Criollo De Morelos-334 Research Articles

Quantitative Trait Loci Controlling Fruit Size and Other Horticultural Traits in Bell Pepper (Capsicum annuum).

Bell pepper ( L.) is a group of fruit vegetables that has large variation in fruit shape, fruit size, and horticultural traits. Using unadapted sources of germplasm to bring in novel alleles while maintaining favorable quality and horticultural traits is challenging for breeding in pepper. A genetic map with 318 loci from genotype-by-sequencing (GBS) and single nucleotide polymorphism assays was generated from a recombinant inbred line population derived from a cultivated bell-type 'Maor' and a landrace highly resistant to , 'Criollo de Morelos-334'. Forty-nine quantitative trait loci (QTLs) were detected for fruit, leaf, and horticultural traits with the scantwo permutation and stepwiseqtl methods from R/qtl. With the availability of a pepper reference genome and GBS data, candidate genes for pepper organ size and other horticultural traits were predicted. , , and genes were candidate genes for controlling organ sizes on chromosome 1, 2, and 3, respectively. Two candidate genes controlling trichome formation in pepper are located at chromosome 10: and . The locus on chromosome 10, which encodes a member of the R2R3 MYB-domain family of proteins, has a function in anthocyanin accumulation. These QTL results and the candidate genes for each trait emphasize the genetic basis of the important traits for breeding with unadapted parents in bell pepper.

Heterosis and combining ability in bell pepper lines with resistance to multiple pathogens

ABSTRACT The aim of this study was to develop bell pepper hybrids with resistance to multiple pathogens and make inferences in regard to components of heterosis in hybrids obtained from lines presumed to be resistant to Pepper yellow mosaic virus (PepYMV), Phytophthora capsici, or Meloidogyne incognita. The studies were carried out in a greenhouse. We used ten lines, thirty experimental hybrids, and seven controls (Konan-R, Magali-R, Martha-R, Stephany, Mallorca, Magnata Super, and Criollo de Morelos-334). For all experiments, a randomized block design was used with three replications (with plots composed of 16 plants). For evaluation of the reactions to P. capsici and to PepYMV, the percentages of asymptomatic plants were considered. For evaluation of the reactions to M. incognita, the reproduction index and the reproduction factor of the nematode were calculated. The additive gene effects were important for all the traits evaluated, and for percentage of plants resistant to PepYMV and P. capsici, the non-additive effects were also important. The alleles that control resistance to PepYMV, to P. capsici, and to M. incognita have a degree of dominance near 1, in absolute value, which indicates a favorable situation for obtaining hybrids that accumulate multiple resistance to these pathogens.

Assessment of resistances to multiple pathogens in experimental sweet pepper hybrids

The aim of this study was to assess resistance to major sweet pepper pathogens ( Phytophthora capsici, Pepper yellow mosaic virus – PepYMV and Meloidogyne incognita ) in a group of experimental hybrids and their respective parental lines, and to identity hybrids possibly resistant to all three pathogens. Ten parental breeding lines, thirty experimental hybrids and seven commercial controls (Konan-R, Magali-R, Martha-R, Stephany, Mallorca, Magnata Super and Criollo de Morelos-334) were used. Each experiment was set up in a randomized complete block design with three replications. For assessment of resistance to P. capsici and PepYMV, the percent of asymptomatic plants was considered. In evaluating reactions to M. incognita, both the nematode reproduction index and the nematode reproduction factor were calculated. Five hybrids were found with resistant to all three pathogens. For all three pathogens, there was evidence that hybrids with two resistant parental lines showed slightly higher levels of pathogen resistance than those with only one resistant parental line.

Assessment of resistances to multiple pathogens in experimental sweet pepper hybrids

ABSTRACT The aim of this study was to assess resistance to some of the major sweet pepper pathogens {Phytophthora capsici, Pepper yellow mosaic virus (PepYMV) and Meloidogyne incognita} in a group of experimental hybrids and their respective parental lines, and to identify hybrids possibly resistant to all three pathogens. Ten parental breeding lines, thirty experimental hybrids and seven commercial controls (Konan-R, Magali-R, Martha-R, Stephany, Mallorca, Magnata Super and Criollo de Morelos-334) were used. Each experiment was set up in a randomized complete block design with three replications and plots consisting of 16 plants. For assessment of resistance to P. capsici and PepYMV, the percent of asymptomatic plants was considered. In evaluating reactions to M. incognita, both the nematode reproduction index and the nematode reproduction factor were calculated. Five hybrids were found with resistance to all three pathogens. For all three pathogens, there was evidence that hybrids with two resistant parental lines showed slightly higher levels of pathogen resistance than those with only one resistant parental line.

Seleção assistida com uso de marcador molecular para resistência a potyvírus em pimentão

O objetivo deste trabalho foi determinar a presença do alelo Pvr4, que confere resistência contra o PepYMV (Pepper yellow mosaic virus), em genótipos de pimentão comunmente encontrados no mercado brasileiro, com uso de um marcador molecular codominante tipo CAPS. A resistência ao PepYMV, nos genótipos CM-334-INRA, Myr-29 e em genótipos derivados do híbrido comercial Mônica-R, foi detectada como associada à banda de 444 pb, ligada ao alelo de resistência Pvr4. As plantas resistentes homozigotas (pvr4/pvr4) mostraram uma banda de 444 pb, as suscetíveis (Pvr4+/Pvr4+) uma banda de 458 pb e as resistentes heterozigotas (Pvr4+/Pvr4) mostraram as duas bandas. No entanto, no acesso resistente CM-334-UFV, nos híbridos Magali-R e Martha-R, assim como em populações derivadas desse acesso e desses híbridos, a resistência ao PepYMV não esteve associada ao marcador CAPS. O acesso CM-334-UFV ('Criollo de Morelos-334', de Viçosa, MG) distinguiu-se do CM-334-INRA ('Criollo de Morelos-334', da França); embora ambos os acessos tenham sido resistentes ao PepYMV, apenas em CM-334-INRA foi encontrada a associação da resistência com a banda de 444 pb.

De novo assembly of the pepper transcriptome (Capsicum annuum): a benchmark for in silico discovery of SNPs, SSRs and candidate genes

BackgroundMolecular breeding of pepper (Capsicum spp.) can be accelerated by developing DNA markers associated with transcriptomes in breeding germplasm. Before the advent of next generation sequencing (NGS) technologies, the majority of sequencing data were generated by the Sanger sequencing method. By leveraging Sanger EST data, we have generated a wealth of genetic information for pepper including thousands of SNPs and Single Position Polymorphic (SPP) markers. To complement and enhance these resources, we applied NGS to three pepper genotypes: Maor, Early Jalapeño and Criollo de Morelos-334 (CM334) to identify SNPs and SSRs in the assembly of these three genotypes.ResultsTwo pepper transcriptome assemblies were developed with different purposes. The first reference sequence, assembled by CAP3 software, comprises 31,196 contigs from >125,000 Sanger-EST sequences that were mainly derived from a Korean F1-hybrid line, Bukang. Overlapping probes were designed for 30,815 unigenes to construct a pepper Affymetrix GeneChip® microarray for whole genome analyses. In addition, custom Python scripts were used to identify 4,236 SNPs in contigs of the assembly. A total of 2,489 simple sequence repeats (SSRs) were identified from the assembly, and primers were designed for the SSRs. Annotation of contigs using Blast2GO software resulted in information for 60% of the unigenes in the assembly. The second transcriptome assembly was constructed from more than 200 million Illumina Genome Analyzer II reads (80–120 nt) using a combination of Velvet, CLC workbench and CAP3 software packages. BWA, SAMtools and in-house Perl scripts were used to identify SNPs among three pepper genotypes. The SNPs were filtered to be at least 50 bp from any intron-exon junctions as well as flanking SNPs. More than 22,000 high-quality putative SNPs were identified. Using the MISA software, 10,398 SSR markers were also identified within the Illumina transcriptome assembly and primers were designed for the identified markers. The assembly was annotated by Blast2GO and 14,740 (12%) of annotated contigs were associated with functional proteins.ConclusionsBefore availability of pepper genome sequence, assembling transcriptomes of this economically important crop was required to generate thousands of high-quality molecular markers that could be used in breeding programs. In order to have a better understanding of the assembled sequences and to identify candidate genes underlying QTLs, we annotated the contigs of Sanger-EST and Illumina transcriptome assemblies. These and other information have been curated in a database that we have dedicated for pepper project.

A Rapid Technique for Multiple-race Disease Screening of Phytophthora Foliar Blight on Single Capsicum annuum L. Plants

Phytophthora blight, caused by the oomycete Phytophthora capsici Leon., is a major disease that threatens production and long-term viability of the chile pepper (Capsicum annuum L.) industry. For each phytophthora disease syndrome such as root rot, foliar blight, and stem blight separate and independent resistant systems have evolved in the host. In addition, several physiological races of the pathogen have been identified. A novel, effective, and accurate screening technique is described that allows for multiple races to be evaluated on a single plant of C. annuum. The P. capsici resistant line Criollo de Morelos-334, a susceptible cultivar, Camelot, and three New Mexico Recombinant Inbred Lines, -F, -I, -S, were used to evaluate the new technique for phytophthora foliar blight multiple-race screening. Using three P. capsici physiological races, no interaction among the physiological races was observed with this technique. This novel technique provided a rapid disease screen evaluating multiple physiological races for phytophthora foliar blight resistance in a single chile pepper plant and can assist plant breeders in selecting for disease-resistant plants.

Fine mapping of pepper trichome locus 1 controlling trichome formation in Capsicum annuum L. CM334

Trichomes are present on nearly all land plants and protect plants against insect herbivores, drought and UV radiation. The trichome-bearing phenotype is conferred by the dominant allele of the pepper trichome locus 1 (Ptl1) in Capsicum annuum, Mexican 'Criollo de Morelos-334' (CM334). A genetic analysis using simple sequence repeats from pepper cDNA identified the HpmsE031 marker as tightly linked to Ptl1 in 653 individuals of an F(2) population derived from a cross between CM334 and Chilsungcho varieties. A bacterial artificial chromosome (BAC) library from CM334 covering 12x of the genome was screened using the HpmsE031 SSR marker as a probe and three BAC clones were identified. The Ptl1 region was covered by one 80 kb BAC clone, TT1B7. Fluorescence in situ hybridization (FISH) confirmed that TT1B7 localized to pepper chromosome 10. One co-dominant marker, Tco, and one dominant marker, Tsca, were successfully developed from the TT1B7 BAC sequence. Tco mapped 0.33 cM up from Ptl1 and Tsca mapped 0.75 cM down from Ptl1. Analysis of the BAC sequence predicts the presence of 14 open reading frames including 60S ribosomal protein L21-like protein (Solanum demissum), protein kinase 2 (Nicotiana tabacum), hypothetical proteins, and unnamed protein products. These results will provide not only useful information for map-based cloning of Ptl1 in Capsicum but also the starting points for analysis of R-gene cluster inked with Ptl1.

Gene expression profiles unique to chile ( Capsicum annuum L.) resistant to Phytophthora root rot

Transcriptome profiling in chile ( Capsicum annuum) roots was used to determine those genes with expression profiles correlated with a resistance phenotype to the pathogen, Phytophthora capsici. Two microarrays were generated; a 10K element array printed with cDNAs from a library of transcripts expressed in Criollo de Morelos-334 variety of C. annuum 6 h post-challenge with P. capsici and a 2K element array printed with sequenced cDNA clones selected based on their preliminary patterns of expression. This second array was enriched for clones that were differentially expressed in susceptible (New Mexico 6-4) vs. resistant (CM334) varieties of C. annuum. Gene expression profiles were revaluated at 0, 4 and 24 h post-inoculation. Control treatments included samples collected at 0, 4, and 24 h post-mock-inoculation. In addition to the parental CM334, a resistant backcross line (01-1688) was also used to identify gene expression patterns associated with the resistance phenotype. Based on a principal component analysis, CM334 samples showed the most significant transcription induction at 4 and 24 h post-inoculation, while the predominant variability in the susceptible line was in genes repressed at 24 h. A set of 168 genes with significant changes in expression following P. capsici challenge was identified; of these, 22 were uniquely expressed only in the resistant lines (CM334 or 01-1688). This set of genes represent candidates for further study as markers for recurrent selection programs and as candidate genes for the mechanism of disease resistance.

Genetic Analysis of Phytophthora Root Rot Race-specific Resistance in Chile Pepper

Phytophthora capsici Leon., causal agent of phytophthora root rot, is one of the most devastating pathogens attacking chile pepper (Capsicum annuum L.) plants. Many studies have tried to better understand phytophthora resistance, but the genetic behavior is not completely understood. To determine if phytophthora root rot resistance in chile pepper is controlled by multiple alleles at a few loci, or multiple genes at different loci, five recombinant inbred lines (RILs) were evaluated. The resistant accession, Criollo de Morelos-334, and the susceptible cultivar, Early Jalapeno, were hybridized to develop multiple RILs. After seven generations of selfing using the single seed descent method, four RILs were selected based on their phenotypic response to inoculation by five P. capsici isolates. The RILs were hybridized to each other to obtain F1 and F2 populations. The F2 populations were inoculated with single and a pair of races of P. capsici. When the F2 populations were inoculated with a single race, ratios of three resistant:one susceptible were obtained in the majority of the populations, indicating the action of an independent single gene. When the F2 populations were inoculated with a combination of two races, segregation ratios of 15 resistant:one susceptible were observed in two populations out of the four populations. The presence of susceptible individuals in all of the F2 population indicates that the resistant genes for the different P. capsici races are located at different loci. However, the rejection of the segregation ratio in one of the F2 population under a single race inoculation and in two of the F2 populations challenged with a combination of two races suggest a linkage phenomenon between some of the R genes. None of the RILs evaluated in this study displayed allelism for phytophthora root rot resistance.

Recombinant Inbred Line Differential Identifies Race-Specific Resistance to Phytophthora Root Rot in Capsicum annuum

A differential series is the normal method for identification of races within a plant pathogen and a host interaction. A host differential is extremely useful for phytopathological as well as breeding purposes. A set of recombinant inbred lines (RILs) were developed and characterized for race differentiation of Phytophthora root rot caused by Phytophthora capsici. The highly resistant Capsicum annuum accession Criollo de Morelos-334 was hybridized to a susceptible cultivar, Early Jalapeno, to generate the RIL population. The host differential characterized 17 isolates of P. capsici into 13 races. The establishment of a stable host differential for the P. capsici and C. annuum interaction will assist researchers in understanding the complex inheritance of resistance to Phytophthora root rot and to develop resistant cultivars.

Pepper morphological traits related with resistance to Phytophthora capsici

Inheritance of 10 morphological and quantitative traits related to plant and fruit development and resistance to the pathogen Phytophthora capsici was studied in an intraspecific cross between a non-pungent, susceptible Capsicum annuum parent (cv. Americano) and a wild, pungent and resistant line (Serrano Criollo de Morelos-334). Data were obtained from the segregation of 166 F2 plants and 50 F3 plants in four years. Three of the traits analyzed (necrosis length, leaf width and leaf length) exhibited a transgressive segregation. A multiple linear regression analysis was applied in order to establish a relationship between necrosis length and some of the morphological traits measured such as length and width of leaf, length, diameter and mass of fruit, capsaicin content in fruits, and presence of hair on leaves and stems. The results identified a linear dependence between necrosis length (as an inverse measurement of resistance) and leaf width, fruit diameter and hair presence in the stem. Pungency was not related with resistance.

New inheritance studies related to Potato Virus Y (PVY) resistance in Capsicum annuum L. ‘Serrano Criollo de Morelos-334’

C. annuum L. ‘Serrano Criollo de Morelos-334’ (SCM-334) is a well-known source of resistance against pepper diseases, including Potato Virus Y (PVY). In this work, inheritance studies involving ‘SCM-334’ and related to PVY resistance were described. For this purpose, ‘SCM-334’ derived lines were used, and plant material from the cross between ‘SCM-334’ and ‘Yolo Wonder’ (YW) was employed as well. Five PVY isolates were used for the inoculations. The first resistance described is a monogenic and recessive gene, controlling a specific-isolate resistance, and provisionally named as pvr14. The second one is related to the inheritance of systemic necrotic symptoms after PVY inoculation. In this case a codominant gene is proposed and expressed only when the Pvr4 gene is not present.

Development of RAPD and SCAR markers linked to the Pvr4 locus for resistance to PVY in pepper ( Capsicum annuum L.).

Potato Virus Y (PVY) is the only potyvirus infecting pepper ( Capsicum annuum L.) in Europe. Currently, the development of pepper varieties resistant to PVY seems to be the most-efficient method to control PVY damage. Among the sources of resistance, a monogenic dominant gene Pvr4 confers resistance against all known PVY pathotypes. In this work, bulked segregant analysis (BSA) was used to search for randomly amplified polymorphic DNA (RAPD) markers linked to the Pvr4 gene, using segregating progenies obtained by crossing a homozygous resistant ('Serrano Criollo de Morelos-334') with a homozygous susceptible ('Yolo Wonder') cultivar. Eight hundred decamer primers were screened to identify one RAPD marker (UBC19(1432)) linked in repulsion phase to Pvr4. This marker was converted into a dominant sequence characterised amplified region (SCAR) marker (SCUBC19(1423)). This marker was mapped into a dense Capsicum genetic map in a region where several genes for resistance to different diseases are located. This marker can be useful to identify PVY-resistant genotypes in segregating progenies of pepper in marker-assisted selection (MAS) breeding programs.

Inheritance of Phytophthora Root Rot and Foliar Blight Resistance in Pepper

The inheritance of resistance to Phytophthora capsici Leonian root rot and foliar blight was compared in two different Capsicum annuum L. var. annuum pod types. The seedling was screened for phytophthora root rot, while a genetically identical stem cutting was screened for phytophthora foliar blight to determine if the same gene(s) confer resistance to both disease syndromes. The susceptible parents were `Keystone Resistant Giant #3' (`Keystone'), a bell pepper type, and `Early Jalapeño', while `Criollo de Morelos-334' was the resistant parent. Resistance was observed in both F1 populations screened for phytophthora root and foliar infection indicating dominance for resistance. Reciprocal effects were not detected. To determine if the same gene(s) conferred root rot and foliar resistance, root rot screening results were matched to the corresponding foliar blight stem cutting reaction. The segregation of resistance in the F2 generations was dependent on the susceptible parent. In the F2 generation derived from `Early Jalapeño', root rot resistance and foliar blight resistance segregated in a 9:3:3:1 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. One independent, dominant gene was necessary for root rot resistance, and a different independent, dominant gene was needed for foliar blight resistance. In the F2 generation derived from `Keystone', root rot and foliar blight resistance segregated in a 7:2:2:5 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. This segregation ratio is expected when one dominant gene is required for root resistance, and a different dominant gene is required for foliar resistance. In addition to these two genes, at least one dominant allele of a third gene must be present for expression of root rot and foliar blight resistance.