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1.
Tholl D Chen F Petri J Gershenzon J Pichersky E 《The Plant journal : for cell and molecular biology》2005,42(5):757-771
Despite the fact that Arabidopsis is largely self-pollinating, its flowers emit a complex mixture of terpene volatiles consisting predominantly of a large group of over 20 sesquiterpenes. Here we report that only two terpene synthases, encoded by the florally expressed genes At5g23960 and At5g44630, are responsible for the formation of virtually all sesquiterpenes found in the Arabidopsis floral volatile blend. Two independent mutant lines with T-DNA insertions in the previously identified At5g23960 gene lacked the emission of three sesquiterpenes, including the main sesquiterpene volatile (E)-beta-caryophyllene, confirming the previous in vitro functional assignment for this gene. Flowers of a mutant line carrying a T-DNA insertion in gene At5g44630 emitted these three sesquiterpenes, but did not emit any of the remaining sesquiterpene volatiles. An At5g44630 cDNA was expressed in Escherichia coli and the produced protein catalyzed the conversion of farnesyl diphosphate into over 15 sesquiterpenes in similar proportions to those found in the floral volatile blend. At5g23960 and At5g44630 promoter-beta-glucuronidase (GUS) fusion experiments demonstrated that both genes are expressed in several parts of the Arabidopsis flower, with strong At5g23960 promoter-GUS activity in the stigma and strong expression of At5g44630 in intrafloral nectaries. Given the previously reported antimicrobial activity of terpenes, their production in stigmas and nectaries may serve to inhibit microbial infection at these vulnerable sites. A survey of 37 Arabidopsis thaliana ecotypes revealed quantitative, but almost no qualitative, variations of floral monoterpene and sesquiterpene emissions suggesting that floral terpene volatiles must play some significant role in the life of the Arabidopsis plant. 相似文献
2.
Nina Joffard Iris Le Ronc Alban Langlois Julien Renoult Bruno Buatois Laurent Dormont Bertrand Schatz 《Journal of evolutionary biology》2020,33(8):1028-1038
Current divergent selection may promote floral trait differentiation among conspecific populations in flowering plants. However, whether this applies to complex traits such as colour or scents has been little studied, even though these traits often vary within species. In this study, we compared floral colour and odour as well as selective pressures imposed upon these traits among seven populations belonging to three subspecies of the widespread, generalist orchid Anacamptis coriophora. Colour was characterized using calibrated photographs, and scents were sampled using dynamic headspace extraction and analysed using gas chromatography–mass spectrometry. We then quantified phenotypic selection exerted on these traits by regressing fruit set values on floral trait values. We showed that the three studied subspecies were characterized by different floral colour and odour, with one of the two predominant floral volatiles emitted by each subspecies being taxon‐specific. Plant size was positively correlated with fruit set in most populations, whereas we found no apparent link between floral colour and female reproductive success. We detected positive selection on several taxon‐specific compounds in A. coriophora subsp. fragrans, whereas no selection was found on floral volatiles of A. coriophora subsp. coriophora and A. coriophora subsp. martrinii. This study is one of the first to document variation in phenotypic selection exerted on floral scents among conspecific populations. Our results suggest that selection could contribute to ongoing chemical divergence among A. coriophora subspecies. 相似文献
3.
Vanilloideae comprises 15 genera distributed worldwide, among which are Vanilla and Epistephium (tribe Vanilleae). Based on field and laboratory investigations, the pollination biology of V. dubia and E. sclerophyllum was analysed. The former was surveyed in a semi‐deciduous mesophytic forest at the biological reserve of Serra do Japi and in a marshy forest at the city of Pradópolis, southeastern Brazil. The latter was examined in rocky outcrop vegetation in the Chapada Diamantina, northeastern Brazil. In the studied populations, the tubular flowers of V. dubia and E. sclerophyllum were pollinated by bees. Pollen was deposited on either their scutellum (V. dubia) or scutum (E. sclerophyllum). The mentum region of V. dubia is dry, whereas that of E. sclerophyllum presents a small quantity of dilute nectar. Flowers of E. sclerophyllum are scentless, while those of V. dubia are odoriferous. Although V. dubia is self‐compatible, it needs a pollinator to produce fruit. In contrast, E. sclerophyllum sets fruit through spontaneous self‐pollination, but biotic pollination also occurs. Both species are primarily adapted to pollination by euglossine bees. Pollination by Euglossina seems to have occurred at least twice during the evolution of Vanilleae. Furthermore, shifts between rewarding and reward‐free flowers and between autogamous and allogamous species have been reported among vanillas. 相似文献
4.
- Heat and odour production can have profound effects on pollination in cycads. It is therefore expected that these traits would co‐vary geographically with pollinator assemblages. Such intraspecific variation, may lead to the evolution of pollination ecotypes, which can be an early stage of pollinator‐mediated speciation.
- We measured cone temperatures using miniature temperature data loggers and examined the composition of cone volatile odours using headspace sampling and analysis with gas chromatography‐mass spectrometry in four populations spanning the range of the African cycad Encephalartos ghellinckii. Pollinator assemblages were also investigated in three populations.
- Male and female cones were thermogenic at pollen shed and receptive stages, respectively, but patterns of thermogenesis did not vary among populations. Scent emissions from cones in populations in the Drakensberg Mountains were characterised by cis‐β‐ocimene, β‐myrcene and (3E)‐1,3‐octadiene, while camphene and α‐pinene were characteristic of scent emissions from cones in populations closer to the coast. These differences in volatile blends corresponded with differences in insect assemblages.
- These results confirm intraspecific variation in volatile emissions of E. ghellinckii and support the predictions that intraspecific variation in volatile emissions will be associated with shifts in pollinator assemblages. While further work needs to be done to test for local adaptation in this system, this preliminary evidence is consistent with the formation of pollination ecotypes in the E. ghellinckii species complex.
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6.
R. D. Phillips B. Bohman J. M. Anthony S. L. Krauss K. W. Dixon R. Peakall 《Journal of evolutionary biology》2015,28(3):601-612
Plants are predicted to show floral adaptation to geographic variation in the most effective pollinator, potentially leading to reproductive isolation and genetic divergence. Many sexually deceptive orchids attract just a single pollinator species, limiting opportunities to experimentally investigate pollinator switching. Here, we investigate Drakaea concolor, which attracts two pollinator species. Using pollinator choice tests, we detected two morphologically similar ecotypes within D. concolor. The common ecotype only attracted Zaspilothynnus gilesi, whereas the rare ecotype also attracted an undescribed species of Pogonothynnus. The rare ecotype occurred at populations nested within the distribution of the common ecotype, with no evidence of ecotypes occurring sympatrically. Surveying for pollinators at over 100 sites revealed that ecotype identity was not correlated with wasp availability, with most orchid populations only attracting the rare Z. gilesi. Using microsatellite markers, genetic differentiation among populations was very low (GST = 0.011) regardless of ecotype, suggestive of frequent gene flow. Taken together, these results may indicate that the ability to attract Pogonothynnus has evolved recently, but this ecotype is yet to spread. The nested distribution of ecotypes, rather than the more typical formation of ecotypes in allopatry, illustrates that in sexually deceptive orchids, pollinator switching could occur throughout a species' range, resulting from multiple potentially suitable but unexploited pollinators occurring in sympatry. This unusual case of sympatric pollinators highlights D. concolor as a promising study system for further understanding the process of pollinator switching from ecological, chemical and genetic perspectives. 相似文献
7.
Y. Aranguren B. J. Płachno M. Stpiczyńska V. F. O. Miranda 《Plant biology (Stuttgart, Germany)》2018,20(3):591-601
- Genlisea violacea is a Brazilian endemic carnivorous plant species distributed in the cerrado biome, mainly in humid environments, on sandy and oligotrophic soil or wet rocks. Studies on reproductive biology or pollination in the Lentibulariaceae are notably scarce; regarding the genus Genlisea, the current study is the first to show systematic and standardised research on reproductive biology from field studies to describe the foraging of visiting insects and determine the effective pollinators of Genlisea.
- We studied two populations of G. violacea through the observation of flower visitors for 4 months of the rainy and dry seasons. Stigmatic receptivity, pollen viability, and breeding system were evaluated together with histochemistry and morphological analyses of flowers.
- The flowers showed stigmatic receptivity of 100% in open buds and mature flowers, reducing to 80% for senescent flowers. Nearly 80% of pollen grains are viable, decreasing to 40–45% after 48 h. Nectar is produced by glandular trichomes inside the spur. Two bee species are effective pollinators: one of the genus Lasioglossum (subgenus Dialictus: Halictidae) and the other of the genus Ceratina (subgenus Ceratinula: family Apidae). Moreover, bee‐like flies of the Syrphidae family may also be additional pollinators.
- Genlisea violacea is an allogamous and self‐compatible species. The differences in flower‐visiting fauna for both populations can be attributed to factors such as climate, anthropogenic effect, seasonal factors related to insects and plants, as well as the morphological variation of flowers in both populations.
8.
天南星科植物具有特殊的佛焰苞花序及多样化的传粉策略, 是研究被子植物花的分化与动植物之间进化生态学联系的理想材料。本文简述了天南星科不同类型的花序结构及其传粉适应意义, 总结了天南星科传粉策略的基本类型与演化历史。天南星科的苞片结构主要包括原始型、外展平面型、直立宽佛焰苞型和直立狭佛焰苞4种类型, 呈现出从简单的片状与外展平面状结构向复杂的立体包裹状的佛焰苞结构演化的趋势。肉穗花序可分为两性花花序、单性花雌雄同序和单性花雌雄异序3种类型, 演化路线为两性花花序→单性花雌雄同序→单性花雌雄异序。天南星科的传粉者主要有鞘翅目、双翅目、膜翅目昆虫, 表现出5种主要传粉策略: 食物报酬型互利传粉、气味吸引型欺骗性传粉、交配场所型互利传粉、产卵场所型互利传粉和致死陷阱型欺骗性传粉。天南星科植物通过花序的形状、颜色、产热以及花部挥发物来吸引传粉者, 其中最主要的挥发物有二甲基硫化物、甲基吲哚化合物、萜类和苯类化合物, 模拟食物或产卵场所信号吸引鞘翅目甲虫和双翅目昆虫为其传粉。天南星科植物的佛焰苞被认为是促进该科物种分化的一个重要结构, 但该性状的演化历史及其与传粉系统分化之间的内在联系尚不明确。利用现代分子生物学技术以及模型模拟等手段, 结合生理生态学方法深入探究传粉事件与天南星科植物的花多样性以及物种分化之间的联系, 有望提升关于植物-传粉者互作与植物的花多样性分化之间关系的认识, 并丰富对被子植物多样性演化相关研究的理解。 相似文献
9.
Nagegowda DA Gutensohn M Wilkerson CG Dudareva N 《The Plant journal : for cell and molecular biology》2008,55(2):224-239
Terpenoids emitted from snapdragon flowers include three monoterpenes derived from geranyl diphosphate (GPP), myrcene, ( E )-β-ocimene and linalool, and a sesquiterpene, nerolidol, derived from farnesyl diphosphate (FPP). Using a functional genomics approach, we have isolated and biochemically characterized two nearly identical nerolidol/linalool synthases, AmNES/LIS-1 and AmNES/LIS-2, two enzymes responsible for the terpenoid profile of snapdragon scent remaining to be characterized. The AmNES/LIS-2 protein has an additional 30 amino acids in the N-terminus, and shares 95% amino acid sequence identity with AmNES/LIS-1, with only 23 amino acid substitutions distributed across the homologous regions of the proteins. Although these two terpene synthases have very similar catalytic properties, and synthesize linalool and nerolidol as specific products from GPP and FPP, respectively, they are compartmentally segregated. GFP localization studies and analysis of enzyme activities in purified leucoplasts, together with our previous feeding experiments, revealed that AmNES/LIS-1 is localized in cytosol, and is responsible for nerolidol biosynthesis, whereas AmNES/LIS-2 is located in plastids, and accounts for linalool formation. Our results show that subcellular localization of bifunctional enzymes, in addition to the availability of substrate, controls the type of product formed. By directing nearly identical bifunctional enzymes to more than one cellular compartment, plants extend the range of available substrates for enzyme utilization, thus increasing the diversity of the metabolites produced. 相似文献
10.
I. Paul A. Chatterjee S. Maiti P.B.S. Bhadoria A. Mitra 《Plant biology (Stuttgart, Germany)》2019,21(5):899-910
- Ephemeral flowers, especially nocturnal ones, usually emit characteristic scent profiles within their post‐anthesis lifespans of a few hours. Whether these flowers exhibit temporal variability in the composition and profile of volatile and non‐volatile specialised metabolites has received little attention.
- Flowers of Murraya paniculata bloom in the evenings during the summer and monsoon, and their sweet, intense fragrance enhances the plant's value as an ornamental. We aimed to investigate profiles of both volatile and non‐volatile endogenous specialised metabolites (ESM) in nocturnal ephemeral flowers of M. paniculata to examine whether any biochemically diverse groups of ESM follow distinct patterns of accumulation while maintaining synchrony with defensive physiological functions.
- Targeted ESM contents of M. paniculata flowers were profiled at ten time points at 2‐h intervals, starting from late bud stage (afternoon) up to the start of petal senescence (mid‐morning). Emitted volatiles were monitored continuously within the whole 20‐h period using headspace sampling. The ESM contents were mapped by time point to obtain a highly dynamic and biochemically diverse profile. Relative temporal patterns of ESM accumulation indicated that the active fragrance‐emitting period might be divided into ‘early bloom’, ‘mid‐bloom’ and ‘late bloom’ phases. Early and late bloom phases were characterised by high free radical generation, with immediate enhancement of antioxidant enzymes and phenolic compounds. The mid‐bloom phase was relatively stable and dedicated to maximum fragrance emission, with provision for strong terpenoid‐mediated defence against herbivores. The late bloom phase merged into senescence with the start of daylight; however, even the senescent petals continued to emit fragrance to attract diurnal pollinators.
- Our study suggests that dynamic relations between the different ESM groups regulate the short‐term requirements of floral advertisement and phytochemical defence in this ephemeral flower. This study also provided fundamental information on the temporal occurrence of emitted volatiles and internal pools of specialised metabolites in M. paniculata flowers, which could serve as an important model for pollination biology of Rutaceae, which includes many important fruit crops.
11.
M. Shrestha A. G. Dyer A. Dorin Z.‐X. Ren M. Burd 《Plant biology (Stuttgart, Germany)》2020,22(4):555-561
About one‐third of orchid species are thought to offer no floral reward and therefore attract pollinators through deception. Statements of this idea are common in the botanical literature, but the empirical basis of the estimate is rarely mentioned. We traced citation pathways for the one‐third estimate in a sample of the literature and found that the paths lead to empirical foundations that are surprisingly narrow. Moreover, recent measurements have detected minute quantities of sugar available to insect visitors in some orchids thought to be rewardless, raising the possibility of a pollination strategy that is largely deceitful but different to absolute rewardlessness. The orchids are a well‐studied group and there is no doubt that rewardlessness is common in the family. However, greater empirical effort is needed to verify rewardlessness in orchids and to explore geographic and environmental variation in the proportion of rewardless species. 相似文献
12.
Assembly of microbial communities is the result of neutral and selective processes. However, the relative importance of these processes is still debated. Microbial communities of flowers, in particular, have gained recent attention because of their potential impact to plant fitness and plant‐pollinator interactions. However, the role of selection and dispersal in the assembly of these communities remains poorly understood. Here, we evaluated the role of pollinator‐mediated dispersal on the contribution of neutral and selective processes in the assembly of floral microbiomes of the yellow monkeyflower (Mimulus guttatus). We sampled floral organs from flowers in the presence and absence of pollinators within five different serpentine seeps in CA and obtained 16S amplicon data on the epiphytic bacterial communities. Consistent with strong microenvironment selection within flowers we observed significant differences in community composition across floral organs and only a small effect of geographic distance. Pollinator exposure affected the contribution of environmental selection and depended on the rate and intimacy of interactions with flower visitors. This study provides evidence of the importance of dispersal and within‐flower heterogeneity in shaping epiphytic bacterial communities of flowers, and highlights the complex interplay between pollinator behaviour, environmental selection and additional abiotic factors in shaping the epiphytic bacterial communities of flowers. 相似文献
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Andreas Jürgens Suk‐Ling Wee Adam Shuttleworth Steven D. Johnson 《Ecology letters》2013,16(9):1157-1167
Floral mimicry of decaying plant or animal material has evolved in many plant lineages and exploits, for the purpose of pollination, insects seeking oviposition sites. Existing studies suggest that volatile signals play a particularly important role in these mimicry systems. Here, we present the first large‐scale phylogenetically informed study of patterns of evolution in the volatile emissions of plants that mimic insect oviposition sites. Multivariate analyses showed strong convergent evolution, represented by distinct clusters in chemical phenotype space of plants that mimic animal carrion, decaying plant material, herbivore dung and omnivore/carnivore faeces respectively. These plants deploy universal infochemicals that serve as indicators for the main nutrients utilised by saprophagous, coprophagous and necrophagous insects. The emission of oligosulphide‐dominated volatile blends very similar to those emitted by carrion has evolved independently in at least five plant families (Annonaceae, Apocynaceae, Araceae, Orchidaceae and Rafflesiaceae) and characterises plants associated mainly with pollination by necrophagous flies and beetles. 相似文献
15.
Bleiweiss R 《Evolution; international journal of organic evolution》2001,55(8):1706-1709
Ecological studies suggest that hummingbird-pollinated plants in North America mimic each other to increase visitation by birds. Published quantitative trait locus (QTL) data for two Mimulus species indicate that floral traits associated with hummingbird versus bee pollination results from a few loci with major effects on morphology, as predicted by classical models for the evolution of mimicry. Thus, the architecture of genetic divergence associated with speciation may depend on the ecological context. 相似文献
16.
S. H. Ji M. A. Gururani J. W. Lee B.‐O. Ahn S.‐C. Chun 《Plant biology (Stuttgart, Germany)》2014,16(2):428-439
17.
Shun Kobayashi Tetsuo Denda Chi‐Cheng Liao Yu‐Hsiu Lin Shu‐Hui Wu Masako Izawa 《Ecology and evolution》2018,8(16):8607-8615
Floral traits are adapted by plants to attract pollinators. Some of those plants that have different pollinators in different regions adapt to each pollinator in each region to maximize their pollination success. Mucuna macrocarpa (Fabaceae) limits the pollinators using its floral structure and is pollinated by different mammals in different regions. Here, we examine the relationships between floral traits of M. macrocarpa and the external morphology of mammalian pollinators in different regions of its distribution. Field surveys were conducted on Kyushu and Okinawajima Island in Japan, and in Taiwan, where the main pollinators are the Japanese macaque Macaca fuscata, Ryukyu flying fox Pteropus dasymallus, and red‐bellied squirrel Callosciurus erythraeus, respectively. We measured the floral shapes, nectar secretion patterns, sugar components, and external morphology of the pollinators. Results showed that floral shape was slightly different among regions and that flower sizes were not correlated with the external morphology of the pollinators. Volume and sugar rate of nectar were not significantly different among the three regions and did not change throughout the day in any of the regions. However, nectar concentration was higher in Kyushu than in the other two regions. These results suggest that the floral traits of M. macrocarpa are not adapted to each pollinator in each region. Although this plant limits the number of pollinators using its flower structure, it has not adapted to specific mammals and may attract several species of mammals. Such generalist‐like pollination system might have evolved in the Old World. 相似文献
18.
Yuan JS Köllner TG Wiggins G Grant J Degenhardt J Chen F 《The Plant journal : for cell and molecular biology》2008,55(3):491-503
Rice plants fed on by fall armyworm ( Spodoptera frugiperda , FAW) caterpillars emit a blend of volatiles dominated by terpenoids. These volatiles were highly attractive to females of the parasitoid Cotesia marginiventris . Microarray analysis identified 196 rice genes whose expression was significantly upregulated by FAW feeding, 18 of which encode metabolic enzymes potentially involved in volatile biosynthesis. Significant induction of expression of seven of the 11 terpene synthase ( TPS ) genes identified through the microarray experiments was confirmd using real-time RT-PCR. Enzymes encoded by three TPS genes, Os02g02930, Os08g07100 and Os08g04500, were biochemically characterized. Os02g02930 was found to encode a monoterpene synthase producing the single product S- linalool, which is the most abundant volatile emitted from FAW-damaged rice plants. Both Os08g07100 and Os08g04500 were found to encode sesquiterpene synthases, each producing multiple products. These three enzymes are responsible for production of the majority of the terpenes released from FAW-damaged rice plants. In addition to TPS genes, several key genes in the upstream terpenoid pathways were also found to be upregulated by FAW feeding. This paper provides a comprehensive analysis of FAW-induced volatiles and the corresponding volatile biosynthetic genes potentially involved in indirect defense in rice. Evolution of the genetic basis governing volatile terpenoid biosynthesis for indirect defense is discussed. 相似文献
19.
Atsushi Kawakita Ko Mochizuki Makoto Kato 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(3):507-518
A major goal in the study of mutualism is to understand how co‐operation is maintained when mutualism may potentially turn into parasitism. Although certain mechanisms facilitate the persistence of mutualism, parasitic species have repeatedly evolved from mutualistic ancestors. However, documented examples of mutualism reversals are still rare. Leafflowers (Phyllantheae; Phyllanthaceae) include approximately 500 species that engage in obligate mutualism with leafflower moths (Epicephala; Gracillariidae), which actively pollinate flowers, and whose larvae feed on the resulting seeds. We found that the Taiwanese population of the Phyllanthus reticulatus species complex was associated with six sympatric Epicephala species, of which three were derived parasites that induced gall formation on flowers/buds and produced no seeds. Notably, two parasitic species have retained mutualistic pollination behaviour, suggesting that the parasitism was likely not selected for to reduce the cost of mutualism. We propose that the galling habit evolved as an adaptation to escape parasitism by a specialized braconid wasp. The tough gall produced by one species was almost free of braconid parasitism, and the swollen gall induced by the other species probably prevents attack as a result of the larger airspace inside the gall. Our findings suggest that the presence of a third‐party partner can greatly influence the evolutionary fate of mutualisms, regardless of whether the pairwise interaction continues to favour co‐operation. 相似文献
20.
- In explosive pollination, many structures and mechanisms have evolved to achieve high‐speed stamen movement. The male flower of the submerged plant Hydrilla verticillata is reported to be able to release pollen explosively some time after leaving the mother plant time, but the mechanism of stamen movement and the related functional structure in this species are unclear.
- In this study, we observed the male flower structure and pollen dispersal process of H. verticillata. We analysed the stamen movements during the pollen dispersal process and conducted several controlled experiments to study the process of storage and release of elastic potential energy in explosive pollination.
- When the male flower of H. verticillata is bound to the united bracts, the sepals accumulate elastic potential energy through the expansion of basal extensor cells. After the male flower is liberated from the mother plant, the stamens unfold rapidly with the sepals under adhesion and transfer the elastic potential energy to the filament in seconds. Once stamens unfold to a critical angle, at which the elasticity of the filament just exceeds the adhesion between sepals and anthers, the stamens automatically rebound and release pollen in milliseconds.
- These results reveal that Catapult‐like stamens, spoon‐shaped sepals and enclosed united bracts in the spathe together constitute the functional structure in rapid stamen movement of H. verticillata. They ensure that the pollen can be released on the water surface, and thus adapt successfully to the pollen‐epihydrophilous pollination.