Exceptional Diversity Research Articles

Identification and transcriptome data analysis of ARF family genes in five Orchidaceae species

The Orchidaceae is a large family of perennial herbs especially noted for the exceptional diversity of specialized flowers. Elucidating the genetic regulation of flowering and seed development of orchids is an important research goal with potential utility in orchid breeding programs. Auxin Response Factor (ARF) genes encode auxin-responsive transcription factors, which are involved in the regulation of diverse morphogenetic processes, including flowering and seed development. However, limited information on the ARF gene family in the Orchidaceae is available. In this study, 112 ARF genes were identified in the genomes of 5 orchid species (Apostasia shenzhenica, Dendrobium catenatum, Phalaenopsis aphrodite, Phalaenopsis equestris and Vanilla planifolia,). These genes were grouped into 7 subfamilies based on their phylogenetic relationships. Compared with the ARF family in model plants, such as Arabidopsis thaliana and Oryza sativa, one group of ARF genes involved in pollen wall synthesis has been lost during evolution of the Orchidaceae. This loss corresponds with absence of the exine in the pollinia. Through mining of the published genomic and transcriptomic data for the 5 orchid species: the ARF genes of subfamily 4 may play an important role in flower formation and plant growth, whereas those of subfamily 3 are potentially involved in pollen wall development. the study results provide novel insights into the genetic regulation of unique morphogenetic phenomena of orchids, which lay a foundation for further analysis of the regulatory mechanisms and functions of sexual reproduction-related genes in orchids.

Systematic analysis of prophage elements in actinobacterial genomes reveals a remarkable phylogenetic diversity

Actinobacteria represent one of the largest bacterial phyla harboring many species of high medical, biotechnological and ecological relevance. Prophage elements are major contributors to bacterial genome diversity and were shown to significantly shape bacterial fitness and host-microbe interactions. In this study, we performed a systematic analysis of prophage elements in 2406 complete actinobacterial genomes. Overall, 2106 prophage elements were predicted to be present in about 50% (1172/2406) of the analyzed datasets. Interestingly, these identified sequences compose a high prevalence of cryptic prophage elements, indicating genetic decay and domestication. Analysis of the sequence relationship of predicted prophages with known actinobacteriophage genomes revealed an exceptional high phylogenetic diversity of prophage elements. As a trend, we observed a higher prevalence of prophage elements in vicinity to the terminus. Analysis of the prophage-encoded gene functions revealed that prophage sequences significantly contribute to the bacterial antiviral immune system, but no biosynthetic gene clusters involved in the synthesis of known antiphage molecules were identified in prophage genomes. Overall, the current study highlights the remarkable diversity of prophages in actinobacterial genomes, with highly divergent prophages in actinobacterial genomes and thus provides an important basis for further investigation of phage-host interactions in this important bacterial phylum.

DNA‐Encoded Synthetic Systems: Coding More than Life

DNA‐Encoded Synthetic Systems: Coding More than Life

Apomictic Mountain Whitebeam (Sorbus austriaca, Rosaceae) Comprises Several Genetically and Morphologically Divergent Lineages

The interplay of polyploidisation, hybridization, and apomixis contributed to the exceptional diversity of Sorbus (Rosaceae), giving rise to a mosaic of genetic and morphological entities. The Sorbus austriaca species complex from the mountains of Central and South-eastern Europe represents an allopolyploid apomictic system of populations that originated following hybridisation between S. aria and S. aucuparia. However, the mode and frequency of such allopolyploidisations and the relationships among different, morphologically more or less similar populations that have often been described as different taxa remain largely unexplored. We used amplified fragment length polymorphism (AFLP) fingerprinting, plastid DNA sequencing, and analyses of nuclear microsatellites, along with multivariate morphometrics and ploidy data, to disentangle the relationships among populations within this intricate complex. Our results revealed a mosaic of genetic lineages-many of which have not been taxonomically recognised-that originated via multiple allopolyploidisations. The clonal structure within and among populations was then maintained via apomixis. Our results thus support previous findings that hybridisation, polyploidization, and apomixis are the main drivers of Sorbus diversification in Europe.

Characterization of the microbiota dynamics associated with Moniliophthora roreri, causal agent of cocoa frosty pod rot disease, reveals new viral species.

Theobroma cacao, the cocoa tree, is a target for pathogens, such as fungi from the genera Phytophthora, Moniliophthora, Colletotrichum, Ceratocystis, among others. Some cacao pathogens are restricted to specific regions of the world, such as the Cacao swollen shoot virus (CSSV) in West African countries, while others are expanding geographically, such as Moniliophthora roreri in the Americas. M. roreri is one of the most threatening cacao pathogens since it directly attacks the cacao pods driving a significant reduction in production, and therefore economic losses. Despite its importance, the knowledge about the microenvironment of this pathogen and the cocoa pods is still poorly characterized. Herein we performed RNA sequencing of spores in differential stages of culture in a medium supplemented with cacao pod extract and mycelium collected of the susceptible variety ICT 7121 naturally infected by the pathogen to evaluate the diversity and transcriptional activity of microorganisms associated with the in vitro sporulation of M. roreri. Our data revealed a great variety of fungi and bacteria associated with M. roreri, with an exceptional diversity of individuals from the genus Trichoderma sp. Interestingly, the dynamics of microorganisms from different kingdoms varied proportionally, suggesting they are somehow affected by M. roreri culture time. We also identified three sequences similar to viral genomes from the Narnaviridae family, posteriorly confirmed by phylogenetic analysis as members of the genus Narnavirus. Screening of M. roreri public datasets indicated the virus sequences circulating in samples from Ecuador, suggesting a wide spread of these elements. Of note, we did not identify traces of the viral sequences in the M. roreri genome or DNA sequencing, restricting the possibility of these sequences representing endogenized elements. To the best of our knowledge, this is the first report of viruses infecting the fungus of the genus Moniliophthora and only the third description of viruses that are able to parasite elements from the Marasmiaceae family.

Omic-Scale High-Throughput Quantitative LC-MS/MS Approach for Circulatory Lipid Phenotyping in Clinical Research.

Lipid analysis at the molecular species level represents a valuable opportunity for clinical applications due to the essential roles that lipids play in metabolic health. However, a comprehensive and high-throughput lipid profiling remains challenging given the lipid structural complexity and exceptional diversity. Herein, we present an 'omic-scale targeted LC-MS/MS approach for the straightforward and high-throughput quantification of a broad panel of complex lipid species across 26 lipid (sub)classes. The workflow involves an automated single-step extraction with 2-propanol, followed by lipid analysis using hydrophilic interaction liquid chromatography in a dual-column setup coupled to tandem mass spectrometry with data acquisition in the timed-selective reaction monitoring mode (12 min total run time). The analysis pipeline consists of an initial screen of 1903 lipid species, followed by high-throughput quantification of robustly detected species. Lipid quantification is achieved by a single-point calibration with 75 isotopically labeled standards representative of different lipid classes, covering lipid species with diverse acyl/alkyl chain lengths and unsaturation degrees. When applied to human plasma, 795 lipid species were measured with median intra- and inter-day precisions of 8.5 and 10.9%, respectively, evaluated within a single and across multiple batches. The concentration ranges measured in NIST plasma were in accordance with the consensus intervals determined in previous ring-trials. Finally, to benchmark our workflow, we characterized NIST plasma materials with different clinical and ethnic backgrounds and analyzed a sub-set of sera (n = 81) from a clinically healthy elderly population. Our quantitative lipidomic platform allowed for a clear distinction between different NIST materials and revealed the sex-specificity of the serum lipidome, highlighting numerous statistically significant sex differences.

Investigating the Origin and Evolution of Polyploid Trifolium medium L. Karyotype by Comparative Cytogenomic Methods.

Trifolium medium L. is a wild polyploid relative of the agriculturally important red clover that possesses traits promising for breeding purposes. To date, T. medium also remains the only clover species with which agriculturally important red clover has successfully been hybridized. Even though allopolyploid origin has previously been suggested, little has in fact been known about the T. medium karyotype and its origin. We researched T. medium and related karyotypes using comparative cytogenomic methods, such as fluorescent in situ hybridization (FISH) and RepeatExplorer cluster analysis. The results indicate an exceptional karyotype diversity regarding numbers and mutual positions of 5S and 26S rDNA loci and centromeric repeats in populations of T. medium ecotypes and varieties. The observed variability among T. medium ecotypes and varieties suggests current karyotype instability that can be attributed to ever-ongoing battle between satellite DNA together with genomic changes and rearrangements enhanced by post-hybridization events. Comparative cytogenomic analyses of a T. medium hexaploid variety and diploid relatives revealed stable karyotypes with a possible case of chromosomal rearrangement. Moreover, the results provided evidence of T. medium having autopolyploid origin.

Neolucia bollami Eastwood, Braby & Graham, sp. nov. (Lepidoptera: Lycaenidae): speciation of a new allochronic cryptic butterfly from south-western Western Australia

South-western Western Australia is a global biodiversity hotspot renowned for exceptional diversity of plants and animals. The evolutionary processes that have generated this high biodiversity are not always clear, particularly for invertebrates, yet the area supports a very large number of endemic species that have diversified in situ. We use an integrative taxonomic approach based on adult and immature morphology, ecology, behaviour and molecular data to investigate the taxonomic status of a sympatric but seasonally isolated form (Neolucia agricola occidens Waterhouse & Lyell, 1914 form ‘Julimar’) of the polyommatine butterfly Neolucia agricola (Westwood, 1851) in south-western Western Australia. Our molecular dataset comprised 112 samples representing all Neolucia Waterhouse & Turner, 1905 species (100 COI 5′ sequences, 658 bp, plus 12 COI 3′, tRNA Leu, COII and EF1-α sequences, 3303 bp). Maximum likelihood phylogenetic analysis of the combined dataset recovered form ‘Julimar’ and N. agricola as reciprocally monophyletic, with a mean uncorrected ‘p’ pairwise divergence of 5.77% for the ‘barcode’ region of COI. Based on this and other evidence we recognise form ‘Julimar’ as a new species, Neolucia bollami Eastwood, Braby & Graham, sp. nov., sister to N. agricola and endemic to south-western Western Australia. As a result of these findings, we evaluated the evolutionary history of the two Neolucia species in WA and the processes that may have contributed to the diversification in sympatry or allopatry. We conclude that the multiple effect traits associated with a host shift, including host fidelity and temporal divergence, played an important role in the diversification process and in maintaining the reproductive integrity of the nascent allochronic species. ZooBank: urn:lsid:zoobank.org:act:53D9AD14-9694-4B5E-889C-A8D533E7F57D

Exceptional structural diversity of hybrid halocuprates(I) with methylammonium and formamidinium cations.

Hybrid halocuprates(I) are nowadays the subject of intensive studies as promising materials for various optoelectronic applications. This class of materials is characterized by wide structural diversity enabled by a great variety in the size and shape of organic cations. Therefore, the study of composition-structure-property relationships is a key step for the rational design of new halocuprate materials with desired properties. In this paper, we comprehensively studied MABr/CuBr and FABr/CuBr systems (MA+ = methylammonium and FA+ = formamidinium) and established the existence of five novel phases (namely, MACu2Br3, FA2[Cu4Br6], MACuBr2, FACuBr2, and FA3CuBr4) related to four different structural types and three distinct A+ : Cu+ stoichiometries (A+ = MA+/FA+). The optical properties of the discovered phases are studied by absorption and low-temperature photoluminescence spectroscopy. Based on a crystal-chemical analysis, we explained a unique structural diversity of the MA- and FA-based bromocuprates, as well as revealed new structure-property relationships.

Social-ecological System Health in Transfrontier Conservation Areas to Promote the Coexistence Between People and Nature

Summary Africa has managed to conserve an exceptional mammal diversity but is also facing an increasing demand for agricultural land to address a booming human population. Conserving natural resources while producing food in natural landscapes is a challenge that requires ecosystem health and social-ecological systems thinking. A logo of the company Pro SuLi. The logo has several curved arrows. A logo of the European Union. A logo of the Research platform; Production and conservation in partnership. The logo has a circle with three spiral divisions.

Rapid Evolution of the Fine-scale Recombination Landscape in Wild House Mouse (Mus musculus) Populations.

Meiotic recombination is an important evolutionary force and an essential meiotic process. In many species, recombination events concentrate into hotspots defined by the site-specific binding of PRMD9. Rapid evolution of Prdm9's zinc finger DNA-binding array leads to remarkably abrupt shifts in the genomic distribution of hotspots between species, but the question of how Prdm9 allelic variation shapes the landscape of recombination between populations remains less well understood. Wild house mice (Mus musculus) harbor exceptional Prdm9 diversity, with >150 alleles identified to date, and pose a particularly powerful system for addressing this open question. We employed a coalescent-based approach to construct broad- and fine-scale sex-averaged recombination maps from contemporary patterns of linkage disequilibrium in nine geographically isolated wild house mouse populations, including multiple populations from each of three subspecies. Comparing maps between wild mouse populations and subspecies reveals several themes. First, we report weak fine- and broad-scale recombination map conservation across subspecies and populations, with genetic divergence offering no clear prediction for recombination map divergence. Second, most hotspots are unique to one population, an outcome consistent with minimal sharing of Prdm9 alleles between surveyed populations. Finally, by contrasting aggregate hotspot activity on the X versus autosomes, we uncover evidence for population-specific differences in the degree and direction of sex dimorphism for recombination. Overall, our findings illuminate the variability of both the broad- and fine-scale recombination landscape in M. musculus and underscore the functional impact of Prdm9 allelic variation in wild mouse populations.

The Politics of Fire and the Social Impacts of Fire Exclusion on the Klamath1

The exceptional biological diversity of the mid-Klamath River region of northern California has emerged in conjunction with sophisticated Karuk land management practices, including the regulation of the forest and fisheries through ceremony and the use of fire. Over three quarters of Karuk traditional food and cultural use species are enhanced by fire. Fire is also central to cultural and spiritual practices. Land management techniques since the early 1900s have emphasized fire suppression and the “exclusion” of wildfire from the landscape. This paper uses data from interviews, surveys and other documents to describe the social impacts of fire exclusion for Karuk tribal members. The exclusion of fire from the ecosystem has a host of interrelated ecological and social impacts including impacts to cultural practice, political sovereignty, social relations, subsistence activities, and the mental and physical health of individual tribal members. In addition, Karuk tribal members are negatively impacted by the effects of catastrophic fires and intensive firefighting activities that in turn result from fire exclusion. Whereas existing literature has addressed ecological and social impacts of changing ecosystems as separate categories, the social, ecological and economic impacts of fire exclusion are here understood to be intrinsically linked.

Tribe Shoreae (Dipterocarpaceae subfamily Dipterocarpoideae) Finally Dissected

SummaryThe dipterocarp tribe Shoreae, perhaps more than any other members of this elegant family of often giant emergent trees, is familiar to all who visit the once ubiquitous lowland forests of tropical Asia. Timbers of the genus Shorea comprised the bulk of hardwood traded on international markets for thirty years, since the nineteen seventies. Distinct species groups came to be recognised by taxonomists: for their characteristic androecia, and sometimes differences in bark and wood anatomy, while generic status for some was then proposed on embryological evidence. A new molecular phylogeny of the family, and this tribe, substantially confirms the embryological case. This paper formalises resultant nomenclatural changes. Those of us who recall the majestic forested former landscapes of the Sunda lands may regret this decision. But now, with landscapes irretrievably changed by serried ranks of oil palm and forest degradation, the case for recognition of the proposed new entities can guide conservation planners in recognising and making the case for permanently conserving surviving undisturbed stands of exceptional composition or diversity.

Species richness and abundance of small mammals from Nimba region, Northeastern Liberia

This study was carried out in a biodiversity hotspot within the Nimba region located in the northeastern part of Liberia. The Nimba region is known to harbor exceptional fauna diversity. However, the small mammal communities in Nimba region are poorly documented. The aim of this study was to determine the species richness and relative abundance of rodents and shrews in five sites: Bento, East Nimba, Gangra-Yuelliton, Tokadeh and Vayampah. A total of 244 individual of small mammals comprising 18 species were trapped on 4,375 trap nights. Rodent species recorded include: Arvicanthis rufinus, Dephomys defua, Grammomys buntingi, Graphiurus lorraineus, Hybomys planifrons, Hybomys trivirgatus, Hylomyscus simus, Lemniscomys striatus, Lophuromys sikapusi, Malacomys edwardsi, Mastomys erythroleucus, Mus muscoloides, Mus setulosus and Praomys rostratus. Shrew species were Crocidura eburnea, Crocidura jouvenetae, Crocidura muricauda and Crocidura obscurior. The most dominant species was Hylomyscus simus (22.95%), followed by Praomys rostratus, Crocidura muricauda and Crocidura eburnea. The highest species richness was recorded at Gangra-Yuelliton and lowest at Tokadeh. Diversity indexes were higher at East nimba (H’ = 2.01; 1-D = 0.82) and Gangra-Yuelliton (H’ = 2.00; 1-D = 0.83) and lower at Tokadeh (H’ = 1.57; 1-D = 0.75). Similarity index revealed high resemblance in species composition between Bento and Vayampah. The lowest similarity was observed between Tokadeh and Gangra-Yuelliton. This study highlighted the high biological diversity of small mammal communities in Liberia's Mount Nimba region. Thus, this zoological group should now be taken into account in the biodiversity conservation strategies of Mount Nimba

Peach for the future: A specialty crop revisited

• Current trends on peach cultivar and rootstock breeding initiatives are highlighted. • Efficient cropping system is linked to appropriate rootstock selection and canopy architecture. • Training system selection is of equal importance with rootstock selection. • High density plantation may result in reduced production cost and enhanced orchard sustainability. • Decision making in the orchard and packinghouse is critical for optimum fruit quality. • Peach industry needs to shift to a systems approach through a re-design of the whole supply chain. Peach is the most important temperate fruit crop worldwide in terms of production after apple. However, a descending trend has been registered over the recent years in several key producing peach countries, mainly due to the increased labor cost and the reduced revenue for the farmer. The present perspective review aims to shed light on the current trends on peach fruit production related to cultivar and rootstock breeding initiatives, appropriate training system selection and targeted integrated management of main diseases, most promptly Monilinia spp. Cultivar breeding programs should focus on the most relevant outcomes about the main drivers of consumer's acceptance. In the near future, a contribution from the breeding sector should be expected in the reduction of the trade-off between quality and yield, towards selection of elite cultivars with enhanced aroma (a pool of compounds still scarcely known), with appreciable nutritional properties and extended market life. Such cultivars need an appropriate rootstock and canopy architecture to facilitate efficient cropping systems. The training/cropping system selection is of equal importance with rootstock selection as it can also determine efficiency and potential for mechanization. A tendency for the future is that several semi- and dwarfing Prunus hybrid rootstocks aligned with the innovations on peach tree architecture will lead to higher planting densities, reduced tree height and thus enhanced peach production with reduced labor cost. With the aim to advance peach fruit production and consumption, there is an urgent need to dissect solutions to valorize on the market the exceptional peach diversity and flavor potential, already present in the varietal landscape. The development of sophisticated non-destructive tools that will allow in cost-effective manner to determine fruit quality and maturity stage is expected to facilitate consumer eating experience and storage requirements with minimum risk of chilling injury symptoms development. Lastly, the phytosanitary protocol of small-sized wall-grown plants would most likely be more effective and would require reduced quantities of pesticides while simultaneously responding to the needs of a market that is increasingly attentive to fruit healthiness and environment protection. Phytosanitary issues can be addressed by controlling diseases and/or by improving genetic resistance.

Tailoring Redox Reactions for Stable Cycling of High-Capacity Li-Ion Cathodes

Development of new cathode materials with even better performance and lower cost is needed to meet the ever-increasing global demand on lithium-ion batteries. As such, extensive efforts have been devoted to developing next-generation cathodes for high-energy Li-ion batteries, e.g., Li-rich transition metal oxides. As a counterpart to the conventional cation-ordered layered oxides, cation-disordered rocksalts (DRXs) have emerged as a new class of high-capacity cathode materials. One unique advantage of the DRX chemistry is the structural flexibility that substantially lessens the elemental constraints and enables the incorporation of a wide variety of TMs and fluorine anion at a decent amount in the crystal lattice. As a result, the dominant TMs have been extended from redox-active Ni and Co in layered cathodes to cost-effective and earth-abundant Mn and Fe as well as redox-inactive TM (e.g., Nb, Ti, Zr, Mo) to facilitate the DRX phase formation. This exceptional chemical diversity largely opens up the opportunity to tune the material compositions for optimal performance through the control of redox reactions.In this talk, I will present our recent work on several high-capacity cathodes based on Mn and Ni redox centers. We specifically focused on understanding the redox chemistry, including cationic and anionic redox, using combined electrochemical, soft X-ray absorption (XAS), and resonant inelastic X-ray spectroscopy (RIXS) techniques. This presentation summarizes the different TM and O redox behaviors and their roles in the electrochemical processes of these high-capacity cathodes. I will then show some examples on how this understanding leads to improved cathodes with enhanced performance by tailoring the redox reactions.

Deep vicariance and frequent transoceanic dispersal shape the evolutionary history of a globally distributed fern family.

The historical biogeography of ferns is typically expected to be dominated by long-distance dispersal due to their minuscule spores. However, few studies have inferred the historical biogeography of a large and widely distributed group of ferns to test this hypothesis. Our aims were to determine the extent to which long-distance dispersal vs. vicariance have shaped the history of the fern family Blechnaceae, to explore ecological correlates of dispersal and diversification, and to determine whether these patterns differ between the northern and southern hemispheres. We used sequence data for three chloroplast loci to infer a time-calibrated phylogeny for 154 of 265 species of Blechnaceae, including representatives of all genera in the family. This tree was used to conduct ancestral range reconstruction and stochastic character mapping, estimate diversification rates, and identify ecological correlates of diversification. Blechnaceae originated in Eurasia and began diversifying in the late Cretaceous. A lineage comprising most extant diversity diversified principally in the austral Pacific region around the Paleocene-Eocene Thermal Maximum. Land connections that existed near the poles during periods of warm climates likely facilitated migration of several lineages, with subsequent climate-mediated vicariance shaping current distributions. Long-distance dispersal is frequent and asymmetrical, with New Zealand/Pacific Islands, Australia, and tropical America being major source areas. Ancient vicariance and extensive long-distance dispersal have shaped the history of Blechnaceae in both the northern and southern hemispheres. The exceptional diversity in austral regions appears to reflect rapid speciation in these areas; mechanisms underlying this evolutionary success remain uncertain.

Species diversity and phylogeography of the Australoheros autrani group (Teleostei, Cichlidae) in eastern Brazil

Cichlid fishes are an important model system in evolutionary biology, primarily because of their exceptional diversity. However, while some cichlid assemblages, such as the ones of the African Great Lakes, have received considerable attention, others are not well studied, including many riverine species. Here, we focus on the Australoheros autrani species group and first report a new record of Australoheros in the upper Paranaíba River drainage, extending the known distribution range of this genus. Through Bayesian inference and maximum likelihood phylogenetic analyses of the mitochondrial cytochrome b gene of these specimens as well as available sequences, we assigned the newly discovered population to Australoheros barbosae. We corroborate the monophyly of the A. autrani species group and the presence of three species in the upper/middle Paraíba do Sul River basin as well as molecular diagnostic characters for each. Finally, we provide evidence for a recent expansion of A. barbosae.

A new genus and species of shrew-like mouse (Rodentia: Muridae) from a new center of endemism in eastern Mindanao, Philippines.

The Philippine archipelago hosts an exceptional diversity of murid rodents that have diversified following several independent colonization events. Here, we report the discovery of a new species of rodent from Mt. Kampalili on eastern Mindanao Island. Molecular and craniodental analyses reveal this species as a member of a Philippine "New Endemic" clade consisting of Tarsomys, Limnomys, and Rattus everetti (tribe Rattini). This new species of "shrew-mouse" is easily distinguished from its relatives in both craniodental and external characteristics including a long, narrow snout; small eyes and ears; short, dark, dense fur dorsally and ventrally; stout body with a tapering, visibly haired tail shorter than head and body length; stout forepaws; bulbous and nearly smooth braincase; narrow, tapering rostrum; short incisive foramina; slender mandible; and narrow, slightly opisthodont incisors. This new genus and species of murid rodent illustrates that murids of the tribe Rattini have exhibited greater species and morphological diversification within the Philippines than previously known and provides evidence that Mt. Kampalili represents a previously unrecognized center of mammalian endemism on Mindanao Island that is deserving of conservation action.

Price Spread Analysis of Castor in Salem and Namakkal District

India is the world’s largest producer of castor oil, producing over 75% of the total world’s supply. Castor oil is unique owing to its exceptional diversity of applications. The oil and its derivatives are used in over 100 different applications in diverse industries such as paints, lubricants, pharmaceuticals, cosmetics, paper, rubber and more. Castor oil is possibly the plant oil industry’s most underappreciated asset. This study is conducted in Salem and Namakkal district to find out the price spread among the marketing channels as well as the marketing efficiency of various marketing channels in the castor crop. Random sampling method was adopted for the study where the primary data has been collected from 100 castor farmers. Among the three marketing channels, the value chain III, namely Farmer – Processors (Oil Millers) - Retailers – Consumers was the most efficient value chain because it had the highest value chain efficiency 2.57 because it had fewer intermediaries than the other value chains.