Search

Botryosphaeriaceae are fungi involved in the decay of various woody species, including the grapevine, leading to significant production losses. This fungal family is largely ubiquitous, and seven species of Botryosphaeriaceae have been identified in French vineyards, with variable levels of aggressiveness, both in vitro and in planta. Mycoviruses can impact the life traits of their fungal hosts, including aggressiveness, and are one of the factors influencing fungal pathogenicity. In this study, the RNA mycovirome of fifteen Botryosphaeriaceae isolates was characterized through the high-throughput sequencing of double-stranded RNA preparations from the respective samples. Eight mycoviruses were detected, including three potential novel species in the Narnaviridae family, as well as in the proposed Mycobunyaviridae and Fusagraviridae families. A large collection of Botryosphaeriaceae isolates was screened using RT-PCR assays specific for 20 Botryosphaeriaceae-infecting mycoviruses. Among the mycoviruses detected, some appeared to be specialists within a single host species, while others infected isolates belonging to multiple Botryosphaeriaceae species. This screening allowed us to conclude that one-third of the Botryosphaeriaceae isolates were infected by at least one mycovirus, and a significant proportion of isolates (43.5%) were found to be coinfected by several viruses, with very complex RNA mycoviromes for some N. parvum isolates. [ABSTRACT FROM AUTHOR]

Grapevine Trunk Diseases (GTDs) are major threats in Mediterranean countries, causing economic losses due to reduced grape yields and long-term vine productivity, as well as death of grapevines. A survey was conducted in Piedmont (Northern Italy) during 2021-2022 to investigate the species diversity and distribution of GTD pathogens in this important Italian wine region. Morphological and multilocus phylogenetic analyses (based on ITS, tef1, tub2, act and rpb2) identified species of Botryosphaeriaceae at high frequency, including Botryosphaeria dothidea, Diplodia mutila, Diplodia seriata and Neofusicoccum parvum. Other pathogens commonly associated with GTDs, including Eutypa lata, Fomitiporia mediterranea and Phaeomoniella chlamydospora, were also isolated. Less commonly isolated species included Neocucurbitaria juglandicola, Paraconiothyrium brasiliense, Seimatosporium vitis-viniferae and Truncatella angustata. Pathogenicity tests with two representative isolates of each species were carried out using one-year-old potted grapevine cuttings (‘Barbera’). All isolates (except N. juglandicola) caused brown wood necrotic vascular discolourations on inoculated plants and were successfully re-isolated. Effects of temperature on colony growth were also assessed. For all tested isolates there was no growth at 5°C, only four isolates (Botryosphaeriaceae) grew at 35°C, and optimum growth temperatures were between 20 and 25°C. This is the first record of Paraconiothyrium brasiliense and Neocucurbitaria juglandicola associated with symptomatic grapevines in Italy. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases cause severe damage in grapevines. Management strategies focus on protection of grapevine pruning wounds using chemical fungicides or biological control agents. Botryosphaeria dieback, caused mainly by Lasiodiplodia spp., is one of the main trunk diseases in northwest Mexico. This study obtained endophytic bacteria and fungi from the heritage grapevine Vitis vinifera cv. ‘Mission’ for potential biological control of Botryosphaeria dieback. A collection of 135 bacterial and 37 fungal isolates were obtained and initially tested for antagonistic activity against Lasiodiplodia brasiliensis. The most promising isolates belonging to Trichoderma and Bacillus spp. were selected and characterized to determine their modes of action. Bacillus isolates produced volatile organic compounds that inhibited growth of Neofusicoccum parvum, and diffusible organic compounds with antifungal effects against L. brasiliensis and N. parvum. Trichoderma isolates produced diffusible organic compounds and were mycoparasites. In greenhouse assays, plants inoculated with three Trichoderma asperellum isolates (T20BCMX, EF09BCMX, and EF11BCMX), B. amyloliquefaciens (BEVP26BCMX) or Bacillus sp. (rbES015), applied preventively in soil, gave up to 50% smaller necrotic lesions when compared with the plants inoculated only with L. brasiliensis. In the field, plants inoculated with three Bacillus isolates (BEVP02BCMX, BEVP26BCMX, BEVP31BCMX) or five Trichoderma (T11BCMX, T15BCMX, T17BCMX, T20BCMX, and EF11BCMX) had lesions up to four times smaller than control plants inoculated only with L. brasiliensis. This study has demonstrated the potential of heritage grapevines to provide biological control agents for Botryosphaeria dieback. [ABSTRACT FROM AUTHOR]

During a study of Botryosphaeriaceae species associated with grapevine trunk diseases in the Czech Republic, a collection of 22 Botryosphaeriaceae-like strains were isolated from four cultivars (Blaufränkisch, Pálava, Pinot Noir, and Welschriesling) in four distinct vineyards. Based on morphology and DNA sequence data (ITS, tub2, and tef), four species were identified: Botryosphaeria dothidea, Diplodia mutila, D. seriata, and Neofusicoccum parvum. These species are reported for the first time from grapevine in the Czech Republic. Relationships between vascular lesions and particular species were highlighted in this study. Diplodia seriata was the most frequently isolated species, present in all four sampled cultivars, while D. mutila was the least frequent, present only in 'Pálava'. The cultivar Pinot Noir was the most tolerant host for Botryosphaeriaceae fungi. [ABSTRACT FROM AUTHOR]

(1) Background: Grapevine trunk diseases (GTDs) have become a global threat to vineyards worldwide. These diseases share three main common features. First, they are caused by multiple pathogenic micro-organisms. Second, these pathogens often maintain a long latent phase, which makes any research in pathology and symptomatology challenging. Third, a consensus is raising to pinpoint combined abiotic stresses as a key factor contributing to disease symptom expression. (2) Methods: We analyzed the impact of combined abiotic stresses in grapevine cuttings artificially infected by two fungi involved in Botryosphaeria dieback (one of the major GTDs), Neofusicoccum parvum and Diplodia seriata. Fungal-infected and control plants were subjected to single or combined abiotic stresses (heat stress, drought stress or both). Disease intensity was monitored thanks to the measurement of necrosis area size. (3) Results and conclusions: Overall, our results suggest that combined stresses might have a stronger impact on disease intensity upon infection by the less virulent pathogen Diplodia seriata. This conclusion is discussed through the impact on plant physiology using metabolomic and transcriptomic analyses of leaves sampled for the different conditions. [ABSTRACT FROM AUTHOR]

Production from crops of pome, stone fruit, nut, berry fruit, citrus, grapevine, and olive is increasingly threatened by fungal trunk diseases (FTD). These diseases and the consequent production losses are major problems. Many fungi (including Botryosphaeriaceae, Calosphaeriaceae, Diaporthaceae, Diatrypaceae, Nectriaceae, Phaeomoniellaceae, Pleosporaceae, Togniniaceae, Valsaceae) infect host wood, mainly through wounds and subsequent colonization of woody tissues, causing symptoms such as cankers, gummosis, wood rotting, blight and dieback. Propagative plant material, seedlings and fruit play a significant role in pathogen spread. Several abiotic factors (e.g. shifts in cultural practices and climate change) are involved in the disease development. This paper reviews recent literature on FTD of fruit crops, particularly focusing on the European status of pathogen occurrence. Case studies are described related to diseases of apple, citrus, grapevine, berry, nut and stone fruit, and olive trees. Aspects related to epidemiology and the increase in disease incidence along with the future perspectives on the FTD research are also discussed. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae are a family of fungi associated with the decay of a large number of woody plants with economic importance and causing particularly great losses in viticulture due to grapevine trunk diseases. In recent years, major advances in the knowledge of the pathogenicity factors of these pathogens have been made possible by the development of next-generation sequencing. This review highlights the knowledge gained on genes encoding small secreted proteins such as effectors, carbohydrate-associated enzymes, transporters and genes associated with secondary metabolism, their representativeness within the Botryosphaeriaceae family and their expression during grapevine infection. These pathogenicity factors are particularly expressed during host–pathogen interactions, facilitating fungal development and nutrition, wood colonization, as well as manipulating defense pathways and inducing impacts at the cellular level and phytotoxicity. This work highlights the need for further research to continue the effort to elucidate the pathogenicity mechanisms of this family of fungi infecting grapevine in order to improve the development of control methods and varietal resistance and to reduce the development and the effects of the disease on grapevine harvest quality and yield. [ABSTRACT FROM AUTHOR]

Botryosphaeria dieback is one of the most prevalent grapevine trunk diseases (GTDs), and is caused by fungi in the Botryosphaeriaceae. Fungi invade grapevine vascular systems mainly through pruning wounds, and cause cankers and necrotic lesions, which lead to grapevine decline and death. Lasiodiplodia theobromae has been reported as a highly virulent pathogen of grapevine, and was previously reported in Mexican vineyards. The taxonomy of Lasiodiplodia was recently revised, adding new species, and some were reduced to synonymy. This study aimed to characterize Lasiodiplodia producing grapevine dieback symptoms in Sonora and Baja California, Mexico. Using the phylogenetic markers tef1-a and ITS regions, Lasiodiplodia brasiliensis, L. crassispora, L. exigua, and L. gilanensis were identified. Lasidiplodia exigua was the most prevalent species. Lasiodiplodia brasiliensis and L. gilanensis were very virulent to 'Cabernet Sauvignon' plants, while L. exigua and L. gilanensis were less virulent, and L. crassispora did not produce lesions at 2 months post-inoculation. The optimum temperature of the Lasiodiplodia spp. was 28°C, but all four species grew up to 37°C, and the isolates of L. exigua grew slowly at 40°C. This is the first report of the four of Lasiodiplodia species in vineyards of Mexico. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae fungi are plant pathogens associated with Botryosphaeria dieback. To better understand the virulence factors of these fungi, we investigated the diversity of secreted pro- teins and extracellular enzyme activities involved in wood degradation and stilbene metabolization in Neofusicoccum parvum and Diplodia seriata, which are two major fungi associated with grapevine B. dieback. Regarding the analysis of proteins secreted by the two fungi, our study revealed that N. parvum, known to be more aggressive than D. seriata, was characterized by a higher quantity and diversity of secreted proteins, especially hydrolases and oxidoreductases that are likely involved in cell wall and lignin degradation. In addition, when fungi were grown with wood powder, the extra- cellular laccase and Mn peroxidase enzyme activities were significantly higher in D. seriata compared to N. parvum. Importantly, our work also showed that secreted Botryosphaeriaceae proteins produced after grapevine wood addition are able to rapidly metabolize the grapevine stilbenes. Overall, a higher diversity of resveratrol and piceatannol metabolization products was found with enzymes of N. parvum compared to D. seriata. This study emphasizes the diversity of secreted virulence factors found in B. dieback fungi and suggests that some resveratrol oligomers produced in grapevine wood after pathogen attack could be formed via pathogenic fungal oxidases. [ABSTRACT FROM AUTHOR]

The Botryosphaeriaceae is a fungal family that includes many destructive vascular pathogens of woody plants (e.g., Botryosphaeria dieback of grape, Panicle blight of pistachio). Species in the genera Botryosphaeria , Diplodia , Dothiorella , Lasiodiplodia , Neofusicoccum , and Neoscytalidium attack a range of horticultural crops, but they vary in virulence and their abilities to infect their hosts via different infection courts (flowers, green shoots, woody twigs). Isolates of seventeen species, originating from symptomatic apricot, grape, pistachio, and walnut were tested for pathogenicity on grapevine wood after 4 months of incubation in potted plants in the greenhouse. Results revealed significant variation in virulence in terms of the length of the internal wood lesions caused by these seventeen species. Phylogenomic comparisons of the seventeen species of wood-colonizing fungi revealed clade-specific expansion of gene families representing putative virulence factors involved in toxin production and mobilization, wood degradation, and nutrient uptake. Statistical analyses of the evolution of the size of gene families revealed expansions of secondary metabolism and transporter gene families in Lasiodiplodia and of secreted cell wall degrading enzymes (CAZymes) in Botryosphaeria and Neofusicoccum genomes. In contrast, Diplodia , Dothiorella , and Neoscytalidium generally showed a contraction in the number of members of these gene families. Overall, species with expansions of gene families, such as secreted CAZymes, secondary metabolism, and transporters, were the most virulent (i.e., were associated with the largest lesions), based on our pathogenicity tests and published reports. This study represents the first comparative phylogenomic investigation into the evolution of possible virulence factors from diverse, cosmopolitan members of the Botryosphaeriaceae. [ABSTRACT FROM AUTHOR]

Lasiodiplodia (Botryosphaeriaceae) includes fungi that are considered among the most aggressive to grapevine, capable of causing cankers and necrotic lesions which eventually lead to death of host plants. A common characteristic of this genus is the presence of melanin in conidia and mycelium. Melanin is produced by the oxidation of phenolic and/or indolic compounds. For some fungi, this pigment is an essential factor for pathogenicity. This study characterized the types and the roles of melanin produced by Lasiodiplodia gilanensis. Using specific melanin inhibitors, L. gilanensis was shown to synthesize DOPA-melanin, DHN-melanin, and pyomelanin. DOPA-melanin was shown to be involved in production of aerial mycelium and protection against enzymatic lysis and oxidative stress; DHN-melanin to be involved in ramification of mycelium when exposed to nutrient deficiency; and pyomelanin to be related with hyphae development. The fungus used tyrosine as a precursor of DOPA-melanin and as carbon and nitrogen sources, and produced melanin inside the piths of infected plants. Genes involved in melanin synthesis were conserved among the Botryosphaeriaceae, highlighting the importance of melanin in this family. [ABSTRACT FROM AUTHOR]

Neofusicoccum australe is one of the most important Botryosphaeriaceae pathogens occurring on fruit and vine crops. This fungus was recently taxonomically reassessed, identifying N. stellenboschiana as a separate species. Previous pathogenicity studies used N. stellenboschiana and N. australe isolates as N. australe, so assessment of the pathogenicity of these two species on grapevine and other hosts was required. A pathogenicity trial was conducted on detached shoots of grapevine, plum, apple, olive and Peruvian pepper tree. Shoots were individually inoculated with 11 N. australe and eight N. stellenboschiana isolates originally isolated from grapevine, plum, apple, olive, Peruvian pepper and fig. Both species formed lesions on all five hosts and were reisolated 5 weeks post-inoculation. In general, the largest lesions were formed on plum and smallest on Peruvian pepper. Isolate host origin did not influence ability to cause lesions on other hosts. Isolates of N. australe and N. stellenboschiana differed in virulence on the various hosts, ranging from those that caused the largest lesions, a group causing intermediate lesions, and another causing lesions similar to uninoculated controls. The study demonstrates that N. australe and N. stellenboschiana isolates originating from various fruit hosts can infect alternative hosts including grapevine and other major fruit crops. [ABSTRACT FROM AUTHOR]

After the first report of grapevine decline caused by Botryosphaeriaceae in Sicily in 2007, epidemiological studies carried out in mature vineyards until 2011 confirmed the widespread occurrence of "Botryosphaeria dieback" and the "Esca complex" disease. Dieback symptoms were also recently observed in two young vineyards in Partanna and Castellammare del Golfo in western Sicily (Trapani province). Declining vines were inspected for grapevine trunk disease (GTD) symptoms, and were uprooted and submitted for analyses. Fungal isolates were collected and identified using culturing and molecular analyses. One isolate per identified species was inoculated to three grapevine shoots to evaluate pathogenicity and fulfil Koch's postulates. Several GTD Botryosphaeriaceae pathogens in the genera Cadophora, Ilyonectria, Neonectria, Phaeoacremonium and Phaeomoniella were isolated from the symptomatic young vines. Artificial inoculation confirmed the pathogenicity of these fungi. In addition, virulence variability was observed among the isolates, with P. chlamydospora causing the largest lesions. The different species were associated with specific symptoms and/or host vine parts, especially in the roots and around the grafting areas. Several fungi associated with Petri disease and black foot were shown to be responsible of young vine decline. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTDs) are one of the most economically important diseases of grapevines, causing yield reductions and limiting vineyard lifespans. Fungal pathogens responsible for GTDs primarily infect grapevines through pruning wounds. The lack of systemic fungicides to stop the advance of fungi in vine vascular systems makes the use of pruning wound protection with either synthetic chemicals or biological control agents (BCAs) the main available GTD control strategy. Demands for sustainable grape production and increasing limitations on pesticide usage have raised interest in potential use of BCAs as pruning wound protectants against GTDs. The objectives of this study were to characterize 16 Trichoderma isolates from southern Italy using molecular methods, and to evaluate their potential activity as BCAs in vitro against the GTD canker-causing fungi Diplodia seriata, Eutypa lata and Neofusicoccum parvum. Molecular studies along with phylogenetic analyses identified eight species, including Trichoderma atroviride, T. guizhouense, T. harzianum, T. koningiopsis, T. longibrachiatum, T. paratroviride, T. paraviridescens, T. spirale, and one unidentified Trichoderma sp. All these species had optimum mycelium growth between 25 and 35°C. In vitro dual culture experiments assessed antagonistic capabilities of all the Trichoderma isolates against D. seriata, E. lata and N. parvum, and showed that the isolates inhibited mycelial growth of the pathogens by up to 70%. The most inhibitory isolates were tested in planta for capability to protect pruning wounds against D. seriata and N. parvum in a detached cane assay. All the selected Trichoderma isolates gave >80% control of D. seriata and 60% control of N. parvum, and protected pruning wounds for up to 21 d after treatment. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTD) are important threats to long-term longevity, productivity, and profitability in all grape production systems. Botryosphaeria dieback is caused by at least 32 Botryosphaeriaceae fungi. The main symptoms of this disease on grapevines are wedge-shaped cankers in the trunks, general decline and eventually death of affected plants. Pathogens from this family have broad host ranges and varying virulence. This study aimed to compare, and gain some insight into how, Lasiodiplodia gilanensis, Diplodia seriata, and D. corticola colonize grapevine tissues. In vitro studies using pycnidiospores as inoculum, showed that the presence of grapevine wood affected spore germination, hyphal growth and branching, and biomass production, especially in L. gilanensis. In planta, microscopy revealed the use of xylem vessels as the preferred sites of pathogen entry, and differences in growth and hyphal branching among species. Lasiodiplodia gilanensis produced cellulases at the beginning of the pathogen/host interaction to degrade plant tissues and invade parenchymal tissue, while D. seriata and D. corticola grew endophytically in the first stages of grapevine colonization. [ABSTRACT FROM AUTHOR]

A survey was carried out in 22 European and some non-European Mediterranean countries in 2015 and 2016, to gain insights into the main fungal grapevine trunk diseases (GTDs) in Europe. Information was obtained from 105 viticulture regions, representing approx. four million ha of vineyards. Vintage and table wines are the main industry products, followed by nursery plants and table grapes. Diverse scion cultivars are grown, with 13 cultivars providing 50% of survey respondent production, and Riesling Italico, Chardonnay, Cabernet Sauvignon and Merlot predominating. The five most used rootstocks are SO4, 110R, K5BB, 41B and 1103P, together representing about 50% of survey respondent production. Despite the diversity of grapevine training, Guyot and cordon remain the most widespread methods, and grapevines are mainly handpruned. The use of pneumatic shears and mechanical pruning is becoming more common in some countries. The survey questionnaire proposed a simplified set of symptoms or diseases occurring in mature vineyards [apoplexy, esca complex leaf symptoms (including Grapevine Leaf Stripe Disease, GLSD), dead cordon, Eutypa related dieback, Botryosphaeria or unidentified agent dieback, Phomopsis cane and leaf spot]. Apoplexy and esca/GLSD, defining the esca complex, were the most frequent and increasing syndromes in almost all countries, except Israel and the United Kingdom, where these diseases are not present or not recorded in the survey. Dead cordon and Phomopsis cane and leaf spot were mentioned as occurring in a large number of regions but not frequently. Within individual countries, the profile of GTDs varied according to the region, and to pedo-climatic and production conditions. GTDs on young vines were uncommon, but remain a subject of concern in some of European countries with large nursery production. This overview on spread and relevance of GTDs in Europe and related aspects will be a useful starting point for policy makers and for collaborative research on factors contributing to the increasing disease incidence of GTDs. [ABSTRACT FROM AUTHOR]

Long non-coding RNAs (lncRNAs) refer to a class of RNA molecules that are longer than 200 nucleotides and do not encode proteins. Numerous lncRNAs have recently emerged as important regulators of many biological processes in animals and plants, including responses to environmental stress and pathogens. Botryosphaeria dieback is one of the more severe grapevine trunk diseases worldwide. However, how lncRNAs function during Botryosphaeriaceae infection is largely unknown. We performed high-throughput RNA-sequencing (RNA-seq) of susceptible and more tolerant grapevine cultivars infected with Lasiodiplodia theobromae. Overall, we predicted 1826 novel candidate lncRNAs, including long intergenic non-coding RNAs (lincRNAs) and natural antisense transcripts (lncNATs). The data reveal the functions of a set of lncRNAs that were differentially expressed between the resistant cultivar Merlot and the susceptible cultivar Cabernet Franc. Several lncRNAs were predicted to be precursors for grape microRNAs involved in the L theobromae infection. These results provide new insight into the lncRNAs of grapevine that are involved in the response to L theobromae infection. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTD) are one of the most important constraints for grapevine and wine production worldwide. Most of the published studies on these diseases in Europe relate to the major vine growing regions mainly located in southern Europe. This is the first study of GTD incidence and associated fungal pathogens in Czech vineyards, as an example of the north-eastern European grape-growing region. Annual incidence of GTD symptoms in vineyards of cvs. 'Chardonnay' and 'Cabernet Sauvignon' in three Czech locations was surveyed. On average, 3.7% of the 'Chardonnay' plants showed GTD symptoms and 0.7% suddenly collapsed each year. Within the 'Cabernet Sauvignon' vineyards, 10.1% of the plants showed GTD symptoms and 2.5% suddenly collapsed. Several fungal pathogens were associated with the suddenly collapsed grapevines, and the most frequent was Phaeomoniella chlamydospora (77% of analyzed grapevines), followed by Eutypa lata (62%), Diaporthe ampelina (31%), Botryosphaeria dothidea (15%) and Fomitiporia mediterranea (15%). [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTDs) are one of the most important groups of fungal diseases affecting grapevine plants worldwide. One of the main causes of GTDs infection occur during nursery plant production processes. The phytosanitary status was determined for 150 young grapevine plants (two varieties grafted onto different rootstocks) that were produced in three European nurseries. Some plants were analyzed upon submission, while others were assessed after up to 12 months growth in a greenhouse. Fungal species associated with GTDs were identified and characterized from the scions, graft unions, rootstocks, or roots. A total of 449 fungal isolates associated with GTDs were obtained, and 20 species were identified by morphological characteristics and DNA analyses. Five species were involved in Botryosphaeria dieback, six in black foot disease, six in Diaporthe dieback, and three in Petri disease. Incidence of GTDs on grapevine plants was between 81 and 100%, with different diseases varying between rootstocks and grapevine varieties. Isolates of other fungal genera not involved in the GTD complex were also detected, including Colletotrichum, Fusarium, and Rhizoctonia. The high presence of GTDs during nursery production of grapevine plants raises the need to implement effective control methods that could prevent the spread of these diseases to vineyards. [ABSTRACT FROM AUTHOR]

Botryosphaeria dieback, caused by species of Botryosphaeriaceae, is an important grapevine trunk disease in Australia. Inocula produced by the pathogens are primarily dispersed by rain splash and wind and infect pruning wounds leading to cankers, dieback. and eventually death of vines. The objective of this study was to develop molecular tools to detect and quantify Botryosphaeriaceae inocula from the environment. These tools are essential for investigating spore dispersal patterns of Botiyosphaeriaceae pathogens in Australian vineyards. DNA extraction protocols were evaluated and one modified protocol was found suitable for extracting Botiyosphaeriaceae DNA from artificially and naturally inoculated Burkard volumetric spore sampler tapes. Multispecies primers and a hydrolysis probe for quantitative PCR (qPCR) were further developed to detect and quantify Botryosphaeriaceae inocula from environmental samples. Specificity tests showed that the multispecies primers were able to amplify the DNA of 10 Botiyosphaeriaceae species (58 isolates) found in Australia while none of the 27 nontarget fungal species (90 isolates) tested were amplified. The qPCR assay was suitable for amplifying purified DNA, synthetic DNA fragments (gBlocks). and mixed DNA from spore trap tapes. The qPCR method developed in this study was shown to be rapid and sensitive in detecting Botryosphaeriaceae inocula from the environment using spore traps. [ABSTRACT FROM AUTHOR]

Genotypic and virulence diversity of Neofusicoccum luteum and N. australe isolates recovered from grapevines displaying symptoms of dieback and decline in New Zealand were investigated. The universally primed PCR ( UP- PCR) method was used to investigate the genetic diversity of 40 isolates of N. luteum and 33 isolates of N. australe. Five UP- PCR primers produced a total of 51 loci from N. luteum and 57 from N. australe with a greater number of polymorphic loci produced in N. australe (86%) compared with N. luteum (69%). Analysis of UP- PCR data showed both species found in New Zealand vineyards were genetically diverse at both the inter- and intra-vineyard levels with only a single pair of clonal isolates in N. luteum. Cluster analysis of UP- PCR data produced four genetic groups in N. luteum and 10 in N. australe ( P < 0.05). For both species, there was no relationship between the genetic groups and the origin of isolates. The mean genetic diversity ( H) of N. luteum was less than for N. australe, being 0.1791 and 0.2417, respectively. Pathogenicity assays of both species using isolates from either the same or different genetic groups inoculated onto either green shoots or grapevine trunks, showed virulence diversity within the population; however, no correlation was identified between genetic groups and virulence. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae species are important pathogens of grapevines so the effect of environmental conditions on sporulation from naturally infected Sauvignon blanc grapevines in two Marlborough vineyards was studied. Shoot lesions characteristic of Botryosphaeriaceae infection were marked on 24 grapevines in each vineyard for observation between September 2014 and April 2015. Pycnidia on the lesions oozed conidia during or soon after rainfall on five occasions at maximum air temperatures of 8.4-19.9°C and relative humidities of 77-94.7%. Microscopic observation of the ooze showed conidia characteristic of either Neofusicoccum or Diplodia species in 67% and 50% of samples from Vineyard A and B, respectively. Sixtynine colonies characteristic of Botryosphaeriaeae species were recovered after plating of conidial ooze and identified by DNA analysis as Diplodia mutila (39.1%), Neofusicoccum australe (30.4%), N. parvum (14.5%), N. luteum (5.8%), D. seriata (7.2%) and N. ribis (3.0%). All species have been reported previously as grapevine pathogens in New Zealand. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare 11 treatment regimes (TR) in grapevine nurseries in order to eradicate trunk pathogens. Grapevine propagation material was subjected to treatments before cold storage, before and after grafting, before planting and after uprooting. Isolations were made from roots, rootstocks and graft unions of uprooted vines. None of the treatments consistently affected the number of certifiable vines produced. TR 1 (benomyl), TR 3 (Sporekill) and TR 4 (Trichoflow) increased root mass. Phaeomoniella chlamydospora was the most frequently isolated pathogen from all plant parts. In general, TR 2, 7, 9 and 11 caused the lowest occurrence of Phaeomoniella. TR 9 consistently reduced the incidence of Phaeoacremonium. Pleurostomophora richardsiae occurred most frequently in graft unions, but treatments were too inconsistent to draw meaningful conclusions. TR 7 (hot water treatment (HWT) of uprooted grapevines) consistently reduced incidences of black foot disease (BFD) pathogens. The highest incidence of Botryosphaeriaceae occurred in graft unions, but all treatments significantly reduced infections. The colonisation of rootstocks and graft unions by Trichoderma was significantly better with TR 4 (Trichoflow). The other Trichoderma treatments (TR 9, 10 and 11) differed from the control treatment only in the graft unions. This is a first report of an integrated strategy covering all the phases of the propagation process, from the moment the nursery receives the propagation material until the dormant vines are removed. TR 9 is recommended for use in nurseries, although HWT of dormant vines is recommended to eradicate BFD pathogens. Benomyl can be replaced by carbendazim when benomyl is no longer available. [ABSTRACT FROM AUTHOR]

Botryosphaeria dieback is an important disease of table grape in the São Francisco Valley, the main Brazilian exporting region. The objectives of this study were to identify species of Lasiodiplodia associated with botryosphaeria dieback of table grapes in the São Francisco Valley, investigate the prevalence and distribution of the species in the region, and evaluate their pathogenicity and virulence in green shoots of table grape. A total of 112 Lasiodiplodia isolates were obtained from 14 vineyards, located in Casa Nova, Juazeiro and Petrolina. Fungal identifications were made using phylogenetic analysis based on partial sequences of translation elongation factor 1- α ( EF1-α) and internal transcribed spacer ( ITS) sequences, in combination with morphometric characteristics of conidia. Eight species of Lasiodiplodia were identified: L. brasiliense, L. crassispora, L. egyptiacae, L. euphorbicola, L. hormozganensis, L. jatrophicola, L. pseudotheobromae and L. theobromae. Except for L. crassispora, L. pseudotheobromae and L. theobromae, all the other species are reported for the first time on grapevine worldwide. The distribution of Lasiodiplodia species differed between the three table grape populations of São Francisco Valley. All Lasiodiplodia species isolated in this study were present in the population of Casa Nova and Lasiodiplodia theobromae was the most prevalent. All species of Lasiodiplodia were pathogenic on detached green shoots of grapevine, with L. brasiliense being the most virulent. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae spp. have a cosmopolitan distribution and a wide range of plant hosts. Over the last 15 years, worldwide, 21 species of this family have been associated with grapevine trunk diseases that cause cankers and dieback on grapevines. Here, we surveyed vineyards of Vitis vinifera 'Lambrusco', 'Sangiovese', and 'Montepulciano' in three areas of the Foggia province (Cerignola, Foggia, and San Severo) in southern Italy. Wood samples from grapevines showing general decline, dieback, cankers, and wood and foliar discoloration yielded 344 fungal isolates identified as Botryosphaeriaceae spp. A phylogenetic study combining internal transcribed spacer and translation elongation factor 1-α sequences of 60 representative isolates identified nine botryosphaeriaceous species: Botryosphaeria dothidea, Diplodia corticola, D. mutila, D. seriata, Dothiorella iberica, Do. sarmentorum, Lasiodiplodia citricola, L. theobromae, and Neofusicoccum parvum. Pathogenicity tests confirmed that all nine species cause canker and dieback of grapevines. However, this is the first report of L. citricola as causal agent of wood cankers and dieback of grapevine. To date, including L. citricola, there are 25 botryosphaeriaceous species associated with V. vinifera worldwide, of which 12 have been reported for grapevines in Italy. [ABSTRACT FROM AUTHOR]

The article presents abstracts on topics including the disease cycles of fungi associated with grapevine trunk diseases, diversity of Diatrypaceae species in three Spanish grapevine, and molecular diagnostic tool for detection of Botryosphaeriaceae species.

The Botryosphaeriaceae represents an important, cosmopolitan family of pathogens infecting woody plants. Grapevines (Vitis vinifera) suspected of being affected by Botryosphaeria dieback were collected from different Provinces of China and several Botryosphaeriaceae species were identified. This research was conducted to further study the species of Botryosphaeriaceae associated with grapevines in China and to estimate the prevalence and severity of the disease. Symptoms were characterized by partial or total death of grapevine cordons, with brown U-shaped necrotic sectors and brownish-black spots in cross-sections of affected trunks and arms. A fungus isolated from diseased vines in Henan and Anhui Provinces was identified as Neofusicoccum mangiferae on the basis of its morphological and cultural characteristics as well as an analysis of combined sequence data from the internal transcribed spacer (ITS) cluster of the ribosomal DNA together with partial sequences of the β-tubulin (BT) and translation elongation factor (EF1-α) genes. Pathogenicity was assessed by inoculating the fungus onto detached green grapevine shoots under controlled laboratory conditions and mature wood of standing vines cv. Summer Black in a greenhouse. This is the first record of N. mangiferae associated with grapevine dieback in the world. [ABSTRACT FROM AUTHOR]

The article presents abstracts of articles related to grapevine trunk diseases including "Fungal pathogens involved in Grapevine Trunk Diseases in China,' by J. Y. Yan and colleagues, "The identity, distribution and diversity of botryosphaeriaceous species in New Zealand vineyards - a national perspective," by H. J. Ridgway and colleagues, and "Identification of Cylindrocladiella species isolated from rootstock wood cankers in California," by L. J. Betiga and colleagues.

During a study of Botryosphaeriaceae species associated with grapevine trunk diseases in North Algeria, a collection of 67 Neofusicoccum-like strains were isolated from three cultivars (Cinsaut, Alphonse Lavallée and Cardinal) from two different locations. Based on morphology and DNA sequence data (ITS and TEF-1α), four species were identified. Of these, Neofusicoccum parvum, N. mediterraneum and N. australe are known, while N. algeriense is described here as new. These species are reported for the first time from Algeria. In this study, relationships between vascular lesions and Neofusicoccum species isolated were highlighted. The Neofusicoccum spp. were most often isolated from wedge-shaped and yellow soft wood rots and more rarely from central brown necrosis and black streaking. Neofusicoccum parvum was the most frequently isolated (48 isolates) followed by N. algeriense (four), while N. mediterraneum and N. australe were each found only once. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceous species are significant grapevine trunk pathogens worldwide, which can be difficult to identify to species level using conventional morphological methods. This study developed and optimized a quick, reliable molecular identification method that could facilitate investigations into the epidemiology of these diseases in vineyards. The multi-species primers, BOT100F and BOT472R, amplified a 371-372 bp portion of the rRNA gene region from the six botryosphaeriaceous species commonly found in New Zealand vineyards. In silico analysis indicated that they would amplify DNA from six of the 12 lineages of the Botryosphaeriaceae, including all of the main species pathogenic to grapevines. A detection sensitivity of 1 and 0·1 pg DNA in standard and nested PCR, respectively, was achieved and this was calculated as equivalent to 2·5 conidia. Validation of the primers for environmental samples showed that their specificity was not compromized by the presence of competing DNA templates extracted from wood and soil. Single stranded conformational polymorphism (SSCP) analysis of the amplicons could resolve Neofusicoccum australe, N. luteum, Diplodia mutila and D. seriata, but did not differentiate between N. parvum and N. ribis. The optimized PCR-SSCP was used to identify botryosphaeriaceous species present in rainwater traps collected over 1 year in a vineyard known to contain infected vines. It could detect multiple species in individual samples and demonstrated differences in the dispersal patterns of conidia from different species. Given the specificity and sensitivity of this method it could prove useful in epidemiology studies involving the numerous botryosphaeriaceous species that infect a wide range of host species. [ABSTRACT FROM AUTHOR]

Using Trichoderma species to protect grapevine pruning wounds from trunk disease pathogens is one of the options available for managing grapevine trunk diseases. The growth and persistence of Trichoderma species in the pruning wound and the resulting control effect may depend on intrinsic wound factors and hence may vary between cultivars. Cultivar variability to pruning wound protection by Trichoderma species was evaluated in eight wine grape (Cabernet Sauvignon, Chardonnay, Chenin blanc, Colombar, Merlot, Pinotage, Sauvignon blanc and Shiraz) and four table grape (Prime, Red Globe, Thompson Seedless and Victoria) cultivars. Two strains of Trichoderma atroviride (USPP-T1 and USPP-T2) separately or in combination and Eco 77® a registered pruning wound biocontrol agent based on T. harzianum, were applied to fresh pruning wounds of spur-pruned wine grapevines and cane-pruned table grapevines. Trichoderma spp. and a variety of trunk pathogens, Phaeomoniella chlamydospora and species of Phaeoacremonium, Phomopsis, Botryosphaeriaceae and Diatrypaceae, were isolated from the pruning wounds eight months after treatment. Significant treatment × cultivar interactions (P<0.01) were found in the incidence of Trichoderma spp. in table and wine grapes. Trichoderma incidence varied greatly between cultivars and was less between Trichoderma treatments within the same cultivar. The highest Trichoderma incidence in wine grapes was found in Chenin blanc (71.4-82.5%) and in table grapes in Thompson Seedless (43.5-76.7%). In the remaining wine grape cultivars Trichoderma incidence varied between 20-50% while with all treatments in Chardonnay Trichoderma incidence was less than 24%. In table grapes Trichoderma incidence varied from 20-67% in the other cultivars. Trichoderma reduced the pathogen by between 10.3% in Chardonnay to 66.7% in Chenin blanc. Trichoderma incidence and pathogen reduction were significantly correlated in most cultivars (r> 0.50; P<0.05) though not in Chardonnay (r=0.37; P=0.11), Pinotage (r=-0.12; P=0.62), Sauvignon blanc (r=0.26; P=0.26) and Victoria (r=0.29; P=0.22). It was concluded that the wound protection effect of Trichoderma spp. is also dependent on the Trichoderma-grapevine interaction and is not only due to the suppressive effect of Trichoderma spp. on the pathogens. [ABSTRACT FROM AUTHOR]

Several species in Botryosphaeriaceae have been associated with grapevine trunk diseases. To evaluate the effect of water stress on infection of grapevines by Botryosphaeriaceae spp., 1-year-old Shiraz/101-14 Mgt nursery grapevine plants were planted in plastic potting bags and placed outdoors under shade netting. Five weeks after planting, vines were pruned and the pruning wounds inoculated with spore suspensions of Neofusicoccum australe, Neofusicoccum parvum, Lasiodiplodia theobromae or Diplodia seriata. Control treatments consisted of applications of sterile water or a Trichoderma harzianum spore suspension. Stem inoculations were done by inserting a colonised or uncolonised agar plug into a wound made in each stem. Four different irrigation regimes were introduced 12 weeks after planting to simulate varying degrees of water stress. Measurements of stomatal conductance, photosynthetic rate and leaf spectrometry were made to monitor physiological stress. Eight months after inoculation, vines were uprooted and the root, shoot and plant mass of each vine determined. Lesions observed in the inoculated pruning wounds and stems were also measured. Vines subjected to the lowest irrigation regime were significantly smaller than optimally irrigated vines. Water stressed vines also had significantly lower photosynthetic rates and levels of stomatal conductance compared with vines receiving optimal irrigation, indicating that these plants experienced significantly higher levels of physiological stress. The mean lesion length was significantly longer in the pruning wounds and stems of plants subjected to the lowest irrigation regime, with lesion length declining linearly with increasing irrigation volume. These results clearly indicate that when a grapevine is exposed to water stress, colonisation and disease expression by Botryosphaeriaceae spp. are much more severe. [ABSTRACT FROM AUTHOR]

Trunk diseases of grapevine are caused by numerous pathogens, including Eutypa lata, Phaeomoniella chlamydospora, and species of Botryosphaeriaceae (incl. Botryosphaeria and aggregate genera), Phomopsis and Phaeoacremonium. Since infections occur mainly through pruning wounds, that have been shown by previous research to stay susceptible for up to 16 weeks after pruning, long-term pruning wound protection is required for prevention of infection. This study evaluated several biocontrol agents against a range of trunk disease pathogens in dual plate laboratory trials to determine macroscopic and microscopic interactions. The biocontrol agents had a substantial effect on all the pathogens, with a wide range of macroscopic and microscopic interactions observed. The best performing biocontrol agents were tested in two field trials. Fresh pruning wounds were treated with benomyl, Trichoderma products (Biotricho®, Vinevax® and ECO 77®) and isolates (USPP-T1 and -T2, identified as T. atroviride) and Bacillus subtilis. Seven days after treatment the pruning wounds were inoculated by spraying with spore suspensions of Neofusicoccum australe, N. parvum, Diplodia seriata, Lasiodiplodia theobromae, Eutypa lata, Phaeomoniella chlamydospora or Phomopsis viticola. Eight months after inoculation, the treatments were evaluated by isolation onto potato dextrose agar. The efficacy of the biocontrol agents was in most cases similar or superior to that observed for benomyl. Isolate USPP-T1, in particular, was very effective, reducing incidence of Ph. viticola, E. lata, Pa. chlamydospora, N. australe, N. parvum, D. seriata and L. theobromae by 69, 76, 77, 78, 80, 85 and 92%, respectively. This is the first report of biological protection of grapevine pruning wounds against this group of grapevine trunk disease pathogens. [ABSTRACT FROM AUTHOR]

Eutypa lata and Phaeomoniella chlamydospora, as well as several species in Botryosphaeriaceae, Phomopsis and Phaeoacremonium are known trunk pathogens of grapevines, which use pruning wounds as infection portals. Duration of pruning wound susceptibility to some of these pathogens was largely unknown. To address this question, plants of the cv. Chenin Blanc in a vineyard in the Stellenbosch area of South Africa were pruned at two stages, and then spray-inoculated with spore suspensions of E. lata, Pa. chlamydospora, Neofusicoccum australe and Phomopsis viticola directly after pruning, and 1, 2, 3, 7, 10, 14, 17 and 21 days after pruning. Eight months after inoculation, pathogen incidence in the treated wounds was determined by means of isolation from the pith and xylem tissue of treated plants. Lesions observed in these tissues were also measured and recorded. Results indicated that, irrespective of pathogen inoculated, pathogen incidence in the inoculated pruning wounds of both mid- and late winter declined with increasing wound age. The rate of decline was much slower in 2004 compared to 2005; however, wounds remained susceptible for 3 or more weeks after pruning in both years. Late winter wounds were more susceptible to infection than wounds made earlier in the season, while xylem tissue of pruning wounds generally proved more susceptible to all pathogens compared to exposed pith tissue. [ABSTRACT FROM AUTHOR]

The seasonal abundance of Botryosphaeriaceae spp. spores was studied in California vineyards by using glass microscope slides covered with petroleum jelly placed on grapevine cordons and Burkard volumetric spore traps at seven and two different locations, respectively. Correlation analysis was used to determine which meteorological variables (precipitation, relative humidity, temperature, and wind speed) influenced Botryosphaeriaceae spp. spore release. Among all variables, regression analysis resulted in a strong relationship between spore release and precipitation. Additionally, a positive relationship between irrigation and spore release was also observed in the Riverside County vineyard. During the study period, spore discharge of Botryosphoeriaceae spp. occurred from the first fall rain through the last spring rains, coinciding with September to April. However, based on the results obtained from the spore traps, most spores (over 60%) were trapped following rain events during the winter months of December, January, and February, which coincides with the grapevine pruning season. Botryosphacriaceae spp. spore release was much lower in fall and early spring (22%) and very few or no spores were trapped in late spring and summer (3%). This work suggests that a delay of pruning time in California may. be warranted to reduce grapevine infection because the current timing coincides with the greatest period of spore discharge. [ABSTRACT FROM AUTHOR]

Lipophilic phytotoxins produced by Neofusicoccum parvum, a Botryosphaeriaceae species pathogenic to grapevine, were isolated and identified by spectroscopic methods as (3R,4R)-(-)-4-hydroxymellein, (3R,4S)-(-)-4-hydroxymellein, isosclerone and tyrosol. When assayed for phytotoxicity on tomato plants, all four metabolites showed phytotoxic activity, with (3R,4R)-(-)-4-hydroxymellein and isosclerone the most active. Isosclerone is reported for the first time as produced by a Botryosphaeriaceae species. [ABSTRACT FROM AUTHOR]

In the work presented herein, we analyze the efficacy of three basic substances that comply with European Regulation (EC) No 1107/2009, namely chitosan, horsetail (Equisetum arvense L.) and nettle (Urtica dioica L.), for the control of grapevine trunk diseases (GTDs) in organic farming. The E. arvense and U. dioica aqueous extracts, prepared according to SANCO/12386/2013 and SANTE/11809/2016, have been studied by gas chromatography–mass spectrometry (GC-MS), identifying their main active constituents. The three basic substances, either alone or in combination (forming conjugate complexes), have been tested in vitro against eight Botryosphaeriaceae species, and in vivo, in grafted plants artificially inoculated with Neofusicoccum parvum and Diplodia seriata. A clear synergistic behavior between chitosan and the two plant extracts has been observed in the mycelial growth inhibition tests (resulting in EC90 values as low as 208 μg·mL−1 for some of the isolates), and statistically significant differences have been found in terms of vascular necroses lengths between treated and non-treated plants, providing further evidence of aforementioned synergism in the case of D. seriata. The reported data supports the possibility of extending the applications of these three basic substances in Viticulture beyond the treatment of mildew. [ABSTRACT FROM AUTHOR]

In a context in which the incidence and severity of grapevine fungal diseases is increasing as a result of both climate change and modern management culture practices, reducing the excessive use of phytosanitary products in viticulture represents a major challenge. Specifically, grapevine trunk diseases (GTDs), caused by several complexes of wood decay or xylem-inhabiting fungi, pose a major challenge to vineyard sustainability. In this study, the efficacy of chitosan oligomers (COS)–amino acid conjugate complexes against three fungal species belonging to the Botryosphaeriaceae family (Neofusicoccum parvum, Diplodia seriata, and Botryosphaeria dothidea) was investigated both in vitro and in planta. In vitro tests led to EC50 and EC90 effective concentrations in the 254.6−448.5 and 672.1−1498.5 µg·mL−1 range, respectively, depending on the amino acid involved in the conjugate complex (viz. cysteine, glycine, proline or tyrosine) and on the pathogen assayed. A synergistic effect between COS and the amino acids was observed against D. seriata and B. dothidea (synergy factors of up to 2.5 and 2.8, respectively, according to Wadley's method). The formulations based on COS and on the conjugate complex that showed the best inhibition rates, COS−tyrosine, were further investigated in a greenhouse trial on grafted vines of two varieties ("Tempranillo" on 775P and "Garnacha" on 110R rootstock), artificially inoculated with the mentioned three Botryosphaeriaceae species. The in planta bioassay revealed that the chosen formulations induced a significant decrease in disease severity against N. parvum and B. dothidea. In summary, the reported conjugate complexes may be promising enough to be worthy of additional examination in larger field trials. [ABSTRACT FROM AUTHOR]

Botryosphaeria dieback caused by several Botryosphaeriaceae species is one of the most important grapevine trunk diseases affecting vineyards worldwide. These fungi cause wedge-shaped perennial cankers and black streaking of the wood and have also been associated with intervein leaf chlorosis, dried or mummified berries, and eventually, the death of the plant. Early season symptoms may sometimes be disregarded by growers, being mistaken with symptoms from other diseases such as downy mildew or botrytis rot. Currently, few studies are available to determine what species may be causing these early season symptoms in grapevines. During the 2018 season, during the flowering period, grapevine samples showing necrosis on green shoots, dried inflorescences, and flowers, were collected in vineyards throughout the central regions of Portugal. Isolations were performed from symptomatic organs, and twenty-three isolates of Botryosphaeriaceae were selected. An analysis of the ITS and part of the translation elongation factor 1-α sequences was performed, revealing that the two main species apparently responsible for these symptoms were Diplodia seriata and Neofusicoccum parvum. In pathogenicity tests conducted on 1-year-old plants grown under controlled conditions in a greenhouse and on field-grown clusters, symptoms were reproduced, confirming the pathogenic behavior of the selection of isolates. [ABSTRACT FROM AUTHOR]