Aerial Parasitism Research Articles

Pharmacological activities of parasitic plants of Loranthaceae – A review

Medicinal plants are the part of human Society to combat many disorders. The plant derived drugs and other herbal therapeutics are widely used against several malfunctions. Other than medicinal herbs, mistletoe–hemi parasitic plants are also used to treat many diseases. Usually, mistletoe family is recognized based on their host plants. Loranthaceae, the largest family in the order Santalales with 76 genera and more than 1,100 species. Most of the Loranthaceae family members are aerial parasites. Family comprises of 10 genera and 60 species which are found in India. It has been scientifically established that every part of these plants has medicinal properties (flower, stem, leaf, fruits, seed and whole plants). Only a few species are having potential traditional medicinal values and extensively used in several medicinal systems. Dendrophthoe falcata holds the major part in this taxon. This species shows traditional medicinal values in Indian Ayurvedic system of medicine and other systems of natural medicine widely. There are many biologically active components present in the parasitic plants, flavonoid, quercetin, kaempferol, rutin, tannins, β- sitosterol, stigmasterol, β- amyrin and oleanolic acid. Dendrophthoe falcata was rich in flavonoids and quercetin and the major components are reportedly present in the leaves. Quercitrin (quercetin 3-0-α- rhamnoside) has been separately isolated as a major component from the ethanolic extract of Dendrophthoe falcata leaves and this quercitrin phytochemical is highly responsible for antioxidative potency. Nanoparticles phytosynthesized from these plants are also studied for their pharmacological activities. It has been revealed that the medicinal properties of mistletoes based on host plants are scanty.

Did Mammals Bring the First Mistletoes into the Treetops?

AbstractThe growth habit of mistletoes, the only woody, parasitic plants to infect host canopies, represents a key innovation. How this aerially parasitic habit originated is unknown; mistletoe macrofossils are relatively recent, from long after they adapted to canopy life and evolved showy, bird-pollinated flowers; sticky, bird-dispersed seeds; and woody haustoria diverting water and nutrients from host branches. Since the transition to aerial parasitism predates the origin of mistletoes' contemporary avian seed dispersers by 20-40 million years, this leaves unanswered the question of who the original mistletoe dispersers were. By integrating fully resolved phylogenies of mistletoes and aligning the timing of historic events, I identify two ancient mammals as likely candidates for planting Viscaceae and Loranthaceae in the canopy. Just as modern mouse lemurs and galagos disperse viscaceous mistletoe externally (grooming the sticky seeds from their fur), Cretaceous primates (e.g., Purgatorius) may have transported seeds of root-parasitic understory shrubs up into the canopy of Laurasian forests. In the Eocene, ancestors of today's mistletoe-dispersing marsupials, Dromiciops, likely fed on the nutritious fruit of root-parasitic loranthaceous shrubs, depositing the seeds atop western Gondwanan forest crowns. Once mistletoes colonized the canopy, subsequent evolution and diversification coincided with the rise of nectar- and fruit-dependent birds.

Morphology, geographic distribution, and host preferences are poor predictors of phylogenetic relatedness in the mistletoe genus Viscum L.

Besides their alleged therapeutic effects, mistletoes of the genus Viscum L. (Viscaceae) are keystone species in many ecosystems across Europe, Africa, Asia and Australia because of their complex faunal interactions. We here reconstructed the evolutionary history of Viscum based on plastid and nuclear DNA sequence data. We obtained a highly resolved phylogenetic tree with ten well-supported clades, which we used to understand the spatio-temporal evolution of these aerial parasites and evaluate the contribution of reproductive switches and shifts in host ranges to their distribution and diversification. The genus Viscum originated in the early Eocene in Africa and appeared to have diversified mainly through geographic isolation, in several cases apparently coinciding with shifts in host preferences. During its evolution, switches in the reproductive mode from ancestral dioecy to monoecy imply an important role in the long-distance dispersal of the parasites from Africa to continental Asia and Australia. We also observed multiple cases of photosynthetic surface reduction (evolution of scale leaves) within the genus, probably indicative of increasing specialization associated with the parasitic lifestyle. Even compared with other parasitic angiosperms, where more host generalists than specialists exist, Viscum species are characterized by extraordinarily broad host ranges. Specialization on only a few hosts from a single family or order occurs rarely and is restricted mostly to very recently evolved lineages. The latter mostly derive from or are closely related to generalist parasites, implying that niche shifting to a new host represents an at least temporary evolutionary advantage in Viscum.

The status of the mistletoe genus Dufrenoya Chatin (Amphorogynaceae) with a specific focus on Nepal

The genus Dufrenoya Chatin (Amphorogynaceae) is a rarely collected and studied aerial parasite found of southeastern Asia. Our goal is to provide a modern treatment of the genus for Nepal where two species occur: D. platyphylla (the type of the genus), and D. granulata. Fresh, fixed, and dried material of the former species and herbarium material of the latter was examined and used to prepare morphological descriptions. In addition, the ITS rDNA region was sequenced and phylogenetic analyses conducted on five genera of Amphorogynaceae. Strong support for the sister relationship between Dufrenoya and Phacellaria was obtained. The complex nomenclatural history of Dufrenoya is reviewed and discussed in the context of intergeneric relationships in the family. The morphology and anatomy of flowers and fruits are photographically illustrated and discussed. Collections of both species plotted on a map of Nepal showing ecological zones and physiographic regions indicates Dufrenoya is primarily distributed in the Middle Mountains region.

Phylogenetic relationships of Santalales with insights into the origins of holoparasitic Balanophoraceae

AbstractTo date molecular data have not revealed the exact phylogenetic position of Balanophoraceae in relation to hemiparasitic Santalales. To elucidate the phylogeny of Santalales and the position of Balanophoraceae, three plastid genes (matK, rbcL, accD), three nuclear genes (SSU and LSU rDNA and RPB2) and one mitochondrial gene (matR) from 197 Santalales samples (including 11 Balanophoraceae species) were analyzed with parsimony, maximum likelihood and Bayesian inference methods. Our results demonstrate that Balanophoraceae is composed of two well‐supported clades: a relatively slow‐evolving one including Dactylantus, Hachettea, and Mystropetalon (Mystropetalaceae) and an extremely fast‐evolving one composed of the remaining Balanophoraceae s.str. Support for monophyly of the two clades was low, thus it appears holoparasitism has arisen twice independently in Santalales. These two clades appeared during a time of great change in the order (ca. 100 Ma) when several major evolutionary innovations emerged, e.g., the root hemiparasites of Santalaceae s.l., the first aerial parasites (Misodendraceae), herbaceous root parasites (Schoepfiaceae), root parasitic Loranthaceae (the ancestors of aerial parasitic mistletoes), as well as the holoparasites in Balanophoraceae and Mystropetalaceae.

New State Record for the Army AntNeivamyrmex texanus(Hymenoptera: Formicidae) and New Report of the Dipteran ParasiteCremersia adunca(Diptera: Phoridae)

Abstract The known distribution of the army ant Neivamyrmex texanus in the United States is limited to eight southern and western states. The range of N. texanus is extended to Oklahoma. Neivamyrmex texanus is the known host of only two symbionts. I report for the first time a parasitic phorid fly, Cremersia adunca, and include a brief description of the defensive behavior of the army ants to this aerial parasite.

Mistletoe specialist frugivores: latterday ‘Johnny Appleseeds’ or self-serving market gardeners?

Many plants use birds to disperse their propagules, but mistletoes are especially reliant on their services. As aerial parasites, mistletoe seeds need to be deposited upon branches of suitable hosts, and mistletoe specialist frugivores (from eight different avian families) have long been regarded as their coevolved dispersers. Like the pioneer Johnny 'Appleseed' Chapman who established nurseries that helped open up land for settlement, these birds are considered benevolent dispersers of this keystone resource and often invoked as illustrative examples of mutualistic interactions. We have compared recent research on these specialists with studies of other birds with broader diets (generalists) which also disperse mistletoe seed. Rather than mutualists, we suggest that mistletoe specialist frugivores are better considered exploitative, with multiple lineages evolving independently to capitalize on this reliable, nutritious resource. Although mistletoe specialist frugivores are quantitatively important seed dispersers in some regions, their specialized diet restricts them to areas with high mistletoe densities, resulting in contagious dispersal patterns. By intensifying existing infections, mistletoe specialist frugivores increase their own medium-term food security-akin to market gardeners profiting from intensive cultivation. Exploring the ecological and evolutionary implications of this proposition, we evaluate the consequences of different dispersal patterns on mistletoe fitness and highlight the neglected role of dietary generalists in the stabilization of plant-animal interactions.

Biosurfactants in Dwarf Mistletoe (<i>Arceuthobium</i>)

flowering plants that parasitize members of Pinaceae and Cupressaceae throughout North America, Central America, Asia, and Africa. As DMT is an aerial parasite that disrupts water relations, we suspected that he plant might contain biosurfactants, biologically-derived agents that act to lower surface tension. Using an oil drop assay coupled to image analysis, we detected biosurfactants in a crude methanol extract from stem tissue and subsequently performed three purification steps, quantifying the extract at each successive stage of purification in its ability to reduce surface tension. The biosurfactant in the final purified sample elicited a spread of 4.31 ± 0.15 mm in the oil drop assay. This value, which is significantly different than those of the negative controls ( p <0.01), reflects a drop in water surface tension from 72 mN/m to under 30 mN/m, a purification factor of 575-fold, and a significantly more active ( p <0.05) purified sample relative to the crude. The biosurfactant has a critical micellar concentration (CMC) of 8.50 g/L and consists of a short alkyl chain with aromatic groups and peptide bonds, based on preliminary 1 H and 13 C NMR spectroscopic analysis. These structural components are more consistent with a bacterially-produced polymyxin as opposed to a plantproduced saponin. The polarity of the DMT biosurfactant lies between the polarity of chloroform and that of a 6:4 methanol:water solution. Key Words: Arceuthobium americanum , biosurfactants, dwarf mistletoe, oil drop assay, parasite, surface tension, surfactin, water relations.

A revised classification of Santalales

AbstractWe present here a revised classification of Santalales, an angiosperm order that contains 18 families, 160 genera, and over 2200 species. Both nonparasitic and parasitic flowering plants occur in the traditionally circumscribed family Olacaceae whereas all other families are composed entirely of parasites. The five evolutionary radiations of aerial parasitism produced mistletoes that constitute most of the generic and specific diversity seen in the order. This classification, although based primarily upon results from molecular phylogenetic investigations, brings together all currently available information that contributes to our understanding of relationships among these plants. Monophyletic groups (clades) obtained from molecular analyses were named using a Linnaean ranked system. Four new families are named that formerly resided in Santalaceae s.l.: Amphorogynaceae, Cervantesiaceae, Comandraceae, and Nanodeaceae. A new tribal and subtribal classification for Loranthaceae is presented where nine new subtribe names are proposed.

Evolutionary relationships in the showy mistletoe family (Loranthaceae)

Loranthaceae (73 genera and ca. 900 species) comprise mostly aerial hemiparasitic plants. Three monotypic genera considered relicts are root parasites. The family is diverse in tropical areas, but representatives are also found in temperate habitats. Previous classifications were based on floral and inflorescence morphology, karyological information, and biogeography. The family has been divided into three tribes: Nuytsiae, Elytrantheae (subtribes Elytranthinae and Gaiadendrinae), and Lorantheae (subtribes Loranthinae and Psittacanthinae). Nuytsiae and Elytrantheae are characterized by a base chromosome number of x = 12, whereas subtribes Loranthinae (x = 9) and Psittacanthinae (x = 8) numbers are derived via aneuploid reduction. To elucidate the phylogeny of the family, we analyzed sequences from five genes (nuclear small and large subunit rDNA and the chloroplast genes rbcL, matK, and trnL-F) representing most genera using parsimony, likelihood, and Bayesian inference. The three root parasites, Nuytsia, Atkinsonia, and Gaiadendron, are supported as successive sister taxa to the remaining genera, resulting in a monophyletic group of aerial parasites. Three major clades are resolved each corresponding to a subtribe. However, two South American genera (Tristerix and Notanthera) and the New Zealand genus Tupeia, which were previously classified in subtribe Elytranthinae, are weakly supported as part of a clade representing the South American subtribe Psittacanthinae.

The first mistletoes: Origins of aerial parasitism in Santalales

Past molecular phylogenetic work has shown that aerial parasites have evolved five times independently in the sandalwood order (Santalales), but the absolute timing of these diversifications was not addressed. DNA sequences from nuclear SSU and LSU rDNA, and chloroplast rbcL, matK and trnL-F from 39 santalalean taxa were obtained. Separate and combined data partitions were analyzed with maximum parsimony and Bayesian inference. Time estimates were performed with Bayesian relaxed molecular clock and penalized likelihood methods using published fossil data. Both methods gave comparable divergence dates for the major clades. These data confirm five origins of aerial parasitism, first in Misodendraceae ca. 80Mya and subsequently in Viscaceae (72Mya), “Eremolepidaceae” (53Mya), tribe Amphorogyneae in Santalaceae (46Mya), and Loranthaceae (28Mya). The rapid adaptive radiation and speciation in Loranthaceae coincides with the appearance of savanna biomes during the Oligocene. In all clades except Misodendraceae, it appears that aerial parasites evolved from ancestors that were polymorphic for either root or stem parasitism—a condition here termed amphiphagous. Convergences in morphological features associated with the mistletoe habit have occurred such as the squamate habit, seed attachment structures, unisexual flowers, and loss of chlorophyll.

An origin of aerial branch parasitism in the mistletoe family, Loranthaceae

The large mistletoe family, Loranthaceae, contains 75 genera and approximately 1000 species. The family originated in the Southern Hemisphere and dispersed, apparently early, between fragments of Gondwana. It is now widely distributed on land surfaces of the former supercontinent. The Loranthaceae has three terrestrial, root-parasitic genera-a habit considered ancestral-and 72 genera of aerial, branch parasites. For almost two centuries, the origin of the mistletoe habit has been of interest to biologists. Two main evolutionary pathways have been proposed to explain the transition from terrestrial to aerial parasitism in the family. One theorizes the presence of an intermediate climbing ancestor in the path to the aerial habit. The other proposes a direct transfer from terrestrial to epiphytic growth following the germination of seeds on tree branches. Here we present molecular and morphological evidence that (1) the terrestrial species Nuytsia floribunda is ancestral within the Loranthaceae, (2) aerial parasitism has had multiple origins in the family, (3) the first aerial branch parasites had epicortical roots, and (4) the origin of aerial parasitism in one Old World clade involved the direct transfer from terrestrial to epiphytic growth following the germination of seeds on tree branches. Our results suggest that it is not necessary to evoke a climbing intermediate in the origins of aerial parasitism in the Santalales.

Character divergences and convergences in canopy-dwelling Loranthaceae

The Loranthaceae is the largest plant family with aerial branch parasites termed mistletoes. Three genera of Loranthaceae are terrestrial root parasites and the remaining 72 genera are aerial parasites. Several characters, including habit, haustorial type, germination pattern, pollen morphology, chromosome number, inflorescence morphology and flower merosity, fusion, symmetry and size, are considered to reflect evolutionary relationships within the family. Convergence is a common evolutionary pattern and can confound interpretations of evolution. We investigated character evolution by mapping character states onto a phylogenetic tree based on the nuclear ITS and chloroplast trnL–trnF regions. Convergences in form were found in several characters, including habit, haustorial type, flower symmetry and merosity. These convergences typically correspond to ecological parameters such as pollination syndrome or stresses associated with the canopy habit. Other characters such as chromosome number and germination pattern illustrate divergent evolution among clades.

Comparative morphology of epicortical roots in Old and New World Loranthaceae with reference to root types, origin, patterns of longitudinal extension and potential for clonal growth

The large mistletoe family, Loranthaceae, contains 75 genera, three of which are terrestrial root parasites. The remaining 72 genera are aerial parasites. Four basic haustorial system types are found in aerial genera: epicortical roots (ERs), wood roses, clasping unions and bark strands. The focus of this report is on genera in which ERs are present. Presence of ERs is based on our worldwide collection of haustoria and from literature sources. Our collections include 78% of all aerial genera and 72% of genera with ERs. Collections were analyzed using comparative morphological methods. Of the 72 aerial genera 40 (56%) have ERs and 75% of these are Old World. ERs are the most common haustorial type for Loranthaceae on every major landmass except Africa. Three ER types are described, basal, cauline and adventitious. Basal and adventitious ERs occur in both the Old and New World, whereas cauline ERs are exclusively New World. Adventitious ERs form in a few species in response to injury or epiparasitism. Significant differences occur between basal and cauline ERs in the extent and pattern of elongation, frequency of lateral root formation, and production of haustoria and shoots. Three patterns of axis extension of ERs are recognized, the monochasial sympodium, dichasial sympodium and monopodium. Marked differences in patterns of axis elongation occur between the Old and New World genera analyzed. In Old World taxa 94% of lateral roots contributed to a monochasial sympodium, whereas in New World taxa 84% of root extension was monopodial. Two strategies of resource procurement occur in genera with ERs; the “phalanx” strategy is found in species with basal ERs only, the “guerilla” strategy in New World species with cauline ERs. Species with ERs have the potential for clonal growth through fragmentation of stems, ERs, or both, but the extent of clonal growth in nature is unknown. The large number and wide distribution of genera with ERs add support to the hypothesis that the presence of ERs is an ancestral trait for aerial Loranthaceae.

Photosynthetic Characteristics of Eastern Dwarf Mistletoe (Arceuthobium pusillum Peck) and its Effects on the Needles of Host White Spruce (Picea glauca [Moench] Voss)

Abstract: We studied the biochemical composition and photosynthetic characteristics of the aerial parasite eastern dwarf mistletoe (Arceuthobium pusillum) and the effect of infection on the needles of host white spruce (Picea glauca) in a coastal forest stand in Maine, USA. Eastern dwarf mistletoe was capable of photosynthetic oxygen evolution; however, rates were low and were exceeded by respiratory oxygen consumption at all light intensities through full sunlight. Therefore, eastern dwarf mistletoe acts as a net sink for host photosynthate. Relative to those of uninfected trees, needles from infected branches of white spruce were significantly smaller in terms of length, fresh weight, maximum cross section and the diameter of the vascular cylinder. Needles of uninfected and infected trees did not differ in terms of fresh weight to dry weight ratio, nor in nitrogen, soluble sugar or starch content. Needles of infected trees possessed significantly less α‐carotene and neoxanthin, but did not otherwise differ from uninfected needles in terms of chlorophyll and carotenoid composition. Since specific physiological roles for α‐carotene and neoxanthin have not been described, the functional significance of the decreases in their content is not known. Photosynthetic capacities of needles from infected and uninfected white spruce did not differ significantly, as measured by oxygen evolution. These findings suggest that dwarf mistletoe infection does not substantially perturb host white spruce source‐sink balance at the end of the growing season and that carbon exchange dynamics between the host and parasite are unlikely to fully explain the detrimental effects of infection on white spruce.

Histochemical Responses of Leaves of In Vitro Plantlets ofVitisspp. to Infection withPlasmopara viticola

Leaves excised from in vitro plantlets of Vitis vinifera «Grenache» (susceptible, S), V. rupestris «du Lot» (intermediate, M), and V. rotundifolia «Carlos» (resistant, R) were inoculated with sporangia of Plasmopara viticola and examined microscopically after they were stained with a series of reagents. These three cultivars showed necrotic spots without sporulation (R); diffuse necrosis with limited sporulation and short, highly branched aerial hyphae (M); and no visible necrosis with heavy sporulation and long aerial parasite hyphae (S). During histochemical studies, a blue autofluorescence (trans-resveratrol) was detected at 1 day on R, at 2 days on M, but not at all on S. Flavonoids were present at 2 days on R but at 8 days on M and at 12 days on S. These data suggest that the presence of trans-resveratrol and flavonoids in the resistant cultivar at a very early stage of infection may play an important role in inhibiting growth of the fungus. Moreover, on the intermediate cultivar, the peroxidase activity, catechins, and lignins appeared at a late stage of infection. The production of these molecules seems to restrict the development of this pathogen. In the susceptible cultivar, these reactions presumably were too late and too weak to limit development of the fungus

Broadcast Aerial Release of an Egg Parasite for Lepidopterous Insect Control

ABSTRACT A conventional dry materials dispersal system on an agricultural aircraft was modified for broadcast release of parasitized host insect eggs attached to wheat bran flakes. The modified system was calibrated for low rates of bran application, and bran distribution patterns were determined. Field trials were conducted to evaluate the equipment performance and to determine the sup-pression of Heliothis populations in cotton by aerial release of the parasite wasp, Trichogramma pretoisum Riley. Average Heliothis egg parasitism in treated plots increased dramatically after the aerial parasite releases.

THE CYTOGEOGRAPHY AND RELATIONSHIPS OF THE VISCACEOUS AND EREMOLEPIDACEOUS MISTLETOES

SummaryKnown chromosome numbers in the Viscaceae and Eremolepidaceae are reviewed and 73 new records added. No basic number is presently evident for either family as a whole. In the Vicaceae two fundamental chromosome groups are apparent. The first is characterized by x = 14 and is itself composed of two subgroups, one with large chromosomes (Dendrophthora‐Phoradendron), and the other with medium sized chromosomes (Arceuthobium‐Korthalsella). The second chromosome group is composed of Viscum and its close relatives which possess numbers of x = 10, 11, 12, and 13 and which have large chromosomes.In the x = 14 group, the Dendrophthora‐Phoradendron alliance is strictly New World. The Arceuthobium‐Korthalsella alliance, however, has both Old and New World representation. Arceuthobium is present in both the Old and New Worlds and Korthalsella has an Old World and Pacific distribution. The Viscum alliance is strictly Old World.Some infra‐generic aneuploidy is known in Viscum and Dendrophthora. Polyploidy is apparently rare, known only in Phoradendron from the Galápagos Islands and in Viscum from New Guinea and northern Australia.A northern origin is postulated for the Viscaceae, with subsequent widespread radiation into the tropics of both the New and Old Worlds.The Eremolepidaceae, a group of three New World genera, does not appear to be karyologically related to other mistletoe families; it is postulated they may be aerial parasites in the Santalaceae, which is primarily a family of terrestrial root parasites.