2023
Permanent URI for this collectionhttps://hdl.handle.net/1807/126401
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Item Petalophyllites speirsiae gen. et sp. nov. (Marchantiophyta: Fossombroniales), a fossil liverwort gametophyte from the Paleocene of Alberta, Canada(Canadian Science Publishing, 2023-07-28) Hoffman, Georgia L. L.; Crandall-Stotler, BarbaraAbstract: Although liverworts (Marchantiophyta) are postulated to be one of the oldest lineages of land plants, their documented fossil record is sparse. This study describes five new fossil liverwort gametophytes, one of which bears antheridia, from the Paleocene Paskapoo Formation of Alberta, Canada. The thalli are bilaterally symmetrical, with two undissected wings that bear oppositely arranged dorsal lamellae. One specimen is dichotomously branched, and one bears clusters of antheridia along the midrib area of its dorsal surface. These characters are consistent with those of extant Petalophyllum (Fossombroniales: Petalophyllaceae), and the genus Petalophyllites gen. nov. (Fossombroniales: Petalophyllaceae) is here erected for these fossils. They are the first representatives of Petalophyllaceae and the Fossombroniales from the fossil record. Most of the specimens are in growth position. Their geologic setting and associated fossils indicate that Petalophyllites lived at the margin of a lake or pond in a habitat that may have been intermittently dry, as is also common in extant species of Petalophyllum. The well-preserved thalli and antheridia of these fossils, and their well-documented middle Paleocene age, provide new evidence of liverwort diversification at the dawn of the Cenozoic Era.Item We do not see evidence for the presence of female gametangia (oospores) in North American Nitellopsis obtusa (Desvaux) J. Groves.(Canadian Science Publishing, 2023-09-16) Gottschalk, Stephen; Boissezon, Aurélie; Hamsher, Sarah E.; McCourt, Richard M.; Perleberg, Donna J.; Skawinski, Paul M.; Sleith, Robin S.; Karol, Kenneth G.An article titled: “First report of female gametangia in the invasive macroalga starry stonewort (Nitellopsis obtusa) in North America” was published in this journal. Harrow-Lyle et al. (2023) outlined what they asserted was the first documented evidence of female gametangia of Nitellopsis obtusa (Desvaux) J. Groves in North America. We disagree with the main finding that the structure in their image is a N. obtusa female gametangium. The appearance of N. obtusa female gametangia in North America is a real possibility, and their presence would impact both the invasion biology of this aquatic invasive and the efforts to control it. Nevertheless, we maintain that only male N. obtusa have conclusively been documented in North America and that better observational data are required.Item The importance of taxonomy for determining species distribution: A case study using the disjunct lichen Brodoa oroarctica.(Canadian Science Publishing, 2023-10-27) Paquette, Hayley Anne; McMullin, Richard Troy; Wiersma, YolandaSpecies-focused conservation requires a thorough understanding of species’ distributions. Delineating a species’ distribution requires taxonomic knowledge and adequate occurrence data. For plants and fungi, herbaria represent a valuable source of large-scale occurrence data. Advances in digital technology mean that data from many herbarium collections worldwide are now easily accessible. However, species concepts can change over time requiring herbarium records to be re-examined and databases updated, which does not always occur synchronously across all collections. Therefore, non-critical use of these data can promote inaccuracies in understanding species distributions. Taxonomic revisions are common in understudied organisms, such as lichens. Here, we illustrate how changing taxonomy and non-critical acceptance of online data affects our understanding of disjunct distributions, using the lichen Brodoa oroarctica (Krog) Goward as an example. Defining the distribution of the arctic lichen B. oroarctica is confounded by changing taxonomy and uncertainty of herbarium records that pre-date taxonomic revisions. We review the distribution of this species in the literature and in aggregate occurrence databases, and verify herbarium specimens that represent disjunct occurrences in eastern North America to present an updated account of its distribution and frequency in eastern North America. We show that knowledge of changing species taxonomy is essential to depicting accurate species distributions.Item Cannibal plants: intraspecific autoparasitism among host-specific holoparasites(Canadian Science Publishing, 2023-09-22) Teixeira-Costa, LuizaIntraspecific autoparasitism, the phenomenon in which a parasite serves as the host for another individual of the same species, is a well described interaction among hemi-parasitic flowering plants. Here I describe a rare case of autoparasitism in Epifagus virginiana (Orobanchaceae), a holo-parasitic plant normally found exclusively on the roots of Fagus grandifolia (Fagaceae). Confirmation of the autoparasitic relationship was obtained through micro-tomography and anatomical analyses. Results show the presence of vessel connections between the two E. virginiana plants and the unobstructed passage of solutes from one plant to another, thus suggesting the autoparasitic connection to be fully functional. While several segments of nearby host roots were entangled with the adventitious roots of the parasite, no parasite-host vascular connection was detected. Additionally, an analysis of digitized herbarium specimens showed that albeit rare, the observed autoparasitic relationship in E. virginiana is not a one-of case. A total of 3,097 digitized herbarium specimens were also analyzed, among which 1.69% were observed to potentially include an autoparasitic connection. Altogether, these results provide new clues for the investigation of host-specificity and haustorium development processes in parasitic flowering plants.Item Outcrossing rates in the permanent translocation heterozygote Oenothera biennis L. (Onagraceae)(Canadian Science Publishing, 2023-09-28) Johnson, Marc T J; Godfrey, RyanIn species that primarily reproduce asexually, occasional sex can have important evolutionary consequences. Many plant species in the genus Oenothera have a genetic system called permanent translocation heterozygosity (PTH), which renders plants functionally asexual when they self-fertilize. PTH results from reciprocal translocations of chromosomes that suppresses recombination, and a balanced lethal mortality of homozygous gametes that prevents independent assortment of alleles. When PTH plants self-fertilize, the offspring are genetically identical to the parents, but when they outcross they can create new genotypes. Here we sought to determine the rate of outcrossing of natural populations of PTH Oenothera biennis L (Onagraceae). We genotyped 46 parents from 14 populations in Tompkins County, NY, USA, and 754 of their offspring at highly polymorphic microsatellite loci. 99.5% of offspring were genetically identical to their seed parents, whereas 4 offspring out of 754 exhibited allelic mismatches with their seed parent. The estimated outcrossing rate ranged from 0.1 to 0.4%. Our study design also permitted us to estimate mutation rate of microsatellite loci., which ranged from 1.33x10-3 to 3.98x10-3. These results show that O. biennis typically exhibits a functionally asexual genetic system, but rare outcrossing events can generate novel genotypes that may have important evolutionary consequences.Item Mycoheterotrophic plants as indicators of post-agricultural forest regeneration: abundance of Hypopitys monotropa and Monotropa uniflora in post-agricultural forests changes through time(Canadian Science Publishing, 2023-09-23) Holmes, MarionHerbaceous layers in second-growth forests are shaped by past land use. Disturbances such as agriculture may impact populations of mycoheterotrophs, non-photosynthetic mycorrhizal plants that obtain carbon from fungal networks, by altering mycorrhizal communities or removing trees they derive carbon from. I tested the hypotheses that two mycoheterotrophic forest herbs increase in abundance during succession and become most common in older forests as plant communities reassemble through time. Distributions of Hypopitys monotropa and Monotropa uniflora, were sampled in Athens County, Ohio, USA. I surveyed populations in a 40-site post-agricultural forest chronosequence with five upland and five valley sites in each of four age classes: 40-60, 61-80, 81-100, and >130 years since canopy closure. Aspect and elevation were measured to assess environmental influence. Both H. monotropa and M. uniflora were most common in older stands with EM tree-rich canopy composition and West or South-facing aspects, indicating influence of historical, biotic, and edaphic factors. Hypopitys was exclusive to forests > 80 years old, while M. uniflora was present in younger stands. Abundance of both species was also significantly predicted by Fagaceae basal area. Because EM trees were also most abundant in South-and West-facing uplands, environmental influence appears to be mediated through canopy composition.Item Vertical botany: airborne remote sensing as an emerging tool for mistletoe research(Canadian Science Publishing, 2023-07-13) Missarov, Azim; Sosnovsky, Yevhen; Rydlo, Karol; Brovkina, Olga; Maes, Wouter H.; Král, Kamil; Krůček, Martin; Krasylenko, YuliyaMistletoe recognition and sampling remain the challenging tasks for arborists, dendrologists, forest ecologists and other specialists because of the low accessibility of the canopy of their host trees. In this review, smart decisions for mistletoe detection on the basis of airborne platforms are discussed. The airborne remote sensing (ARS) has the developing potential to provide rapid, accurate, and cost-efficient detection and research of mistletoe on tree level and large areas within the complex terrain. Geographic and country-based distribution of mistletoe studies using airborne remote sensing methods published within 2007–2023 is overviewed. Here we discuss data types, sensors, and methodologies used in mistletoe ARS research.Item Trends in groundberry cover under climate change in the southern and central Yukon, 1997 to 2022(Canadian Science Publishing, 2023-09-03) Krebs, Charles CJK; Boonstra, Rudy; Kenney, Alice J.; Hofer, Elizabeth J.; Jung, Thomas; O'Donoghue, MarkGroundberries are an important component of the flora of the boreal forest and provide seasonally important food for many birds and mammals, as well as local people in northern Canada. Here we ask if there has been a change in the cover of groundberries in the Yukon boreal forest over the last two decades. We monitored five common species at undisturbed forest sites spaced 300 km apart. At our Kluane site we monitored 710 fixed quadrats per year for 26 years (1997–2022), and at Mayo 500 quadrats per year for 18 years (2005–2022). The cover of four species, Arctostaphylos uva-ursi (bearberry), Arctostaphylos rubra (red bearberry), Empetrum nigrum (crowberry), and Geocaulon lividum (toadflax), declined annually by 0.2-0.8% at both sites. In contrast, Vaccinium vitis-idaea (lingonberry) increased annually by 0.5 and 0.8%. We tested if increases in summer temperature and rainfall were correlated with the observed changes but found no significant relationships. These boreal plants are changing in abundance, but we have limited data on the extent and speed of these changes. We recommend experiments to understand the cause(s) of these changes in groundberry productivity. Our study is a start in monitoring important berry species in this critical ecosystem of northern Canada.Item Leaf morphology and anatomy in Myrcia sect. Aulomyrcia (Myrtaceae): species circumscription and characterization of clades(Canadian Science Publishing, 2023-08-02) Wagner, Mariana A.; Lucas, Eve J.; Soffiatti, Patricia; Cabral, William Santos; Portela, Paulo Ricardo; Fiaschi, PedroMyrcia, a diverse neotropical genus of Myrtaceae, encompasses 793 species. However, species of Myrcia are similar and difficult to distinguish. In Myrcia sect. Aulomyrcia, leaf features help distinguishing clades and species. Our aim is to provide leaf data for species of M. sect. Aulomyrcia’s clades F, and G. We sampled 31 specimens of 13 species of Myrcia sect. Aulomyrcia (Myrcia amazonica, M. eumecephylla, M. hexasticha, M. insularis, M. magna, M. micropetala, M. neodimorpha, M. neoestrellensis, M. obversa, M. pyrifolia, M. riodocensis, M. subobliqua, and M. tetraphylla). Samples were subjected to sectioning and staining techniques for morphological and anatomical analysis through stereo and light-microscopy. Leaf blade and petiole morphological and anatomical features were described carefully for the first time for these 13 species. We provided an identification key based on leaf features. Our findings are discussed in the light of Myrcia sect. Aulomyrcia systematics. We comment of the significance of petiolar and blade features, such as trichomes types and location, phyllotaxis, rhytidome peeling, periderm and lenticels, and petiole, blade, and vascular cylinder shape. Our study brings novel information on leaf structure variation in Myrcia sect. Aulomyrcia, delivering much needed data for species and clades circumscription and identification.Item Returning mistletoe to an urban forest: a restoration success story(Canadian Science Publishing, 2023-07-21) Watson, David M.; Cook, Melinda E; van de Ree, Rodney; Harrison, LeeMistletoes have a fraught public relations history. Vilified as toxic tree-killing weeds, they have long been targeted for removal by arborists and forest managers concerned with tree health. Research on mistletoe ecology has revealed their positive influence on diversity and community structure via complex networks of interactions. In areas where mistletoe has traditionally been removed, managers are now asking whether they can return on their own or whether they should be reintroduced. To evaluate the practicalities of mistletoe restoration, we inoculated 28 London plane trees Platanus x acerfolia in inner Melbourne with Creeping Mistletoe Muellerina eucalyptoides, a locally rare species. Branch dimensions and aspect had no discernible effect on germination or seedling emergence, but trees where access to Brushtail Possums Trichosurus vulpecula was restricted were 30% more likely to host seedlings. Five years after inoculation, seven mistletoes successfully established on five trees, with two mistletoes bearing fruit. Communications with residents and city users elicited positive feedback, catalysing four additional inoculation trials in urban and forest settings elsewhere. In addition to representing a cost-effective means of enhancing habitat values, mistletoe restoration is useful for addressing questions about mistletoe ecology and educating the community about the functional roles these parasitic plants play.Item Variation in establishment success for American mistletoe [Phoradendron leucarpum (Raf.) Reveal M. C. Johnst.] appears most likely to predict its distribution in Virginia and North Carolina, United States(Canadian Science Publishing, 2023-06-29) Flanders, Nicholas; Randle, Christopher P.; Walters, Eric L.; Musselman, Lytton JohnDispersal limitation and variation in habitat suitability may determine an association of American mistletoe (Phoradendron leucarpum, Viscaceae) with forested wetlands in Virginia and North Carolina, United States. Here we first tested the alternative hypothesis that variation in host availability drives this habitat relationship. We used a generalized linear model to show a positive effect of forested wetland habitat on American mistletoe occurrence after accounting for both variation in host availability and differences among regions in host use. We then used seed sowing experiments to quantify how light availability and flood regime determine viability of American mistletoe, allowing us to evaluate the potential for establishment limitation to determine this habitat relationship. Light availability predicted establishment rates but percent canopy openness did not predict seed germination rates. Thus, variation in the ability for American mistletoe to establish across forested habitat types with different local light availabilities is a potentially important mechanism in determining its distribution.Item Transgene silencing in the moss, Physcomitrella (Physcomitrium patens)(Canadian Science Publishing, 2023-07-21) Singer, Stacy; Ashton, Neil WilliamGene targeting is a powerful tool for functional genetic analysis. It has proved especially effective in the model plant, Physcomitrella (Physcomitrium patens), in which integration of exogenous DNA into the genome occurs with very high efficiency at targeted positions by homologous recombination. Here we present a preliminary characterisation of a poorly documented property of Physcomitrella targeted gene knockout lines, namely silencing of reporter and selective marker genes of integrated targeting constructs. We discovered a high incidence of transgene silencing among Physcomitrella knockout lines and, as is the case in seed plants, cytosine (DNA)-methylation of the transgenes is correlated with their silencing. Silencing in Physcomitrella is characterised by metastable epigenetic inheritance through repetitive mitosis and variable stability through meiosis.Item Agrobacterium-mediated transformation of THC-containing Cannabis sativa L. yields a high frequency of transgenic calli expressing bialaphos resistance and non-expressor of PR1 (NPR1) genes(Canadian Science Publishing, 2023-07-11) Holmes, Janesse E.; Punja, Zamir K.We established transformation technologies using Agrobacterium tumefaciens to insert foreign genes into high THC-containing cannabis (Cannabis sativa L.). The Arabidopsis non-expressor of pathogenesis-related protein 1 (AtNPR1) gene was selected as a potentially useful agronomic gene which was linked to the bar gene from Streptomyces that encodes herbicide resistance. We investigated how Agrobacterium strains (EHA105 and GV3101), glufosinate concentrations, explant source, and light intensity, affected transformation frequency (TF). Transformation was confirmed by RT-PCR with primers for the NPR1 or bar genes. Glufosinate at 0.5-1 mg/L inhibited growth of non-transformed calli within 8 weeks following A. tumefaciens infection. Strain EHA105 yielded a higher TF compared to strain GV3101. Whole leaflets yielded a higher TF compared to sectioned leaf explants with strain GV3101. However, this effect was not seen with EHA105. Petiole segments showed a higher TF than leaf sections with strain EHA105. Placing explants under light or dark conditions did not affect TF, which ranged from 5 % to 95 % in different experiments. This is the first report of successful transformation of two high THC-containing C. sativa genotypes with two foreign genes simultaneously - AtNPR1 and bar. The recovery of plantlets from transgenic calli was not attempted and awaits further research.Item Preliminary assessment of the ectomycorrhizal fungi of Quercus garryana on Vancouver Island, British Columbia, Canada(Canadian Science Publishing, 2023-05-02) Berch, Shannon; Witte, Thomas; Tanney, Joey B.Garry oak (Quercus garryana) is the only oak native to British Columbia (BC), where it occupies the northernmost extent of its range. The ecosystem it occupies in BC has been greatly reduced in size and fragmented by European settlement. Garry oak forms ectomycorrhizas that are essential to its existence and will likely play an important role in the response of this tree to climate change. Yet, relatively little is known about the ectomycorrhizal fungi associated with Garry oak in BC. In this study we have documented the occurrence of fungi forming ectomycorrhizas with Garry oak at six locations on Vancouver Island by sequencing the ITS region of ectomycorrhizal root tips collected from Garry oak stands. Of the 47 species we detected, only about 20% can be confidently assigned to known species because not all species have been sequenced and many sequences in public databases are incorrectly or incompletely identified, but the majority of them belong to a community of fungi associated primarily with oaks or other members of Fagaceae. The uniqueness of this community of ectomycorrhizal fungi indicates that the possible expansion of the range of Garry oak in BC in response to climate change may be limited by the co-migration of its ectomycorrhizal fungi.Item Phylogeography of alpine plant Parnassia wightiana (Celastraceae)(Canadian Science Publishing, 2023-05-26) Dai, Xiaosong; Tian, Shuang; Wu, Wei; Yang, Bo; Ma, Yifan; Ge, Gang; Wu, DingParnassia wightiana, a perennial herb, is an alpine plant distributed across three biodiversity hotspots in China. This species offers an excellent study system to analyze the distribution pattern and genetic structure of high mountainous plant populations. Three cpDNA regions (rpl32-trnL, trnL-F, trnS-G) from 442 individuals of 39 populations and ITS from 418 individuals of 38 populations were sequenced and analyzed. We identified a total of 26 haplotypes based on the concatenated sequences of cpDNA and a total of 36 based on ITS sequences. A hierarchical analysis of molecular variance (AMOVA) indicated significant phylogeographic structure among populations. Mismatch analysis of multi-peak and Tajima’s D neutral test demonstrated P.wightiana populations within China had not experienced abrupt expansion recently.The allopatric fragmentation resulted in the geographic isolation due to environmental heterogeneity, producing a high proportion of private haplotypes in the distribution of P. wightiana within China.Item COMPLEX TAXONOMY IN OPUNTIOIDEAE: IS FLORAL MORPHOMETRY ESSENTIAL TO IDENTIFY OPUNTIA SPECIES?(Canadian Science Publishing, 2023-05-23) Galicia-Pérez, Aldanelly; Golubov, Jordan JG; Manzanarez-Villasana, Gerardo; Martínez-Ramos, Linda Mariana; Arias, Salvador; Márquez-Guzmán, Judith; Mandujano, Maria CCorrect species identification is critical for studies on biodiversity, ecology, and conservation. Determining Opuntia s.s. species is difficult because they have similar traits and are phenotypically plastic. Taxonomic keys are based on vegetative traits, rather than reproductive ones such as flowers, because they are assumed to be too similar. We analyzed morphometric characteristics of flowers and cladodes over 6 years to determine which of these is most useful for differentiating Opuntia species from the Chihuahuan Desert. For each species (Opuntia robusta, O. cantabrigiensis, O. tomentosa, and O. streptacantha),we tagged 20 hermaphroditic and 40 dioecious plants (totaling 100) from 2014-2020, to complete the sample size of flowers and cladodes. Seventeen morphometric characters were measured for new cladodes and 15 for flowers, and discriminant analysis was applied to determine which traits enabled species delimitation. Six of the 17 cladode characteristics combined explained 89% of the variation, while nine floral characteristics combined explained 94% of the variation. Floral morphometrics proved to be very useful to accurately differentiate species and should be included, in addition to cladodes, in future taxonomic studies. Here, we provide the first taxonomic key that includes floral traits to identify Opuntia and a new description of each studied species.Item A tale of two mistletoes: phenology and fauna associated with two sympatric species(Canadian Science Publishing, 2023-05-25) Pincheira, Javiera; Villarroel, Javiera; Orellana, José Ignacio; Fonturbel, Francisco EMistletoes are parasitic plants that largely rely on animals for pollination and seed dispersal but establish complex interactions with their host plants. Mistletoes are considered keystone species in forest ecosystems as they facilitate several interactions. We studied the fauna associated with two sympatric mistletoe species (Tristerix corymbosus and Desmaria mutabilis) from the temperate rainforests of southern Chile. We set 40 camera traps from November 2021 to May 2022 to monitor the main pollinator (the hummingbird Sephanoides sephaniodes), the main seed disperser (the arboreal marsupial Dromiciops bozinovici), and other animals (birds, mammals, reptiles, and insects). We compared fauna associated with T. corymbosus between spring and summer-fall periods and between T. corymbosus and D. mutabilis during summer-fall. Species composition associated with T. corymbosus showed a significant temporal variation, mainly explained by S. sephaniodes and D. bozinovici, which are more abundant in the summer-fall period. We found that animal species composition differences between mistletoe species were mainly explained by S. sephaniodes, D. bozinovici, and insects. While T. corymbosus was mainly pollinated by hummingbirds, insects frequently visited D. mutabilis flowers. Although both mistletoes have many similarities, they also have some phenology differences that affect their associations with animals, potentially influencing ecological processes.Item Untargeted and targeted metabolomics to understand plant growth regulation and evolution in Wollemi pine (Wollemia nobilis)(Canadian Science Publishing, 2023-05-11) Giebelhaus, Ryland T; Biggs, Laura; Murch, Susan; Erland, Lauren A EWollemi Pine (Wollemia nobilis (Jones, Hill, Allen)) is a living fossil, known only through fossil records until its 1994 discovery in Australia. Wollemi Pine is closely related to Norfolk Island pine (Araucaria heterophylla (Salisb.) Franco) making it an interesting system to study metabolic evolution. We employed untargeted liquid chromatography mass spectrometry-based (LC-MS) metabolomics, with chemometrics, pathway analysis, and our novel plant growth regulator (PGR) putative identification tool (HormonomicsDB) to explore the metabolomes of both species. We identified PGR conjugates, and found cytokinin, zeatin, and brassinosteroid pathways to be overrepresented in Wollemi Pine tissues, suggesting these PGRs play an important role in it’s survival. Melatonin, a proposed ancient and stress-related PGR was not identified in untargeted analysis of either species. Based on our untargeted results we employed targeted LC-MS to quantify brassinolide and confirm the absence or presence of melatonin in Wollemi and Norfolk Island pine. Both species had similar concentrations of brassinolide. While Wollemi Pine had significantly higher melatonin levels than Norfolk Island. High levels of melatonin and brassinolide in Wollemin pine supports the hypothesis that these are ancient PGRs that conferred an evolutionary advantage in Wollemi, allowing it to persist.Item REPRODUCTIVE BIOLOGY OF CARYOCAR BRASILIENSE (CARYOCARACEAE) IN PRESERVED AND DEGRADED CERRADO AREAS IN BRAZIL(Canadian Science Publishing, 2023-04-06) Roque, Stéphanie Queiroz; Falcão, Luiz Alberto Dolabela; Rech, André Rodrigo; Silva, Jhonathan Oliveira; Oliveira, Priscila Santos; Ferreira, Kleiperry Freitas; do Espírito Santo, Mário MarcosThis study aimed to characterize the reproductive system and determine the importance of pollinators for fruit production of C. brasiliense, an economically important tree, in preserved and degraded Cerrado areas in southeastern Brazil. For this purpose, we performed pollinator exclusion experiments to determine the frequency of self- and cross-pollination, and to determine fruit set. In general, fruit set was extremely low: only 2.92% and 2.71% of the flowers developed into fruits in the degraded and preserved areas, respectively. Fruit set by manual cross-pollination and natural (open) pollination were higher than self-pollination in both areas. Pollen deposition was significantly higher at night and in the preserved area, although a relatively high amount of pollen grains found in the stigmas during the day. The number of ripened and aborted seeds did not differ among areas, but fruits and seeds were heavier in the degraded area than in the preserved area. The abortion level was very high (64.5%), which may be related to low pollen quality due to selfing. Our study presents evidence that Cerrado degradation affects the reproductive biology of C. brasiliense, but whether such effect is a consequence of pollinator decline in degraded areas remains to be determined.Item Review: Understanding bud rot development, caused by Botrytis cinerea, on cannabis (Cannabis sativa L.) plants grown under greenhouse conditions(Canadian Science Publishing, 2023-03-14) Mahmoud, Mohannad; BenRejeb, Ines; Punja, Zamir K.; Buirs, Liam; Jabaji, SuhaBotrytis cinerea is a widespread necrotrophic plant pathogen that causes diseases on > 1,000 plant species, including vegetables and ornamental greenhouse crops. On cannabis (Cannabis sativa L.), the pathogen is responsible for causing “bud rot”, a major disease affecting the inflorescences (compound flowers), as well as seedling damping-off and leaf blight under certain conditions. During greenhouse cultivation, B. cinerea can destroy cannabis inflorescences rapidly under optimal relative humidity conditions (>70%) and moderate temperatures (17-24°C). Little is currently known about the host-pathogen interactions of B. cinerea on cannabis. Information gleaned from other hosts can provide useful information for comparative purposes to understand disease development, epidemiology, and pathogenicity of B. cinerea on cannabis crops. In this review, the pathogenesis and host responses to Botrytis infection are described, and potential mechanisms involved in disease resistance are assessed. The effects of microclimatic and other environmental conditions on disease development, strategies for early disease detection using prediction models, and the application of biological control agents which can prevent B. cinerea development on cannabis, are discussed. Other potential disease management approaches to reduce the impact of Botrytis bud rot are reviewed. Numerous opportunities for conducting additional research to better understand the cannabis-B. cinerea interaction are identified.