Carnivorous plants secrete digestive enzymes for prey degradation. Although carnivorous plants have a polyphyletic origin and evolved several times independently, they surprisingly co-opted similar digestive enzymes during convergent evolution. However, despite having similar digestive enzymes, the mode of their regulation strongly differs across different phylogenetic lineages. But what factors are responsible for such diversity in their digestion? By combining phylogenetic relationships of digestive fluid proteins and biochemical data, the analyses showed that phylogeny seems to be a significant factor determining the regulation of digestion, but environment (water vs terrestrial) and type of trap do not affect regulation. The oldest carnivorous plant lineage, Caryophyllales, co-opted phytohormone jasmonic acid (JA) for regulation of digestive enzyme activity. However, the remaining orders of carnivorous plants do not accumulate JA in response to prey capture, and their digestive enzyme activity is not responsive to exogenous JA application. Instead, they use different modes of regulation, for example, development/senescence, osmotically induced and constitutive. These different modes of regulation can be explained by co-option, albeit of similar genes but different paralogs with different cis regulatory elements that have been fine-tuned during evolution.

• Keywords
• Venus flytrap, carnivorous plants, digestive enzymes, jasmonic acid, pitcher plant,
• MeSH
• Biological Evolution * MeSH
• Cyclopentanes metabolism   MeSH
• Phylogeny MeSH
• Carnivorous Plant * physiology   enzymology   genetics   MeSH
• Oxylipins metabolism   MeSH
• Digestion * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Cyclopentanes MeSH
• jasmonic acid MeSH Browser
• Oxylipins MeSH

Carnivorous plants from the order Caryophyllales co-opted plant phytohormones from a group of jasmonates to regulate digestive enzyme activity. However, not all genera of carnivorous plants have been thoroughly explored, and the digestive physiology of Australian carnivorous rainbow plants of the genus Byblis (order Lamiales) is poorly understood. Here, we investigated the composition of digestive enzymes in the secreted fluid of Byblis filifolia using LC/MS, measured enzyme activity, and analysed tissue phytohormone levels after experimental feeding with fruit flies and coronatine application. Several hydrolytic digestive enzymes were identified in the secreted digestive fluid, the levels of which clearly increased in the presence of insect prey. However, in contrast to the sundew Drosera capensis, endogenous jasmonates do not accumulate, and coronatine, a molecular mimic of jasmonates, is unable to trigger enzyme secretion. Our results showed that B. filifolia is fully carnivorous, with its own digestive enzyme repertoire. However, in contrast to carnivorous genera from the Caryophyllales order, these enzymes are not regulated by jasmonates. This indicates that jasmonates have not been repeatedly co-opted to regulate digestive enzyme activity during the evolution of carnivorous plants.

• Keywords
• Byblis, Carnivorous plant, Drosera, digestive enzyme, jasmonic acid, phytohormones, sundew,
• MeSH
• Amino Acids metabolism   pharmacology   MeSH
• Caryophyllales * enzymology   physiology   metabolism   MeSH
• Cyclopentanes * metabolism   MeSH
• Drosera physiology   MeSH
• Indenes metabolism   pharmacology   MeSH
• Carnivorous Plant * enzymology   physiology   metabolism   MeSH
• Oxylipins * metabolism   MeSH
• Plant Growth Regulators * metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Acids MeSH
• coronatine MeSH Browser
• Cyclopentanes * MeSH
• Indenes MeSH
• jasmonic acid MeSH Browser
• Oxylipins * MeSH
• Plant Growth Regulators * MeSH

The carnivorous plants in the order Caryophyllales co-opted jasmonate signalling from plant defence to botanical carnivory. However, carnivorous plants have at least 11 independent origins, and here we ask whether jasmonate signalling has been co-opted repeatedly in different evolutionary lineages. We experimentally wounded and fed the carnivorous plants Sarracenia purpurea (order Ericales), Cephalotus follicularis (order Oxalidales), Drosophyllum lusitanicum (order Caryophyllales), and measured electrical signals, phytohormone tissue level, and digestive enzymes activity. Coronatine was added exogenously to confirm the role of jasmonates in the induction of digestive process. Immunodetection of aspartic protease and proteomic analysis of digestive fluid was also performed. We found that prey capture induced accumulation of endogenous jasmonates only in D. lusitanicum, in accordance with increased enzyme activity after insect prey or coronatine application. In C. follicularis, the enzyme activity was constitutive while in S. purpurea was regulated by multiple factors. Several classes of digestive enzymes were identified in the digestive fluid of D. lusitanicum. Although carnivorous plants from different evolutionary lineages use the same digestive enzymes, the mechanism of their regulation differs. All investigated genera use jasmonates for their ancient role, defence, but jasmonate signalling has been co-opted for botanical carnivory only in some of them.

• Keywords
• Aspartic protease, carnivorous plant, digestive enzymes, electrical signal, jasmonic acid, phytohormone, plant defence, wounding,
• MeSH
• Carnivory * MeSH
• Carnivorous Plant * MeSH
• Proteomics MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• coronatine MeSH Browser
• jasmonic acid MeSH Browser

In his famous book Insectivorous plants, Charles Darwin observed that the bending response of tentacles in the carnivorous sundew plant Drosera rotundifolia was not triggered by a drop of water, but rather the application of many dissolved chemicals or mechanical stimulation. In this study, we tried to reveal this 150-years-old mystery using methods not available in his time. We measured electrical signals, phytohormone tissue level, enzyme activities and an abundance of digestive enzyme aspartic protease droserasin in response to different stimuli (water drop, ammonia, mechanostimulation, chitin, insect prey) in Cape sundew (Drosera capensis). Drops of water induced the lowest number of action potentials (APs) in the tentacle head, and accumulation of jasmonates in the trap was not significantly different from control plants. On the other hand, all other stimuli significantly increased jasmonate accumulation; the highest was found after the application of insect prey. Drops of water also did not induce proteolytic activity and an abundance of aspartic protease droserasin in contrast to other stimuli. We found that the tentacles of sundew plants are not responsive to water drops due to an inactive jasmonic acid signalling pathway, important for the induction of significant digestive enzyme activities.

• Keywords
• abscisic acid, aspartic protease, carnivorous plant, digestive enzyme, jasmonic acid, sundew,
• Publication type
• Journal Article MeSH

Nepenthespudica, a new species from North Kalimantan, Indonesia, is described and illustrated. The species belongs to the N.hirsuta group (sensu Cheek and Jebb 1999) but exhibits some characters that are unique within the group or even within the genus. Above all, it produces underground, achlorophyllous shoots with well-developed, ventricose lower pitchers that form in soil cavities or directly in the soil. No lower pitchers are formed above ground. The main part of its prey are ants, besides other litter- and soil-inhabiting species of invertebrates. A number of infaunal species were found in both aerial and underground pitchers, mainly Diptera and nematodes. Nepenthespudica is known only from a few neighbouring localities in the Mentarang Hulu district of North Kalimantan, where it grows on ridgetops at an elevation of 1100-1300 m. Its discovery underlines the natural richness of Borneo's rainforest and the necessity to preserve this important ecosystem with its enormous and still undiscovered biodiversity.

• Keywords
• Borneo, Caryophyllales, Mentarang Hulu, carnivorous plant, prey composition, taxonomy, underground trap,
• Publication type
• Journal Article MeSH

BACKGROUND AND AIMS: The carnivorous pitcher plants of the genus Nepenthes have evolved modified leaves that act as pitcher traps. The traps are specialized for prey attraction, capture, digestion and nutrient uptake but not for photosynthetic assimilation. METHODS: In this study, we used antibodies against different photosynthetic (D1, Lhcb2, Lhcb4, RbcL) and respiratory-related (AOX, COXII) proteins for semi-quantification of these proteins in the assimilation part of the leaves and the pitcher traps of different Nepenthes species and hybrids. Different functional zones of the trap and the traps from different ontogenetic stages were investigated. The pitcher traps of the distantly related species Sarracenia purpurea ssp. venosa were used as an outgroup. In addition, chlorophyll fluorescence and infrared gas analysis were used for measurements of the net rate of photosynthesis (AN) and respiration in the dark (RD). KEY RESULTS: The pitcher traps contained the same or lower abundance of photosynthesis-related proteins in accordance with their low AN in comparison to the assimilation part of the leaves. Surprisingly, all traps contained a high amount of alternative oxidase (AOX) and low amount of cytochrome c oxidase subunit II (COX II) than in the assimilation part of the leaves. Thermal imaging did not confirm the role of AOX in pitcher thermogenesis. CONCLUSIONS: The pitcher traps contain a high amount of AOX enzyme. The possible role of AOX in specialized pitcher tissue is discussed based on knowledge of the role and function of AOX in non-carnivorous plants. The roles of AOX in prey attraction, balance between light and dark reactions of photosynthesis, homeostasis of reactive oxygen species, digestive physiology and nutrient assimilation are discussed.

• Keywords
• Nepenthes, Sarracenia purpurea, Alternative oxidase, carnivorous plant, cytochrome c oxidase, photosynthesis, pitcher plant, respiration,
• MeSH
• Carnivorous Plant * MeSH
• Mitochondrial Proteins MeSH
• Organic Chemicals MeSH
• Oxidoreductases MeSH
• Plant Proteins metabolism   MeSH
• Sarraceniaceae * metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• alternative oxidase MeSH Browser
• Mitochondrial Proteins MeSH
• nepenthe MeSH Browser
• Organic Chemicals MeSH
• Oxidoreductases MeSH
• Plant Proteins MeSH

BACKGROUND: Carnivorous plants are an ecological group of approx. 810 vascular species which capture and digest animal prey, absorb prey-derived nutrients and utilize them to enhance their growth and development. Extant carnivorous plants have evolved in at least ten independent lineages, and their adaptive traits represent an example of structural and functional convergence. Plant carnivory is a result of complex adaptations to mostly nutrient-poor, wet and sunny habitats when the benefits of carnivory exceed the costs. With a boost in interest and extensive research in recent years, many aspects of these adaptations have been clarified (at least partly), but many remain unknown. SCOPE: We provide some of the most recent insights into substantial ecophysiological, biochemical and evolutional particulars of plant carnivory from the functional viewpoint. We focus on those processes and traits in carnivorous plants associated with their ecological characterization, mineral nutrition, cost-benefit relationships, functioning of digestive enzymes and regulation of the hunting cycle in traps. We elucidate mechanisms by which uptake of prey-derived nutrients leads to stimulation of photosynthesis and root nutrient uptake. CONCLUSIONS: Utilization of prey-derived mineral (mainly N and P) and organic nutrients is highly beneficial for plants and increases the photosynthetic rate in leaves as a prerequisite for faster plant growth. Whole-genome and tandem gene duplications brought gene material for diversification into carnivorous functions and enabled recruitment of defence-related genes. Possible mechanisms for the evolution of digestive enzymes are summarized, and a comprehensive picture on the biochemistry and regulation of prey decomposition and prey-derived nutrient uptake is provided.

• Keywords
• Dionaea, Drosera, Nepenthes, Carnivorous plant, co-option, cost–benefit relationships, digestive enzymes, evolution of carnivory, hunting cycle, mineral nutrient economy, regulation of enzyme secretion, terrestrial and aquatic species,
• MeSH
• Photosynthesis MeSH
• Plant Leaves MeSH
• Carnivory * MeSH
• Plants * genetics   MeSH
• Nutrients MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Carnivorous plants within the order Caryophyllales use jasmonates, a class of phytohormone, in the regulation of digestive enzyme activities. We used the carnivorous butterwort Pinguicula × Tina from the order Lamiales to investigate whether jasmonate signaling is a universal and ubiquitous signaling pathway that exists outside the order Caryophyllales. We measured the electrical signals, enzyme activities, and phytohormone tissue levels in response to prey capture. Mass spectrometry was used to identify proteins in the digestive secretion. We identified eight enzymes in the digestive secretion, many of which were previously found in other genera of carnivorous plants. Among them, alpha-amylase is unique in carnivorous plants. Enzymatic activities increased in response to prey capture; however, the tissue content of jasmonic acid and its isoleucine conjugate remained rather low in contrast to the jasmonate response to wounding. Enzyme activities did not increase in response to the exogenous application of jasmonic acid or coronatine. Whereas similar digestive enzymes were co-opted from plant defense mechanisms among carnivorous plants, the mode of their regulation differs. The butterwort has not co-opted jasmonate signaling for the induction of enzyme activities in response to prey capture. Moreover, the presence of alpha-amylase in digestive fluid of P. × Tina, which has not been found in other genera of carnivorous plants, might indicate that non-defense-related genes have also been co-opted for carnivory.

• Keywords
• Pinguicula, Butterwort, carnivorous plant, digestive enzymes, electrical signals, jasmonic acid, protease, variation potential,
• MeSH
• Cyclopentanes MeSH
• Lamiales * MeSH
• Carnivory * MeSH
• Oxylipins MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cyclopentanes MeSH
• jasmonic acid MeSH Browser
• Oxylipins MeSH

BACKGROUND AND AIMS: Carnivorous plants can enhance photosynthetic efficiency in response to prey nutrient uptake, but the underlying mechanisms of increased photosynthesis are largely unknown. Here we investigated photosynthesis in the pitcher plant Nepenthes × ventrata in response to different prey-derived and root mineral nutrition to reveal photosynthetic constrains. METHODS: Nutrient-stressed plants were irrigated with full inorganic solution or fed with four different insects: wasps, ants, beetles or flies. Full dissection of photosynthetic traits was achieved by means of gas exchange, chlorophyll fluorescence and immunodetection of photosynthesis-related proteins. Leaf biochemical and anatomical parameters together with mineral composition, nitrogen and carbon isotopic discrimination of leaves and insects were also analysed. KEY RESULTS: Mesophyll diffusion was the major photosynthetic limitation for nutrient-stressed Nepenthes × ventrata, while biochemistry was the major photosynthetic limitation after nutrient application. The better nutrient status of insect-fed and root-fertilized treatments increased chlorophyll, pigment-protein complexes and Rubisco content. As a result, both photochemical and carboxylation potential were enhanced, increasing carbon assimilation. Different nutrient application affected growth, and root-fertilized treatment led to the investment of more biomass in leaves instead of pitchers. CONCLUSIONS: The study resolved a 35-year-old hypothesis that carnivorous plants increase photosynthetic assimilation via the investment of prey-derived nitrogen in the photosynthetic apparatus. The equilibrium between biochemical and mesophyll limitations of photosynthesis is strongly affected by the nutrient treatment.

• Keywords
• Nepenthes, CO2 assimilation, Carnivorous, Rubisco, mesophyll conductance, mineral nutrition, nutrient stress, photosynthesis,
• MeSH
• Chlorophyll MeSH
• Photosynthesis * MeSH
• Plant Leaves MeSH
• Carnivory * MeSH
• Organic Chemicals MeSH
• Carbon Dioxide MeSH
• Nutrients MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Chlorophyll MeSH
• nepenthe MeSH Browser
• Organic Chemicals MeSH
• Carbon Dioxide MeSH

BACKGROUND AND AIMS: General anaesthetics are compounds that induce loss of responsiveness to environmental stimuli in animals and humans. The primary site of action of general anaesthetics is the nervous system, where anaesthetics inhibit neuronal transmission. Although plants do not have neurons, they generate electrical signals in response to biotic and abiotic stresses. Here, we investigated the effect of the general volatile anaesthetic diethyl ether on the ability to sense potential prey or herbivore attacks in the carnivorous plant Venus flytrap (Dionaea muscipula). METHODS: We monitored trap movement, electrical signalling, phytohormone accumulation and gene expression in response to the mechanical stimulation of trigger hairs and wounding under diethyl ether treatment. KEY RESULTS: Diethyl ether completely inhibited the generation of action potentials and trap closing reactions, which were easily and rapidly restored when the anaesthetic was removed. Diethyl ether also inhibited the later response: jasmonic acid (JA) accumulation and expression of JA-responsive genes (cysteine protease dionain and type I chitinase). However, external application of JA bypassed the inhibited action potentials and restored gene expression under diethyl ether anaesthesia, indicating that downstream reactions from JA are not inhibited. CONCLUSIONS: The Venus flytrap cannot sense prey or a herbivore attack under diethyl ether treatment caused by inhibited action potentials, and the JA signalling pathway as a consequence.

• Keywords
• Dionaea muscipula, Anaesthesia, Venus flytrap, action potential, anaesthetic, carnivorous plant, diethyl ether, electrical signal, jasmonic acid, plant movement,
• MeSH
• Anesthesia * MeSH
• Cyclopentanes MeSH
• Droseraceae * MeSH
• Ether MeSH
• Oxylipins MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cyclopentanes MeSH
• Ether MeSH
• jasmonic acid MeSH Browser
• Oxylipins MeSH