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Attractivity and selectivity of two types of traps with synthetic, long-lasting, bisexual generic attractants were compared to conventional light traps to promote their wider use, as an easy-to-use standardised method for entomology. The targeted herbivorous Macroheterocera species playing important role in ecosystems as food source for higher trophic levels (e.g. predatory arthropods, birds and mammals), while other hand they can cause significant economic loss in agriculture. Data on their population dynamic and composition of their assemblages are necessary for both nature conservation and efficient pest management. Light- and semiochemical-baited traps with semisynthetic- (SBL = the acronym stands for semisynthetic bisexual lure) and synthetic lures (FLO = the acronym stands for floral lure of synthetic floral compounds) were used in species rich area of West Ukraine, and in all 10,926 lepidopterans trapped were identified. The attractivity of the light trap was highest with 252 species caught, while traps with semiochemicals captured 132 species including 28 exclusively caught only by them. The qualitative selectivity of light vs. semiochemical-baited traps differed considering both taxa and habitat preferences in such a way that they completed each-other. Differences in quantitative selectivity were also proved even in case of pest species. The parameters of methods varied depending on the phenological phases of the studied assemblages. Considering the revealed attractivity and selectivity, the parallel use of the two methods can offer improved reliable data for conservation biology and pest management.
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Lepidópteros , Feromônios , Animais , Feromônios/farmacologia , Lepidópteros/fisiologia , Ecossistema , Luz , Ucrânia , Controle de Insetos/métodos , EcologiaRESUMO
A growing body of work aims to explore the reasons behind startup failures. However, there is a need for integrative approaches organized around conceptual frameworks to avoid fragmented and perplexing knowledge about these reasons. To our knowledge, no previous research has systematically investigated the role of competency deficits in startup failures, a crucial element of these failures. In our study, we adapted Spencer's behavioral competence model specifically for startups to identify the competencies within startup teams that, according to their Chief Executive Officers, contributed to their downfall. Three coders meticulously analyzed 50 online accounts of startup failures using a modified Critical Incident Technique. This analysis revealed two prominent competency deficits as pivotal determinants of these startups' outcomes: information-seeking and customer service orientation. Additionally, deficits in technical expertise, analytical thinking, and flexibility emerged as significant factors contributing to these failures. The competency deficits identified in this study offer focal points for evaluating and enhancing startup teams, thereby helping to prevent failure.
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In eukaryotic cells, phosphorus is assimilated and utilized primarily as phosphate (Pi). Pi homeostasis is mediated by transporters that have not yet been adequately characterized in green algae. This study reports on PHOSPHATE TRANSPORTER 4-7 (CrPHT4-7) from Chlamydomonas reinhardtii, a member of the PHT4 transporter family, which exhibits remarkable similarity to AtPHT4;4 from Arabidopsis (Arabidopsis thaliana), a chloroplastic ascorbate transporter. Using fluorescent protein tagging, we show that CrPHT4-7 resides in the chloroplast envelope membrane. Crpht4-7 mutants, generated by the CRISPR/Cas12a-mediated single-strand templated repair, show retarded growth, especially in high light, reduced ATP level, strong ascorbate accumulation, and diminished non-photochemical quenching in high light. On the other hand, total cellular phosphorous content was unaffected, and the phenotype of the Crpht4-7 mutants could not be alleviated by ample Pi supply. CrPHT4-7-overexpressing lines exhibit enhanced biomass accumulation under high light conditions in comparison with the wild-type strain. Expressing CrPHT4-7 in a yeast (Saccharomyces cerevisiae) strain lacking Pi transporters substantially recovered its slow growth phenotype, demonstrating that CrPHT4-7 transports Pi. Even though CrPHT4-7 shows a high degree of similarity to AtPHT4;4, it does not display any substantial ascorbate transport activity in yeast or intact algal cells. Thus, the results demonstrate that CrPHT4-7 functions as a chloroplastic Pi transporter essential for maintaining Pi homeostasis and photosynthesis in C. reinhardtii.
Assuntos
Arabidopsis , Chlamydomonas , Chlamydomonas/genética , Saccharomyces cerevisiae , Fotossíntese/genética , Cloroplastos , Homeostase , Ácido Ascórbico , Proteínas de Membrana TransportadorasRESUMO
Intrahepatic cholangiocarcinoma is a challenge to the practicing surgical pathologist for several reasons. It is rare in many parts of the world, and thus practical exposure may be limited. Related to the fact of its rarity is the fact that more common tumors which frequently metastasize to the liver can be morphologically indistinguishable (eg, pancreatic ductal adenocarcinoma). Immunohistochemical testing is generally non-contributory in this context. Other difficulties arise from the protean morphologic manifestations of cholangiocarcinoma (ie, small duct vs. large duct) and the existence of combined cholangiocarcinoma and hepatocellular carcinoma. These, and other issues of concern to the practicing diagnostic pathologist are discussed herein.
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Neoplasias dos Ductos Biliares , Colangiocarcinoma , Neoplasias Hepáticas , Neoplasias Pancreáticas , Humanos , Ductos Biliares Intra-Hepáticos/patologia , Neoplasias dos Ductos Biliares/patologia , Colangiocarcinoma/diagnóstico , Colangiocarcinoma/patologia , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , Neoplasias Pancreáticas/patologiaRESUMO
During field tests implemented in Transcarpathia (West Ukraine) in 2015, 6501 specimens belonging to 26 Brachyceran fly families were collected with traps baited with generic lures (originally developed for noctuid moths) based on fermenting liquid and floral compounds. Isoamyl alcohol-based baits generally attracted more flies than phenylacetaldehyde-based baits and unbaited controls; however, the phenylacetaldehyde-based traps were the most attractive to the Empididae and Milichiidae families. The isoamyl alcohol-based semisynthetic lure showed significant attractivity to the families of Muscidae, Ulidiidae, Sarcophagidae, Calliphoridae, Sciomyzidae, Heleomyzidae, Drosophilidae, Phoridae and Platystomatidae. Additionally, isoamyl alcohol-based semisynthetic lure is the first reported attractant of the Sciomyzidae family. Since our phenylacetaldehyde-based floral lure was also attractive to Heleomyzidae flies, both types of lures can be seen as the first known attractants of this family.
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An important challenge in the study of ecosystem function is resolving how plant antiherbivore chemical defence expression may influence plant-associated microbes, and nutrient release. We report on a factorial experiment that explores a mechanism underlying this interplay using individuals of the perennial plant Tansy that vary genotypically in the chemical content of their antiherbivore defenses (chemotypes). We assessed to what extent soil and its associated microbial community versus chemotype-specific litter determined the composition of the soil microbial community. Microbial diversity profiles revealed sporadic effects of chemotype litter and soil combinations. Soil source and litter type both explained the microbial communities decomposing the litter with soil source having a more important effect. Some microbial taxa are related to particular chemotypes, and thus intra-specific chemical variation of a single plant chemotype can shape the litter microbial community. But we found that ultimately the effect of fresh litter inputs from a chemotype appeared to act secondary as a filter on the composition of the microbial community, with the primary factor being the existing microbial community in the soil.
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Ecossistema , Microbiota , Humanos , Solo/química , Microbiologia do Solo , Plantas/microbiologia , Bactérias , Folhas de Planta/metabolismoRESUMO
Immunotherapy has remained at the vanguard of promising cancer therapeutic regimens due to its exceptionally high specificity for tumor cells and potential for significantly improved treatment-associated quality of life compared to other therapeutic approaches such as surgery and chemoradiation. This is especially true in the digestive system, where high rates of mutation give rise to a host of targetable tumor-specific antigens. Many patients, however, do not exhibit measurable improvements under immunotherapy due to intrinsic or acquired resistance, making predictive biomarkers necessary to determine which patients will benefit from this line of treatment. Many of these biomarkers are assessed empirically by pathologists according to nuanced scoring criteria and algorithms. This review serves to inform clinicians and pathologists of extant and promising upcoming biomarkers predictive of immunotherapeutic efficacy among digestive system malignancies and the ancillary testing required for interpretation by pathologists according to tumor site of origin.
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Neoplasias do Sistema Digestório , Medicina de Precisão , Humanos , Qualidade de Vida , Biomarcadores Tumorais/genética , MutaçãoRESUMO
BACKGROUND: Analyses of small non-coding RNA (ncRNA) expression in malignant germ cell tumours (GCTs) have focused on microRNAs (miRNAs). As GCTs all arise from primordial germ cells, and piwi-interacting RNAs (piRNAs) have important roles in maintaining germline integrity via transposon silencing, we hypothesised that malignant GCTs are characterised by fundamental piRNA dysregulation. AIMS: We undertook global small ncRNA sequencing in malignant GCTs, in order to describe small ncRNA expression changes for both miRNAs and piRNAs. MATERIALS AND METHODS: We performed small ncRNA next generation sequencing on a representative panel of 47 samples, comprising malignant GCT (n = 31) and control (n = 16) tissues/cell lines. Following quality control and normalisation, filtered count reads were used for differential miRNA and piRNA expression analyses via DESeq2. Predicted mRNA targets for piRNAs were identified and utilised for pathway enrichment analyses. RESULTS: Overall, miRNAs and piRNAs comprised 21.9% and 43.0% of small ncRNA species, respectively. There were 749 differentially expressed miRNAs in malignant GCTs, of which 536 (72%) were over-expressed and 213 (28%) under-expressed. The top-ranking over-expressed miRNAs were exclusively from the miR-371â¼373 and miR-302/367 clusters. The most significantly under-expressed miRNAs were miR-100-5p, miR-214-3p, miR-125b-5p and let-7 family members, including miR-202-3p. There were 1,121 differentially expressed piRNAs in malignant GCTs, of which 167 (15%) were over-expressed and 954 (85%) under-expressed. Of note, of the top-20 differentially expressed piRNAs, 16 were over-expressed, of which piR-hsa-2506793 was both top-ranking and most abundant. Mobile element (ME; i.e., transposon)-associated piRNAs comprised 166 (15%) of the 1,121 differentially expressed piRNAs, of which 165 (>99%) were down-regulated. The remaining 955 (85%) non-ME-associated piRNAs may have wider cellular roles. To explore this, predicted mRNA targets of differentially expressed piRNAs identified putative involvement in cancer-associated pathways. CONCLUSION: This study confirms previous miRNA observations, giving credence to our novel demonstration of global piRNA dysregulation in gonadal malignant GCTs, through both ME and non-ME-associated pathways, which likely contributes to GCT pathogenesis.
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MicroRNAs , Neoplasias Embrionárias de Células Germinativas , Pequeno RNA não Traduzido , Humanos , RNA de Interação com Piwi , MicroRNAs/genética , Neoplasias Embrionárias de Células Germinativas/genética , RNA Mensageiro/genética , RNA Interferente Pequeno/genéticaRESUMO
Tobacco is an important commercial crop and a rich source of alkaloids for pharmaceutical and agricultural applications. However, its yield can be reduced by up to 70% due to virus infections, especially by a potyvirus Potato virus Y (PVY). The replication of PVY relies on host factors, and eukaryotic translation initiation factor 4Es (eIF4Es) have already been identified as recessive resistance genes against potyviruses in many plant species. To investigate the molecular basis of PVY resistance in the widely cultivated allotetraploid tobacco variety K326, we developed a dual guide RNA CRISPR/Cas9 system for combinatorial gene editing of two clades, eIF4E1 (eIF4E1-S and eIF4E1-T) and eIF4E2 (eIF4E2-S and eIF4E2-T) in the eIF4E gene family comprising six members in tobacco. We screened for CRISPR/Cas9-induced mutations by heteroduplex analysis and Sanger sequencing, and monitored PVYO accumulation in virus challenged regenerated plants by DAS-ELISA both in T0 and T1 generations. We found that all T0 lines carrying targeted mutations in the eIF4E1-S gene displayed enhanced resistance to PVYO confirming previous reports. More importantly, our combinatorial approach revealed that eIF4E1-S is necessary but not sufficient for complete PVY resistance. Only the quadruple mutants harboring loss-of-function mutations in eIF4E1-S, eIF4E1-T, eIF4E2-S and eIF4E2-T showed heritable high-level resistance to PVYO in tobacco. Our work highlights the importance of understanding host factor redundancy in virus replication and provides a roadmap to generate virus resistance by combinatorial CRISPR/Cas9-mediated editing in non-model crop plants with complex genomes.
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Potyvirus , Solanum tuberosum , Sistemas CRISPR-Cas , Mutação , Doenças das Plantas , NicotianaRESUMO
The impact of epigenetic modifications on the efficacy of CRISPR/Cas9-mediated double-stranded DNA breaks and subsequent DNA repair is poorly understood, especially in plants. In this study, we investigated the effect of the level of cytosine methylation on the outcome of CRISPR/Cas9-induced mutations at multiple Cas9 target sites in Nicotiana benthamiana leaf cells using next-generation sequencing. We found that high levels of promoter methylation, but not gene-body methylation, decreased the frequency of Cas9-mediated mutations. DNA methylation also influenced the ratio of insertions and deletions and potentially the type of Cas9 cleavage in a target-specific manner. In addition, we detected an over-representation of deletion events governed by a single 5'-terminal nucleotide at Cas9-induced DNA breaks. Our findings suggest that DNA methylation can indirectly impair Cas9 activity and subsequent DNA repair, probably through changes in the local chromatin structure. In addition to the well described Cas9-induced blunt-end double-stranded DNA breaks, we provide evidence for Cas9-mediated staggered DNA cuts in plant cells. Both types of cut may direct microhomology-mediated DNA repair by a novel, as yet undescribed, mechanism.
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Sistemas CRISPR-Cas , Metilação de DNA , Sistemas CRISPR-Cas/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Metilação de DNA/genética , Reparo do DNA , Edição de Genes , Mutação/genéticaRESUMO
Single-stranded oligodeoxynucleotides (ssODNs) are widely used as DNA repair templates in CRISPR/Cas precision genome editing. However, the underlying mechanisms of single-strand templated DNA repair (SSTR) are inadequately understood, constraining rational improvements to precision editing. Here we study SSTR at CRISPR/Cas12a-induced DNA double-strand breaks (DSBs) in the eukaryotic model green microalga Chlamydomonas reinhardtii. We demonstrate that ssODNs physically incorporate into the genome during SSTR at Cas12a-induced DSBs. This process is genetically independent of the Rad51-dependent homologous recombination and Fanconi anemia pathways, is strongly antagonized by non-homologous end-joining, and is mediated almost entirely by the alternative end-joining enzyme polymerase θ. These findings suggest differences in SSTR between C. reinhardtii and animals. Our work illustrates the promising potentially of C. reinhardtii as a model organism for studying nuclear DNA repair.
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Chlamydomonas reinhardtii/genética , Reparo do DNA por Junção de Extremidades , DNA de Plantas/metabolismo , DNA de Cadeia Simples/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Quebras de DNA de Cadeia Dupla , DNA de Plantas/genética , DNA de Cadeia Simples/genética , DNA Polimerase Dirigida por DNA/metabolismo , Endodesoxirribonucleases/metabolismo , Edição de Genes/métodos , Instabilidade Genômica , Oligodesoxirribonucleotídeos/genética , Oligodesoxirribonucleotídeos/metabolismo , RNA Guia de Cinetoplastídeos/metabolismo , DNA Polimerase tetaRESUMO
Virus-induced gene silencing (VIGS) can be harnessed to sequence-specifically degrade host transcripts and induce heritable epigenetic modifications referred to as virus-induced post-transcriptional gene silencing (ViPTGS) and virus-induced transcriptional gene silencing (ViTGS), respectively. Both ViPTGS and ViTGS enable manipulation of endogenous gene expression without the need for transgenesis. Although VIGS has been widely used in many plant species, it is not always uniform or highly efficient. The efficiency of VIGS is affected by developmental, physiological and environmental factors. Here, we use recombinant Tobacco rattle viruses (TRV) to study the effect of temperature on ViPTGS and ViTGS using GFP as a reporter gene of silencing in N. benthamiana 16c plants. We found that unlike ViPTGS, ViTGS was impaired at high temperature. Using a novel mismatch-small interfering RNA (siRNA) tool, which precisely distinguishes virus-derived (primary) from target-generated (secondary) siRNAs, we demonstrated that the lack of secondary siRNA production/amplification was responsible for inefficient ViTGS at 29°C. Moreover, inefficient ViTGS at 29°C inhibited the transmission of epigenetic gene silencing to the subsequent generations. Our finding contributes to understanding the impact of environmental conditions on primary and secondary siRNA production and may pave the way to design/optimize ViTGS for transgene-free crop improvement.
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Vírus de Plantas , Vírus de DNA , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Vírus de Plantas/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Temperatura , Nicotiana/genéticaRESUMO
Short non-coding RNA molecules (sRNAs) play a fundamental role in gene regulation and development in higher organisms. They act as molecular postcodes and guide AGO proteins to target nucleic acids. In plants, sRNA-targeted mRNAs are degraded, reducing gene expression. In contrast, sRNA-targeted DNA sequences undergo cytosine methylation referred to as RNA-directed DNA methylation (RdDM). Cytosine methylation can suppress transcription, thus sRNAs are potent regulators of gene expression. sRNA-mediated RdDM is involved in genome stability through transposon silencing, mobile signalling for epigenetic gene control and hybrid vigour. Since cytosine methylation can be passed on to subsequent generations, RdDM contributes to transgenerational inheritance of the epigenome. Using a novel approach, which can differentiate between primary (inducer) and secondary (amplified) sRNAs, we show that initiation of heritable RdDM does not require complete sequence complementarity between the sRNAs and their nuclear target sequences. sRNAs with up to four regularly interspaced mismatches are potent inducers of RdDM, however, the number and disruptive nature of nucleotide polymorphisms negatively correlate with their efficacy. Our findings contribute to understanding how sRNA can directly shape the epigenome and may be used in designing the next generation of RNA silencing constructs.
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Interferência de RNA , Pequeno RNA não Traduzido/química , Metilação de DNA , Genes Homeobox , Vírus de Plantas/genética , Plantas Geneticamente Modificadas , Nicotiana/genéticaRESUMO
Cutin is a polyester matrix mainly composed of hydroxy-fatty acids that occurs in the cuticles of shoots and root-caps. The cuticle, of which cutin is a major component, protects the plant from biotic and abiotic stresses, and cutin has been postulated to constrain organ expansion. We propose that, to allow cutin restructuring, ester bonds in this net-like polymer can be transiently cleaved and then re-formed (transacylation). Here, using pea epicotyl epidermis as the main model, we first detected a cutin:cutin-fatty acid endo-transacylase (CCT) activity. In-situ assays used endogenous cutin as the donor substrate for endogenous enzymes; the exogenous acceptor substrate was a radiolabelled monomeric cutin-acid, 16-hydroxy-[3H]hexadecanoic acid (HHA). High-molecular-weight cutin became ester-bonded to intact [3H]HHA molecules, which thereby became unextractable except by ester-hydrolysing alkalis. In-situ CCT activity correlated with growth rate in Hylotelephium leaves and tomato fruits, suggesting a role in loosening the outer epidermal wall during organ growth. The only well-defined cutin transacylase in the apoplast, CUS1 (a tomato cutin synthase), when produced in transgenic tobacco, lacked CCT activity. This finding provides a reference for future CCT protein identification, which can adopt our sensitive enzyme assay to screen other CUS1-related enzymes.
Assuntos
Lipídeos de Membrana/metabolismo , Mesembryanthemum/enzimologia , Pisum sativum/enzimologia , Epiderme Vegetal/enzimologia , Proteínas de Plantas/metabolismo , Solanum lycopersicum/enzimologia , Agrobacterium tumefaciens , Cromatografia em Camada Fina , Esterificação , Ácidos Graxos/metabolismo , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Técnicas de Inativação de Genes , Concentração de Íons de Hidrogênio , Hidroxiácidos/metabolismo , Lipídeos de Membrana/fisiologia , Mesembryanthemum/crescimento & desenvolvimento , Epiderme Vegetal/crescimento & desenvolvimento , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Plantas Geneticamente Modificadas , Polimerização , Proteínas Recombinantes/metabolismo , Contagem de Cintilação/métodos , NicotianaRESUMO
BACKGROUND: Antirrhinum (snapdragon) species are models for genetic and evolutionary research but recalcitrant to genetic transformation, limiting use of transgenic methods for functional genomics. Transient gene expression from viral vectors and virus-induced gene silencing (VIGS) offer transformation-free alternatives. Here we investigate the utility of Tobacco rattle virus (TRV) for homologous gene expression in Antirrhinum and VIGS in Antirrhinum and its relative Misopates. RESULTS: A. majus proved highly susceptible to systemic TRV infection. TRV carrying part of the Phytoene Desaturase (PDS) gene triggered efficient PDS silencing, visible as tissue bleaching, providing a reporter for the extent and location of VIGS. VIGS was initiated most frequently in young seedlings, persisted into inflorescences and flowers and was not significantly affected by the orientation of the homologous sequence within the TRV genome. Its utility was further demonstrated by reducing expression of two developmental regulators that act either in the protoderm of young leaf primordia or in developing flowers. The effects of co-silencing PDS and the trichome-suppressing Hairy (H) gene from the same TRV genome showed that tissue bleaching provides a useful marker for VIGS of a second target gene acting in a different cell layer. The ability of TRV-encoded H protein to complement the h mutant phenotype was also tested. TRV carrying the native H coding sequence with PDS to report infection failed to complement h mutations and triggered VIGS of H in wild-type plants. However, a sequence with 43% synonymous substitutions encoding H protein, was able to complement the h mutant phenotype when expressed without a PDS VIGS reporter. CONCLUSIONS: We demonstrate an effective method for VIGS in the model genus Antirrhinum and its relative Misopates that works in vegetative and reproductive tissues. We also show that TRV can be used for complementation of a loss-of-function mutation in Antirrhinum. These methods make rapid tests of gene function possible in these species, which are difficult to transform genetically, and opens up the possibility of using additional cell biological and biochemical techniques that depend on transgene expression.
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The discovery of CRISPR/Cas systems and their subsequent application in genome modifications and in gene expression control have fundamentally changed both basic and applied research. They have already been employed to generate novel virus resistance traits either by modifying host factors in the plant genome or by directly inducing targeted virus degradation. Here we summarise the latest developments in this field and discuss the potential applications and concerns around this technology.
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Edição de Genes , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Plantas/genética , Resistência à Doença , Genoma de Planta , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Vírus de Plantas/genética , Plantas/imunologia , Plantas/virologiaRESUMO
Many members of the family Gesneriaceae are cultivated as ornamental plants, including Cape primrose (Streptocarpus) species. The range of plant architecture found in this genus has also made it a model to study leaf and meristem development and their evolution. However, the lack of tools to study gene functions through reverse genetics in Streptocarpus has limited the exploitation of its genetic potential. To aid functional genomic studies in Streptocarpus rexii, we sought to investigate virus-induced gene silencing (VIGS). Using the broad host range Tobacco Rattle Virus (TRV) to target the PHYTOENE DESATURASE (PDS) gene of S. rexii, we show that infection with sap from Nicotiana benthamiana triggered VIGS efficiently. VIGS was most effective in the seedling leaves 8 weeks after sowing, but was limited in duration and systemic spread. This study reports the first successful use of VIGS in Streptocarpus and in the family Gesneriaceae. The inoculation of viral sap derived from N. benthamiana was able to overcome the difficulties of standard Agrobacterium-mediated transformation in this genus. Irrespective of its transient effect, this VIGS system will be useful to assess gene function at the cellular level and represent an important tool for further understanding molecular mechanisms in Streptocarpus.
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Nicotiana/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Inativação Gênica/fisiologia , Oxirredutases/genética , Oxirredutases/metabolismo , Fenótipo , Folhas de Planta/genética , Vírus de Plantas/genética , Vírus de Plantas/patogenicidadeRESUMO
Most angiosperms produce trichomes-epidermal hairs that have protective or more specialized roles. Trichomes are multicellular in almost all species and, in the majority, secretory. Despite the importance of multicellular trichomes for plant protection and as a source of high-value products, the mechanisms that control their development are only poorly understood. Here, we investigate the control of multicellular trichome patterns using natural variation within the genus Antirrhinum (snapdragons), which has evolved hairy alpine-adapted species or lowland species with a restricted trichome pattern multiple times in parallel. We find that a single gene, Hairy (H), which is needed to repress trichome fate, underlies variation in trichome patterns between all Antirrhinum species except one. We show that H encodes a novel epidermis-specific glutaredoxin and that the pattern of trichome distribution within individuals reflects the location of H expression. Phylogenetic and functional tests suggest that H gained its trichome-repressing role late in the history of eudicots and that the ancestral Antirrhinum had an active H gene and restricted trichome distribution. Loss of H function was involved in an early divergence of alpine and lowland Antirrhinum lineages, and the alleles underlying this split were later reused in parallel evolution of alpines from lowland ancestors, and vice versa. We also find evidence for an evolutionary reversal from a widespread to restricted trichome distribution involving a suppressor mutation and for a pleiotropic effect of H on plant growth that might constrain the evolution of trichome pattern.
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Antirrhinum/genética , Evolução Biológica , Glutarredoxinas/genética , Proteínas de Plantas/genética , Tricomas/crescimento & desenvolvimento , Antirrhinum/crescimento & desenvolvimento , Glutarredoxinas/antagonistas & inibidores , Mutação , Proteínas de Plantas/antagonistas & inibidores , Tricomas/genéticaRESUMO
The shift of dark-grown seedlings into light causes enormous transcriptome changes followed by a dramatic developmental transition. Here, we show that microRNA (miRNA) biogenesis also undergoes regulatory changes during de-etiolation. Etiolated seedlings maintain low levels of primary miRNAs (pri-miRNAs) and miRNA processing core proteins, such as Dicer-like 1, SERRATE, and HYPONASTIC LEAVES 1, whereas during de-etiolation both pri-miRNAs and the processing components accumulate to high levels. However, the levels of most miRNAs do not notably increase in response to light. To reconcile this inconsistency, we demonstrated that an unknown suppressor decreases miRNA-processing activity and light-induced SMALL RNA DEGRADING NUCLEASE 1 shortens the half-life of several miRNAs in de-etiolated seedlings. Taken together, these data suggest a novel mechanism, miRNA-biogenetic inconsistency, which accounts for the intricacy of miRNA biogenesis during de-etiolation. This mechanism is essential for the survival of de-etiolated seedlings after long-term skotomorphogenesis and their optimal adaptation to ever-changing light conditions.