scholarly journals Management of Infection by Parasitic Weeds: A Review

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1184
Author(s):  
Mónica Fernández-Aparicio ◽  
Philippe Delavault ◽  
Michael P. Timko
Keyword(s):  
Molecular Mechanisms ◽  
Agricultural Practices ◽  
Parasitic Plants ◽  
Natural Ecosystems ◽  
High Fecundity ◽  
Parasitic Weeds ◽  
Crop Resistance ◽  
Rapid Responses ◽  
New Hosts ◽  
Vascular Connections

Parasitic plants rely on neighboring host plants to complete their life cycle, forming vascular connections through which they withdraw needed nutritive resources. In natural ecosystems, parasitic plants form one component of the plant community and parasitism contributes to overall community balance. In contrast, when parasitic plants become established in low biodiversified agroecosystems, their persistence causes tremendous yield losses rendering agricultural lands uncultivable. The control of parasitic weeds is challenging because there are few sources of crop resistance and it is difficult to apply controlling methods selective enough to kill the weeds without damaging the crop to which they are physically and biochemically attached. The management of parasitic weeds is also hindered by their high fecundity, dispersal efficiency, persistent seedbank, and rapid responses to changes in agricultural practices, which allow them to adapt to new hosts and manifest increased aggressiveness against new resistant cultivars. New understanding of the physiological and molecular mechanisms behind the processes of germination and haustorium development, and behind the crop resistant response, in addition to the discovery of new targets for herbicides and bioherbicides will guide researchers on the design of modern agricultural strategies for more effective, durable, and health compatible parasitic weed control.

scholarly journals Regulation of TRH neurons and energy homeostasis-related signals under stress

2015 ◽  
Vol 224 (3) ◽  
pp. R139-R159 ◽  
Author(s):  
Patricia Joseph-Bravo ◽  
Lorraine Jaimes-Hoy ◽  
Jean-Louis Charli
Keyword(s):  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cellular Phenotype ◽  
Energy Demands ◽  
Rapid Responses ◽  
Hpt Axis

Energy homeostasis relies on a concerted response of the nervous and endocrine systems to signals evoked by intake, storage, and expenditure of fuels. Glucocorticoids (GCs) and thyroid hormones are involved in meeting immediate energy demands, thus placing the hypothalamo–pituitary–thyroid (HPT) and hypothalamo–pituitary–adrenal axes at a central interface. This review describes the mode of regulation of hypophysiotropic TRHergic neurons and the evidence supporting the concept that they act as metabolic integrators. Emphasis has been be placed on i) the effects of GCs on the modulation of transcription ofTrhin vivoandin vitro, ii) the physiological and molecular mechanisms by which acute or chronic situations of stress and energy demands affect the activity of TRHergic neurons and the HPT axis, and iii) the less explored role of non-hypophysiotropic hypothalamic TRH neurons. The partial evidence gathered so far is indicative of a contrasting involvement of distinct TRH cell types, manifested through variability in cellular phenotype and physiology, including rapid responses to energy demands for thermogenesis or physical activity and nutritional status that may be modified according to stress history.

scholarly journals Genome-wide transcriptome analysis between Small-tail Han sheep and the Surabaya fur sheep using high-throughput RNA sequencing

Reproduction ◽  
2013 ◽  
Vol 145 (6) ◽  
pp. 587-596 ◽  
Author(s):  
Xiangyang Miao ◽  
Qingmiao Luo
Keyword(s):  
Candidate Genes ◽  
Molecular Mechanisms ◽  
Complex Trait ◽  
Future Research ◽  
Rna Seq ◽  
Molecular Biology Technique ◽  
High Fecundity ◽  
Next Generation Sequencing Technology ◽  
Genome Wide ◽  
Generation Sequencing

The Small-tail Han sheep and the Surabaya fur sheep are two local breeds in North China, which are characterized by high-fecundity and low-prolificacy breed respectively. Significant genetic differences between these two breeds have provided increasing interests in the identification and utilization of major prolificacy genes in these sheep. High prolificacy is a complex trait, and it is difficult to comprehensively identify the candidate genes related to this trait using the single molecular biology technique. To understand the molecular mechanisms of fecundity and provide more information about high prolificacy candidate genes in high- and low-fecundity sheep, we explored the utility of next-generation sequencing technology in this work. A total of 1.8 Gb sequencing reads were obtained and resulted in more than 20 000 contigs that averaged ∼300 bp in length. Ten differentially expressed genes were further verified by quantitative real-time RT-PCR to confirm the reliability of RNA-seq results. Our work will provide a basis for the future research of the sheep reproduction.

scholarly journals Improving architectural traits of maize inflorescences

2021 ◽  
Vol 41 (3) ◽  
Author(s):  
Zongliang Chen ◽  
Andrea Gallavotti
Keyword(s):  
Molecular Mechanisms ◽  
Animal Feed ◽  
Genetic Regulation ◽  
Agricultural Practices ◽  
Hormonal Control ◽  
Human Consumption ◽  
Inflorescence Development ◽  
Maize Productivity ◽  
Ligand Interactions ◽  
Architectural Traits

AbstractThe domestication and improvement of maize resulted in radical changes in shoot architecture relative to its wild progenitor teosinte. In particular, critical modifications involved a reduction of branching and an increase in inflorescence size to meet the needs for human consumption and modern agricultural practices. Maize is a major contributor to global agricultural production by providing large and inexpensive quantities of food, animal feed, and ethanol. Maize is also a classic system for studying the genetic regulation of inflorescence formation and its enlarged female inflorescences directly influence seed production and yield. Studies on the molecular and genetic networks regulating meristem proliferation and maintenance, including receptor-ligand interactions, transcription factor regulation, and hormonal control, provide important insights into maize inflorescence development and reveal potential avenues for the targeted modification of specific architectural traits. In this review, we summarize recent findings on the molecular mechanisms controlling inflorescence formation and discuss how this knowledge can be applied to improve maize productivity in the face of present and future environmental challenges.

scholarly journals Evolution of pathogen tolerance and emerging infections: A missing experimental paradigm

2021 ◽  
Author(s):  
Srijan Seal ◽  
Guha Dharmarajan ◽  
imroze khan
Keyword(s):  
Infectious Period ◽  
Emerging Infections ◽  
Natural Ecosystems ◽  
Zoonotic Pathogens ◽  
Natural Hosts ◽  
Pathogen Prevalence ◽  
In The Wild ◽  
Severe Infections ◽  
New Hosts ◽  
Reservoir Hosts

Researchers worldwide are repeatedly warning us against future zoonotic diseases resulting from mankind’s insurgence into natural ecosystems. The same zoonotic pathogens that cause severe infections in a human host fail to produce any disease outcome in their natural hosts. What precise features of the immune system enable natural reservoirs to carry these pathogens so efficiently? To understand these effects, we analyse the evolutionary basis of pathogen tolerance in reservoir hosts, while drawing implications from their diverse physiological and life-history traits, and ecological contexts of host-pathogen interactions. Long-term co-evolution might allow reservoir hosts to modulate immunity and evolve tolerance to zoonotic pathogens, increasing their circulation and infectious period. Such processes can also create a genetically diverse pathogen pool by allowing more mutations and genetic exchanges between circulating strains, thereby harbouring rare alive-on-arrival variants with extended infectivity to new hosts (i.e., spillover). Finally, we end by underscoring the indispensability of a large multi-disciplinary empirical framework to explore the proposed link between evolved tolerance, pathogen prevalence and spillover in the wild.

scholarly journals Spatial-temporal analysis of the risk to water pollution against land use changes in Lobo Stream Drainage Basin, Itirapina-SP, Brazil

2019 ◽  
Vol 23 ◽  
pp. 34
Author(s):  
Phelipe Da Silva Anjinho ◽  
Allita Rezende dos Santos ◽  
Mariana Abibi Guimarães Araujo Barbosa ◽  
Frederico Fabio Mauad
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Forest Restoration ◽  
Drainage Basin ◽  
Land Use Changes ◽  
Water System ◽  
Agricultural Practices ◽  
Temporal Analysis ◽  
Land Use Classification ◽  
Natural Ecosystems

The landscape transformation caused by economical activities generates impacts on natural ecosystems and the water system is one of the most susceptible to anthropic alterations. In this context, the objective of this study was to analyze the vulnerability of the water resources of the Lobo Stream Drainage Basin (LSDB), Itirapina-SP, through the application of the Environmental Quality Index of Water Resources (EQI-Hydro), in a 32 years period, corresponding to the years 1985 and 2017. The EQI-Hydro was calculated from the analysis of the Euclidean distance of the water resources to the impacting sources, determined by means of land use classification, and then rescaled based on fuzzy logic. The results show that approximately 57% of the watershed area is classified as high and very high EQI-Hydro. The Itaqueri River and the Água Branca Stream are the most vulnerable to pollution due to their proximity to pollution sources. This manifests the need for adequate agricultural practices and public policies for forest restoration, aiming the preservation of the LSDB water resources.

Disentangling parasitic vines in the tropics: taxonomic notes for an accurate identification of Cuscuta (Convolvulaceae) and Cassytha (Lauraceae)

Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
Simone Soares da Silva ◽  
Rosângela Simão-Bianchini ◽  
Ana Rita Giraldes Simões ◽  
Mihai Costea
Keyword(s):  
Current Practice ◽  
Keystone Species ◽  
Parasitic Plants ◽  
Economic Losses ◽  
Herbarium Specimens ◽  
Natural Ecosystems ◽  
Accurate Identification ◽  
Identification Guide ◽  
Macroscopic Observation ◽  
The Tropics

Abstract Parasitic plants are often associated with agricultural, forestry and grassland economic losses, but they are also keystone species in their natural ecosystems. Cuscuta (Convolvulaceae) and Cassytha (Lauraceae) are parasitic plants which have evolved similar stem habit and morphology, rendering them remarkably similar during the vegetative stage. Since both genera are common in the tropics, misidentifications are frequent, which is detrimental for understanding their geographical distribution, biology and ecology, as well as to the development of adequate control or conservation practices. We here present a practical identification guide for a clear and accurate distinction between Cuscuta and Cassytha, using stems and reproductive structures of both fresh plants and herbarium specimens, aimed at taxonomists and agricultural experts. An identification key, a comparative table, detailed descriptions and illustrations are included to facilitate genus recognition. The current practice of macroscopic observation of the filiform stems, on which many professionals rely, may not be enough to distinguish the two genera. The analysis of stem micromorphology, and/or of the flower or fruit morphology, are necessary for a conclusive identification.

Landuse-based nonpoint source pollution. A threat to water resources in developing countries

1996 ◽  
Vol 33 (4-5) ◽  
pp. 53-61 ◽  
Author(s):  
Andrzej Tonderski
Keyword(s):  
Developing Countries ◽  
Water Resources ◽  
Crop Production ◽  
Agricultural Land ◽  
Agricultural Practices ◽  
Industrialized Countries ◽  
Natural Ecosystems ◽  
Steady Rate ◽  
Chemical Inputs ◽  
Near Future

This article intends to raise some reflections on the increasing pollution from landuse-based nonpoint sources in developing countries. It is focused on historical development of agro-environmental factors such as deforestation, wetland transformation, monocultural crop production, agro-chemical inputs, concentrated animal production, and irrigation. It is shown that reduction of natural ecosystems in favour of agricultural land and intensification of the agricultural practices in developing countries continue on a larger scale and speed than in the industrialized countries. Some practices (e.g. the use of commercial fertilizers) show dramatic increases over last decades, others (e.g. deforestation) have increased at a steady rate over time. The major conclusion of this analysis is the necessity for urgent action of national and international communities on scientific and political level. If we do not focus our activities on controling pollution originating from landuse-based sources, developing countries will, in the near future, face dangerous deterioration of water resources with limited financial means to tackle the problem.

Molecular Dialog Between Parasitic Plants and Their Hosts

2019 ◽  
Vol 57 (1) ◽  
pp. 279-299 ◽  
Author(s):  
Christopher R. Clarke ◽  
Michael P. Timko ◽  
John I. Yoder ◽  
Michael J. Axtell ◽  
James H. Westwood
Keyword(s):  
Immune Responses ◽  
Agricultural Production ◽  
Host Plants ◽  
Plant Pathogens ◽  
Molecular Mechanisms ◽  
Parasitic Plants ◽  
Transcriptomic Data ◽  
Plant Parasitism ◽  
Body Of Knowledge ◽  
Plant Pathogen Interactions

Parasitic plants steal sugars, water, and other nutrients from host plants through a haustorial connection. Several species of parasitic plants such as witchweeds ( Striga spp.) and broomrapes ( Orobanche and Phelipanche spp.) are major biotic constraints to agricultural production. Parasitic plants are understudied compared with other major classes of plant pathogens, but the recent availability of genomic and transcriptomic data has accelerated the rate of discovery of the molecular mechanisms underpinning plant parasitism. Here, we review the current body of knowledge of how parasitic plants sense host plants, germinate, form parasitic haustorial connections, and suppress host plant immune responses. Additionally, we assess whether parasitic plants fit within the current paradigms used to understand the molecular mechanisms of microbial plant–pathogen interactions. Finally, we discuss challenges facing parasitic plant research and propose the most urgent questions that need to be answered to advance our understanding of plant parasitism.

scholarly journals Global Dimensions of Plant Virus Diseases: Current Status and Future Perspectives

2019 ◽  
Vol 6 (1) ◽  
pp. 387-409 ◽  
Author(s):  
Roger A.C. Jones ◽  
Rayapati A. Naidu
Keyword(s):  
Crop Production ◽  
Production Systems ◽  
Virus Disease ◽  
Cropping Systems ◽  
Agricultural Practices ◽  
Viral Disease ◽  
Current Status ◽  
Natural Ecosystems ◽  
Geographical Regions ◽  
Epidemiological Characteristics

Viral diseases provide a major challenge to twenty-first century agriculture worldwide. Climate change and human population pressures are driving rapid alterations in agricultural practices and cropping systems that favor destructive viral disease outbreaks. Such outbreaks are strikingly apparent in subsistence agriculture in food-insecure regions. Agricultural globalization and international trade are spreading viruses and their vectors to new geographical regions with unexpected consequences for food production and natural ecosystems. Due to the varying epidemiological characteristics of diverent viral pathosystems, there is no one-size-fits-all approach toward mitigating negative viral disease impacts on diverse agroecological production systems. Advances in scientific understanding of virus pathosystems, rapid technological innovation, innovative communication strategies, and global scientific networks provide opportunities to build epidemiologic intelligence of virus threats to crop production and global food security. A paradigm shift toward deploying integrated, smart, and eco-friendly strategies is required to advance virus disease management in diverse agricultural cropping systems.

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