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1.
Int J Mol Sci ; 23(13)2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35806046

RESUMO

Plants have various self-defense mechanisms against biotic attacks, involving both physical and chemical barriers. Physical barriers include spines, trichomes, and cuticle layers, whereas chemical barriers include secondary metabolites (SMs) and volatile organic compounds (VOCs). Complex interactions between plants and herbivores occur. Plant responses to insect herbivory begin with the perception of physical stimuli, chemical compounds (orally secreted by insects and herbivore-induced VOCs) during feeding. Plant cell membranes then generate ion fluxes that create differences in plasma membrane potential (Vm), which provokes the initiation of signal transduction, the activation of various hormones (e.g., jasmonic acid, salicylic acid, and ethylene), and the release of VOCs and SMs. This review of recent studies of plant-herbivore-infection interactions focuses on early and late plant responses, including physical barriers, signal transduction, SM production as well as epigenetic regulation, and phytohormone responses.


Assuntos
Herbivoria , Compostos Orgânicos Voláteis , Animais , Epigênese Genética , Herbivoria/fisiologia , Insetos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Compostos Orgânicos Voláteis/metabolismo
2.
Sci Total Environ ; 845: 157171, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35809724

RESUMO

Drought stress poses adverse influence on plant growth and further alters plant-herbivore interactions. Such effect is enhanced as drought occurrence is reported to increase due to global warming. Although dioecious plant species have shown sex-specific response to drought stress through the changes in growth performance and stress tolerance, whether such changes will drive sex-specific differences in defense against herbivores between male and female plant conspecifics is barely studied. In the current study, female and male poplar full-siblings were submitted to moderate (75 % field water capacity) and severe drought (50 % field water capacity) stresses, followed by herbivore growth and feeding bioassays to test the effect of plant gender on herbivore growth and feeding performance of two specialist and two generalist leaf herbivores. The results showed that although the growth of both plant sexes was inhibited by the two drought levels, male plants performed better than female conspecifics. In the paired-choice bioassays, the specialist herbivores preferred female plants while the generalist herbivores fed more on the male plants without drought stress. Both the moderate and severe drought stresses reversed such preferences. In the triple-choice bioassays, the specialist herbivores preferred female control plants while the generalist herbivores fed more on female plants under severe drought. In addition, the specialist herbivores fed on female plants from severe drought stress grew the worst while the generalist herbivores gained the highest fresh weight. The transcriptomic and metabolomic profiling revealed that female plant leaves contained higher levels of flavonoids than males under control condition while severe drought stress remarkably reduced the levels of defensive metabolites such as flavonoids, isoflavonoids, neoflavonoids and alkaloids in female but not in male plant leaves.


Assuntos
Herbivoria , Populus , Secas , Flavonoides , Herbivoria/fisiologia , Metaboloma , Plantas , Água
3.
Ying Yong Sheng Tai Xue Bao ; 33(5): 1251-1259, 2022 May.
Artigo em Chinês | MEDLINE | ID: mdl-35730083

RESUMO

In order to clarify the influence of livestock grazing managements on C:N:P stoichiometry of grassland ecosystem and improve grassland management ability at global scale, 83 Chinese and English papers were selected for meta-analysis in this study. We explored the effects of grazing herbivore assemblage (sheep alone, cattle alone, and mixed cattle and sheep) and grazing intensity (light grazing, moderate grazing and heavy grazing) on leaf, litter, root and soil C, N and P stoichiometry of grassland ecosystems. The results showed that grazing significantly decreased C content, C/N and C/P, and increased N, P content and N/P in leaf and litter. C content, N content, C/P and N/P were significantly reduced, and P content and C/N were increased in root and soil. Leaf and litter stoichiometry were more sensitive to cattle and sheep grazing alone, while root and soil stoichiometry were more sensitive to mixed grazing. Heavy grazing had a greater impact on the stoichiometry of grassland ecosystems. Grazing reduced soil N content and increased P content, indicating that grazing had different pathways of influence on grassland N and P content. Further research on the mechanisms of N and P content changes in response to unbalanced grazing activities and the incorporation of the effects of grazing herbivore assemblage and intensity into models for predicting and managing grassland ecosystems could effectively improve grassland ecosystem management.


Assuntos
Ecossistema , Gado , Animais , Bovinos , Pradaria , Herbivoria/fisiologia , Ovinos , Solo
4.
Curr Biol ; 32(11): R525-R528, 2022 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-35671727

RESUMO

Electrical signaling is a critical initial trigger of systemic plant resistance to herbivory, but channels and pumps involved in signal maintenance are poorly understood. A new study identifies P-type calcium ATPases as necessary for both sustained vascular excitability during prolonged attack and physiological resilience.


Assuntos
Herbivoria , Oxilipinas , Ciclopentanos , Herbivoria/fisiologia , Folhas de Planta/fisiologia , Transdução de Sinais
5.
Curr Opin Plant Biol ; 68: 102242, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35696775

RESUMO

Rapid systemic signals travel within the first seconds and minutes after herbivore infestation to mount defense responses in distal tissues. Recent studies have revealed that wound-induced hydraulic pressure changes play an important role in systemic electrical signaling and subsequent calcium and reactive oxygen species waves. These insights raise new questions about signal specificity, the role of insect feeding guild and feeding style and the impact on longer term plant defenses. Here, we integrate the current molecular understanding of wound-induced rapid systemic signaling in the framework of insect-plant interactions.


Assuntos
Herbivoria , Plantas , Animais , Herbivoria/fisiologia , Insetos , Espécies Reativas de Oxigênio
6.
New Phytol ; 235(6): 2378-2392, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35717563

RESUMO

Plants face attackers aboveground and belowground. Insect root herbivores can lead to severe crop losses, yet the underlying transcriptomic responses have rarely been studied. We studied the dynamics of the transcriptomic response of Brussels sprouts (Brassica oleracea var. gemmifera) primary roots to feeding damage by cabbage root fly larvae (Delia radicum), alone or in combination with aboveground herbivory by cabbage aphids (Brevicoryne brassicae) or diamondback moth caterpillars (Plutella xylostella). This was supplemented with analyses of phytohormones and the main classes of secondary metabolites; aromatic, indole and aliphatic glucosinolates. Root herbivory leads to major transcriptomic rearrangement that is modulated by aboveground feeding caterpillars, but not aphids, through priming soon after root feeding starts. The root herbivore downregulates aliphatic glucosinolates. Knocking out aliphatic glucosinolate biosynthesis with CRISPR-Cas9 results in enhanced performance of the specialist root herbivore, indicating that the herbivore downregulates an effective defence. This study advances our understanding of how plants cope with root herbivory and highlights several novel aspects of insect-plant interactions for future research. Further, our findings may help breeders develop a sustainable solution to a devastating root pest.


Assuntos
Brassica , Mariposas , Animais , Brassica/genética , Brassica/metabolismo , Glucosinolatos/metabolismo , Herbivoria/fisiologia , Insetos/metabolismo , Larva/fisiologia , Mariposas/fisiologia , Transcriptoma/genética
7.
Oecologia ; 199(2): 407-417, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35711067

RESUMO

Higher temperatures can increase metabolic rates and carbon demands of invertebrate herbivores, which may shift leaf-chewing herbivory among plant functional groups differing in C:N (carbon:nitrogen) ratios. Biotic factors influencing herbivore species richness may modulate these temperature effects. Yet, systematic studies comparing leaf-chewing herbivory among plant functional groups in different habitats and landscapes along temperature gradients are lacking. This study was conducted on 80 plots covering large gradients of temperature, plant richness and land use in Bavaria, Germany. We investigated proportional leaf area loss by chewing invertebrates ('herbivory') in three plant functional groups on open herbaceous vegetation. As potential drivers, we considered local mean temperature (range 8.4-18.8 °C), multi-annual mean temperature (range 6.5-10.0 °C), local plant richness (species and family level, ranges 10-51 species, 5-25 families), adjacent habitat type (forest, grassland, arable field, settlement), proportion of grassland and landscape diversity (0.2-3 km scale). We observed differential responses of leaf-chewing herbivory among plant functional groups in response to plant richness (family level only) and habitat type, but not to grassland proportion, landscape diversity and temperature-except for multi-annual mean temperature influencing herbivory on grassland plots. Three-way interactions of plant functional group, temperature and predictors of plant richness or land use did not substantially impact herbivory. We conclude that abiotic and biotic factors can assert different effects on leaf-chewing herbivory among plant functional groups. At present, effects of plant richness and habitat type outweigh effects of temperature and landscape-scale land use on herbivory among legumes, forbs and grasses.


Assuntos
Herbivoria , Mastigação , Animais , Biodiversidade , Carbono , Ecossistema , Herbivoria/fisiologia , Humanos , Invertebrados/fisiologia , Plantas , Temperatura
8.
J Exp Bot ; 73(14): 4996-5015, 2022 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-35522985

RESUMO

While traits of plant resistance to herbivory often change during ontogeny, it is unknown whether the primability of this resistance depends on the plant's developmental stage. Resistance in non-flowering Arabidopsis thaliana against Pieris brassicae larvae is known to be primable by prior egg deposition on leaves. We investigated whether this priming effect is maintained in plants at the flowering stage. Larval performance assays revealed that flowering plants' resistance to herbivory was not primable by egg deposition. Accordingly, transcriptomes of flowering plants showed almost no response to eggs. In contrast, egg deposition on non-flowering plants enhanced the expression of genes induced by subsequent larval feeding. Strikingly, flowering plants showed constitutively high expression levels of these genes. Larvae performed generally worse on flowering than on non-flowering plants, indicating that flowering plants constitutively resist herbivory. Furthermore, we determined the seed weight in regrown plants that had been exposed to eggs and larvae during the non-flowering or flowering stage. Non-flowering plants benefitted from egg priming with a smaller loss in seed yield. The seed yield of flowering plants was unaffected by the treatments, indicating tolerance towards the larvae. Our results show that the primability of anti-herbivore defences in Arabidopsis depends on the plant's developmental stage.


Assuntos
Arabidopsis , Borboletas , Animais , Arabidopsis/metabolismo , Borboletas/fisiologia , Herbivoria/fisiologia , Larva/fisiologia , Oviposição/fisiologia , Folhas de Planta/metabolismo
9.
Oecologia ; 199(1): 27-38, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35396976

RESUMO

Nutritional ecologists aim to predict population or landscape-level effects of food availability, but the tools to extrapolate nutrition from small to large extents are often lacking. The appropriate nutritional ecology currencies should be able to represent consumer responses to food while simultaneously be simple enough to expand such responses to large spatial extents and link them to ecosystem functioning. Ecological stoichiometry (ES), a framework of nutritional ecology, can meet these demands, but it is typically associated with ecosystem ecology and nutrient cycling, and less often used to study wildlife nutrition. Despite the emerging zoogeochemical evidence that animals, and thus their diets, play critical roles in nutrient movement, wildlife nutritional ecology has not fully embraced ES, and ES has not incorporated nutrition in many wildlife studies. Here, we discuss how elemental currencies are "nutritionally, organismally, and ecologically explicit" in the context of terrestrial herbivore nutritional ecology. We add that ES and elemental currencies offer a means to measure resource quality across landscapes and compare nutrient availability among regions. Further, we discuss ES shortcomings and solutions, and list future directions to advance the field. As ecological studies increasingly grow in spatial extent, and attempt to link multiple levels of biological organization, integrating more simple and unifying currencies into nutritional studies, like elements, is necessary for nutritional ecology to predict herbivore occurrences and abundances across regions.


Assuntos
Ecossistema , Herbivoria , Animais , Ecologia , Herbivoria/fisiologia
10.
Ecol Lett ; 25(6): 1387-1400, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35384215

RESUMO

Climate change may affect plant-herbivore interactions and their associated ecosystem functions. In an experimental evolution approach, we subjected replicated populations of the invasive Ambrosia artemisiifolia to a combination of simulated warming and herbivory by a potential biocontrol beetle. We tracked genomic and metabolomic changes across generations in field populations and assessed plant offspring phenotypes in a common environment. Using an integrated Bayesian model, we show that increased offspring biomass in response to warming arose through changes in the genetic composition of populations. In contrast, increased resistance to herbivory arose through a shift in plant metabolomic profiles without genetic changes, most likely by transgenerational induction of defences. Importantly, while increased resistance was costly at ambient temperatures, warming removed this constraint and favoured both vigorous and better defended plants under biocontrol. Climate warming may thus decrease biocontrol efficiency and promote Ambrosia invasion, with potentially serious economic and health consequences.


Assuntos
Ambrosia , Ecossistema , Teorema de Bayes , Mudança Climática , Herbivoria/fisiologia , Plantas
11.
Plant J ; 110(5): 1255-1270, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35315556

RESUMO

Chewing herbivores activate plant defense responses through a combination of mechanical wounding and elicitation by herbivore-associated molecular patterns (HAMPs). HAMPs are wound response amplifiers; however, specific defense outputs may also exist that strictly require HAMP-mediated defense signaling. To investigate HAMP-mediated signaling and defense responses, we characterized cowpea (Vigna unguiculata) transcriptome changes following elicitation by inceptin, a peptide HAMP common in Lepidoptera larvae oral secretions. Following inceptin treatment, we observed large-scale reprogramming of the transcriptome consistent with three different response categories: (i) amplification of mechanical wound responses, (ii) temporal extension through accelerated or prolonged responses, and (iii) examples of inceptin-specific elicitation and suppression. At both early and late timepoints, namely 1 and 6 h, large sets of transcripts specifically accumulated following inceptin elicitation. Further early inceptin-regulated transcripts were classified as reversing changes induced by wounding alone. Within key signaling- and defense-related gene families, inceptin-elicited responses included target subsets of wound-induced transcripts. Transcripts displaying the largest inceptin-elicited fold changes included transcripts encoding terpene synthases (TPSs) and peroxidases (POXs) that correspond with induced volatile production and increased POX activity in cowpea. Characterization of inceptin-elicited cowpea defenses via heterologous expression in Nicotiana benthamiana demonstrated that specific cowpea TPSs and POXs were able to confer terpene emission and the reduced growth of beet armyworm (Spodoptera exigua) herbivores, respectively. Collectively, our present findings in cowpea support a model where HAMP elicitation both amplifies concurrent wound responses and specifically contributes to the activation of selective outputs associated with direct and indirect antiherbivore defenses.


Assuntos
Fabaceae , Vigna , Animais , Fabaceae/genética , Regulação da Expressão Gênica de Plantas , Herbivoria/fisiologia , Plantas , Spodoptera , Terpenos/metabolismo , Vigna/genética
12.
Sci Rep ; 12(1): 5254, 2022 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-35347200

RESUMO

The Late Triassic saw a flourish of plant-arthropod interactions. By the Late Triassic, insects had developed all distinct strategies of herbivory, notably including some of the earliest occurrences of leaf-mining. Herein we describe exceptionally well-preserved leaf-mine trace fossils on a Cladophlebis Brongniart fern pinnule from the Momonoki Formation, Mine Group, Japan (Middle Carnian), representing the oldest unequivocal leaf-mines from East Asia. The mines all display a distinctive frass trail-a continuous meandering line, which later becomes a broad band containing spheroidal particles-demonstrating larval development. Although the shapes of the frass trails are generally comparable to those of Lepidoptera or Coleoptera, they cannot be unequivocally assigned to a specific extant leaf-mining taxon. Furthermore, elemental analyses by X-ray fluorescence (XRF) reveals that the frass trail comprises phosphate coprolites. The quantitative variations in P, S, and Si between coprolites and leaf veins may reflect physiological processes (e.g., consumption, absorption, and excretion) mediated by plant chemicals. Our findings reinforce the idea that leaf-mining had become a pervasive feeding strategy of herbivorous insects by the Late Triassic.


Assuntos
Fósseis , Herbivoria , Animais , Extremo Oriente , Herbivoria/fisiologia , Insetos/fisiologia , Plantas
13.
Int J Mol Sci ; 23(5)2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35269836

RESUMO

Plants have evolved several adaptive strategies through physiological changes in response to herbivore attacks. Plant secondary metabolites (PSMs) are synthesized to provide defensive functions and regulate defense signaling pathways to safeguard plants against herbivores. Herbivore injury initiates complex reactions which ultimately lead to synthesis and accumulation of PSMs. The biosynthesis of these metabolites is regulated by the interplay of signaling molecules comprising phytohormones. Plant volatile metabolites are released upon herbivore attack and are capable of directly inducing or priming hormonal defense signaling pathways. Secondary metabolites enable plants to quickly detect herbivore attacks and respond in a timely way in a rapidly changing scenario of pest and environment. Several studies have suggested that the potential for adaptation and/or resistance by insect herbivores to secondary metabolites is limited. These metabolites cause direct toxicity to insect pests, stimulate antixenosis mechanisms in plants to insect herbivores, and, by recruiting herbivore natural enemies, indirectly protect the plants. Herbivores adapt to secondary metabolites by the up/down regulation of sensory genes, and sequestration or detoxification of toxic metabolites. PSMs modulate multi-trophic interactions involving host plants, herbivores, natural enemies and pollinators. Although the role of secondary metabolites in plant-pollinator interplay has been little explored, several reports suggest that both plants and pollinators are mutually benefited. Molecular insights into the regulatory proteins and genes involved in the biosynthesis of secondary metabolites will pave the way for the metabolic engineering of biosynthetic pathway intermediates for improving plant tolerance to herbivores. This review throws light on the role of PSMs in modulating multi-trophic interactions, contributing to the knowledge of plant-herbivore interactions to enable their management in an eco-friendly and sustainable manner.


Assuntos
Proteção de Cultivos , Herbivoria , Animais , Herbivoria/fisiologia , Insetos/fisiologia , Reguladores de Crescimento de Plantas , Plantas/genética
14.
Ecology ; 103(4): e3635, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35060616

RESUMO

While large herbivores are critically important components of terrestrial ecosystems and can have pronounced top-down effects on plants, our understanding of the underlying mechanisms driving these effects remains incomplete. Large herbivores can alter plant growth, reproduction, and abundance through direct effects (predominantly consumption) and through indirect effects via altered interactions with abiotic factors and other species. We know considerably less about these indirect effects than the direct effects. Here, we integrate medium- and small-scale field experiments to investigate how a large vertebrate herbivore, cattle (Bos taurus), affects the aboveground biomass of a dominant forb species, Artemisia scoparia, via diverse direct and indirect pathways in a temperate grassland in northeast China. Although cattle consumed this forb, its biomass increased significantly in response to grazing, due to multiple indirect positive effects that outweighed the direct negative effects of consumption. Cattle preferentially consumed the competing grass Leymus chinensis, and altered Artemisia microhabitats by reducing total plant cover and litter biomass and by increasing the abundance of co-occurring ant species (e.g., Formica spp. and Lasius spp.). This led to additional indirect positive effects on A. scoparia likely due to (1) increased light availability in understory layers and other limiting resources (e.g., soil nutrients and moisture) caused by removal of competitors and plant litter at the soil surface and (2) the changes in resource availability (e.g., soil nutrients and moisture) associated with ant colonies. Our results show that large herbivores can affect plant growth not only via direct consumption, but also via multiple indirect effects. Focusing on the causes and consequences of herbivore-induced indirect effects will not only help us to better understand the influence of these animals in ecological systems, but will also lead to more effective land management and conservation practices in the regions they inhabit.


Assuntos
Pradaria , Herbivoria , Animais , Biomassa , Bovinos , Ecossistema , Herbivoria/fisiologia , Poaceae , Solo
15.
Ecology ; 103(4): e3649, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35084743

RESUMO

Diverse communities of large mammalian herbivores (LMH), once widespread, are now rare. LMH exert strong direct and indirect effects on community structure and ecosystem functions, and measuring these effects is important for testing ecological theory and for understanding past, current, and future environmental change. This in turn requires long-term experimental manipulations, owing to the slow and often nonlinear responses of populations and assemblages to LMH removal. Moreover, the effects of particular species or body-size classes within diverse LMH guilds are difficult to pinpoint, and the magnitude and even direction of these effects often depends on environmental context. Since 2008, we have maintained the Ungulate Herbivory Under Rainfall Uncertainty (UHURU) experiment, a series of size-selective LMH exclosures replicated across a rainfall/productivity gradient in a semiarid Kenyan savanna. The goals of the UHURU experiment are to measure the effects of removing successively smaller size classes of LMH (mimicking the process of size-biased extirpation) and to establish how these effects are shaped by spatial and temporal variation in rainfall. The UHURU experiment comprises three LMH-exclusion treatments and an unfenced control, applied to nine randomized blocks of contiguous 1-ha plots (n = 36). The fenced treatments are MEGA (exclusion of megaherbivores, elephant and giraffe), MESO (exclusion of herbivores ≥40 kg), and TOTAL (exclusion of herbivores ≥5 kg). Each block is replicated three times at three sites across the 20-km rainfall gradient, which has fluctuated over the course of the experiment. The first 5 years of data were published previously (Ecological Archives E095-064) and have been used in numerous studies. Since that publication, we have (1) continued to collect data following the original protocols, (2) improved the taxonomic resolution and accuracy of plant and small-mammal identifications, and (3) begun collecting several new data sets. Here, we present updated and extended raw data from the first 12 years of the UHURU experiment (2008-2019). Data include daily rainfall data throughout the experiment; annual surveys of understory plant communities; annual censuses of woody-plant communities; annual measurements of individually tagged woody plants; monthly monitoring of flowering and fruiting phenology; every-other-month small-mammal mark-recapture data; and quarterly large-mammal dung surveys. There are no copyright restrictions; notification of when and how data are used is appreciated and users of UHURU data should cite this data paper when using the data.


Assuntos
Ecossistema , Herbivoria , Animais , Pradaria , Herbivoria/fisiologia , Quênia , Mamíferos
16.
Ecol Appl ; 32(3): e2536, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35038207

RESUMO

Woody-plant encroachment is a global phenomenon that has been affecting the southwestern United States since the late 1800s. Drought, overgrazing, herbivory, and competition between grasses and shrub seedlings have been hypothesized as the main drivers of shrub establishment. However, there is limited knowledge about the interactions among these drivers. Using a rainfall manipulation system and various herbivore exclosures, we tested hypotheses about how precipitation (PPT), competition between grasses and shrub seedlings, and predation affect the germination and first-year survival of mesquite (Prosopis glandulosa), a shrub that has encroached in Southern Great Plains and Chihuahuan Desert grasslands. We found that mesquite germination and survival (1) increased with increasing PPT, then saturated at about the mean growing season PPT level, (2) that competition between grasses and shrub seedlings had no effect on either germination or survival, and (3) that herbivory by small mammals decreased seedling establishment and survival, while ant granivory showed no effect. In addition to its direct positive effect on survival, PPT had an indirect negative effect via increasing small mammal activity. Current models predict a decrease in PPT in the southwestern United States with increased frequency of extreme events. The non-linear nature of PPT effects on Mesquite recruitment suggests asymmetric responses, wherein drought has a relatively greater negative effect than the positive effect of wet years. Indirect effects of PPT, through its effects on small mammal abundance, highlight the importance of accounting for interactions between biotic and abiotic drivers of shrub encroachment. This study provides quantitative basis for developing tools that can inform effective shrub management strategies in grasslands and savannas.


Assuntos
Poaceae , Prosopis , Animais , Ecossistema , Herbivoria/fisiologia , Mamíferos , Plantas , Prosopis/fisiologia
17.
Nat Commun ; 13(1): 129, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013233

RESUMO

Large mammal herbivores are important drivers of plant evolution and vegetation patterns, but the extent to which plant trait and ecosystem geography currently reflect the historical distribution of extinct megafauna is unknown. We address this question for South and Central America (Neotropical biogeographic realm) by compiling data on plant defence traits, climate, soil, and fire, as well as on the historical distribution of extinct megafauna and extant mammal herbivores. We show that historical mammal herbivory, especially by extinct megafauna, and soil fertility explain substantial variability in wood density, leaf size, spines and latex. We also identified three distinct regions (''antiherbiomes''), differing in plant defences, environmental conditions, and megafauna history. These patterns largely matched those observed in African ecosystems, where abundant megafauna still roams, and suggest that some ecoregions experienced savanna-to-forest shifts following megafauna extinctions. Here, we show that extinct megafauna left a significant imprint on current ecosystem biogeography.


Assuntos
Adaptação Fisiológica , Coevolução Biológica , Extinção Biológica , Herbivoria/fisiologia , Defesa das Plantas contra Herbivoria/fisiologia , Dispersão Vegetal/fisiologia , Plantas/classificação , África , Animais , América Central , Ecossistema , Incêndios/história , Florestas , História Antiga , Mamíferos , Filogeografia , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Plantas/anatomia & histologia , Solo , Clima Tropical
18.
Plant Cell ; 34(5): 1497-1513, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35026025

RESUMO

Plant defense responses against insect herbivores are induced through wound-induced signaling and the specific perception of herbivore-associated molecular patterns (HAMPs). In addition, herbivores can deliver effectors that suppress plant immunity. Here we review plant immune recognition of HAMPs and effectors, and argue that these initial molecular interactions upon a plant-herbivore encounter mediate and structure effective resistance. While the number of distinct HAMPs and effectors from both chewing and piercing-sucking herbivores has expanded rapidly with omics-enabled approaches, paired receptors and targets in the host are still not well characterized. Herbivore-derived effectors may also be recognized as HAMPs depending on the host plant species, potentially through the evolution of novel immune receptor functions. We compile examples of HAMPs and effectors where natural variation between species may inform evolutionary patterns and mechanisms of plant-herbivore interactions. Finally, we discuss the combined effects of wounding and HAMP recognition, and review potential signaling hubs, which may integrate both sensing functions. Understanding the precise mechanisms for plant sensing of herbivores will be critical for engineering resistance in agriculture.


Assuntos
Herbivoria , Plantas , Animais , Herbivoria/fisiologia , Insetos/fisiologia , Imunidade Vegetal/genética , Plantas/genética , Transdução de Sinais
19.
Sci Rep ; 12(1): 482, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013461

RESUMO

Jarman-Bell (1974) hypothesized that in the dry savanna of Africa, small-bodied herbivores tend to browse more on forage with high protein and low fibre content. This implies browsing on high nutritive forage by meso-herbivores, and grazing and mixed feeding on coarse forage by mega-herbivores. We tested this hypothesis in the riverine alluvial grasslands of the Kaziranga National Park (KNP), where seasonal flood and fire play an important role in shaping the vegetation structure. We analyzed the feeding habits and quality of major forage species consumed by three mega-herbivores, viz. greater one-horned rhino, Asian elephant, and Asiatic wild buffalo, and three meso-herbivores, viz. swamp deer, hog deer, and sambar. We found that both mega and meso-herbivores were grazers and mixed feeders. Overall, 25 forage plants constituted more than 70% of their diet. Among monocots, family Poaceae with Saccharum spp. (contributing > 9% of the diet), and, among dicots, family Rhamnaceae with Ziziphus jujuba (contributing > 4% of the diet) fulfilled the dietary needs. In the dry season, the concentration of crude protein, neutral detergent fibre, calcium, sodium, and phosphorous varied significantly between monocots and dicots, whereas only calcium and sodium concentrations varied significantly in the wet season. Dicots were found to be more nutritious throughout the year. Compared to the dry season, the monocots, viz. Alpinia nigra, Carex vesicaria, Cynodon dactylon, Echinochloa crus-galli, Hemarthria compressa, Imperata cylindrica, and Saccharum spp., with their significantly high crude protein, were more nutritious during the wet season. Possibly due to the availability of higher quality monocots in the wet season, both mega and meso-herbivores consume it in high proportion. We concluded that the Jarman-Bell principle does not apply to riverine alluvial grasslands as body size did not explain the interspecific dietary patterns of the mega and meso-herbivores. This can be attributed to seasonal floods, habitat and forage availability, predation risk, and management practices such as controlled burning of the grasslands. The ongoing succession and invasion processes, anthropogenic pressures, and lack of grassland conservation policy are expected to affect the availability of the principal forage and suitable habitat of large herbivores in the Brahmaputra floodplains, which necessitates wet grassland-based management interventions for the continued co-existence of large herbivores in such habitats.


Assuntos
Animais Selvagens/fisiologia , Comportamento Alimentar , Herbivoria/fisiologia , Animais , Ecossistema , Inundações , Pradaria , Índia , Parques Recreativos , Plantas/química , Plantas/classificação , Plantas/metabolismo , Estações do Ano
20.
New Phytol ; 233(2): 618-623, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34506634

RESUMO

The ability to predict future risks is essential for many organisms, including plants. Plants can gather information about potential future herbivory by detecting volatiles that are emitted by herbivore-attacked neighbors. Several individual volatiles have been identified as active danger cues. Recent work has also shown that plants may integrate multiple volatiles into their defense responses. Here, I discuss how the integration of multiple volatiles can increase the capacity of plants to predict future herbivore attack. I propose that integration of multiple volatile cues does not occur at the perception stage, but may through downstream early defense signaling and then be further consolidated by hormonal crosstalk. Exploring plant volatile cue integration can facilitate our understanding and utilization of chemical information transfer.


Assuntos
Sinais (Psicologia) , Compostos Orgânicos Voláteis , Herbivoria/fisiologia , Plantas , Compostos Orgânicos Voláteis/química
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