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1.
Int J Mol Sci ; 20(9)2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31085987

RESUMO

Sheepgrass (Leymus chinensis (Trin.) Tzvel.) is an economically and ecologically important forage in the grass family. Self-incompatibility (SI) limits its seed production due to the low seed-setting rate after self-pollination. However, investigations into the molecular mechanisms of sheepgrass SI are lacking. Therefore, microscopic observation of pollen germination and pollen tube growth, as well as transcriptomic analyses of pistils after self- and cross-pollination, were performed. The results indicated that pollen tube growth was rapidly inhibited from 10 to 30 min after self-pollination and subsequently stopped but preceded normally after cross-pollination. Time course comparative transcriptomics revealed different transcriptome dynamics between self- and cross-pollination. A pool of SI-related signaling genes and pathways was generated, including genes related to calcium (Ca2+) signaling, protein phosphorylation, plant hormone, reactive oxygen species (ROS), nitric oxide (NO), cytoskeleton, and programmed cell death (PCD). A putative SI response molecular model in sheepgrass was presented. The model shows that SI may trigger a comprehensive calcium- and phytohormone-dominated signaling cascade and activate PCD, which may explain the rapid inhibition of self-pollen tube growth as observed by cytological analyses. These results provided new insight into the molecular mechanisms of sheepgrass (grass family) SI.


Assuntos
Perfilação da Expressão Gênica/métodos , Poaceae/genética , Transcriptoma/genética , Cálcio/metabolismo , Flores/genética , Flores/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polinização/genética , Polinização/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
2.
Gene ; 699: 43-53, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30858139

RESUMO

Ribes diacanthum Pall. (Grossulariaceae), a species with dioecious, unixsexual flowers, has great economic and medicinal value and is widespread in northeastern China. After the initiation of intact floral organs, male flowers develop an abnormal stigma, and female flowers develop fading stamens incapable of pollination. To explore the genes governing dioecious unisexual floral development in R. diacanthum, we used high-throughput sequencing to obtain transcriptome data for male and female inflorescences and analyzed expression patterns of candidate genes at various developmental stages of male and female flowers. The combined transcriptomic data were successfully assembled into 72,791 transcripts (N50 = 1467) and 48,600 unigenes (N50 = 1378); 62% of the unigenes were annotated by NR, Swissprot, KEGG, GO and COG database based on orthology. Analysis of the differentially expressed genes (DEGs) showed that 2785 annotated genes were differentially expressed, and significantly more genes were male-biased than were female-biased in expression in the inflorescences. Both male and female flowers were found to be complete hermaphroditic flowers during early floral development; sex determination was a late event. Several MADS-box genes such as comp53946_c0 (putative AGL11) might be directly correlated with the establishment of sexual dimorphism. The sex-specific transcripts and genes identified may regulate coordinated events during floral development and be involved in the molecular regulation of dioecious, unisexual floral development in R. diacanthum. The transcriptome from the male and the female inflorescences will provide a valuable reference for further functional research on the development of dioecious, unisexual flowers.


Assuntos
Flores/genética , Inflorescência/genética , Ribes/genética , Transcriptoma/genética , China , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Anotação de Sequência Molecular/métodos , Proteínas de Plantas/genética , Polinização/genética
3.
Theor Appl Genet ; 132(7): 1965-1979, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30899967

RESUMO

KEY MESSAGE: Elite wheat pollinators are critical for successful hybrid breeding. We identified Rht-B1 and Ppd-D1 loci affecting multiple pollinator traits and therefore represent major targets for improving hybrid seed production. Hybrid breeding has a great potential to significantly boost wheat yields. Ideal male pollinators would be taller in stature, contain many spikelets well-spaced along the spike and exhibit high extrusion of large anthers. Most importantly, flowering time would match with that of the female parent. Available genetic resources for developing an elite wheat pollinator are limited, and the genetic basis for many of these traits is largely unknown. Here, we report on the genetic analysis of pollinator traits using biparental mapping populations. We identified two anther extrusion QTLs of medium effect, one on chromosome 1BL and the other on 4BS coinciding with the semi-dwarfing Rht-B1 locus. The effect of Rht-B1 alleles on anther extrusion is genotype dependent, while tall plant Rht-B1a allele is consistently associated with large anthers. Multiple QTLs were identified at the Ppd-D1 locus for anther length, spikelet number and spike length, with the photoperiod-sensitive Ppd-D1b allele associated with favourable pollinator traits in the populations studied. We also demonstrated that homeoloci, Rht-D1 and Ppd-B1, influence anther length among other traits. These results suggest that combinations of Rht-B1 and Ppd-D1 alleles control multiple pollinator traits and should be major targets of hybrid wheat breeding programs.


Assuntos
Flores/genética , Polinização/genética , Locos de Características Quantitativas , Triticum/genética , Alelos , Mapeamento Cromossômico , Genes de Plantas , Genótipo , Fenótipo , Fotoperíodo
4.
Plant Cell Rep ; 38(5): 577-586, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30758711

RESUMO

KEY MESSAGE: We developed a novel Agrobacterium-mediated anther transformation for Wucai in planta, and in this procedure, the male germ line was the predominant target. Wucai (Brassica campestris L.), a variant of non-heading Chinese cabbage, is widely cultured in China and only improved by classic breeding methods. Here, a novel and efficient in planta Agrobacterium-mediated anther transformation method is developed based on the optimization of several factors that affect anther transformation. After optimization, transformation with the manual pollination application led to increased transient GUS expression in anthers (reaching 91.59%) and the transformation efficacies in planta (0.59-1.56% for four commercial cultivars). The stable integration and inheritance of the transgenes were further examined by molecular and genetic analyses. Three T2 transgenic lines presented a segregation ratio of 3:1, which was consistent with the Mendelian feature of a single dominant gene. In addition, the GUS histochemical assay and genetic crossing analysis revealed that the male germ line was the predominant target in this transformation. This optimized transformation system could provide a useful tool for both the improvement of cultivar qualities and investigation of functional genes in Wucai.


Assuntos
Agrobacterium tumefaciens/genética , Brassica/genética , Brassica/fisiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Transformação Genética/genética , Brassica/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Polinização/genética , Polinização/fisiologia
5.
PLoS Genet ; 15(2): e1007934, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30742622

RESUMO

Ovules contain the female gametophytes which are fertilized during pollination to initiate seed development. Thus, the number of ovules that are produced during flower development is an important determinant of seed crop yield and plant fitness. Mutants with pleiotropic effects on development often alter the number of ovules, but specific regulators of ovule number have been difficult to identify in traditional mutant screens. We used natural variation in Arabidopsis accessions to identify new genes involved in the regulation of ovule number. The ovule numbers per flower of 189 Arabidopsis accessions were determined and found to have broad phenotypic variation that ranged from 39 ovules to 84 ovules per pistil. Genome-Wide Association tests revealed several genomic regions that are associated with ovule number. T-DNA insertion lines in candidate genes from the most significantly associated loci were screened for ovule number phenotypes. The NEW ENHANCER of ROOT DWARFISM (NERD1) gene was found to have pleiotropic effects on plant fertility that include regulation of ovule number and both male and female gametophyte development. Overexpression of NERD1 increased ovule number per fruit in a background-dependent manner and more than doubled the total number of flowers produced in all backgrounds tested, indicating that manipulation of NERD1 levels can be used to increase plant productivity.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Genes de Plantas , Óvulo Vegetal/genética , Arabidopsis/crescimento & desenvolvimento , Contagem de Células , Fertilidade/genética , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Variação Genética , Estudo de Associação Genômica Ampla , Óvulo Vegetal/citologia , Óvulo Vegetal/crescimento & desenvolvimento , Filogenia , Plantas Geneticamente Modificadas , Polinização/genética , Polimorfismo de Nucleotídeo Único
6.
Int J Mol Sci ; 20(4)2019 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-30781591

RESUMO

A PACLOBUTRAZOL-RESISTANCE (PRE) gene family, consisting of six genes in Arabidopsis thaliana, encodes a group of helix-loop-helix proteins that act in the growth-promoting transcriptional network. To delineate the specific role of each of the PRE genes in organ growth, we took a reverse genetic approach by constructing high order pre loss-of-function mutants of Arabidopsis thaliana. In addition to dwarf vegetative growth, some double or high order pre mutants exhibited defective floral development, resulting in reduced fertility. While pre2pre5 is normally fertile, both pre2pre6 and pre5pre6 showed reduced fertility. Further, the reduced fertility was exacerbated in the pre2pre5pre6 mutant, indicative of the redundant and critical roles of these PREs. Self-pollination assay and scanning electron microscopy analysis showed that the sterility of pre2pre5pre6 was mainly ascribed to the reduced cell elongation of anther filament, limiting access of pollens to stigma. We found that the expression of a subset of flower-development related genes including ARGOS, IAA19, ACS8, and MYB24 was downregulated in the pre2pre5pre6 flowers. Given these results, we propose that PREs, with unequal functional redundancy, take part in the coordinated growth of floral organs, contributing to successful autogamous reproduction in Arabidopsis thaliana.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Flores/genética , Pólen/genética , Fatores de Transcrição/genética , Arabidopsis/crescimento & desenvolvimento , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Família Multigênica/genética , Mutação/genética , Pólen/crescimento & desenvolvimento , Polinização/genética , Triazóis/química
7.
Gene ; 696: 113-121, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30776462

RESUMO

Multiple-allele-inherited male sterility (MAMS) is important in Chinese cabbage (Brassica rapa L. ssp. pekinensis) breeding, but the molecular mechanisms leading to male sterility are poorly understood. In this study, we cloned a novel gene, BrSKS13, that is differentially expressed in fertile and sterile flower buds of Chinese cabbage. BrSKS13 is most similar to Arabidopsis thaliana AT3G13400 (SKS13) and encodes a predicted 61.87 kDa protein with three cupredoxin superfamily conserved domains in the multicopper oxidase family. Semi-quantitative reverse-transcription PCR (sqRT-PCR) showed that expression of BrSKS13 is higher in fertile buds than in sterile buds. Quantitative RT-PCR (qRT-PCR) and in situ hybridization showed that BrSKS13 is highly expressed in fertile anthers, peaking at pollen-maturation stage VI, but is weakly expressed in other tissues and floral organs. Expression patterns of BrSKS13 promoter::GUS reporter fusions in Arabidopsis showed that the BrSKS13 promoter drives expression of the GUS gene only in anthers. The relative expression of Brsks13 in fertile buds was higher than in sterile buds for all other MAMS lines of Chinese cabbage examined. These results suggest that BrSKS13 affects pollen development. In situ hybridization analysis of flower stigmas at different times after pollination showed that BrSKS13 expression was first observed in stigmas and immature seeds at 1 h after pollination, and the signal intensity in seeds increased with increasing maturity. Compared to Col-0, A. thaliana sks13 mutant plants have shorter and fewer siliques, shriveled pollen grains, pollen tube abnormalities, and reduced seed number. The phenotype of sks13 mutant was recovered by over-expressing BrSKS13. Our results suggest that BrSKS13 affects pollen development and the pollination/fertilization process, and will enable further study of the genetic mechanisms underlying MAMS in Chinese cabbage.


Assuntos
Brassica rapa/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica de Plantas/genética , Infertilidade das Plantas/genética , Proteínas de Plantas/genética , Polinização/genética , Alelos , Arabidopsis/genética , Brassica rapa/crescimento & desenvolvimento , Fertilização/genética , Perfilação da Expressão Gênica , Herança Multifatorial/genética , Plantas Geneticamente Modificadas , Pólen/crescimento & desenvolvimento
8.
PLoS Genet ; 15(2): e1007903, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30716069

RESUMO

The impact of pesticides on the health of bee pollinators is determined in part by the capacity of bee detoxification systems to convert these compounds to less toxic forms. For example, recent work has shown that cytochrome P450s of the CYP9Q subfamily are critically important in defining the sensitivity of honey bees and bumblebees to pesticides, including neonicotinoid insecticides. However, it is currently unclear if solitary bees have functional equivalents of these enzymes with potentially serious implications in relation to their capacity to metabolise certain insecticides. To address this question, we sequenced the genome of the red mason bee, Osmia bicornis, the most abundant and economically important solitary bee species in Central Europe. We show that O. bicornis lacks the CYP9Q subfamily of P450s but, despite this, exhibits low acute toxicity to the N-cyanoamidine neonicotinoid thiacloprid. Functional studies revealed that variation in the sensitivity of O. bicornis to N-cyanoamidine and N-nitroguanidine neonicotinoids does not reside in differences in their affinity for the nicotinic acetylcholine receptor or speed of cuticular penetration. Rather, a P450 within the CYP9BU subfamily, with recent shared ancestry to the Apidae CYP9Q subfamily, metabolises thiacloprid in vitro and confers tolerance in vivo. Our data reveal conserved detoxification pathways in model solitary and eusocial bees despite key differences in the evolution of specific pesticide-metabolising enzymes in the two species groups. The discovery that P450 enzymes of solitary bees can act as metabolic defence systems against certain pesticides can be leveraged to avoid negative pesticide impacts on these important pollinators.


Assuntos
Abelhas/efeitos dos fármacos , Abelhas/genética , Neonicotinoides/farmacologia , Animais , Evolução Biológica , Sistema Enzimático do Citocromo P-450/genética , Europa (Continente) , Genômica/métodos , Inseticidas/farmacologia , Polinização/efeitos dos fármacos , Polinização/genética , Tiazinas/farmacologia
9.
PLoS One ; 14(1): e0209176, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30601846

RESUMO

Populations of scarlet Indian paintbrush (Castilleja coccinea) in the Midwestern United States exhibit a bract color polymorphism, with each population having predominantly yellow or scarlet bracts. We investigated a possible mechanism for this maintenance of bract color polymorphism in C. coccinea by conducting hand-pollination experiments in two nearby populations, one predominantly yellow and one predominantly scarlet. The hand-pollination treatments were either self-pollination or cross pollination using pollen from within and between populations. Both color morphs were used as pollen donors for the within and between crosses. We found that both color morphs of C. coccinea were self-compatible. When the scarlet morph was the maternal plant it had higher seed set. When pollinators were excluded, the yellow morph outperformed the scarlet morph in fruit set and seed set. The apparent trade-offs between a higher reproductive output in the scarlet morph and a reproductive assurance advantage in the yellow morph may explain the maintenance of the polymorphism in C. coccinea. While many previous studies have provided evidence for pollinator preference playing a role in floral color polymorphism, the results of the current study indicate that reproductive assurance, which would be important for fluctuations in pollinator abundance or colonizing new areas, may act as a selective agent to maintain such polymorphisms.


Assuntos
Flores/fisiologia , Orobanchaceae/fisiologia , Polimorfismo Genético/genética , Flores/genética , Orobanchaceae/genética , Pigmentação/genética , Pigmentação/fisiologia , Pólen/genética , Pólen/fisiologia , Polinização/genética , Polinização/fisiologia , Reprodução/genética , Reprodução/fisiologia
10.
Methods Mol Biol ; 1931: 49-59, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30652282

RESUMO

Sorghum is the fifth most important cereal grain crop after corn, wheat, rice, and pearl millet in the world. Conventional sorghum breeding relies on multiple generations of self-pollination to achieve the adequate levels of homozygosity for hybrid evaluation, which adds several years and great cost to the breeding process. As in maize, doubled haploid (DH) is the key technology to speed up the breeding process in sorghum. Through 3 years of efforts, two haploid inducer lines, SMHI01 and SMHI02, were discovered by screening 4000 germplasms worldwide. These two inducers have been evaluated in different growth environments and have shown to generate haploids at frequency of 1-2%. The putative haploids produced with these two inducers were evaluated and ploidy was confirmed cytologically and biochemically. The discovery of these inducer lines is the first step toward a revolutionary change in sorghum breeding.


Assuntos
Sorghum/genética , Grão Comestível/genética , Haploidia , Melhoramento Vegetal/métodos , Polinização/genética
11.
Gene ; 681: 86-92, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30253182

RESUMO

Maize often exhibits asynchronous pollination under abiotic and biotic stress conditions; however, the molecular basis of this developmental deficiency has not been elucidated. Tassel development is a key process affecting the anthesis-silking interval (ASI) in maize. In this study, we showed that pollen shedding was delayed and ASI was significantly increased in B73 and Chang7-2 inbred lines under water deficit conditions, which resulted in longer barren tip length and decreased yields under both controlled and field conditions. Comparative transcriptome analysis performed on immature tassels derived from plants grown under well-watered and water deficit conditions identified 1931 and 1713 differentially expressed genes (DEGs) in B73 and Chang7-2, respectively. Further, 28 differentially co-expressed transcription factors were identified across both lines. Collectively, we demonstrated that the molecular regulation of tassel development is associated with water deficit stress at early vegetative stage in maize. This finding extends our understanding of the molecular basis of maize tassel development during abiotic stress.


Assuntos
Desidratação , Inflorescência/crescimento & desenvolvimento , Inflorescência/metabolismo , Água/metabolismo , Zea mays , Desidratação/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes Controladores do Desenvolvimento , Genes de Plantas , Inflorescência/genética , Polinização/genética , Locos de Características Quantitativas , Estações do Ano , Transcriptoma/fisiologia , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
12.
BMC Plant Biol ; 18(1): 323, 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30509158

RESUMO

BACKGROUND: Observations of precocious (early bearing) genotypes of walnut (Juglans regia L.) under natural conditions encouraged us to study the origin and genetic control of these fascinating traits. RESULTS: In this study, the self-fertility, progeny performance, and simple sequence repeat (SSR) locus variation of iron walnut (Juglans sigillata Dode), an ecotype of J. regia, were investigated. The average self-pollinated fruit set rate of J. sigillata cv. 'Dapao' (DP) was 7.0% annually from 1979 to 1982. The average germination rate of self-pollinated seeds was 45.2% during the 4-year period. Most progeny had inbreeding depression. Nine representative self-pollinated progeny (SP1-SP9), with special or typical traits of DP, were selected. SP1-SP4 were precocious because they initiated flowers as early as 2 years after germination, compared to the 7-10-yr period that is typical of DP. SP9 had not flowered since 1980. Twelve SSR markers were used to analyze the SP and DP. The genome of SP had a tendency toward high levels of homozygosity. The high levels of homozygosity reported in 18 additional precocious walnut genotypes complemented the results of this study. CONCLUSIONS: These results provide evidence of precocious phenotypes and genomes with high levels of homozygosity that might be generated from self-pollinating walnut. This suggests that self-pollination might facilitate the generation of unique homozygous parents for subsequent use in walnut-breeding programs. The results also indicate that more attention should be focused on adequate management of precocious walnut to avoid early depression in the production of nuts.


Assuntos
Homozigoto , Juglans/genética , Polinização/genética , Estudos de Associação Genética , Genótipo , Juglans/fisiologia , Repetições de Microssatélites/genética , Polinização/fisiologia , Autoincompatibilidade em Angiospermas/genética
13.
PLoS One ; 13(12): e0207861, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30513103

RESUMO

Artificial pollination of black walnut (Juglans nigra L.) is not practical and timber breeders have historically utilized only open-pollinated half-sib families. An alternate approach called "breeding without breeding," consists of genotyping open-pollinated progeny using DNA markers to identify paternal parents and then constructing full-sib families. In 2014, we used 12 SSR markers to genotype 884 open-pollinated half-sib progeny harvested from two clonal orchards containing 206 trees, comprised of 52 elite timber selections. Seed was harvested in 2011 from each of two ramets of 23 clones, one upwind and one downwind, based on prevailing wind direction from the west-southwest. One orchard was isolated from wild black walnut and composed of forward selections while the other orchard was adjacent to a natural forest containing mature black walnut composed of backward selections. Isolation significantly increased within-orchard pollination (85%) of the progeny from the isolated orchard compared to 42% from the non-isolated orchard. Neither prevailing wind direction nor seed tree position in the orchard affected paternity patterns or wild pollen contamination. Genetic diversity indices revealed that progeny from both orchards were in Hardy-Weinberg equilibrium with very little inbreeding and no selfing. A significant level of inbreeding was present among the forward selected parents, but not the first generation (backward selected) parents. Some orchard clones failed to sire any progeny while other clones pollinated upwards of 20% of progeny.


Assuntos
Juglans/genética , Juglans/fisiologia , DNA de Plantas/genética , Variação Genética , Endogamia , Indiana , Juglans/crescimento & desenvolvimento , Repetições de Microssatélites , Melhoramento Vegetal , Pólen/genética , Pólen/fisiologia , Polinização/genética , Polinização/fisiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Seleção Genética , Vento
14.
Genes Genet Syst ; 93(5): 209-220, 2018 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-30473573

RESUMO

Stigmatic papillae develop at the apex of the gynoecium and play an important role as a site of pollination. The papillae in Brassicaceae are of the dry and unicellular type, and more than 15,000 genes are expressed in the papillae; however, the molecular and physiological mechanisms of their development remain unknown. We found that the papillae in Arabidopsis thaliana change their length in response to altered ambient humidity: papillae of flowers incubated under high humidity elongated more than those under normal humidity conditions. Genetic analysis and transcriptome data suggest that an abscisic acid-mediated abiotic stress response mechanism regulates papilla length. Our data suggest a flexible regulation of papilla elongation at the post-anthesis stage, in response to abiotic stress, as an adaptation to environmental conditions.


Assuntos
Flores/metabolismo , Polinização/genética , Polinização/fisiologia , Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassicaceae/genética , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Umidade , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Transcriptoma/genética
15.
PLoS One ; 13(10): e0205354, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30321199

RESUMO

In the Alps phylogeographic studies indicate for small insect-pollinated herbs that climatic fluctuations caused significant population migrations and fragmentations into glacial refugia at the periphery of the Alps. Here we investigate whether this holds also for wind-pollinated and -dispersed species. We therefore analysed the phylogeographic pattern (nuclear and chloroplast dataset) of a clade of the four species of the Helictotrichon parlatorei species group (Poaceae) endemic to the Alps. In contrast to earlier findings for small insect-pollinated herbs no clear barriers to gene flow could be detected in this species group. Instead a few haplotypes are widespread across the entire Alpine region. While the complete absence of a phylogeographic structure in the plastid dataset hints towards very efficient long distance seed dispersal, the moderate phylogeographic structure in the nuclear dataset indicates at least some spatial restriction to pollen dispersal. Rare haplotypes cluster solely in the Western and Southern central Alps and thereby suggest this to be the area of origin for the H. parlatorei species group from where expansion occurred following the presence of calcareous bedrock into the Eastern Alps. We thus conclude that the inclusion of taxa with complementary life-history traits is vital in understanding the glacial history of the Alpine flora.


Assuntos
Filogeografia , Poaceae/genética , Polinização/genética , Especiação Genética , Haplótipos/genética , Filogenia , Poaceae/crescimento & desenvolvimento , Polinização/fisiologia , Refúgio , Vento
16.
Mol Plant ; 11(11): 1389-1399, 2018 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-30296598

RESUMO

The process of pollen germination is crucial for flowering plant reproduction, but the mechanisms through which pollen grains establish polarity and select germination sites are not well understood. In this study, we report that a formin family protein, AtFH5, is localized to the vesicles and rotates ahead of Lifeact-mEGFP-labeled actin filaments during pollen germination. The translocation of AtFH5 to the plasma membrane initiates the assembly of a collar-like actin structure at the prospective germination site prior to germination. Genetic and pharmacological evidence further revealed an interdependent relationship between the mobility of AtFH5-labeled vesicles and the polymerization of actin filaments: vesicle-localized AtFH5 promotes actin assembly, and the polymerization and elongation of actin filaments, in turn, is essential for the mobility of AtFH5-labeled vesicles in pollen grains. Taken together, our work revealed a molecular mechanism underlying the polarity establishment and vesicle mobility during pollen germination.


Assuntos
Actinas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Germinação/genética , Germinação/fisiologia , Pólen/genética , Pólen/metabolismo , Polinização/genética , Polinização/fisiologia
17.
Sci Rep ; 8(1): 11640, 2018 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-30076357

RESUMO

Deceptive pollination is key to the species richness of Orchidaceae. However, the genetic basis of species diversification is still under study. Section Trigonopedia is a monophyletic clade of genus Cypripedium distributed in the southwest of China. The species of this section are pollinated by different flies. Pollinator differentiation makes section Trigonopedia an ideal group for studying the genetic basis underlying species diversification. Here, we sequenced the transcriptomes of eight species of the genus Cypripedium, including six co-flowering species of section Trigonopedia and two species outside this section as an outgroup. We reconstructed the phylogeny of the section with the combined 1572 single-copy genes extracted from the eight species and produced a highly resolved tree of the section. Furthermore, we combined substitution rate estimation and differential expression analysis to identify candidate genes, including genes related to floral scent synthesis and environmental adaptation, involved in species differentiation. Field investigations showed that these species have adapted to different habitats. We propose that the species diversification in this section is initiated by floral scent differentiation, followed by habitat differentiation, finally leading to speciation. This study sheds novel light on the diversification of closely related orchid species in the Qinghai-Tibetan region.


Assuntos
Adaptação Fisiológica/genética , Orchidaceae/genética , Polinização/genética , Transcriptoma/genética , Animais , Dípteros/genética , Dípteros/fisiologia , Flores/genética , Flores/crescimento & desenvolvimento , Orchidaceae/crescimento & desenvolvimento , Especificidade da Espécie
18.
Sci Rep ; 8(1): 12066, 2018 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-30104579

RESUMO

Simplification by reduction has occurred many times independently in the floral evolution of angiosperms. These reductions have often been attributed to changes in reproductive biology. In the angiosperm plant family Annonaceae, most species have flowers with six petals, and many stamens and carpels. In the genus Monanthotaxis several deviations from this pattern have been observed, including flowers that contain three petals and three stamens only. New DNA sequences were generated for 42 specimens of Monanthotaxis. Five chloroplast markers and two nuclear markers for 72 out of 94 species of Monanthotaxis were used to reconstruct a phylogeny of the genus, which revealed several well-supported, morphologically distinct clades. The evolution of four quantitative and two qualitative floral characters was mapped onto this phylogeny, demonstrating a reduction in flower size and number of flower parts in Monanthotaxis. A large variation in stamen forms and numbers, strong correlations between petal size, stamen and carpel number, combined with a non-gradual mode of evolution and the sympatric co-occurrence of Monanthotaxis species from different clades suggest that the high diversity in the African rainforest of this genus is caused by switches in pollination systems.


Assuntos
Annonaceae/fisiologia , Biodiversidade , Evolução Biológica , Flores/genética , Polinização/genética , Núcleo Celular/genética , DNA de Cloroplastos/genética , Filogenia , Floresta Úmida
19.
Nat Plants ; 4(9): 651-654, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30104651

RESUMO

Re-domestication of potato into an inbred line-based diploid crop propagated by seed represents a promising alternative to traditional clonal propagation of tetraploid potato, but self-incompatibility has hindered the development of inbred lines. To address this problem, we created self-compatible diploid potatoes by knocking out the self-incompatibility gene S-RNase using the CRISPR-Cas9 system. This strategy opens new avenues for diploid potato breeding and will also be useful for studying other self-incompatible crops.


Assuntos
Diploide , Técnicas de Silenciamento de Genes/métodos , Proteínas de Plantas/genética , Polinização , Ribonucleases/genética , Autofertilização , Solanum tuberosum/genética , Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Filogenia , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Polinização/genética , Polinização/fisiologia , Reação em Cadeia da Polimerase , Ribonucleases/fisiologia , Autofertilização/genética , Autofertilização/fisiologia , Autoincompatibilidade em Angiospermas/genética , Solanum tuberosum/fisiologia
20.
Plant Cell ; 30(9): 2057-2081, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30120167

RESUMO

Pollen tube growth requires a high amount of metabolic energy and precise targeting toward the ovules. Sugars, especially glucose, can serve as nutrients and as signaling molecules. Unexpectedly, in vitro assays revealed an inhibitory effect of glucose on pollen tube elongation, contradicting the hypothesis that monosaccharide uptake is a source of nutrition for growing pollen tubes. Measurements with Förster resonance energy transfer-based nanosensors revealed that glucose is taken up into pollen tubes and that the intracellular concentration is in the low micromolar range. Pollen tubes of stp4-6-8-9-10-11 sextuple knockout plants generated by crossings and CRISPR/Cas9 showed only a weak response to glucose, indicating that glucose uptake into pollen tubes is mediated mainly by these six monosaccharide transporters of the SUGAR TRANSPORT PROTEIN (STP) family. Analyses of HEXOKINASE1 (HXK1) showed a strong expression of this gene in pollen. Together with the glucose insensitivity and altered semi-in vivo growth rate of pollen tubes from hxk1 knockout lines, this strongly suggests that glucose is an important signaling molecule for pollen tubes, is taken up by STPs, and detected by HXK1. Equimolar amounts of fructose abolish the inhibitory effect of glucose indicating that only an excess of glucose is interpreted as a signal. This provides a possible model for the discrimination of signaling and nutritional sugars.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Tubo Polínico/metabolismo , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Transporte Biológico/genética , Transporte Biológico/fisiologia , Regulação da Expressão Gênica de Plantas , Hexoquinase , Proteínas de Transporte de Monossacarídeos/genética , Tubo Polínico/crescimento & desenvolvimento , Polinização/genética , Polinização/fisiologia
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