Plant Identity Research Articles

Phylogeny of five predominant pospiviroid species in Belgium

In Belgium pospiviroids are routinely detected in various hosts. The most frequently found pospiviroids are: Citrus exocortis viroid (CEVd), Chrysanthemum stunt viroid (CSVd), Potato spindle tuber viroid (PSTVd), Tomato apical stunt viroid (TASVd) and Tomato chlorotic dwarf viroid (TCDVd). Apart from the high incidence of pospiviroids in latently-infected ornamentals, viroids have also been found in plants where they cause disease: PSTVd and TCDVd in tomatoes and CSVd in chrysanthemum. In order to gain more epidemiological data on these infections, this study has conducted phylogenetic analyses of Belgian isolates for each of these five pospiviroid species. PSTVd and CEVd-isolates show a clustering depending on host plant identity. This was not observed for TCDVd and TASVd. A very high degree of sequence similarity was noticeable for CSVd-isolates from various hosts. During the past decade, PSTVd and CSVd-infected mother plants have been systematically eradicated in Belgium after positive detection results, also when found in symptomless plants, leading to a decreased trend of these quarantine pests in the past few years. However, other non-quarantine pospiviroid species are still ubiquitously present in many ornamentals. Since these pospiviroids can be equally harmful to crops as the two quarantine pests PSTVd and CSVd, there is still a risk that transmission occurs from symptomless-infected ornamental plants to economically important crops in Belgium such as tomato, pepper and chrysanthemum.

Medicinal Plant Diversity and Inter-Cultural Interactions between Indigenous Guarani, Criollos and Polish Migrants in the Subtropics of Argentina.

Numerous studies highlight the importance of phytotherapy for indigenous and non-indigenous people in different parts of the world. In this work we analyze the richness (number of species), diversity (plant identity and the number of illnesses for which it is used) and similarity of plant species and illnesses treated with them, in order to contribute new data and insight into the importance of plant medicines to the local medical systems of people living in Misiones province, in the subtropics of Argentina. Three sympatric groups were compared: Guarani Indians, Criollos (mestizos) and Polish migrants. Quantitative scrutiny was focused on both primary and secondary sources. The similarity and diversity of medicinal plants and uses between groups was calculated by applying the Sørensen quantitative coefficient and the Shannon-Wiener index, respectively. In order to identify the characteristic plant species used by each group, the Cultural Importance and Prevalence Value (CIPV) was calculated based on the species Indicator Value (IndVal), which combines a species relative abundance with its relative frequency of occurrence in the various groups, and modified according to the type of the analyzed data. The important finding is a great variation in the number of species used by the study groups. Altogether, 509 botanical species were registered: Guarani (397), Criollos (243) and Polish migrants (137). For all groups, the use of native medicinal plants prevailed. The Guarani appear to be the local experts in use of medicinal plants. There is the significant difference in the number of treated illnesses by each taxon among three groups. Criollos and Polish migrants exhibit the greatest similarity in illnesses treated with medicinal plants. These groups share a corpus of knowledge related to illness nosology, and have a symptomatic approach to illness treatment. The Guarani have an etiological approach to illness diagnosis and healing, which may be viewed as a barrier to the exchange of knowledge about home medicine with other ethnic groups of Misiones.

Plant diversity and plant identity influence Fusarium communities in soil

ABSTRACTFusarium communities play important functional roles in soil and in plants as pathogens, endophytes, and saprotrophs. This study tests how rhizosphere Fusarium communities may vary with plant species, changes in the diversity of the surrounding plant community, and soil physiochemical characteristics. Fusarium communities in soil associated with the roots of two perennial prairie plant species maintained as monocultures or growing within polyculture plant communities were characterized using targeted metagenomics. Amplicon libraries targeting the RPB2 locus were generated from rhizosphere soil DNAs and sequenced using pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs) and assigned a taxonomy using the Evolutionary Placement Algorithm. Fusarium community composition was differentiated between monoculture and polyculture plant communities, and by plant species in monoculture, but not in polyculture. Taxonomic classification of the Fusarium OTUs showed a predominance of F. tricinctum and F. oxysporum as well of the presence of a clade previously only found in the Southern Hemisphere. Total Fusarium richness was not affected by changes in plant community richness or correlated with soil physiochemical characteristics. However, OTU richness within two predominant phylogenetic lineages within the genus was positively or negatively correlated with soil physiochemical characteristics among samples within each lineage. This work shows that plant species, plant community richness, and soil physiochemical characteristics may all influence the composition and richness of Fusarium communities in soil.

Impact of native and non-native aquatic plants on methane emission and phytoplankton growth

Freshwater plants affect the ecosystem functioning of shallow aquatic ecosystems. However, because native plants are threatened by environmental change such as eutrophication, global warming and biological invasions, continued ecosystem functioning may be at risk. In this study, we explored how the growth of native and non-native plant species in eutrophic, warm conditions impacts two plant ecosystem functions: regulation of phytoplankton growth and methane emission. We expected that plants would inhibit phytoplankton growth, while for methane emission both inhibition and stimulation are possible. We conducted an outdoor experiment using monocultures of four native and four non-native freshwater plant species planted at three different densities, as well as a no-plant control. Monocultures of each species were planted in 65 L mesocosms and after three weeks of acclimatisation each mesocosm was inoculated with phytoplankton. Subsequently, we added nutrients twice a week for eight weeks, before harvesting the plant biomass. During these eight weeks, we measured chlorophyll-a concentration thirteen times and the diffusive methane emissions once after four weeks. The mesocosms amplified the temperature of a warm summer so that plants were exposed to higher-than-average temperatures. We found that five plant species lost biomass, two species increased their biomass only at the highest initial plant density (native Myriophyllum spicatum and non-native Lagarosiphon major) and a single species increased its biomass at all densities (on average 14 times its initial mass; amphibious non-native Myriophyllum aquaticum). Overall, the mean biomass change of non-natives was positive, whereas that of natives was negative. This difference in biomass change between native and non-native plants did not relate to overall differences in phytoplankton mass or diffusive methane emissions. In mesocosms where submerged plant species gained biomass, chlorophyll-a concentration was lower than in the noplant control and mesocosms with biomass loss. Diffusive methane emissions were highest in mesocosms where plants lost considerable biomass, likely because it increased substrate availability for methanogenesis. However, mesocosms where plant biomass increased had emissions similar to the no-plant control, hence we found no inhibitory effects of plant presence on diffusive methane emission. We conclude that plant growth in eutrophic, warm conditions varies strongly with plant identity. Our results furthermore suggest that plant identity determines whether the replacement of native by non-native freshwater plants will alter ecosystem functions such as regulation of phytoplankton growth and methane emission.

DNA BARCODE CHARACTERIZATION OF MISTLETOE INFESTATION IN TEAK CLONAL SEED ORCHARD (CSO) IN PADANGAN, EAST JAVA PROVINCE, INDONESIA

For effective teak plantation management, early detection system in controlling teak mistletoe requires various basic information, including degree of infestation and accuracy of the species names. Mistletoe infestations in teak and mistletoe species name have been reported, but there are still problems in identifying the correct species or subspecies due to morphological similarity. The objective of this study was to clarify the species identity of hemi-parasitic mistletoe plants, which were found in teak Clonal Seed Orchard (CSO) in Padangan, East Java Province, Indonesia using DNA barcodes. Species identification of teak mistletoe based on leaf morphological characteristics and universal DNA barcode regions (i.e. matK and rbcL) were carried out. The results showed that the Canonical Discriminant Analysis (CDA) could differentiate Dendrophthoe pentandra and Macrosolen tetragonus based on leaf morphological characteristics. Variables having high correlation to distinguish both species were length of petiole,  width of the widest leaf, number of secondary leaf veins, leaf base shape, aspect ratio, form factor and perimeter ratio of diameter. The results of DNA barcoding showed that the two DNA barcode regions presented good  amplification and sequence results. Both DNA barcode regions successfully differentiated two species i.e. D. pentandra and M. tetragonus which belong to Loranthaceae family and have similar leaf morphological characteristics. Those regions were also able to identify Viscum articulatum and other species belonging to Santalaceae family. These results suggested that the two DNA regions could become recommended universal DNA barcode for identifying teak mistletoe.

Laser Capture Microdissection for Amplification of Alternative Oxidase (AOX) Genes in Target Tissues in Daucus carota L.

Laser microdissection provides a useful method for isolating specific cell types from complex biological samples for downstream applications. In contrast to the texture of mammalian cells, most plant tissues exhibit a cell organization with hard, cellulose-containing cell walls, large vacuoles, and air spaces, thus complicating tissue preparation and extraction of macromolecules such as DNA. In this study, we report a method that allows tissue-specific gene amplification. An improved perception of genetic identity of the entire plant can contribute to improved functional marker strategies. Alternative oxidase (AOX) has crucial position for stress-induced responses/adaptation. Daucus carota sequence polymorphisms in AOX were identified, however, never at tissue/cell level. This technology will support studying AOX gene sequences in carrot organs/tissues/cells and specifically exploring differential polymorphisms in root meristem that might be associated to adaptive growth upon all kind of stresses. Details on aspects of tissue preparation, including fixation and embedding procedures, laser capture microdissection, DNA extraction, and amplification, are provided. A combination of laser microdissection and polymerase chain reaction amplification provides a powerful tool for the analysis of AOX gene amplification in methacarn-fixed paraffin-embedded tissues.

Ayurvedic Plants in Brain Disorders: The Herbal Hope

Synthetic drugs for human brain disorders are expensive symptomatic long treatments, sometimes showing serious and unavoidable side effects with poor patient compliance. Therefore, the herbal and Ayurvedic treatments are preferred over synthetic drugs for a range of human brain disorders including, Alzheimer’s disease, Parkinson’s disease, depression, epilepsy, schizophrenia, anxiety, etc. Ayurvedic system of medicine has traditionally been used in several neurological conditions. The accessibility, negligible incidence of side effects and cost effectiveness of plant products offer considerable advantages. These days much attention is drawn towards the established traditional systems of herbal remedies for many brain disorders, generating positive hopes for the patients. It is estimated that more than 60 million Indian populations suffers from mental disorders while the country lags far behind the world for treatments and spending in the hospitals for mental cure. Nearly 1-2% Indians suffered from schizophrenia and bipolar disorder whereas 5% population showed common mental disorders like depression, anxiety, convulsion, etc. The term mental disease is not restricted to mean insanity and allied conditions of mental derangement but also includes, to a certain extent, the emotional disorders. When emotional factors cross the state of normalcy, one gets deranged to show the syndromes of mental disorder, very often. With the current alarming situation, it is high time to look back to the ancient Indian Ayurvedic system of medicine wherein a number of plants have been described for specific uses for a range of mental disorders, including migraine, epilepsy, convulsion, hysteria, paralysis, memory loss (Alzheimer’s), insomnia, anxiety, Parkinson’s disease, insanity, depression, etc. The Ayurvedic prescriptions which contain either a single identity of plant or a mixture of plant materials have been proven to be very useful against such disorders. The plant materials prescribed for these problems range from herbs to perennial trees with varied plant parts, ranging from whole plant, roots, stem, bark, leaves, flowers, fruits to seeds. The chemical structure of the major compounds from these plants range from straight chain fatty acids to terpenoids, steroids, flavonoids, alkaloids, peptides, etc. It has been attempted to review the current situation of mental disorder in the society vis-a-vis its effective solution described in the Ayurveda and problem of side effects in synthetic medicines. Graphical Abstract

Interactions between a root hemiparasite and 27 different hosts: Growth, biomass allocation and plant architecture

The aim of this study was to investigate the effect of many different host species and their traits on the performance, morphology and architecture of the root hemiparasite Melampyrum arvense L., as well as the effect of the parasite on the growth and biomass allocation of its hosts. M. arvense was grown at two nutrient levels with 27 host species (grasses, legumes, and forbs) from habitats differing in nutrient availability. The biomass of the parasite varied enormously (475-fold) depending on the host species. The mean fraction of parasite biomass allocated to roots (RMF) decreased with increasing quality of a host (measured as total biomass of the parasite) and was only 3% with the best host. An extensive review of published studies showed that access to a host in most cases reduces RMF of root hemiparasites and that the RMF of annual root hemiparasites is low compared to that of autotrophic plants, suggesting that a reduced expenditure on roots is an important advantage of hemiparasitism for annual parasites. In contrast, the RMF of hemiparasitic perennial herbs and woody plants was found to be similar to that of autotrophic plants.Host identity and nutrients also strongly influenced traits of M. arvense other than biomass, e.g. leaf size, seed mass, leaf chlorophyll concentration, nitrogen concentration, height, and the number of vegetative internodes. However, while host plant identity influenced allometric relationships, most of the effects of nutrient level were due to simple changes in overall parasite size. Individual parasite biomass was not correlated with the final shoot or root mass of the host plants growing in the same pot, but increased weakly with host nitrogen concentration. Mean host size at the time of parasite planting, host functional type and the nutrient state of the typical host habitat influenced mean parasite biomass and together explained 64% of its variation. Parasite growth increased with initial host mass, was higher with legumes and forbs than with grasses, and higher with hosts from nutrient-rich habitats.Host damage due to parasitism increased with mean biomass of the parasite, and was lower for fast-growing species and higher for legumes and forbs than for grasses. Differences in damage between similarly good hosts indicated that not only resistance but also tolerance may be important for host responses to parasitism. M. arvense also caused changes in host allometry and increased host RMF, particularly in good host species. However, an extensive literature review found that there is no consistent general pattern of a higher RMF in hosts that are parasitized. Total productivity per pot was reduced by parasite presence suggesting lower resource use efficiency of the parasite, but not for all parasite – host combinations. Patterns of host quality for M. arvense and for its impact on host species differed strongly from those found for the related model hemiparasite Rhinanthus and suggest that hemiparasite – host species interactions may be parasite-specific.

In Vitro Propagation of Rhododendron tomentosum – an Endangered Essential Oil Bearing Plant from Peatland

AbstractRhododendron tomentosumHarmaja (formerlyLedum palustreL.) is a medicinal peat bog plant native to northern Europe, Asia and North America. This plant has a distinctive aroma thanks to the presence of essential oil, to which it also owes its anti-inflammatory, analgesic, antimicrobial and insecticidal properties. However, in EuropeR. tomentosumis classified as an endangered species, mainly due to degradation of peatlands. In the present work, the micropropagation protocol forR. tomentosumwas established for the first time, providing both anex situconservation tool and a means of continuous production ofin vivoandin vitroplant material for further studies.R. tomentosummicroshoots were initiated from leaf explants and further multiplied using Schenk-Hildebrandt (SH) medium supplemented with 9.84 μM 2iP and 1.00 μM TDZ. The shoots were elongated on the SH medium supplemented with 24.6 μM 2iP and subsequently rooted using the perlite substrate saturated with half-strength Woody Plant medium supplemented with 1.0% sucrose and 4.92 μM IBA. The regenerated plants were hardened on the phytohormone-free SH medium and acclimatized using 3:1:1 deacidified peat:perlite:gravel substrate. The identity of the mother plant was confirmed at morphological and molecular levels and Random Amplified Polymorphic DNA (RAPD) method was implemented to assess the genetic fidelity of the regenerants. The essential oil content of the maternal plant,in vitroshoots and the regenerants was determined by steam-distillation, and the obtained volatile fractions were analyzed by GC/MS.

Intraspecific trait variation across multiple scales: the leaf economics spectrum in coffee

Summary Understanding species differences in plant functional traits has been critical in developing a mechanistic understanding of terrestrial ecological processes. Greater attention is now being placed on understanding the extent, causes and consequences of intraspecific trait variation (ITV). ITV is especially important in governing ecological processes in cropping systems, where only a small number of species or genotypes exist in high abundances. However, it remains unclear if key principles of trait‐based ecology – namely the leaf economics spectrum (LES) – also describe intraspecific variation in crop functional biology. There also remains a need to understand whether ITV within crops is random, or structured across environmental, management‐related or biological levels of organization in agroecosystems. We employed a nested design field survey to evaluate ITV in leaf traits in coffee (Coffea arabica), one of the world's most widespread tropical crops. We evaluated ITV in eight physiological, morphological and chemical leaf traits, across five nested categorical levels (sites, management systems, spatial location, plant identity, branch identity). We compared patterns of LES trait covariation in coffee, to interspecific patterns observed across over 700 wild plant species. Patterns of bivariate and multivariate ITV in coffee were broadly consistent with, but considerably weaker than, interspecific patterns associated with the LES, indicating that crops may systematically diverge from global patterns of trait trade‐offs observed in wild plants. Physiological traits varied most widely (coefficient of variation (cv) 42–107%), followed by morphological traits (cv = 15–38%) and chemical traits (cv = 3–11%). Physiological ITV was best explained by the site in which a coffee plant was growing (17–55% explained), while ITV for chemical traits was best explained by management treatments within sites (25–36%); morphological ITV was higher even at the individual tree level or branch level and remained largely unexplained. Our results support the hypothesis that artificial selection and high‐resource agricultural environments lead crops to systematically deviate from patterns of leaf trait covariation observed across wild plants species. Coupled with an understanding of how different traits vary systematically across multiple levels of biological organization, these findings help integrate ITV into future analyses of agroecosystem structure and function. A lay summary is available for this article.

Influences of host plant identity and disturbance on spatial structure and community composition of ectomycorrhizal fungi in a northern Mississippi uplands ecosystem

Abstract We sought to characterize how abiotic and biotic factors, including identities of tree hosts, influence ectomycorrhizal (ECM) fungal composition on tree roots in mixed upland forests of northern Mississippi, where sites have been subject to restoration treatments through burning, manual and natural (tornado) thinning. We identified both plant and fungal components of root tips and collected data on abiotic factors that potentially drive variation in ECM fungal community composition. We found that plant host identity and measured abiotic factors explained less than 8% of variation in ECM fungal community composition. ECM fungal community composition did not differ significantly between control and burned/thinned plots; however, it did differ substantially at the tornado-damaged plot, which also exhibited significant spatial structure. These results suggest that much variation in ECM communities is unexplained by commonly measured biotic and abiotic variables and natural disturbance may play a role in both community and spatial structure of ECM fungi.

Arbuscular mycorrhizal fungi diversity associated with two halophytes Lycium barbarum L. and Elaeagnus angustifolia L. in Ningxia, China

ABSTRACTThe Arbuscular mycorrhizal fungi (AMF) community in saline soils of Ningxia, China, was rarely reported. Soils in the rhizosphere of two important food plants, Lycium barbarum L. (Goji) and Elaeagnus angustifolia L. (Oleaster), were sampled from Ningxia (Goji from Huinong, HNGQ; Goji from Yinchuan, YCGQ; Oleaster from Yinchuan, YCSZ) to investigate the AMF community. Thirty-three AMF species from 11 genera were identified in total. The dominant family and genera were Glomeraceae, Acaulospora and Glomus, respectively. Septoglomus constrictum was the most abundant species. The AMF community composition of Goji was different from that of Oleaster (R = 0.26, p < 0.05), while the AMF community from Huinong differed from Yinchuan (R = 1.0, p = 0.01). These findings suggest a high AMF diversity in Ningxia saline soils and the effect of host plant identity on AMF community composition. Furthermore, the AMF diversity index positively correlated with available potassium (AK), available phosphorus (AP), available nitrogen (AN) and organic matter (OM), but negatively correlated with electric conductivity (EC). This result demonstrated that a high level of salinity might reduce soil fertility and AMF diversity. The saline area with high diversity of the AMF community in Ningxia is promising for screening AMF isolates for utilization in crop production.

Cover crops to increase soil microbial diversity and mitigate decline in perennial agriculture. A review

Commercial perennial agriculture is prone to declining productivity due to negative plant-soil feedback. An alternative to costly and environmentally harmful conventional treatment such as soil fumigation could be to manipulate soil microbial diversity through careful selection and management of cover crop mixtures. Although cover crops are already used in these systems for other reasons, their capacity to influence soil biota is unexploited. Here, we examine the role of plant diversity and identity on plant-soil feedbacks in the context of perennial agriculture. We identify key microorganisms involved in these feedbacks and explore plant-based strategies for mitigating decline of perennial crop plants. We conclude that (1) increasing plant diversity increases soil microbial diversity, minimizing the proliferation of soil-borne pathogens; (2) populations of beneficial microbes can be increased by increasing plant functional group richness, e.g., legumes, C4 grasses, C3 grasses, and non-leguminous forbs; (3) brassicas suppress fungal pathogens and promote disease-suppressive bacteria; (4) native plants may further promote beneficial soil microbiota; and (5) frequent tillage, herbicide use, and copper fungicides can harm populations of beneficial microbes and, in some cases, contribute to greater crop decline. Non-crop vegetation management is a viable and cost-effective means of minimizing crop decline in perennial monocultures but is in need of more direct experimental investigation in perennial agroecosystems.

Mycorrhizal Symbiotic Efficiency on C3 and C4 Plants under Salinity Stress - A Meta-Analysis.

A wide range of C3 and C4 plant species could acclimatize and grow under the impact of salinity stress. Symbiotic relationship between plant roots and arbuscular mycorrhizal fungi (AMF) are widespread and are well known to ameliorate the influence of salinity stress on agro-ecosystem. In the present study, we sought to understand the phenomenon of variability on AMF symbiotic relationship on saline stress amelioration in C3 and C4 plants. Thus, the objective was to compare varied mycorrhizal symbiotic relationship between C3 and C4 plants in saline conditions. To accomplish the above mentioned objective, we conducted a random effects models meta-analysis across 60 published studies. An effect size was calculated as the difference in mycorrhizal responses between the AMF inoculated plants and its corresponding control under saline conditions. Responses were compared between (i) identity of AMF species and AMF inoculation, (ii) identity of host plants (C3 vs. C4) and plant functional groups, (iii) soil texture and level of salinity and (iv) experimental condition (greenhouse vs. field). Results indicate that both C3 and C4 plants under saline condition responded positively to AMF inoculation, thereby overcoming the predicted effects of symbiotic efficiency. Although C3 and C4 plants showed positive effects under low (EC < 4 ds/m) and high (>8 ds/m) saline conditions, C3 plants showed significant effects for mycorrhizal inoculation over C4 plants. Among the plant types, C4 annual and perennial plants, C4 herbs and C4 dicot had a significant effect over other counterparts. Between single and mixed AMF inoculants, single inoculants Rhizophagus irregularis had a positive effect on C3 plants whereas Funneliformis mosseae had a positive effect on C4 plants than other species. In all of the observed studies, mycorrhizal inoculation showed positive effects on shoot, root and total biomass, and in nitrogen, phosphorous and potassium (K) uptake. However, it showed negative effects in sodium (Na) uptake in both C3 and C4 plants. This influence, owing to mycorrhizal inoculation, was significantly higher in K uptake in C4 plants. For our analysis, we concluded that AMF-inoculated C4 plants showed more competitive K+ ions uptake than C3 plants. Therefore, maintenance of high cytosolic K+/Na+ ratio is a key feature of plant salt tolerance. Studies on the detailed mechanism for the selective transport of K in C3 and C4 mycorrhizal plants under salt stress is lacking, and this needs to be explored.

Effects of Cushion Plants on High-Altitude Soil Microarthropod Communities: Cushions Increase Abundance and Diversity of Mites (Acari), but not Springtails (Collembola)

ABSTRACTCushion plants in alpine ecosystems act as nurse species, which modify and alleviate environmental conditions and positively influence the diversity and abundance of other organisms. Soil fauna in alpine environments should benefit from nurse plant facilitation, but this has not been investigated. We compared diversity, abundance, and community structure of soil microarthropods (Collembola, Oribatida, Mesostigmata, Prostigmata, Endeostigmata, and Astigmata) under cushion plants and in adjacent open microsites in high altitude patterned ground landscapes in New Zealand. We investigated how cushion plants influence environmental factors, and how environmental factors and species traits contribute to microarthropod community structure. The results show that cushion plants are a key in maintaining the biodiversity of soil microarthropods in the high alpine. Cushion plants maintain higher moisture and organic matter content in the soil, provide productive and structurally complex habitat, and mitigate disturbance. Abundance and species richness of Oribatida, Mesostigmata, and Prostigmata were higher under cushion plants. In contrast, abundance of Collembola was higher in open microsites, while their species richness similar in and out of cushions. Oribatida assemblages were dominated by small asexual species, indicating a disturbed environment. Oribatida community structure was significantly related to the microhabitat in two out of three mountain ranges. Collembola assemblages were similar in and out of cushions. Higher soil moisture and organic matter content under cushion plants were significant in explaining patterns in microarthropod assemblages, although high percentage of variability was not explained by environmental variables. There was no effect of cushions on soil temperatures. Species identity of the cushion plant did not influence abundance, species richness, or community assemblages of mites and springtails; however, some species were associated with either Dracophyllum or Raoulia cushions.

Petroleum hydrocarbon contamination, plant identity and arbuscular mycorrhizal fungal (AMF) community determine assemblages of the AMF spore-associated microbes.

The root-associated microbiome is a key determinant of pollutant degradation, soil nutrient availability and plant biomass productivity, but could not be examined in depth prior to recent advances in high-throughput sequencing. Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of vascular plants. They are known to enhance mineral uptake and promote plant growth and are postulated to influence the processes involved in phytoremediation. Amplicon sequencing approaches have previously shown that petroleum hydrocarbon pollutant (PHP) concentration strongly influences AMF community structure in in situ phytoremediation experiments. We examined how AMF communities and their spore-associated microbiomes were structured within the rhizosphere of three plant species growing spontaneously in three distinct waste decantation basins of a former petrochemical plant. Our results show that the AMF community was only affected by PHP concentrations, while the AMF-associated fungal and bacterial communities were significantly affected by both PHP concentrations and plant species identity. We also found that some AMF taxa were either positively or negatively correlated with some fungal and bacterial groups. Our results suggest that in addition to PHP concentrations and plant species identity, AMF community composition may also shape the community structure of bacteria and fungi associated with AMF spores.

A PtdIns(4)P-driven electrostatic field controls cell membrane identity and signalling in plants.

Many signaling proteins permanently or transiently localize to specific organelles for function. It is well established that certain lipids act as biochemical landmarks to specify compartment identity. However, they also influence membrane biophysical properties, which emerge as important features in specifying cellular territories. Such parameters include the membrane inner surface potential, which varies according to the lipid composition of each organelle. Here, we found that the plant plasma membrane (PM) and the cell plate of dividing cells have a unique electrostatic signature controlled by phosphatidylinositol-4-phosphate (PI4P). Our results further reveal that, contrarily to other eukaryotes, PI4P massively accumulates at the PM, establishing it as a critical hallmark of this membrane in plants. Membrane surface charges control the PM localization and function of the polar auxin transport regulator PINOID, as well as proteins from the BRI1 KINASE INHIBITOR1 (BKI1)/MEMBRANE ASSOCIATED KINASE REGULATORs (MAKRs) family, which are involved in brassinosteroid and receptor-like kinase signaling. We anticipate that this PI4P-driven physical membrane property will control the localization and function of many proteins involved in development, reproduction, immunity and nutrition.

Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile.

Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses.

Tree species, spatial heterogeneity, and seasonality drive soil fungal abundance, richness, and composition in Neotropical rainforests.

Tropical ecosystems remain poorly understood and this is particularly true for belowground soil fungi. Soil fungi may respond to plant identity when, for example, plants differentially allocate resources belowground. However, spatial and temporal heterogeneity in factors such as plant inputs, moisture, or nutrients can also affect fungal communities and obscure our ability to detect plant effects in single time point studies or within diverse forests. To address this, we sampled replicated monocultures of four tree species and secondary forest controls sampled in the drier and wetter seasons over 2 years. Fungal community composition was primarily related to vegetation type and spatial heterogeneity in the effects of vegetation type, with increasing divergence partly reflecting greater differences in soil pH and soil moisture. Across wetter versus drier dates, fungi were 7% less diverse, but up to four-fold more abundant. The combined effects of tree species and seasonality suggest that predicted losses of tropical tree diversity and intensification of drought have the potential to cascade belowground to affect both diversity and abundance of tropical soil fungi.

Botanical Identity of Seasonal Flowering Plants Available and Maintained in the Home Gardens of District Nainital, Uttarakhand

Uttarakhand is a store house of plant genetic resources of several crop groups including ornamentals and seasonal flowering plant species. A wide range of seasonal flowering plants are being grown in the region because of its various and favourable agro-geo climatic zones. Ornamental plant enhances aesthetic value of our environment. There are 8 developmental blocks and 1082 villages in district Nainital of Uttarakhand. Nainital district, is a part of Kumaun region of Uttarakhand. It lies between 29?0.1' to 29?36' 21'' N latitude and 78?50' 53'' to 80?06' E longitude. More than 7.62 lakh population reside in 4064 km2 of geographical area of district Nainital. The district falls under sub-tropical to temperate zones. During the course of field survey (2013-2015), we came across wide range of seasonal flowering plants mostly belong to exotic origin being grown in the home gardens of natives of the region situated in different agro-ecological niches. The present study highlighted a total of 150 seasonal flowering plants with 120 genera belonging to 50 families. These were arranged alphabetically with botanical names followed by vernacular and trade name, family, origin or native place, nature, season with appropriate remarks of variation in shape, size and colour, method of propagation with economic status.