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1.
J Integr Plant Biol ; 66(3): 484-509, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38456625

RESUMO

Brassica napus, commonly known as rapeseed or canola, is a major oil crop contributing over 13% to the stable supply of edible vegetable oil worldwide. Identification and understanding the gene functions in the B. napus genome is crucial for genomic breeding. A group of genes controlling agronomic traits have been successfully cloned through functional genomics studies in B. napus. In this review, we present an overview of the progress made in the functional genomics of B. napus, including the availability of germplasm resources, omics databases and cloned functional genes. Based on the current progress, we also highlight the main challenges and perspectives in this field. The advances in the functional genomics of B. napus contribute to a better understanding of the genetic basis underlying the complex agronomic traits in B. napus and will expedite the breeding of high quality, high resistance and high yield in B. napus varieties.


Assuntos
Brassica napus , Brassica napus/genética , Locos de Características Quantitativas/genética , Melhoramento Vegetal , Genômica , Fenótipo
2.
Plant Commun ; 5(4): 100884, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38494786

RESUMO

Rapeseed (Brassica napus L.) is one of the major global sources of edible vegetable oil and is also used as a feed and pioneer crop and for sightseeing and industrial purposes. Improvements in genome sequencing and molecular marker technology have fueled a boom in functional genomic studies of major agronomic characters such as yield, quality, flowering time, and stress resistance. Moreover, introgression and pyramiding of key functional genes have greatly accelerated the genetic improvement of important traits. Here we summarize recent progress in rapeseed genomics and genetics, and we discuss effective molecular breeding strategies by exploring these findings in rapeseed. These insights will extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process, ultimately contributing to more sustainable agriculture throughout the world.


Assuntos
Brassica napus , Brassica napus/genética , Locos de Características Quantitativas , Embaralhamento de DNA , Melhoramento Vegetal , Genômica
3.
Theor Appl Genet ; 137(3): 61, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38411751

RESUMO

KEY MESSAGE: We identified two stable and homologous major QTLs for sucrose content in peanut, and developed breeder-friendly molecular markers for marker-assisted selection breeding. Sucrose content is a crucial quality trait for edible peanuts, and increasing sucrose content is a key breeding objective. However, the genetic basis of sucrose content in peanut remains unclear, and major quantitative trait loci (QTLs) for sucrose content have yet to be identified. In this study, a high-density genetic map was constructed based on whole-genome re-sequencing data from a peanut RIL population. This map consisted of 2,042 bins and 24,142 SNP markers, making it one of the most comprehensive maps to date in terms of marker density. Two major QTLs (qSCA06.2 and qSCB06.2) were identified, explaining 31.41% and 24.13% of the phenotypic variance, respectively. Notably, these two QTLs were located in homologous genomic regions between the A and B subgenomes. The elite allele of qSCA06.2 was exclusive to Valencia-type, while the elite allele of qSCB06.2 existed in other peanut types. Importantly, the distribution of alleles from two homologous QTLs in the RIL population and diverse germplasm accessions consistently demonstrated that only the combination of elite allelic genotypes from both QTLs/genes resulted in a significantly dominant phenotype, accompanied by a substantial increase in sucrose content. The newly developed diagnostic markers for these QTLs were confirmed to be reliable and could facilitate future breeding efforts to enhance sucrose content using marker-assisted selection techniques. Overall, this study highlights the co-regulation of sucrose content by two major homologous QTLs/genes and provides valuable insights into the genetic basis of sucrose in peanuts.


Assuntos
Arachis , Locos de Características Quantitativas , Arachis/genética , Melhoramento Vegetal , Alelos , Sacarose
4.
Theor Appl Genet ; 136(6): 133, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-37204504

RESUMO

KEY MESSAGE: A single nucleotide (G) deletion in the third exon of BraA02.PES2-2 (Bra032957) leads to the conversion of flower color from yellow to white in B. rapa, and knockout mutants of its orthologous genes in B. napus showed white or pale yellow flowers. Brassica rapa (2n = 20, AA) is grown worldwide as an important crop for edible oil and vegetables. The bright yellow flower color and long-lasting flowering period give it aesthetic qualities appealing to countryside tourists. However, the mechanism controlling the accumulation of yellow pigments in B. rapa has not yet been completely revealed. In this study, we characterized the mechanism of white flower formation using a white-flowered natural B. rapa mutant W01. Compared to the petals of yellow-flowered P3246, the petals of W01 have significantly reduced content of yellowish carotenoids. Furthermore, the chromoplasts in white petals of W01 are abnormal with irregularly structured plastoglobules. Genetic analysis indicated that the white flower was controlled by a single recessive gene. By combining BSA-seq with fine mapping, we identified the target gene BraA02.PES2-2 (Bra032957) homologous to AtPES2, which has a single nucleotide (G) deletion in the third exon. Seven homologous PES2 genes including BnaA02.PES2-2 (BnaA02g28340D) and BnaC02.PES2-2 (BnaC02g36410D) were identified in B. napus (2n = 38, AACC), an allotetraploid derived from B. rapa and B. oleracea (2n = 18, CC). Knockout mutants of either one or two of BnaA02.PES2-2 and BnaC02.PES2-2 in the yellow-flowered B. napus cv. Westar by the CRISPR/Cas9 system showed pale-yellow or white flowers. The knock-out mutants of BnaA02.PES2-2 and BnaC02.PES2-2 had fewer esterified carotenoids. These results demonstrated that BraA02.PES2-2 in B. rapa, and BnaA02.PES2-2 and BnaC02.PES2-2 in B. napus play important roles in carotenoids esterification in chromoplasts that contributes to the accumulation of carotenoids in flower petals.


Assuntos
Brassica napus , Brassica rapa , Brassica , Brassica rapa/genética , Flores/genética , Carotenoides , Nucleotídeos , Brassica napus/genética
5.
Plant Cell Environ ; 46(2): 549-566, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36354160

RESUMO

Salt stress is a major limiting factor that severely affects the survival and growth of crops. It is important to understand the salt stress tolerance ability of Brassica napus and explore the underlying related genetic resources. We used a high-throughput phenotyping platform to quantify 2111 image-based traits (i-traits) of a natural population under three different salt stress conditions and an intervarietal substitution line (ISL) population under nine different stress conditions to monitor and evaluate the salt stress tolerance of B. napus over time. We finally identified 928 high-quality i-traits associated with the salt stress tolerance of B. napus. Moreover, we mapped the salt stress-related loci in the natural population via a genome-wide association study and performed a linkage analysis associated with the ISL population, respectively. These results revealed 234 candidate genes associated with salt stress response, and two novel candidate genes, BnCKX5 and BnERF3, were experimentally verified to regulate the salt stress tolerance of B. napus. This study demonstrates the feasibility of using high-throughput phenotyping-based quantitative trait loci mapping to accurately and comprehensively quantify i-traits associated with B. napus. The mapped loci could be used for genomics-assisted breeding to genetically improve the salt stress tolerance of B. napus.


Assuntos
Brassica napus , Locos de Características Quantitativas , Locos de Características Quantitativas/genética , Brassica napus/fisiologia , Mapeamento Cromossômico/métodos , Estudo de Associação Genômica Ampla , Tolerância ao Sal/genética
6.
Front Plant Sci ; 13: 1028779, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36457523

RESUMO

Three ecotypes of rapeseed, winter, spring, and semi-winter, have been formed to enable the plant to adapt to different geographic areas. Although several major loci had been found to contribute to the flowering divergence, the genomic footprints and associated dynamic plant architecture in the vegetative growth stage underlying the ecotype divergence remain largely unknown in rapeseed. Here, a set of 41 dynamic i-traits and 30 growth-related traits were obtained by high-throughput phenotyping of 171 diverse rapeseed accessions. Large phenotypic variation and high broad-sense heritability were observed for these i-traits across all developmental stages. Of these, 19 i-traits were identified to contribute to the divergence of three ecotypes using random forest model of machine learning approach, and could serve as biomarkers to predict the ecotype. Furthermore, we analyzed genomic variations of the population, QTL information of all dynamic i-traits, and genomic basis of the ecotype differentiation. It was found that 213, 237, and 184 QTLs responsible for the differentiated i-traits overlapped with the signals of ecotype divergence between winter and spring, winter and semi-winter, and spring and semi-winter, respectively. Of which, there were four common divergent regions between winter and spring/semi-winter and the strongest divergent regions between spring and semi-winter were found to overlap with the dynamic QTLs responsible for the differentiated i-traits at multiple growth stages. Our study provides important insights into the divergence of plant architecture in the vegetative growth stage among the three ecotypes, which was contributed to by the genetic differentiation, and might contribute to environmental adaption and yield improvement.

7.
Front Plant Sci ; 13: 1065766, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36479520

RESUMO

Flowering time is strongly related to the environment, while the genotype-by-environment interaction study for flowering time is lacking in Brassica napus. Here, a total of 11,700,689 single nucleotide polymorphisms in 490 B. napus accessions were used to associate with the flowering time and related climatic index in eight environments using a compressed variance-component mixed model, 3VmrMLM. As a result, 19 stable main-effect quantitative trait nucleotides (QTNs) and 32 QTN-by-environment interactions (QEIs) for flowering time were detected. Four windows of daily average temperature and precipitation were found to be climatic factors highly correlated with flowering time. Ten main-effect QTNs were found to be associated with these flowering-time-related climatic indexes. Using differentially expressed gene (DEG) analysis in semi-winter and spring oilseed rapes, 5,850 and 5,511 DEGs were found to be significantly expressed before and after vernalization. Twelve and 14 DEGs, including 7 and 9 known homologs in Arabidopsis, were found to be candidate genes for stable QTNs and QEIs for flowering time, respectively. Five DEGs were found to be candidate genes for main-effect QTNs for flowering-time-related climatic index. These candidate genes, such as BnaFLCs, BnaFTs, BnaA02.VIN3, and BnaC09.PRR7, were further validated by the haplotype, selective sweep, and co-expression networks analysis. The candidate genes identified in this study will be helpful to breed B. napus varieties adapted to particular environments with optimized flowering time.

8.
Genome Biol ; 23(1): 233, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36345039

RESUMO

BACKGROUND: Regulation of gene expression plays an essential role in controlling the phenotypes of plants. Brassica napus (B. napus) is an important source for the vegetable oil in the world, and the seed oil content is an important trait of B. napus. RESULTS: We perform a comprehensive analysis of the transcriptional variability in the seeds of B. napus at two developmental stages, 20 and 40 days after flowering (DAF). We detect 53,759 and 53,550 independent expression quantitative trait loci (eQTLs) for 79,605 and 76,713 expressed genes at 20 and 40 DAF, respectively. Among them, the local eQTLs are mapped to the adjacent genes more frequently. The adjacent gene pairs are regulated by local eQTLs with the same open chromatin state and show a stronger mode of expression piggybacking. Inter-subgenomic analysis indicates that there is a feedback regulation for the homoeologous gene pairs to maintain partial expression dosage. We also identify 141 eQTL hotspots and find that hotspot87-88 co-localizes with a QTL for the seed oil content. To further resolve the regulatory network of this eQTL hotspot, we construct the XGBoost model using 856 RNA-seq datasets and the Basenji model using 59 ATAC-seq datasets. Using these two models, we predict the mechanisms affecting the seed oil content regulated by hotspot87-88 and experimentally validate that the transcription factors, NAC13 and SCL31, positively regulate the seed oil content. CONCLUSIONS: We comprehensively characterize the gene regulatory features in the seeds of B. napus and reveal the gene networks regulating the seed oil content of B. napus.


Assuntos
Brassica napus , Brassica napus/genética , Brassica napus/metabolismo , Redes Reguladoras de Genes , Sementes/genética , Sementes/metabolismo , Locos de Características Quantitativas , Óleos de Plantas/metabolismo
9.
Front Plant Sci ; 13: 936958, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35909760

RESUMO

Winter rapeseed (Brassica rapa L.) is an important overwintering oilseed crop that is widely planted in northwest China and suffers chronic low temperatures in winter. So the cold stress becomes one of the major constraints that limit its production. The currently existing genomes limit the understanding of the cold-tolerant genetic basis of rapeseed. Here we assembled a high-quality long-read genome of B. rapa "Longyou-7" cultivar, which has a cold-tolerant phenotype, and constructed a graph-based pan-genome to detect the structural variations within homologs of currently reported cold-tolerant related genes in the "Longyou-7" genome, which provides an additional elucidation of the cold-tolerant genetic basis of "Longyou-7" cultivar and promotes the development of cold-tolerant breeding in B. rapa.

10.
BMC Plant Biol ; 22(1): 207, 2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35448951

RESUMO

BACKGROUND: Aflatoxin contamination caused by Aspergillus fungi has been a serious factor affecting food safety of peanut (Arachis hypogaea L.) because aflatoxins are highly harmful for human and animal health. As three mechanisms of resistance to aflatoxin in peanut including shell infection resistance, seed infection resistance and aflatoxin production resistance exist among naturally evolved germplasm stocks, it is highly crucial to pyramid these three resistances for promoting peanut industry development and protecting consumers' health. However, less research effort has been made yet to investigate the differentiation and genetic relationship among the three resistances in diversified peanut germplasm collections. RESULTS: In this study, the Chinese peanut mini-mini core collection selected from a large basic collection was systematically evaluated for the three resistances against A. flavus for the first time. The research revealed a wide variation among the diversified peanut accessions for all the three resistances. Totally, 14 resistant accessions were identified, including three with shell infection resistance, seven with seed infection resistance and five with aflatoxin production resistance. A special accession, Zh.h1312, was identified with both seed infection and aflatoxin production resistance. Among the five botanic types of A. hypogaea, the var. vulgaris (Spanish type) belonging to subspecies fastigiata is the only one which possessed all the three resistances. There was no close correlation between shell infection resistance and other two resistances, while there was a significant positive correlation between seed infection and toxin production resistance. All the three resistances had a significant negative correlation with pod or seed size. A total of 16 SNPs/InDels associated with the three resistances were identified through genome-wide association study (GWAS). Through comparative analysis, Zh.h1312 with seed infection resistance and aflatoxin production resistance was also revealed to possess all the resistance alleles of associated loci for seed infection index and aflatoxin content. CONCLUSIONS: This study provided the first comprehensive understanding of differentiation of aflatoxin resistance in diversified peanut germplasm collection, and would further contribute to the genetic enhancement for resistance to aflatoxin contamination.


Assuntos
Aflatoxinas , Animais , Arachis/genética , Arachis/microbiologia , Aspergillus flavus/genética , China , Estudo de Associação Genômica Ampla
11.
Theor Appl Genet ; 135(5): 1779-1795, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35262768

RESUMO

KEY MESSAGE: Combining QTL-seq, QTL-mapping and RNA-seq identified a major QTL and candidate genes, which contributed to the development of KASP markers and understanding of molecular mechanisms associated with seed weight in peanut. Seed weight, as an important component of seed yield, is a significant target of peanut breeding. However, relatively little is known about the quantitative trait loci (QTLs) and candidate genes associated with seed weight in peanut. In this study, three major QTLs on chromosomes A05, B02, and B06 were determined by applying the QTL-seq approach in a recombinant inbred line (RIL) population. Based on conventional QTL-mapping, these three QTL regions were successfully narrowed down through newly developed single nucleotide polymorphism (SNP) and simple sequence repeat markers. Among these three QTL regions, qSWB06.3 exhibited stable expression, contributing mainly to phenotypic variance across environments. Furthermore, differentially expressed genes (DEGs) were identified at the three seed developmental stages between the two parents of the RIL population. It was found that the DEGs were widely distributed in the ubiquitin-proteasome pathway, the serine/threonine-protein pathway, signal transduction of hormones and transcription factors. Notably, DEGs at the early stage were mostly involved in regulating cell division, whereas DEGs at the middle and late stages were primarily involved in cell expansion during seed development. The expression patterns of candidate genes related to seed weight in qSWB06.3 were investigated using quantitative real-time PCR. In addition, the allelic diversity of qSWB06.3 was investigated in peanut germplasm accessions. The marker Ah011475 has higher efficiency for discriminating accessions with different seed weights, and it would be useful as a diagnostic marker in marker-assisted breeding. This study provided insights into the genetic and molecular mechanisms of seed weight in peanut.


Assuntos
Arachis , Locos de Características Quantitativas , Arachis/genética , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único , RNA-Seq , Sementes/genética
12.
Nat Plants ; 7(6): 757-765, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34045706

RESUMO

The cultivated Brassica species include numerous vegetable and oil crops of global importance. Three genomes (designated A, B and C) share mesohexapolyploid ancestry and occur both singly and in each pairwise combination to define the Brassica species. With organizational errors (such as misplaced genome segments) corrected, we showed that the fundamental structure of each of the genomes is the same, irrespective of the species in which it occurs. This enabled us to clarify genome evolutionary pathways, including updating the Ancestral Crucifer Karyotype (ACK) block organization and providing support for the Brassica mesohexaploidy having occurred via a two-step process. We then constructed genus-wide pan-genomes, drawing from genes present in any species in which the respective genome occurs, which enabled us to provide a global gene nomenclature system for the cultivated Brassica species and develop a methodology to cost-effectively elucidate the genomic impacts of alien introgressions. Our advances not only underpin knowledge-based approaches to the more efficient breeding of Brassica crops but also provide an exemplar for the study of other polyploids.


Assuntos
Brassica/genética , Produtos Agrícolas/genética , Genoma de Planta , Evolução Biológica , Genes de Plantas , Introgressão Genética , Poliploidia
13.
Plant Biotechnol J ; 19(10): 2011-2026, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33982357

RESUMO

Seed oil content (SOC) and fatty acid (FA) composition determine the quality and economic value of rapeseed (Brassica napus). Little is known about the role of gibberellic acid (GA) in regulating FA biosynthesis in B. napus. Here, we discovered that four BnaRGAs (B. napus REPRESSOR OF GA), encoding negative regulators of GA signalling, were suppressed during seed development. Compared to the wild type, SOC was reduced in gain-of-function mutants bnaa6.rga-D and ds-3, which also showed reduced oleic acid and increased linoleic acid contents. By contrast, the loss-of-function quadruple mutant bnarga displayed higher SOC during early seed development than the wild type, with increased oleic acid and reduced linoleic acid contents. Notably, only BnaA6.RGA and BnaC7.RGA physically interacted with two BnaLEC1s, which function as essential transcription factors in FA biosynthesis. The FA composition did not significantly differ between bnarga bnalec1 sextuple mutants and bnalec1, suggesting that BnaLEC1s are epistatic to BnaRGAs in the regulation of FA composition. Furthermore, BnaLEC1-induced activation of BnaABI3 expression was repressed by BnaA6.RGA, indicating that GA triggers the degradation of BnaRGAs to relieve their repression of BnaLEC1s, thus promoting the transcription of downstream genes to facilitate oil biosynthesis. Therefore, we uncovered a developmental stage-specific role of GA in regulating oil biosynthesis via the GA-BnaRGA-BnaLEC1 signalling cascade, providing a novel mechanistic understanding of how phytohormones regulate FA biosynthesis in seeds. BnaRGAs represent promising targets for oil crop improvement.


Assuntos
Brassica napus , Brassica napus/genética , Ácidos Graxos , Reguladores de Crescimento de Plantas , Proteínas de Plantas/genética , Sementes/genética
15.
Plant Biotechnol J ; 19(2): 240-250, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32737959

RESUMO

Genome structural variation (SV) contributes strongly to trait variation in eukaryotic species and may have an even higher functional significance than single-nucleotide polymorphism (SNP). In recent years, there have been a number of studies associating large chromosomal scale SV ranging from hundreds of kilobases all the way up to a few megabases to key agronomic traits in plant genomes. However, there have been little or no efforts towards cataloguing small- (30-10 000 bp) to mid-scale (10 000-30 000 bp) SV and their impact on evolution and adaptation-related traits in plants. This might be attributed to complex and highly duplicated nature of plant genomes, which makes them difficult to assess using high-throughput genome screening methods. Here, we describe how long-read sequencing technologies can overcome this problem, revealing a surprisingly high level of widespread, small- to mid-scale SV in a major allopolyploid crop species, Brassica napus. We found that up to 10% of all genes were affected by small- to mid-scale SV events. Nearly half of these SV events ranged between 100 bp and 1000 bp, which makes them challenging to detect using short-read Illumina sequencing. Examples demonstrating the contribution of such SV towards eco-geographical adaptation and disease resistance in oilseed rape suggest that revisiting complex plant genomes using medium-coverage long-read sequencing might reveal unexpected levels of functional gene variation, with major implications for trait regulation and crop improvement.


Assuntos
Brassica napus , Poliploidia , Brassica napus/genética , Resistência à Doença/genética , Genoma de Planta/genética , Humanos , Polimorfismo de Nucleotídeo Único/genética
16.
Front Plant Sci ; 11: 577, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32477388

RESUMO

Drought is a major threat to plant growth and crop productivity. Reduced level of the gibberellin would result in increased drought tolerance, but the underlying mechanism is still unclear. In Brassica napus, there are four BnaRGA genes that code for DELLA proteins, negative regulators of GA signaling. Among them, expression of BnaA6.RGA was greatly induced by drought and abscisic acid (ABA). Previously, we created the gain-of-function mutant of BnaA6.RGA, bnaa6.rga-D, and the loss-of-function quadruple mutant, bnarga by CRISPR/Cas9, respectively. Here we show that bnaa6.rga-D displayed enhanced drought tolerance, and its stomatal closure was hypersensitive to ABA treatment. By contrast, bnarga displayed reduced drought tolerance and was less sensitive to ABA treatment, but there is no difference in drought tolerance between single BnaRGA mutant and WT, suggesting a functional redundancy between the BnaRGA genes in this process. Furthermore, we found that BnaRGAs were able to interact physically with BnaA10.ABF2, an essential transcription factor in ABA signaling. The BnaA10.ABF2-BnaA6.RGA protein complex greatly increased the expression level of the drought responsive gene BnaC9.RAB18. Taken together, this work highlighted the fundamental roles of DELLA proteins in drought tolerance in B. napus, and provide desirable germplasm for further breeding of drought tolerance in rapeseed.

17.
BMC Genet ; 21(1): 52, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32429836

RESUMO

BACKGROUND: TERMINAL FLOWER 1 (TFL1) is a member of phosphatidylethanolamine-binding protein (PEBP) family, which plays an important role in the determination of floral meristem identity and regulates flowering time in higher plants. RESULTS: Five BnaTFL1 gene copies were identified in the genome of Brassica napus. The phylogenetic analysis indicated that all five BnaTFL1 gene copies were clustered with their corresponding homologous copies in the ancestral species, B. rapa and B. oleracea. The expression of the BnaTFL1s were confined to flower buds, flowers, seeds, siliques and stem tissues and displayed distinct expression profiles. Knockout mutants of BnaC03.TFL1 generated by CRISPR/Cas9 exhibited early flowering phenotype, while the knockout mutants of the other gene copies had similar flowering time as the wild type. Furthermore, knock-out mutants of individual BnaTFL1 gene copy displayed altered plant architecture. The plant height, branch initiation height, branch number, silique number, number of seeds per silique and number of siliques on the main inflorescence were significantly reduced in the BnaTFL1 mutants. CONCLUSIONS: Our results indicated that BnaC03.TFL1 negatively regulates flowering time in B. napus. BnaC03.TFL1 together with the other BnaTFL1 paralogues are essential for controlling the plant architecture.


Assuntos
Brassica napus/genética , Flores/fisiologia , Genes de Plantas , Sequência de Aminoácidos , Brassica napus/fisiologia , Sistemas CRISPR-Cas , Dosagem de Genes , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Técnicas de Inativação de Genes , Fenótipo , Filogenia , Plantas Geneticamente Modificadas/fisiologia , Alinhamento de Sequência
18.
Theor Appl Genet ; 133(8): 2521-2533, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32468093

RESUMO

KEY MESSAGE: The genetic basis of GLS resistance was dissected using two DH populations sharing a common resistant parent. A major QTL repeatedly detected in multiple developmental stages and environments was fine mapped in a backcross population. Grey leaf spot (GLS), caused by Cercospora zeae-maydis or Cercospora zeina, is a highly destructive foliar disease worldwide. However, the mechanism of resistance against GLS is not well understood. To study the inheritance of this resistance, we developed two doubled haploid (DH) populations sharing a common resistant parent. The two DH populations were grown in two locations representing the typical maize-growing mountain area in Southwest China for 2 years. GLS disease severity was investigated 2 or 3 times until maturity in the 2 years, and the area under the disease progress curve was calculated. Two high-density linkage maps were constructed by genotyping-by-sequencing. A total of 22 quantitative trait loci (QTLs) were detected for GLS resistance, with most QTLs being repeatedly detected in different stages, locations and years. The confidence intervals of two major QTLs (qGLS_Y2-2 and qGLS_Z2-1) on chromosome 2 from the two DH populations overlapped with each other and were integrated into one consensus QTL (qGLS_YZ2-1). Using highly resistant and highly susceptible plants from a BC3 population, we fine mapped this genetic locus to a genomic region of 2.4 Mb. Using a panel of 255 inbred lines from breeding programmes, we detected associations between markers in the qGLS_YZ2-1 region and GLS resistance. The peak marker (ID-B1) will be very useful for marker-assisted breeding for GLS resistance.


Assuntos
Mapeamento Cromossômico/métodos , Resistência à Doença/genética , Doenças das Plantas/genética , Zea mays/genética , Cercospora , China , Cromossomos de Plantas , Ligação Genética , Marcadores Genéticos , Genótipo , Haploidia , Sequenciamento de Nucleotídeos em Larga Escala , Fenótipo , Locos de Características Quantitativas , Zea mays/crescimento & desenvolvimento , Zea mays/microbiologia
19.
J Exp Bot ; 71(16): 4729-4741, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32417916

RESUMO

In Brassicaceae, the requirement for vernalization is conferred by high expression of FLOWERING LOCUS C (FLC). The expression of FLC is known to be repressed by prolonged exposure to cold. Rapeseed (Brassica napus L.) cultivars can be classified into spring, winter, and semi-winter crop types, depending on their respective vernalization requirements. In addition to two known distinct transposon insertion events, here we identified a 4.422 kb hAT and a 5.625 kb long interspersed nuclear element transposon insertion within BnaFLC.A10, and a 810 bp miniature inverted-repeat transposable element (MITE) in BnaFLC.A2. Quantitative PCR demonstrated that these insertions lead to distinct gene expression patterns and contribute differentially to the vernalization response. Transgenic and haplotype analysis indicated that the known 621 bp MITE in the promoter region of BnaFLC.A10 is a transcriptional enhancer that appears to be the main determinant of rapeseed vernalization, and has contributed to the adaptation of rapeseed in winter cultivation environments. In the absence of this transposon insertion, the functional allele of BnaFLC.A2 is a major determinant of vernalization demand. Thus, the combination of BnaFLC.A10 carrying the 621 bp MITE insertion and a functional BnaFLC.A2 appears necessary to establish the winter rapeseed crop phenotype.


Assuntos
Brassica napus , Alelos , Benzenoacetamidas , Brassica napus/genética , Flores , Regulação da Expressão Gênica de Plantas , Piperidonas , Estações do Ano
20.
Plant Biotechnol J ; 18(11): 2345-2353, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32367649

RESUMO

Rapeseed is the second most important oil crop species and is widely cultivated worldwide. However, overcoming the 'phenotyping bottleneck' has remained a significant challenge. A clear goal of high-throughput phenotyping is to bridge the gap between genomics and phenomics. In addition, it is important to explore the dynamic genetic architecture underlying rapeseed plant growth and its contribution to final yield. In this work, a high-throughput phenotyping facility was used to dynamically screen a rapeseed intervarietal substitution line population during two growing seasons. We developed an automatic image analysis pipeline to quantify 43 dynamic traits across multiple developmental stages, with 12 time points. The time-resolved i-traits could be extracted to reflect shoot growth and predict the final yield of rapeseed. Broad phenotypic variation and high heritability were observed for these i-traits across all developmental stages. A total of 337 and 599 QTLs were identified, with 33.5% and 36.1% consistent QTLs for each trait across all 12 time points in the two growing seasons, respectively. Moreover, the QTLs responsible for yield indicators colocalized with those of final yield, potentially providing a new mechanism of yield regulation. Our results indicate that high-throughput phenotyping can provide novel insights into the dynamic genetic architecture of rapeseed growth and final yield, which would be useful for future genetic improvements in rapeseed.


Assuntos
Brassica napus , Brassica rapa , Brassica napus/genética , Brassica rapa/genética , Mapeamento Cromossômico , Fenótipo , Locos de Características Quantitativas/genética
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