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1.
Plant Physiol ; 187(2): 829-845, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34608960

RESUMO

Domesticated citrus varieties are woody perennials and interspecific hybrid crops of global economic and nutritional importance. The citrus fruit "hesperidium" is a unique morphological innovation not found in any other plant lineage. Efforts to improve the nutritional quality of the fruit are predicated on understanding the underlying regulatory mechanisms responsible for fruit development, including temporal control of chlorophyll degradation and carotenoid biosynthesis. Here, we investigated the molecular basis of the navel orange (Citrus sinensis) brown flavedo mutation, which conditions flavedo that is brown instead of orange. To overcome the limitations of using traditional genetic approaches in citrus and other woody perennials, we developed a strategy to elucidate the underlying genetic lesion. We used a multi-omics approach to collect data from several genetic sources and plant chimeras to successfully decipher this mutation. The multi-omics strategy applied here will be valuable in driving future gene discovery efforts in citrus as well as in other woody perennial plants. The comparison of transcriptomic and genomic data from multiple genotypes and plant sectors revealed an underlying lesion in the gene encoding STAY-GREEN (SGR) protein, which simultaneously regulates carotenoid biosynthesis and chlorophyll degradation. However, unlike SGR of other plant species, we found that the carotenoid and chlorophyll regulatory activities could be uncoupled in the case of certain SGR alleles in citrus and thus we propose a model for the molecular mechanism underlying the brown flavedo phenotype. The economic and nutritional value of citrus makes these findings of wide interest. The strategy implemented, and the results obtained, constitute an advance for agro-industry by driving opportunities for citrus crop improvement.

2.
Front Plant Sci ; 12: 737219, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34630487

RESUMO

As a member of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) family, the dodecapeptide tracheary element differentiation inhibitory factor (TDIF) has a major impact on vascular development in plants. However, the influence of polymorphisms in the TDIF peptide motif on activity remains poorly understood. The model plant, Arabidopsis provides a fast and effective tool for assaying the activity of TDIF homologs. Five TDIF homologs from a group of 93 CLE genes in switchgrass (Panicum virgatum), a perennial biomass crop, named PvTDIF-like (PvTDIFL) genes were studied. The expression levels of PvTDIFL1, PvTDIFL3 MR3, and PvTDIFL3 MR2 were relatively high and all of them were expressed at the highest levels in the rachis of switchgrass. The precursor proteins for PvTDIFL1, PvTDIFL3MR3, and PvTDIFL3MR2 contained one, three, and two TDIFL motifs, respectively. Treatments with exogenous PvTDIFL peptides increased the number of stele cells in the hypocotyls of Arabidopsis seedlings, with the exception of PvTDIFL_4p. Heterologous expression of PvTDIFL1 in Arabidopsis strongly inhibited plant growth, increased cell division in the vascular tissue of the hypocotyl, and disrupted the cellular organization of the hypocotyl. Although heterologous expression of PvTDIFL3 MR3 and PvTDIFL3 MR2 also affected plant growth and vascular development, PvTDIFL activity was not enhanced by the multiple TDIFL motifs encoded by PvTDIFL3 MR3 and PvTDIFL3 MR2. These data indicate that in general, PvTDIFLs are functionally similar to Arabidopsis TDIF but that the processing and activities of the PvTDIFL peptides are more complex.

3.
Plant Physiol ; 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34636879

RESUMO

The most common response of a host to pathogens is arguably the asymptomatic response. However, the genetic and molecular mechanisms responsible for asymptomatic responses to pathogens are poorly understood. Here we report on the genetic cloning of two genes controlling the asymptomatic response to tobacco mosaic virus (TMV) in cultivated tobacco (Nicotiana tabacum). These two genes are homologous to tobamovirus multiplication 2A (TOM2A) from Arabidopsis, which was shown to be critical for the accumulation of TMV. Expression analysis indicates that the TOM2A genes might play fundamental roles in plant development or in responses to stresses. Consistent with this hypothesis, a null allele of the TOM2A ortholog in tomato (Solanum lycopersicum) led to the development of bent branches and a high tolerance to both TMV and tomato mosaic virus (ToMV). However, the TOM2A ortholog in Nicotiana glauca did not account for the asymptomatic response to TMV in N. glauca. We showed that TOM2A family is plant-specific and originated from Chlorophyte, and the biological functions of TOM2A orthologs to promote TMV accumulation are highly conserved in the plant kingdom-in both TMV host and nonhost species. In addition, we showed that the interaction between tobacco TOM1 and TOM2A orthologs in plant species is conserved, suggesting a conserved nature of TOM1-TOM2A module in promoting TMV multiplication in plants. The tradeoff between host development, the resistance of hosts to pathogens, and their influence on gene evolution are discussed. Our results shed light on mechanisms that contribute to asymptomatic responses to viruses in plants and provide approaches for developing TMV/ToMV-resistant crops.

4.
Hortic Res ; 8(1): 199, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34465762

RESUMO

Self-incompatibility (SI) substantially restricts the yield and quality of citrus. Therefore, breeding and analyzing self-compatible germplasm is of great theoretical and practical significance for citrus. Here, we focus on the mechanism of a self-compatibility mutation in 'Guiyou No. 1' pummelo (Citrus maxima), which is a spontaneous mutant of 'Shatian' pummelo (Citrus maxima, self-incompatibility). The rate of fruit set and the growth of pollen tubes in the pistil confirmed that a spontaneous mutation in the pistil is responsible for the self-compatibility of 'Guiyou No. 1'. Segregation ratios of the S genotype in F1 progeny, expression analysis, and western blotting validated that the reduced levels of S2-RNase mRNA contribute to the loss of SI in 'Guiyou No. 1'. Furthermore, we report a phased assembly of the 'Guiyou No. 1' pummelo genome and obtained two complete and well-annotated S haplotypes. Coupled with an analysis of SV variations, methylation levels, and gene expression, we identified a candidate gene (CgHB40), that may influence the regulation of the S2-RNase promoter. Our data provide evidence that a mutation that affects the pistil led to the loss of SI in 'Guiyou No. 1' by influencing a poorly understood mechanism that affects transcriptional regulation. This work significantly advances our understanding of the genetic basis of the SI system in citrus and provides information on the regulation of S-RNase genes.

5.
Plant Cell ; 33(10): 3293-3308, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34338777

RESUMO

The degree of stigma exsertion has a major influence on self-pollination efficiency in tomato, and its improvement is essential for raising productivity and for fixing advantageous traits in cultivated tomato. To study the evolution of stigma exsertion degree in tomato, we searched for genes associated with this trait and other aspects of flower morphology, including the lengths of anthers, styles, and ovaries. We performed a genome-wide association on 277 tomato accessions and discovered a novel stigma exsertion gene (SE3.1). We reannotated the structure of the gene, which encodes a C2H2-type zinc finger transcription factor. A mutation of the lead single nucleotide polymorphism creates a premature termination codon in SE3.1 and an inserted stigma in cultivated tomatoes. SE3.1 is essential for the conversion of flush stigmas to inserted stigmas. This conversion has a major impact on the rate of self-fertilization. Intriguingly, we found that both SE3.1 and Style2.1 contribute to the transition from stigma exsertion to insertion during the domestication and improvement of tomato. Style2.1 controls the first step of exserted stigmas to flush stigmas, and SE3.1 controls the second step of flush stigmas to inserted stigmas. We provide molecular details for the two-step process that controls the transition from stigma exsertion to insertion, which is of great agronomic importance in tomato.

6.
Curr Biol ; 31(17): 3848-3860.e8, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34314676

RESUMO

The Great Himalayan Mountains and their foothills are believed to be the place of origin and development of many plant species. The genetic basis of adaptation to high plateaus is a fascinating topic that is poorly understood at the population level. We comprehensively collected and sequenced 377 accessions of Prunus germplasm along altitude gradients ranging from 2,067 to 4,492 m in the Himalayas. We de novo assembled three high-quality genomes of Tibetan Prunus species. A comparative analysis of Prunus genomes indicated a remarkable expansion of the SINE retrotransposons occurred in the genomes of Tibetan species. We observed genetic differentiation between Tibetan peaches from high and low altitudes and that genes associated with light stress signaling, especially UV stress signaling, were enriched in the differentiated regions. By profiling the metabolomes of Tibetan peach fruit, we determined 379 metabolites had significant genetic correlations with altitudes and that in particular phenylpropanoids were positively correlated with altitudes. We identified 62 Tibetan peach-specific SINEs that colocalized with metabolites differentially accumualted in Tibetan relative to cultivated peach. We demonstrated that two SINEs were inserted in a locus controlling the accumulation of 3-O-feruloyl quinic acid. SINE1 was specific to Tibetan peach. SINE2 was predominant in high altitudes and associated with the accumulation of 3-O-feruloyl quinic acid. These genomic and metabolic data for Prunus populations native to the Himalayan region indicate that the expansion of SINE retrotransposons helped Tibetan Prunus species adapt to the harsh environment of the Himalayan plateau by promoting the accumulation of beneficial metabolites.

7.
J Exp Bot ; 72(20): 7035-7048, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34255841

RESUMO

Although autocatalytic ethylene biosynthesis plays an important role in the ripening of climacteric fruits, our knowledge of the network that promotes it remains limited. We identified white fruit (wf), a tomato mutant that produces immature fruit that are white and that ripen slowly. We found that an inversion on chromosome 10 disrupts the LUTESCENT2 (L2) gene, and that white fruit is allelic to lutescent2. Using CRISPR/Cas9 technology we knocked out L2 in wild type tomato and found that the l2-cr mutants produced phenotypes that were very similar to white fruit (lutescent2). In the l2-cr fruit, chloroplast development was impaired and the accumulation of carotenoids and lycopene occurred more slowly than in wild type. During fruit ripening in l2-cr mutants, the peak of ethylene release was delayed, less ethylene was produced, and the expression of ACO genes was significantly suppressed. We also found that exogenous ethylene induces the expression of L2 and that ERF.B3, an ethylene response factor, binds to the promoter of the L2 gene and activates its transcription. Thus, the expression of L2 is regulated by exogenous ethylene. Taken together, our results indicate that ethylene may affect the expression of L2 gene and that L2 participates in autocatalytic ethylene biosynthesis during tomato fruit ripening.


Assuntos
Frutas , Regulação da Expressão Gênica de Plantas , Cloroplastos/metabolismo , Etilenos , Frutas/genética , Frutas/metabolismo , Metaloproteases , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
8.
Nat Plants ; 7(7): 954-965, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34140668

RESUMO

Somatic variations are a major source of genetic diversification in asexual plants, and underpin clonal evolution and the breeding of asexual crops. Sweet orange is a model species for studying somatic variation because it reproduces asexually through apomixis and is propagated asexually through grafting. To dissect the genomic basis of somatic variation, we de novo assembled a reference genome of sweet orange with an average of three gaps per chromosome and a N50 contig of 24.2 Mb, as well as six diploid genomes of somatic mutants of sweet oranges. We then sequenced 114 somatic mutants with an average genome coverage of 41×. Categorization of the somatic variations yielded insights into the single-nucleotide somatic mutations, structural variations and transposable element (TE) transpositions. We detected 877 TE insertions, and found TE insertions in the transporter or its regulatory genes associated with variation in fruit acidity. Comparative genomic analysis of sweet oranges from three diversity centres supported a dispersal from South China to the Mediterranean region and to the Americas. This study provides a global view on the somatic variations, the diversification and dispersal history of sweet orange and a set of candidate genes that will be useful for improving fruit taste and flavour.


Assuntos
Ácidos/análise , Citrus sinensis/genética , Frutas/química , Frutas/genética , Genes de Plantas , Melhoramento Vegetal/métodos , China , Regulação da Expressão Gênica de Plantas , Variação Genética , Genoma de Planta , Genótipo , Mutação
9.
Plant J ; 106(3): 630-648, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547692

RESUMO

The mechanism that coordinates cell growth and cell cycle progression remains poorly understood; in particular, whether the cell cycle and cell wall biosynthesis are coordinated remains unclear. Recently, cell wall biosynthesis and cell cycle progression were reported to respond to wounding. Nonetheless, no genes are reported to synchronize the biosynthesis of the cell wall and the cell cycle. Here, we report that wounding induces the expression of genes associated with cell wall biosynthesis and the cell cycle, and that two genes, AtMYB46 in Arabidopsis thaliana and RrMYB18 in Rosa rugosa, are induced by wounding. We found that AtMYB46 and RrMYB18 promote the biosynthesis of the cell wall by upregulating the expression of cell wall-associated genes, and that both of them also upregulate the expression of a battery of genes associated with cell cycle progression. Ultimately, this response leads to the development of curled leaves of reduced size. We also found that the coordination of cell wall biosynthesis and cell cycle progression by AtMYB46 and RrMYB18 is evolutionarily conservative in multiple species. In accordance with wounding promoting cell regeneration by regulating the cell cycle, these findings also provide novel insight into the coordination between cell growth and cell cycle progression and a method for producing miniature plants.


Assuntos
Arabidopsis/metabolismo , Ciclo Celular , Parede Celular/metabolismo , Rosa/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Rosa/genética , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Transcriptoma
10.
New Phytol ; 229(6): 3237-3252, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33247457

RESUMO

NF-Y transcription factors are reported to play diverse roles in a wide range of biological processes in plants. However, only a few active NF-Y complexes are known in plants and the precise functions of NF-Y complexes in flavonoid biosynthesis have not been determined. Using various molecular, genetic and biochemical approaches, we found that NF-YB8a, NF-YB8b and NF-YB8c - a NF-YB subgroup - can interact with a specific subgroup of NF-YC and then recruit either of two distinct NF-YAs to form NF-Y complexes that bind the CCAAT element in the CHS1 promoter. Furthermore, suppressing the expression of particular NF-YB genes increased the levels of H3K27me3 at the CHS1 locus and significantly suppressed the expression of CHS1 during tomato fruit ripening, which led to the development of pink-coloured fruit with colourless peels. Altogether, by demonstrating that NF-Y transcription factors play essential roles in flavonoid biosynthesis and by providing significant molecular insight into the regulatory mechanisms that drive the development of pink-coloured tomato fruit, we provide a major advance to our fundamental knowledge and information that has considerable practical value for horticulture.


Assuntos
Lycopersicon esculentum , Fator de Ligação a CCAAT/genética , Flavonoides , Frutas , Código das Histonas , Lycopersicon esculentum/genética , Fatores de Transcrição/genética
11.
Proc Natl Acad Sci U S A ; 117(52): 33668-33678, 2020 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-33288708

RESUMO

Leafy head is a unique type of plant architecture found in some vegetable crops, with leaves bending inward to form a compact head. The genetic and molecular mechanisms underlying leafy head in vegetables remain poorly understood. We genetically fine-mapped and cloned a major quantitative trait locus controlling heading in lettuce. The candidate gene (LsKN1) is a homolog of knotted 1 (KN1) from Zea mays Complementation and CRISPR/Cas9 knockout experiments confirmed the role of LsKN1 in heading. In heading lettuce, there is a CACTA-like transposon inserted into the first exon of LsKN1 (LsKN1▽). The transposon sequences act as a promoter rather than an enhancer and drive high expression of LsKN1▽. The enhanced expression of LsKN1▽ is necessary but not sufficient for heading in lettuce. Data from ChIP-sequencing, electrophoretic mobility shift assays, and dual luciferase assays indicate that the LsKN1▽ protein binds the promoter of LsAS1 and down-regulates its expression to alter leaf dorsoventrality. This study provides insight into plant leaf development and will be useful for studies on heading in other vegetable crops.


Assuntos
Elementos de DNA Transponíveis/genética , Regulação da Expressão Gênica de Plantas , Alface/genética , Mutagênese Insercional/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/genética , Proteínas de Plantas/genética , Regulação para Cima/genética , Sequência de Bases , Duplicação Gênica , Genes de Plantas , Alface/anatomia & histologia , Filogenia , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/química , Regiões Promotoras Genéticas/genética , Ligação Proteica , Locos de Características Quantitativas/genética , Homologia de Sequência do Ácido Nucleico , Transcrição Genética
13.
BMC Genomics ; 21(1): 709, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33045986

RESUMO

BACKGROUND: The CLV3/ESR-RELATED (CLE) gene family encodes small secreted peptides (SSPs) and plays vital roles in plant growth and development by promoting cell-to-cell communication. The prediction and classification of CLE genes is challenging because of their low sequence similarity. RESULTS: We developed a machine learning-aided method for predicting CLE genes by using a CLE motif-specific residual score matrix and a novel clustering method based on the Euclidean distance of 12 amino acid residues from the CLE motif in a site-weight dependent manner. In total, 2156 CLE candidates-including 627 novel candidates-were predicted from 69 plant species. The results from our CLE motif-based clustering are consistent with previous reports using the entire pre-propeptide. Characterization of CLE candidates provided systematic statistics on protein lengths, signal peptides, relative motif positions, amino acid compositions of different parts of the CLE precursor proteins, and decisive factors of CLE prediction. The approach taken here provides information on the evolution of the CLE gene family and provides evidence that the CLE and IDA/IDL genes share a common ancestor. CONCLUSIONS: Our new approach is applicable to SSPs or other proteins with short conserved domains and hence, provides a useful tool for gene prediction, classification and evolutionary analysis.


Assuntos
Peptídeos , Plantas , Sinais Direcionadores de Proteínas , Sequência de Aminoácidos/genética , Análise por Conglomerados , Regulação da Expressão Gênica de Plantas , Peptídeos/genética , Peptídeos/metabolismo , Plantas/genética , Plantas/metabolismo , Sinais Direcionadores de Proteínas/genética
14.
J Exp Bot ; 71(12): 3613-3625, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32478391

RESUMO

Although abscisic acid (ABA) is a vital regulator of fruit ripening and several transcription factors have been reported to regulate ABA biosynthesis, reports of the effect of ABA on citrus ripening and the regulation of its biosynthesis by a multiple-transcription-factor complex are scarce. In the present study, a systematic metabolic, cytological, and transcriptome analysis of an ABA-deficient mutant (MT) of Citrus reticulata cv. Suavissima confirmed the positive effect of ABA on the citrus ripening process. The analysis of transcriptome profiles indicated that CrNAC036 played an important role in the ABA deficiency of the mutant, most likely due to an effect on the expression of 9-cis-epoxycarotenoid dioxygenase 5 (CrNCED5). Electrophoretic mobility shift assays and dual luciferase assays demonstrated that CrNAC036 can directly bind and negatively regulate CrNCED5 expression. Furthermore, yeast two-hybrid, bimolecular fluorescence complementation, and dual luciferase assays demonstrated that CrNAC036 interacted with CrMYB68, also down-regulating the expression of CrNCED5. Taken together, our results suggest that CrNAC036 and CrMYB68 synergistically inhibit ABA biosynthesis in citrus fruit by regulating the expression of CrNCED5.


Assuntos
Ácido Abscísico , Citrus , Citrus/genética , Citrus/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
15.
Plant Biotechnol J ; 18(8): 1651-1669, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32271968

RESUMO

Over the last three decades, the development of new genome editing techniques, such as ODM, TALENs, ZFNs and the CRISPR-Cas system, has led to significant progress in the field of plant and animal breeding. The CRISPR-Cas system is the most versatile genome editing tool discovered in the history of molecular biology because it can be used to alter diverse genomes (e.g. genomes from both plants and animals) including human genomes with unprecedented ease, accuracy and high efficiency. The recent development and scope of CRISPR-Cas system have raised new regulatory challenges around the world due to moral, ethical, safety and technical concerns associated with its applications in pre-clinical and clinical research, biomedicine and agriculture. Here, we review the art, applications and potential risks of CRISPR-Cas system in genome editing. We also highlight the patent and ethical issues of this technology along with regulatory frameworks established by various nations to regulate CRISPR-Cas-modified organisms/products.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Agricultura , Animais , Sistemas CRISPR-Cas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Humanos , Plantas/genética
16.
Nat Plants ; 6(2): 131-142, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32055045

RESUMO

Self-incompatibility (SI) is an important mechanism that prevents self-fertilization and inbreeding in flowering plants. The most widespread SI system utilizes S ribonucleases (S-RNases) and S-locus F-boxes (SLFs) as S determinants. In citrus, SI is ancestral, and Citrus maxima (pummelo) is self-incompatible, while Citrus reticulata (mandarin) and its hybrids are self-compatible (SC). Here, we identify nine highly polymorphic pistil-specific, developmentally expressed S-RNases from pummelo that segregate with S haplotypes in a gametophytic manner and cluster with authentic S-RNases. We provide evidence that these S-RNases function as the female S determinants in citrus. Moreover, we show that each S-RNase is linked to approximately nine SLFs. In an analysis of 117 citrus SLF and SFL-like (SLFL) genes, we reveal that they cluster into 12 types and that the S-RNases and intra-haplotypic SLF and SLFL genes co-evolved. Our data support the notion that citrus have a S locus comprising a S-RNase and several SLFs that fit the non-self-recognition model. We identify a predominant single nucleotide mutation, Sm-RNase, in SC citrus, which provides a 'natural' loss of function. We show that SI-SC transitions due to the Sm-RNase initially arose in mandarin, spreading to its hybrids and became fixed. Identification of an evolutionarily distant new genus utilizing the S-RNase-based SI system, >100 million years separated from the nearest S-RNase family, is a milestone for evolutionary comparative studies.


Assuntos
Evolução Biológica , Citrus/fisiologia , Mutação , Proteínas de Plantas/genética , Ribonucleases/genética , Citrus/enzimologia , Citrus/genética , Proteínas de Plantas/metabolismo , Reprodução , Ribonucleases/metabolismo
17.
Plant Biotechnol J ; 18(2): 479-490, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31325407

RESUMO

Anthocyanins protect plants from biotic and abiotic stressors and provide great health benefits to consumers. In this study, we cloned four genes (Red Lettuce Leaves 1 to 4: RLL1 to RLL4) that contribute to colour variations in lettuce. The RLL1 gene encodes a bHLH transcription factor, and a 5-bp deletion in some cultivars abolishes its function to activate the anthocyanin biosynthesis pathway. The RLL2 gene encodes an R2R3-MYB transcription factor, which was derived from a duplication followed by mutations in its promoter region. The RLL3 gene encodes an R2-MYB transcription factor, which down-regulates anthocyanin biosynthesis through competing with RLL2 for interaction with RLL1; a mis-sense mutation compromises the capacity of RLL3 to bind RLL1. The RLL4 gene encodes a WD-40 transcription factor, homologous to the RUP genes suppressing the UV-B signal transduction pathway in Arabidopsis; a mis-sense mutation in rll4 attenuates its suppressing function, leading to a high concentration of anthocyanins. Sequence analysis of the RLL1-RLL4 genes from wild and cultivated lettuce showed that their function-changing mutations occurred after domestication. The mutations in rll1 disrupt anthocyanin biosynthesis, while the mutations in RLL2, rll3 and rll4 activate anthocyanin biosynthesis, showing disruptive selection for leaf colour during domestication of lettuce. The characterization of multiple polymorphic genes in this study provides the necessary molecular resources for the rational breeding of lettuce cultivars with distinct levels of red pigments and green cultivars with high levels of health-promoting flavonoids.


Assuntos
Antocianinas , Domesticação , Alface , Pigmentação , Folhas de Planta , Antocianinas/genética , Regulação da Expressão Gênica de Plantas , Alface/genética , Alface/metabolismo , Pigmentação/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Seleção Genética
19.
Plant Cell Environ ; 42(5): 1545-1560, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30375658

RESUMO

Chloroplasts convert solar energy into biologically useful forms of energy by performing photosynthesis. Although light and particular genes are known to promote chloroplast development, little is known about the mechanisms that regulate the tissue-specificity and cell-specificity of chloroplast biogenesis. Thus, the mechanisms that determine whether non-photosynthetic plastids rather than chloroplasts develop in petals remain largely unexplored. Although heat stress is known to inhibit photosynthesis, we do not know whether heat stress affects chloroplast biogenesis. Here, we report that heat stress up-regulates the expression of chlorophyll biosynthesis-related genes and promotes chloroplasts biogenesis in petals overexpressing SOC1 (suppressor of overexpression of CO) and novel SOC1-like genes. We also found that these specific MADS-box transcription factors are present in most photosynthetic eukaryotes and that the expression of more than one homolog is observed in chloroplast-containing tissues. These findings not only provide novel insights into the tissue specificity of chloroplast biogenesis and a method for producing green petals but also are consistent with heat stress influencing chloroplast biogenesis in higher plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Flores/metabolismo , Proteínas de Domínio MADS/metabolismo , Biogênese de Organelas , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Resposta ao Choque Térmico , Proteínas de Domínio MADS/genética , Petunia/genética , Petunia/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Tabaco/genética , Tabaco/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
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