Several Pythium species cause crown and root rot on cannabis (Cannabis sativa L., marijuana) plants grown under commercial greenhouse conditions
13 Jul 2021-Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie (Taylor & Francis)-pp 1-16
TL;DR: Cannabis plants with symptoms of crown rot, root decay, wilting and plant death were sampled during 2018 and 2019 from seven production greenhouses to study the mechanisms behind plant death.
Abstract: Cannabis (Cannabis sativa L., marijuana) plants with symptoms of crown rot, root decay, wilting and plant death were sampled during 2018 and 2019 from seven production greenhouses. Affected tissues...
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01 Jan 2015
TL;DR: Comparative pathogenicity of Pythium species (total diseases) on turfgrasses showed that P.aphanidermatum was the most aggressive species and P. catenulatum andP.
Abstract: Turfgrasses have been widely used in many residential areas and sport fields for many years. Pythium species can cause severe losses on cereals and other crops as well as ornamental plants such as turfgrass. To study the role of Pythium species in causing seed and root rot and damping-off, plant and soil samples were collected from different regions of Tehran province. Isolates were identified on the basis of morphological characters and cardinal temperature. Pathogenicity of the recovered species was determined on common cool season turfgrasses (Loliumperenne, Poaparatensis and Festucaarundinaceae). Of the 48 recovered Pythium isolates, three species were identified include 66.7% P. aphanidermatum, 18.7% P. catenulatum and 14.6% P. okanoganense. Comparative pathogenicity of Pythium species (total diseases) on turfgrasses showed that P.aphanidermatum was the most aggressive species and P. catenulatum and P. okanoganens were in second and third levels respectively.
2 citations
TL;DR: In this article, stem canker symptoms were sampled from indoor and outdoor production sites in British Columbia (BC) and Ontario (Ontario) and affected tissues were sampled and affected tissue were su...
Abstract: Cannabis (Cannabis sativa L., marijuana) plants grown at indoor and outdoor production sites in British Columbia (BC) and Ontario with stem canker symptoms were sampled and affected tissues were su...
1 citations
Cites background from "Several Pythium species cause crown..."
...…in recent years on cannabis plants include those infecting the inflorescences (Punja and Rodriguez 2018; Punja 2021a; Punja and Ni 2021), the foliage (Punja 2018; Scott and Punja 2021), and the roots (Punja and Rodriguez 2018; Punja et al. 2019; Punja 2021c; Punja 2021b; Punja et al. 2021a)....
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TL;DR: The authors investigated the diversity of fungal species present on inflorescences as epiphytes and in stem tissues as endophytes in flowering plants of cannabis grown organically in British Columbia during 2019-2021.
Abstract: We investigated the diversity of fungal species present on inflorescences as epiphytes and in stem tissues as endophytes in flowering plants of cannabis grown organically in British Columbia during 2019-2021. Fresh and dried inflorescence samples were obtained at various times during production while stems were obtained at harvest. Fungal species in the air were assessed by exposing Petri dishes containing potato dextrose agar + streptomycin sulphate for 1 hr in the growing environment while soil samples were dilution-plated to assess soil fungal diversity. Colonies were identified from PCR-derived sequences of the ITS1-5.8S- ITS2 region of rDNA. Twenty-nine species in 26 genera were recovered from inflorescences and 17 species in 11 genera originated from stem tissues. Approximately 96 % of species found on inflorescences were present in air and 45 % were present in organic soil. The fungi comprised plant pathogens, saprophytes, and opportunistic human pathogens. A large proportion of the species found in air and soil in organic facilities are present on cannabis inflorescences, where they may increase total colony- forming units and negatively affect product quality. Some species could contribute to allergies or secondary infections in humans. The potential benefits of endophytes within organically grown cannabis plants remain unexplored.
1 citations
References
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TL;DR: The latest version of the Molecular Evolutionary Genetics Analysis (Mega) software, which contains many sophisticated methods and tools for phylogenomics and phylomedicine, has been optimized for use on 64-bit computing systems for analyzing larger datasets.
Abstract: We present the latest version of the Molecular Evolutionary Genetics Analysis (Mega) software, which contains many sophisticated methods and tools for phylogenomics and phylomedicine. In this major upgrade, Mega has been optimized for use on 64-bit computing systems for analyzing larger datasets. Researchers can now explore and analyze tens of thousands of sequences in Mega The new version also provides an advanced wizard for building timetrees and includes a new functionality to automatically predict gene duplication events in gene family trees. The 64-bit Mega is made available in two interfaces: graphical and command line. The graphical user interface (GUI) is a native Microsoft Windows application that can also be used on Mac OS X. The command line Mega is available as native applications for Windows, Linux, and Mac OS X. They are intended for use in high-throughput and scripted analysis. Both versions are available from www.megasoftware.net free of charge.
33,048 citations
Additional excerpts
...Evolutionary analyses were conducted in MEGA7 (Kumar et al. 2016)....
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01 Jan 2013
TL;DR: The Molecular Evolutionary Genetics Analysis (MEGA) software as discussed by the authors provides facilities for building sequence alignments, inferring phylogenetic histories, and conducting molecular evolutionary analysis, including the inference of timetrees.
Abstract: We announce the release of an advanced version of the Molecular Evolutionary Genetics Analysis (MEGA) software, which currently contains facilities for building sequence alignments, inferring phylogenetic histories, and conducting molecular evolutionary analysis. In version 6.0, MEGA now enables the inference of timetrees, as it implements the RelTime method for estimating divergence times for all branching points in a phylogeny. A new Timetree Wizard in MEGA6 facilitates this timetree inference by providing a graphical user interface (GUI) to specify the phylogeny and calibration constraints step-by-step. This version also contains enhanced algorithms to search for the optimal trees under evolutionary criteria and implements a more advanced memory management that can double the size of sequence data sets to which MEGA can be applied. Both GUI and command-line versions of MEGA6 can be downloaded from www. megasoftware.net free of charge.
30,478 citations
TL;DR: The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomyCete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomy cetes.
Abstract: Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.
448 citations
"Several Pythium species cause crown..." refers methods in this paper
...Since these two species are reported to be distinguished by their mitochondrial cytochrome c oxidase subunit I (COI) sequences (Robideau et al. 2011), we utilized this approach to confirm the presence of P....
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...Since these two species are reported to be distinguished by their mitochondrial cytochrome c oxidase subunit I (COI) sequences (Robideau et al. 2011), we utilized this approach to confirm the presence of P. catenulatum....
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TL;DR: This review will concentrate on examples of the readily available literature of the past 50 years and will emphasize the pathology of the genus Pythium, with only brief treatment of other aspects such as taxonomy and control.
Abstract: The genus Pythium includes a number of readily recognized species with wide distributions and host ranges. The taxonomic position of the genus and its relationship to other Phycomycetes were well established during the latter part of the 19th century. In the early 1900s pathologists found Pythium spp. consistently associated with root diseases and it soon became apparent that these fungi were important plant pathogens. Certainly, while 1),ot all isolates of Pythium species are capable of causing diseases of plants, many are soil borne pathogens that cause serious economic loss on a wide variety of hosts, while others are more limited in host and geographic range or affect plants only under special environmental conditions. New species are being discov ered as pathologists investigate soil organisms associated with plant growth problems. Rands & Dopp (123) in their classic investigation of sugarcane root dis eases established the symptoms and determined the conditions needed for these fungi to become destructive. This work, and others of a similar nature, are part of the extensive literature on diseases caused by species of Pythium. This review will concentrate on examples of the readily available literature of the past 50 years and will emphasize the pathology of the genus, with only brief treatment of other aspects such as taxonomy and control. It will be con fined to Pythium spp. as they affect economic plants and will not deal with those affecting algae, other marine plants, fungi, and unusual hosts.
362 citations
"Several Pythium species cause crown..." refers background in this paper
...Wounding of roots is known to enhance infection by Pythium spp. on a range of host plants (Hendrix and Campbell 1973; Martin and Loper 1999; Sutton et al. 2006)....
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...Root discolouration (browning) is a common early symptom of infection due to Pythium species, which is generally followed by decay of lateral roots and crown tissues (Hendrix and Campbell 1973; Martin and Loper 1999; Sutton et al. 2006; Troth and Thiessen 2019; Osterbauer and Ocamb 2020)....
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...Damping-off, a common symptom caused by Pythium spp. on several crops (Hendrix and Campbell 1973), was not observed on cannabis cuttings and was reported instead to be caused by several species of Fusarium (Punja 2021a, 2021b)....
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TL;DR: Information on the ecology and biological control of plant pathogenic Pythium species is reviewed with the premise that a clear understanding of the ecology of the pathogen will assist in the development of efficacious biocontrol agents.
Abstract: Soilborne root diseases caused by plant pathogenic Pythium species cause serious losses in a number of agricultural production systems, which has led to a considerable effort devoted to the development of biological agents for disease control. In this article we review information on the ecology and biological control of these pathogens with the premise that a clear understanding of the ecology of the pathogen will assist in the development of efficacious biocontrol agents. The lifecycles of the pathogens and etiology of host infection also are reviewed, as are epidemiological concepts of inoculum-disease relationships and the influence of environmental factors on pathogen aggressiveness and host susceptibility. A number of fungal and bacterial biocontrol agents are discussed and parallels between their ecology and that of the target pathogens highlighted. The mechanisms by which these microbial agents suppress diseases caused by Pythium spp., such as interference with pathogen survival, disruption of the...
357 citations
"Several Pythium species cause crown..." refers background in this paper
...The rapid growth rate and production of a range of cell wall degrading enzymes by isolates of these species likely contribute to their pathogenicity (Martin and Loper 1999; Wang et al. 2003; Boudjeko et al. 2006; Geethu et al. 2013)....
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...Isolates of the highly pathogenic species P. aphanidermatum, P. myriotylum and P. ultimum are able to infect a wide range of host plant species (Martin and Loper 1999; Chellemi et al. 2000; Sutton et al. 2006; Ho 2009; Wei et al. 2010)....
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...Previous studies have demonstrated the efficacy of these and other biocontrol agents in reducing Pythium infection on a range of crop species (Martin and Loper 1999; Punja and Yip 2003; Rose et al. 2004; Kipngeno et al. 2015; Elshahawy and El-Mohamedy 2019; Halo et al. 2019)....
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...Root discolouration (browning) is a common early symptom of infection due to Pythium species, which is generally followed by decay of lateral roots and crown tissues (Hendrix and Campbell 1973; Martin and Loper 1999; Sutton et al. 2006; Troth and Thiessen 2019; Osterbauer and Ocamb 2020)....
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...Wounding of roots is known to enhance infection by Pythium spp. on a range of host plants (Hendrix and Campbell 1973; Martin and Loper 1999; Sutton et al. 2006)....
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