Efficient Syntheses of KLS-13019 Using Palladium Mediated Cross Couplings.

KLS-13019 is a structural analogue of cannabidiol, that shows improved bioavailability and potency in both preventing and reversing paclitaxel-induced neurotoxicity in vitro and in vivo. KLS-13019 was selected as a development candidate and attention was turned to development of a scalable synthesis. The original synthesis of KLS-13019 was not efficient, regioselective, or high yielding. Two new syntheses are reported that make use of the palladium catalyzed cross couplings to a chemically advanced intermediate 5, dramatically shortening (3-4 steps) and improving the overall yield. In addition, a convenient one pot Boc-cleavage and acetylation procedure is described to avoid impurities generated from a step-wise process.

Symbiosis and pathogenicity of Geosmithia and Talaromyces spp. associated with the cypress bark beetles Phloeosinus spp. and their parasitoids.

Fungi associated with cypress bark beetles are practically unknown in the Eastern Mediterranean. Our study focused on the fungi associated with the body parts and galleries of two indigenous cypress bark beetles, Phloeosinus armatus and P. bicolor, sampled from Cupressus sempervirens trees in different regions in Israel. Arbitrarily primed PCR, performed on genomic DNA of 302 isolates, clustered the fungal population into five distinct groups. Multilocus phylogeny, split-network analyses and morphological characterization identified the isolates as Geosmithia omnicola, Geosmithia langdonii, Geosmithia sp. 708b, Geosmithia cupressina sp. nov. CBS147103 and Talaromyces cupressi sp. nov. CBS147104. Of these fungal isolates, G. cupressina and T. cupressi are newly described, and their morphological features and phylogenetic designations are presented. Inoculation of intact cypress saplings in an outdoor net-house revealed that only the representative isolate T. cupressi sp. nov. CBS147104 causes 100% disease incidence, whereas Geosmithia spp. isolates are not pathogenic. A number of these fungi were isolated from parasitoids that emerged from branch and stem sections colonized by P. armatus. This study suggests a long and stable association between Phloeosinus and Geosmithia species, and a possible role for additional associated fungal species as pathogens or endophytes of C. sempervirens trees in Israel.

Preinvasion Assessment of Exotic Bark Beetle-Vectored Fungi to Detect Tree-Killing Pathogens.

Exotic diseases and pests of trees have caused continental-scale disturbances in forest ecosystems and industries, and their invasions are considered largely unpredictable. We tested the concept of preinvasion assessment of not yet invasive organisms, which enables empirical risk assessment of potential invasion and impact. Our example assesses fungi associated with Old World bark and ambrosia beetles and their potential to impact North American trees. We selected 55 Asian and European scolytine beetle species using host use, economic, and regulatory criteria. We isolated 111 of their most consistent fungal associates and tested their effect on four important southeastern American pine and oak species. Our test dataset found no highly virulent pathogens that should be classified as an imminent threat. Twenty-two fungal species were minor pathogens, which may require context-dependent response for their vectors at North American borders, while most of the tested fungi displayed no significant impact. Our results are significant in three ways; they ease the concerns over multiple overseas fungus vectors suspected of heightened potential risk, they provide a basis for the focus on the prevention of introduction and establishment of species that may be of consequence, and they demonstrate that preinvasion assessment, if scaled up, can support practical risk assessment of exotic pathogens.

Members of the Fusarium oxysporum Complex Causing Wilt Symptoms in Medical Cannabis in Israel, Italy, and North America Comprise a Polyphyletic Assemblage.

Members of the Fusarium oxysporum complex are ubiquitous soilborne fungal pathogens causing wilt diseases in various plant hosts. Fusarium oxysporum (Fo) f. sp. cannabis was first reported causing wilt disease in hemp in Italy in 1962. To date, Fusarium wilt continues to cause concern in industrial and medicinal cannabis cultivation worldwide. During a 3-year period (2018 to 2021), Fo strains were isolated from medical cannabis plants (Cannabis sativa) exhibiting wilt symptoms that were cultivated in numerous commercial farms in Israel. A diverse set of these strains was subjected to molecular phylogenetic analyses to assess their genetic diversity and to compare them with other f. sp. cannabis isolates included in prior studies. Maximum likelihood bootstrap analysis of a partial translation elongation factor (TEF1) dataset, which included 24 f. sp. cannabis sequences, revealed that the 11 strains from Israel comprised five TEF1 haplotypes. Two of the haplotypes from Israel were identical to isolates previously reported from British Columbia and California and British Columbia and Ontario. Overall, the 24 f. sp. cannabis sequences included 12 unique TEF1 haplotypes. These were phylogenetically diverse, suggesting that pathogenicity to C. sativa may have evolved independently within the F. oxysporum complex. Pathogenicity tests of the Israeli strains were confirmed by Koch's postulates assays. Strains of the five different f. sp. cannabis TEF1 haplotypes all caused wilt in cannabis seedlings but with varying levels of aggressiveness. The same isolates that originated from asymptomatic infected mother plants were found in wilted cuttings indicating that the pathogen can be spread via propagation material.

Occurrence of Macrophomina phaseolina in Israel: Challenges for Disease Management and Crop Germplasm Enhancement.

Macrophomina phaseolina is a soil-borne fungal pathogen infecting many important crop plants. The fungus, which can survive on crop debris for a long period of time, causes charcoal rot disease by secreting a diverse array of cell-wall degrading enzymes and toxins. M. phaseolina thrives during periods of high temperatures and arid conditions, as typically occur in Israel and other countries with a Mediterranean climate. Crop losses due to charcoal rot can be expected to increase and spread to other countries in a warming global climate. Management of this pathogen is challenging, requiring an array of approaches for the various crop hosts. Approaches that have had some success in Israel include grafting of melons and watermelons on resistant squash rootstocks and soil application of fungicide to reduce disease incidence in melons, fumigation and alterations in planting date and mulching of strawberries, and alteration in irrigation regime of cotton. Elsewhere, these approaches, as well as soil amendments and addition of organisms that are antagonistic to M. phaseolina, have had success in some crop situations. Management through host resistance would be the most sustainable approach, but it requires identifying a resistant germplasm for each crop and introgressing the resistance into the leading cultivars. Resistance to charcoal rot is under complex genetic control in most crops, posing a great challenge for its introgression into elite germplasm. Moreover, fast, reliable methods of screening for resistance would have to be developed for each crop. The toothpick-inoculation method used by us holds great promise for selecting resistant germplasm for melons and possibly for sesame, but other methodologies have to be devised for each individual crop.

Phylogenomic Analysis of a 55.1-kb 19-Gene Dataset Resolves a Monophyletic Fusarium that Includes the Fusarium solani Species Complex.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.

Discordant phylogenies suggest repeated host shifts in the Fusarium-Euwallacea ambrosia beetle mutualism.

The mutualism between xyleborine beetles in the genus Euwallacea (Coleoptera: Curculionidae: Scolytinae) and members of the Ambrosia Fusarium Clade (AFC) represents one of 11 known evolutionary origins of fungiculture by ambrosia beetles. Female Euwallacea beetles transport fusarial symbionts in paired mandibular mycangia from their natal gallery to woody hosts where they are cultivated in galleries as a source of food. Native to Asia, several exotic Euwallacea species were introduced into the United States and Israel within the past two decades and they now threaten urban landscapes, forests and avocado production. To assess species limits and to date the evolutionary diversification of the mutualists, we reconstructed the evolutionary histories of key representatives of the Fusarium and Euwallacea clades using maximum parsimony and maximum likelihood methods. Twelve species-level lineages, termed AF 1-12, were identified within the monophyletic AFC and seven among the Fusarium-farming Euwallacea. Bayesian diversification-time estimates placed the origin of the Euwallacea-Fusarium mutualism near the Oligocene-Miocene boundary ∼19-24 Mya. Most Euwallacea spp. appear to be associated with one species of Fusarium, but two species farmed two closely related fusaria. Euwallacea sp. #2 in Miami-Dade County, Florida cultivated Fusarium spp. AF-6 and AF-8 on avocado, and Euwallacea sp. #4 farmed Fusarium ambrosium AF-1 and Fusarium sp. AF-11 on Chinese tea in Sri Lanka. Cophylogenetic analyses indicated that the Euwallacea and Fusarium phylogenies were largely incongruent, apparently due to the beetles switching fusarial symbionts (i.e., host shifts) at least five times during the evolution of this mutualism. Three cospeciation events between Euwallacea and their AFC symbionts were detected, but randomization tests failed to reject the null hypothesis that the putative parallel cladogenesis is a stochastic pattern. Lastly, two collections of Euwallacea sp. #2 from Miami-Dade County, Florida shared an identical cytochrome oxidase subunit 1 (CO1) allele with Euwallacea validus, suggesting introgressive hybridization between these species and/or pseudogenous nature of this marker. Results of the present study highlight the importance of understanding the potential for and frequency of host-switching between Euwallacea and members of the AFC, and that these shifts may bring together more aggressive and virulent combinations of these invasive mutualists.

Deciphering the cryptic genome: genome-wide analyses of the rice pathogen Fusarium fujikuroi reveal complex regulation of secondary metabolism and novel metabolites.

The fungus Fusarium fujikuroi causes "bakanae" disease of rice due to its ability to produce gibberellins (GAs), but it is also known for producing harmful mycotoxins. However, the genetic capacity for the whole arsenal of natural compounds and their role in the fungus' interaction with rice remained unknown. Here, we present a high-quality genome sequence of F. fujikuroi that was assembled into 12 scaffolds corresponding to the 12 chromosomes described for the fungus. We used the genome sequence along with ChIP-seq, transcriptome, proteome, and HPLC-FTMS-based metabolome analyses to identify the potential secondary metabolite biosynthetic gene clusters and to examine their regulation in response to nitrogen availability and plant signals. The results indicate that expression of most but not all gene clusters correlate with proteome and ChIP-seq data. Comparison of the F. fujikuroi genome to those of six other fusaria revealed that only a small number of gene clusters are conserved among these species, thus providing new insights into the divergence of secondary metabolism in the genus Fusarium. Noteworthy, GA biosynthetic genes are present in some related species, but GA biosynthesis is limited to F. fujikuroi, suggesting that this provides a selective advantage during infection of the preferred host plant rice. Among the genome sequences analyzed, one cluster that includes a polyketide synthase gene (PKS19) and another that includes a non-ribosomal peptide synthetase gene (NRPS31) are unique to F. fujikuroi. The metabolites derived from these clusters were identified by HPLC-FTMS-based analyses of engineered F. fujikuroi strains overexpressing cluster genes. In planta expression studies suggest a specific role for the PKS19-derived product during rice infection. Thus, our results indicate that combined comparative genomics and genome-wide experimental analyses identified novel genes and secondary metabolites that contribute to the evolutionary success of F. fujikuroi as a rice pathogen.

New Insights into Mango Malformation Disease Epidemiology Lead to a New Integrated Management Strategy for Subtropical Environments.

Mango (Mangifera indica) is regarded as the king of fruits in India, where it has been cultivated for at least 4,000 years and has great cultural and religious significance. Many Indian mango cultivars originated in the fifteenth century when the best selections of mango seedlings were propagated by grafting and planted in large orchards, in some cases numbering 100,000 trees. With the arrival of voyagers to India from Europe, mango was soon established throughout the tropics and subtropics. Mango malformation disease (MMD) is one of the most important and destructive diseases of this crop. It affects inflorescences and vegetative portions of the plant. Although trees are not killed, the vegetative phase of the disease impedes canopy development and the floral phase reduces fruit yield dramatically; substantial economic losses can occur since malformed inflorescences do not bear fruit. Significant advances have been made in understanding the etiology of MMD, which is caused by more than one agent. However, until recently little progress had been made on the epidemiology of this disease. The results that are discussed in this article are only for MMD caused by F. mangiferae.

An inordinate fondness for Fusarium: phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts.

Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the 11 independent origins and 3500 species of ambrosia beetles. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naïve natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel and Australia. Most AFC fusaria produce unusual clavate macroconidia that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. In a four-locus phylogenetic analysis, the AFC was resolved in a strongly supported monophyletic group within the previously described Clade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene ∼21.2 Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Two strongly supported clades within the AFC (Clades A and B) were identified that include nine species lineages associated with ambrosia beetles, eight with Euwallacea spp. and one reportedly with Xyleborus ferrugineus, and two lineages with no known beetle association. More derived lineages within the AFC showed fixation of the clavate (club-shaped) macroconidial trait, while basal lineages showed a mix of clavate and more typical fusiform macroconidia. AFC lineages consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations, with at least three interspecific hybridization events inferred based on discordant placement in individual gene genealogies and detection of recombinant loci. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization.

One fungus, one name: defining the genus Fusarium in a scientifically robust way that preserves longstanding use.

In this letter, we advocate recognizing the genus Fusarium as the sole name for a group that includes virtually all Fusarium species of importance in plant pathology, mycotoxicology, medicine, and basic research. This phylogenetically guided circumscription will free scientists from any obligation to use other genus names, including teleomorphs, for species nested within this clade, and preserve the application of the name Fusarium in the way it has been used for almost a century. Due to recent changes in the International Code of Nomenclature for algae, fungi, and plants, this is an urgent matter that requires community attention. The alternative is to break the longstanding concept of Fusarium into nine or more genera, and remove important taxa such as those in the F. solani species complex from the genus, a move we believe is unnecessary. Here we present taxonomic and nomenclatural proposals that will preserve established research connections and facilitate communication within and between research communities, and at the same time support strong scientific principles and good taxonomic practice.

Survival, Host-Pathogen Interaction, and Management of Macrophomina phaseolina on Strawberry in Israel.

Crown and root rot of strawberry, caused by Macrophomina phaseolina, have become predominant soilborne diseases of strawberry in Israel over the past 5 years. In total, 151 isolates of the pathogen were isolated from infected strawberry plants of commercially grown cultivars in Israel onto a modified agar medium for the genus Macrophomina. Sclerotia viability declined more rapidly in soil maintained at 25°C or at soil temperatures fluctuating from 18 to 32°C under greenhouse conditions, compared with sclerotia viability in soil kept at 30°C. After 30 to 40 weeks of exposure in soil, inocula maintained at 25 or 30°C or at fluctuating temperatures in a greenhouse declined to negligible levels. A significant increase in plant mortality was observed in infested soils maintained at 30 versus 25°C, whereas water stress at 25 or 30°C did not affect plant mortality in M. phaseolina-infested soils. This demonstrated the importance of elevated soil temperature, not moisture stress, on plant mortality caused by M. phaseolina. Host specificity was not evident when strawberry plants were inoculated with each of seven Israeli isolates of M. phaseolina obtained from six other plant species, suggesting the importance of keeping strawberry crops out of rotation with other host crops of the pathogen. The soil fumigants methyl bromide (applied at 500 kg/ha) and metam sodium (730 liter/ha) caused 90 and 95% pathogen mortality in field experiments, respectively, indicating that fumigation may be an effective method of managing this pathogen in infested soils. The increase in prevalence of crown and root rot caused by M. phaseolina in strawberry crops in Israel may be related to the phase-out of methyl bromide.

Characterization of Colletotrichum Isolates from Strawberry and Other Hosts with Reference to Cross-Inoculation Potential.

Colletotrichum is an important phytopathogenic fungus that causes anthracnose disease in diverse agronomically important tropical food crops. Accurate pathogen identification is critical for early diagnosis and efficient management of anthracnose. ITS is not a reliable marker for this fungal genus due to its failure to phylogenetically resolve cryptic species. In this study, 36 Colletotrichum isolates belonging to the Acutatum, Boninense and Gloeosporioides species complexes were characterized using multigene phylogenetic analyses, morphology and pathogenicity assays. Additionally, the cross-inoculation potential of a representative subset of isolates was evaluated revealing that cross-infection potential is possible among the isolates belonging to the same species complex.

Design of potent and selective GPR119 agonists for type II diabetes.

Screening of the Merck sample collection identified compound 1 as a weakly potent GPR119 agonist (hEC(50)=3600 nM). Dual termini optimization of 1 led to compound 36 having improved potency, selectivity, and formulation profile, however, modest physical properties (PP) hindered its utility. Design of a new core containing a cyclopropyl restriction yielded further PP improvements and when combined with the termini SAR optimizations yielded a potent and highly selective agonist suitable for further preclinical development (58).

Assessment of resistance pathways induced in Arabidopsis thaliana by hypovirulent Rhizoctonia spp. isolates.

Certain hypovirulent Rhizoctonia isolates effectively protect plants against well-known important pathogens among Rhizoctonia isolates as well as against other pathogens. The modes of action involved in this protection include resistance induced in plants by colonization with hypovirulent Rhizoctonia isolates. The qualifications of hypovirulent isolates (efficient protection, rapid growth, effective colonization of the plants, and easy application in the field) provide a significant potential for the development of a commercial microbial preparation for application as biological control agents. Understanding of the modes of action involved in protection is important for improving the various aspects of development and application of such preparations. The hypothesis of the present study is that resistance pathways such as systemic acquired resistance (SAR), induced systemic resistance (ISR), and phytoalexins are induced in plants colonized by the protective hypovirulent Rhizoctonia isolates and are involved in the protection of these plants against pathogenic Rhizoctonia. Changes in protection levels of Arabidopsis thaliana mutants defective in defense-related genes (npr1-1, npr1-2, ndr1-1, npr1-2/ndr1-1, cim6, wrky70.1, snc1, and pbs3-1) and colonized with the hypovirulent Rhizoctonia isolates compared with that of the wild type (wt) plants colonized with the same isolates confirmed the involvement of induced resistance in the protection of the plants against pathogenic Rhizoctonia spp., although protection levels of mutants constantly expressing SAR genes (snc1 and cim6) were lower than that of wt plants. Plant colonization by hypovirulent Rhizoctonia isolates induced elevated expression levels of the following genes: PR5 (SAR), PDF1.2, LOX2, LOX1, CORI3 (ISR), and PAD3 (phytoalexin production), which indicated that all of these pathways were induced in the hypovirulent-colonized plants. When SAR or ISR were induced separately in plants after application of the chemical inducers Bion and methyl jasmonate, respectively, only ISR activation resulted in a higher protection level against the pathogen, although the protection was minor. In conclusion, plant colonization with the protective hypovirulent Rhizoctonia isolates significantly induced genes involved in the SAR, ISR, and phytoalexin production pathways. In the studied system, SAR probably did not play a major role in the mode of protection against pathogenic Rhizoctonia spp.; however, it may play a more significant role in protection against other pathogens.

Effects of steam sterilization on reduction of fungal colony forming units, cannabinoids and terpene levels in medical cannabis inflorescences.

Medical cannabis (MC) production is a rapidly expanding industry. Over the past ten years, many additional phytocannabinoids have been discovered and used for different purposes. MC was reported beneficial for the treatment of a variety of clinical conditions such as analgesia, multiple sclerosis, spinal cord injuries, Tourette's syndrome, epilepsy, glaucoma, Parkinson disease and more. Yet, there is still a major lack of research and knowledge related to MC plant diseases, both at the pre- and postharvest stages. Many of the fungi that infect MC, such as Aspergillus and Penicillium spp., are capable of producing mycotoxins that are carcinogenic, or otherwise harmful when consumed, and especially by those patients who suffer from a weakened immune system, causing invasive contamination in humans. Therefore, there are strict limits regarding the permitted levels of fungal colony forming units (CFU) in commercial MC inflorescences. Furthermore, the strict regulation on pesticide appliance application in MC cultivation exacerbates the problem. In order to meet the permitted CFU limit levels, there is a need for pesticide-free postharvest treatments relying on natural non-chemical methods. Thus, a decontamination approach is required that will not damage or significantly alter the chemical composition of the plant product. In this research, a new method for sterilization of MC inflorescences for reduction of fungal contaminantstes was assessed, without affecting the composition of plant secondary metabolites. Inflorescences were exposed to short pulses of steam (10, 15 and 20 s exposure) and CFU levels and plant chemical compositions, pre- and post-treatment, were evaluated. Steam treatments were very effective in reducing fungal colonization to below detection limits. The effect of these treatments on terpene profiles was minor, resulting mainly in the detection of certain terpenes that were not present in the untreated control. Steaming decreased cannabinoid concentrations as the treatment prolonged, although insignificantly. These results indicate that the steam sterilization method at the tested exposure periods was very effective in reducing CFU levels while preserving the initial molecular biochemical composition of the treated inflorescences.

Three novel Ambrosia Fusarium Clade species producing multiseptate "dolphin-shaped" conidia, and an augmented description of Fusarium kuroshium.

The Ambrosia Fusarium Clade (AFC) is a monophyletic lineage within clade 3 of the Fusarium solani species complex (FSSC) that currently comprises 19 genealogically exclusive species. These fungi are known or predicted to be farmed by adult female Euwallacea ambrosia beetles as a nutritional mutualism (Coleoptera: Scolytinae; Xyleborini). To date, only eight of the 19 AFC species have been described formally with Latin binomials. We describe three AFC species, previously known as AF-8, AF-10, and AF-11, based on molecular phylogenetic analysis of multilocus DNA sequence data and comparative morphological/phenotypic studies. Fusarium duplospermum (AF-8) farmed by E. perbrevis on avocado in Florida, USA, is distinguished by forming two morphologically different types of multiseptate conidia and brownish orange colonies on potato dextrose agar (PDA). Fusarium drepaniforme (AF-10), isolated from an unknown woody host in Singapore and deposited as Herb IMI 351954 in the Royal Botanic Gardens, Kew, UK, under the name F. bugnicourtii, is diagnosed by frequent production of multiseptate sickle-shaped conidia. Fusarium papillatum (AF-11), isolated from mycangia of E. perbrevis infesting tea in Kandy, Sri Lanka, forms multiseptate clavate conidia that possess a papillate apical cell protruding toward the ventral side. Lastly, we prepared an augmented description of F. kuroshium (AF-12), previously isolated from the heads or galleries of E. kuroshio in a California sycamore tree, El Cajon, California, USA, and recently validated nomenclaturally as Fusarium. Conidia formed by F. kuroshium vary widely in size and shape, suggesting a close morphological relationship with F. floridanum, compared with all other AFC species. Maximum likelihood and maximum parsimony analyses of a multilocus data set resolve these three novel AFC species, and F. kuroshium, as phylogenetically distinct based on genealogical concordance. Given the promiscuous nature of several Euwallacea species, and the overlapping geographic range of several AFC species and Euwallacea ambrosia beetles, the potential for symbiont switching among sympatric species is discussed.

Identification and characterization of a novel etiological agent of mango malformation disease in Mexico, Fusarium mexicanum sp. nov.

The primary objective of this study was to characterize Fusarium spp. associated with the economically devastating mango malformation disease (MMD) in Mexico. In all, 142 Fusarium strains were isolated from symptomatic mango inflorescences and vegetative tissues in eight geographically diverse Mexican states from 2002 through 2007. Initially, all the Mexican isolates were screened for genetic diversity using appolymerase chain reaction and random amplified polymorphic DNA markers and were grouped into seven distinct genotypes. Based on results of these analyses, evolutionary relationships and species limits of the genetically diverse MMD-associated Fusarium spp. were investigated using multilocus DNA sequence data and phylogenetic species recognition. Maximum parsimony analyses of a five-locus data set comprising 5.8 kb of aligned DNA sequence data indicated that at least nine phylogenetically distinct Fusarium spp. within the Gibberella fujikuroi species complex are associated with MMD, including one species within the African clade (Fusarium pseudocircinatum), two species within the Asian clade (F. mangiferae and F. proliferatum), and at least six species within the American clade (F. sterilihyphosum and five undescribed Fusarium spp.). Molecular phylogenetic analyses indicate that a novel genealogically exclusive lineage within the American clade was the predominant MMD associate in Mexico. This new Fusarium sp. caused MMD and could be distinguished from all other known species morphologically by the production of mostly sterile, coiled hyphae which are typically associated with sporodochial conidiophores together with unbranched or sparsely branched aerial conidiophores. Koch's postulates were completed for isolates of the new species on nucellar seedlings of mango cv. Ataulfo. This pathogen is formally described herein as F. mexicanum.

The role of eriophyoids in fungal pathogen epidemiology, mere association or true interaction?

A considerable number of plant feeding mites representing different families such as Acaridae, Siteroptidae, Tydeidae, and Tarsonemidae interact with plant pathogenic fungi. While species within the Eriophyoidea appear to be the most common phytophagous mites vectoring virus diseases, little is known of their role in fungal pathogen epidemiology. In the present article, we present two studies on eriophyoid-fungal relationships. The first focusing on the association between Aceria mangiferae and the fungal pathogen Fusarium mangiferae in mango is presented as a case study. The second, as the research is still in a preliminary phase, reports on quantitative and descriptive associations between the cereal rust mite Abacarus hystrix and rusts caused by Puccinia spp. Mango bud tissue colonized with F. mangiferae, and wheat and quackgrass leaves colonized with Puccinia spp., supported significantly higher populations of eriophyoid mites. Both mite species were observed bearing the spores of the respective pathogens on their body integument. Aceria mangiferae vectored the pathogen's spores into the bud, the sole port of entry for the fungal pathogen and the frequency and severity of fungal infection increased in the presence of A. mangiferae. While it appears that eriophyoids are playing a role in fungal epidemiology, clearly further research is needed to enhance our understanding of direct and indirect (plant mediated) interactions between plant pathogens and eriophyoid mites in different plant-pathogen systems.

Fungal Pathogens Affecting the Production and Quality of Medical Cannabis in Israel.

The use of and research on medical cannabis (MC) is becoming more common, yet there are still many challenges regarding plant diseases of this crop. For example, there is a lack of formal and professional knowledge regarding fungi that infect MC plants, and practical and effective methods for managing the casual agents of disease are limited. The purpose of this study was to identify foliar, stem, and soilborne pathogens affecting MC under commercial cultivation in Israel. The predominant major foliage pathogens were identified as Alternaria alternata and Botrytis cinerea, while the common stem and soilborne pathogens were identified as Fusarium oxysporum and F. solani. Other important fungi that were isolated from foliage were those producing various mycotoxins that can directly harm patients, such as Aspergillus spp. and Penicillium spp. The sampling and characterization of potential pathogenic fungi were conducted from infected MC plant parts that exhibited various disease symptoms. Koch postulates were conducted by inoculating healthy MC tissues and intact plants with fungi isolated from infected commercially cultivated symptomatic plants. In this study, we report on the major and most common plant pathogens of MC found in Israel, and determine the seasonal outbreak of each fungus.