a Medicago receptor-like kinase, which can discriminate between the two bacterial species, acting as a genetic barrier against infection by most S. medicae strains. Activation of this receptor-mediated nodulation restriction requires a bacterial gene that encodes a glycine-rich octapeptide repeat protein with distinct variants capable of distinguishing S. medicae from S. meliloti. This study sheds light on the coevolution of host plants and rhizobia, shaping symbiotic selectivity in their respective ecological niches.


Subject(s)
Symbiosis , Species Specificity , Medicago/microbiology , Sinorhizobium meliloti/genetics , Sinorhizobium meliloti/physiology , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Plant Proteins/metabolism , Plant Proteins/genetics , Root Nodules, Plant/microbiology , Root Nodules, Plant/metabolism , Protein Kinases/metabolism , Protein Kinases/genetics
5.
Plant J ; 119(5): 2363-2374, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38976445

ABSTRACT

Plants synthesize an array of volatile compounds, many of which serve ecological roles in attracting pollinators, deterring herbivores, and communicating with their surroundings. Methyl anthranilate (MeAA) is an anti-herbivory defensive volatile responsible for grape aroma that is emitted by several agriculturally relevant plants, including citrus, grapes, and maize. Unlike maize, which uses a one-step anthranilate methyltransferase (AAMT), grapes have been thought to use a two-step pathway for MeAA biosynthesis. By mining available transcriptomics data, we identified two AAMTs in Vitis vinifera (wine grape), as well as one ortholog in "Concord" grape. Many angiosperms methylate the plant hormone salicylic acid (SA) to produce methyl salicylate, which acts as a plant-to-plant communication molecule. Because the Citrus sinensis (sweet orange) SA methyltransferase can methylate both anthranilate (AA) and SA, we used this enzyme to examine the molecular basis of AA activity by introducing rational mutations, which identified several active site residues that increase activity with AA. Reversing this approach, we introduced mutations that imparted activity with SA in the maize AAMT, which uncovered different active site residues from those in the citrus enzyme. Sequence and phylogenetic analysis revealed that one of the Vitis AAMTs shares an ancestor with jasmonic acid methyltransferases, similar to the AAMT from strawberry (Frageria sp.). Collectively, these data demonstrate the molecular mechanisms underpinning AA activity across methyltransferases and identify one-step enzymes by which grapes synthesize MeAA.


Subject(s)
Citrus sinensis , Methyltransferases , Plant Proteins , Vitis , Zea mays , ortho-Aminobenzoates , Zea mays/genetics , Zea mays/metabolism , Vitis/genetics , Vitis/metabolism , ortho-Aminobenzoates/metabolism , Methyltransferases/genetics , Methyltransferases/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Citrus sinensis/genetics , Citrus sinensis/metabolism , Phylogeny , Gene Expression Regulation, Plant , Salicylic Acid/metabolism
6.
Plant Physiol ; 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39074178

ABSTRACT

Type 2C protein phosphatases (PP2Cs) constitute a large family in most plant species but relatively few of them have been implicated in immunity. To identify and characterize PP2C phosphatases that affect tomato (Solanum lycopersicum) immunity, we used CRISPR/Cas9 to generate loss-of-function mutations in 11 PP2C-encoding genes whose expression is altered in response to immune elicitors or pathogens. We report that two closely related PP2C phosphatases, Pic3 (PP2C immunity-associated candidate 3) and Pic12, are involved in regulating resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Loss-of-function mutations in Pic3 led to enhanced resistance to Pst in older but not younger leaves, whereas such mutations in Pic12 resulted in enhanced resistance in both older and younger leaves. Overexpression of Pic3 and Pic12 proteins in leaves of Nicotiana benthamiana inhibited resistance to Pst, and this effect was dependent on Pic3/12 phosphatase activity and an N-terminal palmitoylation motif associated with localization to the cell periphery. Pic3, but not Pic12, had a slight negative effect on flagellin-associated reactive oxygen species generation, although their involvement in the response to Pst appeared independent of flagellin. RNA-sequencing analysis of Rio Grande (RG)-PtoR wild-type plants and two independent RG-pic3 mutants revealed that the enhanced disease resistance in RG-pic3 older leaves is associated with increased transcript abundance of multiple defense related genes. RG-pic3/RG-pic12 double mutant plants exhibited stronger disease resistance than RG-pic3 or RG-pic12 single mutants. Together, our results reveal that Pic3 and Pic12 negatively regulate tomato immunity in an additive manner through flagellin-independent pathways.

7.
Front Plant Sci ; 15: 1419260, 2024.
Article in English | MEDLINE | ID: mdl-38863545

ABSTRACT

Garlic cultivars are predominantly characterized by their sterility and reliance on asexual reproduction, which have traditionally prevented the use of hybrid breeding for cultivar improvement in garlic. Our investigation has revealed a notable exception in the garlic line G398, which demonstrates the ability to produce fertile pollen. Notably, at the seventh stage of anther development, callose degradation in the sterile line G390 was impeded, while G398 exhibited normal callose degradation. Transcriptome profiling revealed an enhanced expression of the callose-degrading gene, AsaNRF1, in the mature flower buds of the fertile line G398 compared to the sterile line G390. An insertion in the promoter of AsaNRF1 in G390 was identified, which led to its reduced expression at the tetrad stage and consequently delayed callose degradation, potentially resulting in the male sterility of G390. A discriminatory marker was developed to distinguish between fertile G398 and sterile G390, facilitating the assessment of male fertility in garlic germplasm resources. This study introduces a practical approach to harnessing garlic hybridization, which can further facilitate the breeding of new cultivars and the creation of novel male-fertile garlic germplasm using modern molecular biology methods.

8.
Hortic Res ; 11(6): uhae100, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38863996

ABSTRACT

Horticultural crops comprising fruit, vegetable, ornamental, beverage, medicinal and aromatic plants play essential roles in food security and human health, as well as landscaping. With the advances of sequencing technologies, genomes for hundreds of horticultural crops have been deciphered in recent years, providing a basis for understanding gene functions and regulatory networks and for the improvement of horticultural crops. However, these valuable genomic data are scattered in warehouses with various complex searching and displaying strategies, which increases learning and usage costs and makes comparative and functional genomic analyses across different horticultural crops very challenging. To this end, we have developed a lightweight universal search engine, HortGenome Search Engine (HSE; http://hort.moilab.net), which allows for the querying of genes, functional annotations, protein domains, homologs, and other gene-related functional information of more than 500 horticultural crops. In addition, four commonly used tools, including 'BLAST', 'Batch Query', 'Enrichment analysis', and 'Synteny Viewer' have been developed for efficient mining and analysis of these genomic data.

9.
Sensors (Basel) ; 24(10)2024 May 16.
Article in English | MEDLINE | ID: mdl-38794027

ABSTRACT

The dependable functioning of switchgear is essential to maintain the stability of power supply systems. Partial discharge (PD) is a critical phenomenon affecting the insulation of switchgear, potentially leading to equipment failure and accidents. PDs are generally grouped into metal particle discharge, suspended discharge, and creeping discharge. Different types of PDs are closely related to the severity of a PD. Partial discharge pattern recognition (PDPR) plays a vital role in the early detection of insulation defects. In this regard, a Back Propagation Neural Network (BPNN) for PDPR in switchgear is proposed in this paper. To eliminate the sensitivity to initial values of BPNN parameters and to enhance the generalized ability of the proposed BPRN, an improved Mantis Search Algorithm (MSA) is proposed to optimize the BPNN. The improved MSA employs some boundary handling strategies and adaptive parameters to enhance the algorithm's efficiency in optimizing the network parameters of BPNN. Principal Component Analysis (PCA) is introduced to reduce the dimensionality of the feature space to achieve significant time saving in comparable recognition accuracy. The initially extracted 14 feature values are reduced to 7, reducing the BPNN parameter count from 183 with 14 features to 113 with 7 features. Finally, numerical results are presented and compared with Decision Tree (DT), k-Nearest Neighbor classifiers (KNN), and Support Vector Machine (SVM). The proposed method in this paper exhibits the highest recognition accuracy in metal particle discharge and suspended discharge.

10.
Plant Cell ; 36(9): 3237-3259, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-38801745

ABSTRACT

The F-box protein Coronatine Insensitive (COI) is a receptor for the jasmonic acid signaling pathway in plants. To investigate the functions of the 6 maize (Zea mays) COI proteins (COI1a, COI1b, COI1c, COI1d, COI2a, and COI2b), we generated single, double, and quadruple loss-of-function mutants. The pollen of the coi2a coi2b double mutant was inviable. The coi1 quadruple mutant (coi1-4x) exhibited shorter internodes, decreased photosynthesis, leaf discoloration, microelement deficiencies, and accumulation of DWARF8 and/or DWARF9, 2 DELLA family proteins that repress the gibberellic acid (GA) signaling pathway. Coexpression of COI and DELLA in Nicotiana benthamiana showed that the COI proteins trigger proteasome-dependent DELLA degradation. Many genes that are downregulated in the coi1-4x mutant are GA-inducible. In addition, most of the proteins encoded by the downregulated genes are predicted to be bundle sheath- or mesophyll-enriched, including those encoding C4-specific photosynthetic enzymes. Heterologous expression of maize Coi genes in N. benthamiana showed that COI2a is nucleus-localized and interacts with maize jasmonate zinc-finger inflorescence meristem domain (JAZ) proteins, the canonical COI repressor partners. However, maize COI1a and COI1c showed only partial nuclear localization and reduced binding efficiency to the tested JAZ proteins. Together, these results show the divergent functions of the 6 COI proteins in regulating maize growth and defense pathways.


Subject(s)
Gene Expression Regulation, Plant , Photosynthesis , Plant Proteins , Zea mays , Zea mays/genetics , Zea mays/metabolism , Zea mays/growth & development , Plant Proteins/metabolism , Plant Proteins/genetics , Photosynthesis/genetics , F-Box Proteins/metabolism , F-Box Proteins/genetics , Gibberellins/metabolism , Mutation , Signal Transduction , Oxylipins/metabolism , Nicotiana/genetics , Nicotiana/metabolism , Plants, Genetically Modified , Cyclopentanes
11.
New Phytol ; 242(5): 2285-2300, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38503725

ABSTRACT

Bottle gourd (Lagenaria siceraria (Mol.) Strandl.) is an economically important vegetable crop and one of the earliest domesticated crops. However, the population history and genomic diversification of bottle gourd have not been extensively studied. We generated a comprehensive bottle gourd genome variation map from genome sequences of 197 world-wide representative accessions, which enables a genome-wide association study for identifying genomic loci associated with resistance to zucchini yellow mosaic virus, and constructed a bottle gourd pangenome that harbors 1534 protein-coding genes absent in the reference genome. Demographic analyses uncover that domesticated bottle gourd originated in Southern Africa c. 12 000 yr ago, and subsequently radiated to the New World via the Atlantic drift and to Eurasia through the efforts of early farmers in the initial Holocene. The identified highly differentiated genomic regions among different bottle gourd populations harbor many genes contributing to their local adaptations such as those related to disease resistance and stress tolerance. Presence/absence variation analysis of genes in the pangenome reveals numerous genes including those involved in abiotic/biotic stress responses that have been under selection during the world-wide expansion of bottle gourds. The bottle gourd variation map and pangenome provide valuable resources for future functional studies and genomics-assisted breeding.


Subject(s)
Genetic Variation , Genome, Plant , Genomics , Genomics/methods , Cucurbitaceae/genetics , Phylogeny , Genetics, Population , Disease Resistance/genetics , Genes, Plant , Genome-Wide Association Study , Plant Diseases/virology , Plant Diseases/genetics
12.
Plant J ; 118(6): 2249-2268, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38430487

ABSTRACT

Melon (Cucumis melo L.), being under intensive domestication and selective breeding, displays an abundant phenotypic diversity. Wild germplasm with tolerance to stress represents an untapped genetic resource for discovery of disease-resistance genes. To comprehensively characterize resistance genes in melon, we generate a telomere-to-telomere (T2T) and gap-free genome of wild melon accession PI511890 (C. melo var. chito) with a total length of 375.0 Mb and a contig N50 of 31.24 Mb. The complete genome allows us to dissect genome architecture and identify resistance gene analogs. We construct a pan-NLRome using seven melon genomes, which include 208 variable and 18 core nucleotide-binding leucine-rich repeat receptors (NLRs). Multiple disease-related transcriptome analyses indicate that most up-regulated NLRs induced by pathogens are shell or cloud NLRs. The T2T gap-free assembly and the pan-NLRome not only serve as essential resources for genomic studies and molecular breeding of melon but also provide insights into the genome architecture and NLR diversity.


Subject(s)
Cucumis melo , Disease Resistance , Genome, Plant , Genome, Plant/genetics , Cucumis melo/genetics , Disease Resistance/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Diseases/genetics , NLR Proteins/genetics , NLR Proteins/metabolism , Cucurbitaceae/genetics
13.
Plant Physiol ; 195(1): 462-478, 2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38395446

ABSTRACT

Grape (Vitis vinifera) is one of the most widely cultivated fruits globally, primarily used for processing and fresh consumption. Seedless grapes are favored by consumers for their convenience, making the study of seedlessness a subject of great interest to scientists. To identify regulators involved in this process in grape, a monoclonal antibody (mAb)-array-based proteomics approach, which contains 21,120 mAbs, was employed for screening proteins/antigens differentially accumulated in grape during development. Differences in antigen signals were detected between seeded and seedless grapes revealing the differential accumulation of 2,587 proteins. After immunoblotting validation, 71 antigens were further immunoprecipitated and identified by mass spectrometry (MS). An in planta protein-protein interaction (PPI) network of those differentially accumulated proteins was established using mAb antibody by immunoprecipitation (IP)-MS, which reveals the alteration of pathways related to carbon metabolism and glycolysis. To validate our result, a seedless-related protein, DUF642 domain-containing protein (VvDUF642), which is functionally uncharacterized in grapes, was ectopically overexpressed in tomato (Solanum lycopersicum "MicroTom") and led to a reduction in seed production. PPI network indicated that VvDUF642 interacts with pectin acetylesterase (VvPAE) in grapes, which was validated by BiFC and Co-IP. As anticipated, overexpression of VvPAE substantially reduced seed production in tomato. Moreover, S. lycopersicum colourless non-ripening expression was altered in VvDUF642- and VvPAE-overexpressing plants. Taken together, we provided a high-throughput method for the identification of proteins involved in the seed formation process. Among those, VvDUF642 and VvPAE are potential targets for breeding seedless grapes and other important fruits in the future.


Subject(s)
Plant Proteins , Proteome , Seeds , Vitis , Vitis/metabolism , Vitis/genetics , Vitis/growth & development , Seeds/metabolism , Seeds/growth & development , Seeds/genetics , Plant Proteins/metabolism , Plant Proteins/genetics , Proteome/metabolism , Solanum lycopersicum/metabolism , Solanum lycopersicum/growth & development , Solanum lycopersicum/genetics , Antibodies, Monoclonal/metabolism , Proteomics/methods , Gene Expression Regulation, Plant , Protein Interaction Maps , Protein Array Analysis/methods
14.
Nucleic Acids Res ; 52(9): 4906-4921, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38407438

ABSTRACT

Eukaryotic genomes are spatially organized within the nucleus in a nonrandom manner. However, fungal genome arrangement and its function in development and adaptation remain largely unexplored. Here, we show that the high-order chromosome structure of Fusarium graminearum is sculpted by both H3K27me3 modification and ancient genome rearrangements. Active secondary metabolic gene clusters form a structure resembling chromatin jets. We demonstrate that these jet-like domains, which can propagate symmetrically for 54 kb, are prevalent in the genome and correlate with active gene transcription and histone acetylation. Deletion of GCN5, which encodes a core and functionally conserved histone acetyltransferase, blocks the formation of the domains. Insertion of an exogenous gene within the jet-like domain significantly augments its transcription. These findings uncover an interesting link between alterations in chromatin structure and the activation of fungal secondary metabolism, which could be a general mechanism for fungi to rapidly respond to environmental cues, and highlight the utility of leveraging three-dimensional genome organization in improving gene transcription in eukaryotes.


Subject(s)
Chromatin , Chromosomes, Fungal , Fusarium , Secondary Metabolism , Acetylation , Chromatin/metabolism , Chromatin/genetics , Chromosomes, Fungal/genetics , Chromosomes, Fungal/metabolism , Fungal Proteins/metabolism , Fungal Proteins/genetics , Fusarium/genetics , Fusarium/metabolism , Gene Expression Regulation, Fungal , Genome, Fungal , Histone Acetyltransferases/metabolism , Histone Acetyltransferases/genetics , Histones/metabolism , Histones/genetics , Multigene Family , Secondary Metabolism/genetics , Transcription, Genetic
15.
Plant Commun ; 5(2): 100791, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38168637

ABSTRACT

The domestication of Brassica oleracea has resulted in diverse morphological types with distinct patterns of organ development. Here we report a graph-based pan-genome of B. oleracea constructed from high-quality genome assemblies of different morphotypes. The pan-genome harbors over 200 structural variant hotspot regions enriched in auxin- and flowering-related genes. Population genomic analyses revealed that early domestication of B. oleracea focused on leaf or stem development. Gene flows resulting from agricultural practices and variety improvement were detected among different morphotypes. Selective-sweep and pan-genome analyses identified an auxin-responsive small auxin up-regulated RNA gene and a CLAVATA3/ESR-RELATED family gene as crucial players in leaf-stem differentiation during the early stage of B. oleracea domestication and the BoKAN1 gene as instrumental in shaping the leafy heads of cabbage and Brussels sprouts. Our pan-genome and functional analyses further revealed that variations in the BoFLC2 gene play key roles in the divergence of vernalization and flowering characteristics among different morphotypes, and variations in the first intron of BoFLC3 are involved in fine-tuning the flowering process in cauliflower. This study provides a comprehensive understanding of the pan-genome of B. oleracea and sheds light on the domestication and differential organ development of this globally important crop species.


Subject(s)
Brassica , Domestication , Brassica/genetics , Genomics , Genome, Plant/genetics , Indoleacetic Acids
16.
Front Plant Sci ; 14: 1281755, 2023.
Article in English | MEDLINE | ID: mdl-38046614

ABSTRACT

Phytophthora fruit rot (PFR) caused by the soilborne oomycete pathogen, Phytophthora capsici, can cause severe yield loss in cucumber. With no resistant variety available, genetic resources are needed to develop resistant varieties. The goal of this work was to identify quantitative trait loci (QTL) associated with resistance to PFR using multiple genomic approaches and populations. Two types of resistances have been identified: age-related resistance (ARR) and young fruit resistance. ARR occurs at 12-16 days post pollination (dpp), coinciding with the end of exponential fruit growth. A major QTL for ARR was discovered on chromosome 3 and a candidate gene identified based on comparative transcriptomic analysis. Young fruit resistance, which is observed during the state of rapid fruit growth prior to commercial harvest, is a quantitative trait for which multiple QTL were identified. The largest effect QTL, qPFR5.1, located on chromosome 5 was fine mapped to a 1-Mb region. Genome-wide association studies (GWAS) and extreme-phenotype genome-wide association study (XP-GWAS) for young fruit resistance were also performed on a cucumber core collection representing > 96% of the genetic diversity of the USDA cucumber germplasm. Several SNPs overlapped with the QTL identified from QTL-seq analysis on biparental populations. In addition, novel SNPs associated with the resistance were identified from the germplasm. The resistant alleles were found mostly in accessions from India and South Asia, the center of diversity for cucumber. The results from this work can be applied to future disease resistance studies and marker-assisted selection in breeding programs.

17.
BMC Plant Biol ; 23(1): 651, 2023 Dec 18.
Article in English | MEDLINE | ID: mdl-38110861

ABSTRACT

BACKGROUND: Geminiviruses are DNA plant viruses that cause highly damaging diseases affecting crops worldwide. During the infection, geminiviruses hijack cellular processes, suppress plant defenses, and cause a massive reprogramming of the infected cells leading to major changes in the whole plant homeostasis. The advances in sequencing technologies allow the simultaneous analysis of multiple aspects of viral infection at a large scale, generating new insights into the molecular mechanisms underlying plant-virus interactions. However, an integrative study of the changes in the host transcriptome, small RNA profile and methylome during a geminivirus infection has not been performed yet. Using a time-scale approach, we aim to decipher the gene regulation in tomato in response to the infection with the geminivirus, tomato yellow leaf curl virus (TYLCV). RESULTS: We showed that tomato undergoes substantial transcriptional and post-transcriptional changes upon TYLCV infection and identified the main altered regulatory pathways. Interestingly, although the principal plant defense-related processes, gene silencing and the immune response were induced, this cannot prevent the establishment of the infection. Moreover, we identified extra- and intracellular immune receptors as targets for the deregulated microRNAs (miRNAs) and established a network for those that also produced phased secondary small interfering RNAs (phasiRNAs). On the other hand, there were no significant genome-wide changes in tomato methylome at 14 days post infection, the time point at which the symptoms were general, and the amount of viral DNA had reached its maximum level, but we were able to identify differentially methylated regions that could be involved in the transcriptional regulation of some of the differentially expressed genes. CONCLUSION: We have conducted a comprehensive and reliable study on the changes at transcriptional, post-transcriptional and epigenetic levels in tomato throughout TYLCV infection. The generated genomic information is substantial for understanding the genetic, molecular and physiological changes caused by TYLCV infection in tomato.


Subject(s)
Begomovirus , Geminiviridae , Solanum lycopersicum , Solanum lycopersicum/genetics , Begomovirus/physiology , Gene Silencing , Geminiviridae/genetics , Plant Diseases
18.
G3 (Bethesda) ; 14(1)2023 Dec 29.
Article in English | MEDLINE | ID: mdl-37936323

ABSTRACT

Apple scab, a fungal disease caused by Venturia inaequalis, leads to losses in both yield and fruit quality of apples (Malus domestica Borkh.). Most commercial apple cultivars, including those containing the well-characterized Rvi6-scab-resistance locus on linkage group (LG) 1, are susceptible to scab. HcrVf2 and HcrVf1 are considered the main paralogs of the Rvi6 locus. The major apple scab-resistance loci Vhc1 in "Honeycrisp" and Rvi17 in "Antonovka," were identified in close proximity to HcrVf2. In this study, we used long-read sequencing and in silico gene sequence characterization to identify candidate resistance genes homologous to HcrVf2 and HcrVf1 in Honeycrisp and Antonovka. Previously published chromosome-scale phased assembly of Honeycrisp and a newly assembled phased genome of Antonovka 172670-B were used to identify HcrVf2 and HcrVf1 homologs spanning Vhc1 and Rvi17 loci. In combination with 8 available Malus assemblies, 43 and 46 DNA sequences highly homologous to HcrVf2 and HcrVf1, respectively, were identified on LG 1 and 6, with identity and coverage ranging between 87-95 and 81-95%, respectively. Among these homologs, 2 candidate genes in Antonovka and Honeycrisp haplome A are located in close physical proximity to the scab-resistance marker Ch-Vf1 on LG 1. They showed the highest identity and coverage (95%) of HcrVf2 and only minor changes in the protein motifs. They were identical by state between each other, but not with HcrVf2. This study offers novel genomic resources and insights into the Vhc1 and Rvi17 loci on LG 1 and identifies candidate genes for further resistance characterization.


Subject(s)
Ascomycota , Malus , Malus/metabolism , Genes, Plant , Chromosomes , Ascomycota/genetics , Plant Diseases/genetics , Plant Diseases/microbiology
20.
Plant Direct ; 7(10): e532, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37794882

ABSTRACT

Sweetpotato, Ipomoea batatas (L.), a key food security crop, is negatively impacted by heat, drought, and salinity stress. The orange-fleshed sweetpotato cultivar "Beauregard" was exposed to heat, salt, and drought treatments for 24 and 48 h to identify genes responding to each stress condition in leaves. Analysis revealed both common (35 up regulated, 259 down regulated genes in the three stress conditions) and unique sets of up regulated (1337 genes by drought, 516 genes by heat, and 97 genes by salt stress) and down regulated (2445 genes by drought, 678 genes by heat, and 204 genes by salt stress) differentially expressed genes (DEGs) suggesting common, yet stress-specific transcriptional responses to these three abiotic stressors. Gene Ontology analysis of down regulated DEGs common to both heat and salt stress revealed enrichment of terms associated with "cell population proliferation" suggestive of an impact on the cell cycle by the two stress conditions. To identify shared and unique gene co-expression networks under multiple abiotic stress conditions, weighted gene co-expression network analysis was performed using gene expression profiles from heat, salt, and drought stress treated 'Beauregard' leaves yielding 18 co-expression modules. One module was enriched for "response to water deprivation," "response to abscisic acid," and "nitrate transport" indicating synergetic crosstalk between nitrogen, water, and phytohormones with genes encoding osmotin, cell expansion, and cell wall modification proteins present as key hub genes in this drought-associated module. This research lays the groundwork for exploring to a further degree, mechanisms for abiotic stress tolerance in sweetpotato.

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