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1.
BMC Plant Biol ; 19(1): 287, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262258

RESUMO

BACKGROUND: The majority of apricot (Prunus armeniaca L.) cultivars display orange or yellow background skin, whereas some cultivars are particularly preferred by consumers because of their red blushed skin on the background. RESULTS: In this study, two blushed ('Jianali' and 'Hongyu') and two nonblushed ('Baixing' and 'Luntaixiaobaixing') cultivars were used to investigate the formation mechanism of blushed skin in apricots. High-performance liquid chromatography (HPLC) analysis showed that the blushed cultivars accumulated higher cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside and peonidin-3-O-rutinoside levels during fruit ripening than the nonblushed cultivars. Based on coexpression network analysis (WGCNA), a putative anthocyanin-related R2R3-MYB, PaMYB10, and seven structural genes were identified from transcriptome data. The phylogenetic analysis indicated that PaMYB10 clustered in the anthocyanin-related MYB clade. Sequence alignments revealed that PaMYB10 contained a bHLH-interaction motif ([DE]Lx2[RK]x3Lx6Lx3R) and an ANDV motif. Subcellular localization analysis showed that PaMYB10 was a nuclear protein. Real-time qRT-PCR analysis demonstrated that the transcript levels of PaMYB10 and seven genes responsible for anthocyanin synthesis were significantly higher in blushed than in nonblushed apricots, which was consistent with the accumulation of anthocyanin. In addition, bagging significantly inhibited the transcript levels of PaMYB10 and the structural genes in 'Jianali' and blocked the red coloration and anthocyanin accumulation. Transient PaMYB10 overexpression in 'Luntaixiaobaixing' fruits resulted in the red blushed skin at the maturation stage. CONCLUSIONS: Taken together, these data reveal that three anthocyanins are responsible for the blushed skin of apricots, identify PaMYB10 as a positive regulator of anthocyanin biosynthesis in apricots, and demonstrate that blush formation depends on light.


Assuntos
Antocianinas/biossíntese , Regulação da Expressão Gênica de Plantas , Pigmentos Biológicos/biossíntese , Proteínas de Plantas/genética , Prunus armeniaca/fisiologia , Fatores de Transcrição/genética , Sequência de Aminoácidos , Antocianinas/genética , Cromatografia Líquida de Alta Pressão , Cor , Frutas/genética , Frutas/fisiologia , Glucosídeos/biossíntese , Glucosídeos/genética , Filogenia , Pigmentos Biológicos/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Prunus armeniaca/genética , Alinhamento de Sequência , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
2.
J Exp Bot ; 68(18): 5069-5078, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29036710

RESUMO

S-RNase based gametophytic self-incompatibility (SI) is a widespread prezygotic reproductive barrier in flowering plants. In the Solanaceae, Plantaginaceae and Rosaceae gametophytic SI is controlled by the pistil-specific S-RNases and the pollen S-locus F-box proteins but non-S-specific factors, namely modifiers, are also required. In apricot, Prunus armeniaca (Rosaceae), we previously mapped two pollen-part mutations that confer self-compatibility in cultivars Canino and Katy at the distal end of chromosome 3 (M-locus) unlinked to the S-locus. Here, we used high-resolution mapping to identify the M-locus with an ~134 kb segment containing ParM-1-16 genes. Gene expression analysis identified four genes preferentially expressed in anthers as modifier gene candidates, ParM-6, -7, -9 and -14. Variant calling of WGS Illumina data from Canino, Katy, and 10 self-incompatible cultivars detected a 358 bp miniature inverted-repeat transposable element (MITE) insertion in ParM-7 shared only by self-compatible apricots, supporting ParM-7 as strong candidate gene required for SI. ParM-7 encodes a disulfide bond A-like oxidoreductase protein, which we named ParMDO. The MITE insertion truncates the ParMDO ORF and produces a loss of SI function, suggesting that pollen rejection in Prunus is dependent on redox regulation. Based on phylogentic analyses we also suggest that ParMDO may have originated from a tandem duplication followed by subfunctionalization and pollen-specific expression.


Assuntos
Oxirredutases/metabolismo , Pólen/enzimologia , Prunus armeniaca/enzimologia , Autoincompatibilidade em Angiospermas/genética , Dissulfetos , Loci Gênicos/genética , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Mutação com Perda de Função , Oxirredutases/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Pólen/genética , Pólen/fisiologia , Prunus armeniaca/genética , Prunus armeniaca/fisiologia , Análise de Sequência de DNA
3.
BMC Plant Biol ; 17(1): 72, 2017 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-28399812

RESUMO

BACKGROUND: A complete and hardened endocarp is a typical trait of drupe fruits. However, the 'Liehe' (LE) apricot cultivar has a thin, soft, cleavable endocarp that represents 60.39% and 63.76% of the thickness and lignin content, respectively, of the 'Jinxihong' (JG) apricot (with normal hardened-endocarp). To understand the molecular mechanisms behind the LE apricot phenotype, comparative transcriptomes of Prunus armeniaca L. were sequenced using Illumina HiSeq™ 2500. RESULTS: In this study, we identified 63,170 unigenes including 15,469 genes >1000 bp and 25,356 genes with Gene Function annotation. Pathway enrichment and expression patterns were used to characterize differentially expression genes. The DEGs encoding key enzymes involved in phenylpropanoid biosynthesis were significantly down-regulated in LE apricot. For example, CAD gene expression levels, encoding cinnamyl alcohol dehydrogenase, were only 1.3%, 0.7%, 0.2% and 2.7% in LE apricot compared with JG cultivar at 15, 21, 30, 49 days after full bloom (DAFB). Furthermore, transcription factors regulating secondary wall and lignin biosynthesis were identified. Especially for SECONDARY WALL THICKENING PROMOTING FACTOR 1 (NST 1), its expression levels in LE apricot were merely 2.8% and 9.3% compared with JG cultivar at 15 and 21 DAFB, respectively. CONCLUSIONS: Our comparative transcriptome analysis was used to understand the molecular mechanisms underlie the endocarp-cleaving phenotype in LE apricot. This new apricot genomic resource and the candidate genes provide a useful reference for further investigating the lignification during development of apricot endocarp. Transcription factors such as NST1 may regulate genes involved in phenylpropanoid pathway and affect development and lignification of the endocarp.


Assuntos
Frutas/fisiologia , Prunus armeniaca/genética , Frutas/genética , Frutas/crescimento & desenvolvimento , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Prunus armeniaca/crescimento & desenvolvimento , Prunus armeniaca/fisiologia
4.
BMC Plant Biol ; 17(1): 82, 2017 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-28441955

RESUMO

BACKGROUND: Apricot (Prunus armeniaca L.) exhibits a gametophytic self-incompatibility (GSI) system and it is mostly considered as a self-incompatible species though numerous self-compatible exceptions occur. These are mainly linked to the mutated S C-haplotype carrying an insertion in the S-locus F-box gene that leads to a truncated protein. However, two S-locus unlinked pollen-part mutations (PPMs) termed m and m' have also been reported to confer self-compatibility (SC) in the apricot cultivars 'Canino' and 'Katy', respectively. This work was aimed to explore whether other additional mutations might explain SC in apricot as well. RESULTS: A set of 67 cultivars/accessions with different geographic origins were analyzed by PCR-screening of the S- and M-loci genotypes, contrasting results with the available phenotype data. Up to 20 S-alleles, including 3 new ones, were detected and sequence analysis revealed interesting synonymies and homonymies in particular with S-alleles found in Chinese cultivars. Haplotype analysis performed by genotyping and determining linkage-phases of 7 SSR markers, showed that the m and m' PPMs are linked to the same m 0-haplotype. Results indicate that m 0-haplotype is tightly associated with SC in apricot germplasm being quite frequent in Europe and North-America. However, its prevalence is lower than that for S C in terms of frequency and geographic distribution. Structures of 34 additional M-haplotypes were inferred and analyzed to depict phylogenetic relationships and M 1-2 was found to be the closest haplotype to m 0. Genotyping results showed that four cultivars classified as self-compatible do not have neither the S C- nor the m 0-haplotype. CONCLUSIONS: According to apricot germplasm S-genotyping, a loss of genetic diversity affecting the S-locus has been produced probably due to crop dissemination. Genotyping and phenotyping data support that self-(in)compatibility in apricot relies mainly on the S- but also on the M-locus. Regarding this latter, we have shown that the m 0-haplotype associated with SC is shared by 'Canino', 'Katy' and many other cultivars. Its origin is still unknown but phylogenetic analysis supports that m 0 arose later in time than S C from a widely distributed M-haplotype. Lastly, other mutants putatively carrying new mutations conferring SC have also been identified deserving future research.


Assuntos
Prunus armeniaca/genética , Autoincompatibilidade em Angiospermas/genética , Genótipo , Mutação , Filogeografia , Pólen/genética , Prunus armeniaca/fisiologia
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