Fig 3 - uploaded by Youbert Ghosta
Content may be subject to copyright.
Cytospora chrysosperma (IRAN 4240C) on Malus domestica. a-b. Habit of conidiomata on a branch with pale luteous to luteous tendril, c-d. Longitudinal section through conidiomata, e-f. Cross-section through conidiomata, g. Conidiogenous cells with attached conidia, h. Conidia, i. Colony on PDA after 3 days (half part, left) and after 30 days (half part, right). Scale bars: b, c, e =250 µm; f, d=100 µm and g, h= 10 µm.
Source publication
In a recent survey on apple orchards showing stem canker, dieback and decline symptoms in West Azerbayjan Province, Iran, several fungal isolates with typical characteristics of the genus Cytospora were obtained. Combination of morphological and cultural characteristics and phylogenetic analysis of internal transcribed spacer region of the nrDNA (I...
Context in source publication
Citations
... Members of diaporthalean fungi are associated with several diseases including canker and dieback in economically and ecologically important woody plants such as Quercus species (Luque et al., 2000;Lynch et al., 2014;Fan et al., 2018;Jiang et al., 2018Jiang et al., , 2019Zhu et al., 2019Zhu et al., , 2021. Among the diaporthalean fungi, Cytospora with approximately 700 species listed in Index Fungorum (November 2023; www.indexfungorum.org) is the most common and widespread genus associated with a wide variety of woody plants around the world, which causes various disease symptoms such as canker and dieback or found as endophyte and saprobe (Adams et al., 2005;Lawrence et al., 2018;Azizi et al., 2020;Fan et al., 2020;Hanifeh et al., 2022;Ilyukhin et al., 2023). Cytospora species are found in association with canker and dieback diseases on various Quercus species (Kowalski, 1991;Adams et al., 2005;Lynch et al., 2014;Fan et al., 2018;Lawrence et al., 2018;Pinna et al., 2019;Pan et al., 2021). ...
Oak decline is a complex disorder that seriously threatens the survival of Zagros forests. In an extensive study on taxonomy and pathology of fungi associated with oak decline in the central and northern part of Zagros forests, 462 fungal isolates were obtained from oak trees showing canker, gummosis, dieback, defoliation, and partial or total death symptoms. Based on inter-simple sequence repeat (ISSR) fingerprinting patterns, morphological characteristics, and sequences of ribosomal DNA (28S rDNA and ITS) and protein coding loci (acl1, act1, caM, tef-1α, rpb1, rpb2, and tub2), 24 fungal species corresponding to 19 genera were characterized. Forty percent of the isolates were placed in eight coelomycetous species from seven genera, namely, Alloeutypa, Botryosphaeria, Cytospora, Didymella, Gnomoniopsis, Kalmusia, and Neoscytalidium. Of these, four species are new to science, which are introduced here as taxonomic novelties: Alloeutypa iranensis sp. nov., Cytospora hedjaroudei sp. nov., Cytospora zagrosensis sp. nov., and Gnomoniopsis quercicola sp. nov. According to pathogenicity trials on leaves and stems of 2-year-old Persian oak (Quercus brantii) seedlings, Alternaria spp. (A. alternata, A. atra, and A. contlous), Chaetomium globosum, and Parachaetomium perlucidum were recognized as nonpathogenic. All coelomycetous species were determined as pathogenic in both pathogenicity trials on leaves and seedling stems, of which Gnomoniopsis quercicola sp. nov., Botryosphaeria dothidea, and Neoscytalidium dimidiatum were recognized as the most virulent species followed by Biscogniauxia rosacearum.
... performed in this study can be comparable to the trials of other pathogenic species of Cytospora on Malus spp. conducted in vitro under the same conditions with different timelines [75]. The phylogenetically close species C. paratranslucens caused necrotic lesions up to 10 cm on detached apple branches after 21 days [75]. ...
... conducted in vitro under the same conditions with different timelines [75]. The phylogenetically close species C. paratranslucens caused necrotic lesions up to 10 cm on detached apple branches after 21 days [75]. The lesions up to 3.9 cm developed on twig segments of Malus sieversii inoculated with mycelium of C. parasitica after 8 days. ...
A new species of Cytospora was isolated from cankered wood of Prunus spp. during a survey of orchards exhibiting symptoms of fruit tree decline syndrome in southern Ontario, Canada. We found isolates that are morphologically similar to species in the Cytosporaceae family, which is characterized by single or labyrinthine locules, filamentous conidiophores or clavate to elongate obovoid asci and allantoid, hyaline conidia. Multi-gene phylogenetic analysis of ITS, LSU, act and tef1- α showed that the isolates form a distinct clade, sister to Cytospora plurivora. Morphologically, our isolates showed differences in the length of conidia and culture characteristics compared to C. plurivora, suggesting the establishment of a new species. The species is described as Cytospora paraplurivora sp. nov. and placed in the family Cytosporaceae of Diaporthales. Additionally, we sequenced, assembled and characterized the genome of the representative isolate for this new species. The phylogenomic analysis confirms the species order and family level classification. C. paraplurivora sp. nov. has the potential to severely affect stone fruits production, causing cankers and dieback in stressed trees, and eventually leads to tree decline. Pathogenicity tests show that the species is pathogenic to Prunus persica var. persica.
... Apple trees are susceptible to a wide range of diseases caused by biotic (e.g., fungi, bacteria, and viruses) and abiotic factors (e.g., temperature, moisture, and nutrients) (Borisova et al., 2014;Goldberg 2000;Thapa et al., 2020). Fungal diseases are known as the main constraints for apple cultivation and production in many countries including Iran (Azizi et al., 2020a(Azizi et al., , 2020bBrown-Rytlewski and McManus 2000;Cloete et al., 2011;Ershad 2009;Hanifeh et al., 2013Hanifeh et al., , 2014Nourian et al., 2021;Sutton et al., 2014;Xiao and Boal 2005). In recent years, disease on apple orchards have become a growing threat to productivity and longevity in Iran. ...
... Even though Cytospora species are principally known as weak pathogens, they negatively affect the longevity and productivity of fruit trees worldwide and cause chronic wood infections on fruit trees such as Malus spp. (Adams et al., 2005(Adams et al., , 2006Azizi et al., 2020a;Biggs 1989;Bills 1996;Christensen 1940;Fan et al., 2014aFan et al., , 2014bFan et al., , 2015aFan et al., , 2015bGonz alez and Tello 2011;Lawrence et al., 2018;Mehrabi et al., 2011;Pan et al., 2020;Sinclair et al., 1987;Wang et al., 2011Wang et al., , 2020Zhu et al., 2018). Disease symptoms initially appear on trunk and branches as slightly sunken areas on bark with brown discoloration in the wood that might result in cracking and scaling-off of the bark with disease progress. ...
... To date, 24 Cytospora species have been reported as the causal agent of apple canker disease worldwide, among which Cytospora ambiens, C. chrysosperma, C. cincta, C. germanica, C. leucostoma, C. paratranslucens, C. rubescens, C. salicina, and C. schulzeri have been recorded on apple trees in Iran (Ashkan 1994;Ashkan and Hedjaroude 1993;Azizi et al., 2020a;Fotouhifar et al., 2010;Ma et al., 2018;Mehrabi et al., 2011;Wang et al., 2011Wang et al., , 2020. As consequences of global climate change during last two decades in the mainland of Iran (including drought stress and high temperatures), canker and die-back diseases have become a major threat for Iranian apple industry. ...
In recent years, canker and die-back diseases have become a growing threat for the productivity and longevity of apple orchards in Iran. In this study, 131 Cytospora isolates were recovered from symptomatic tissues of apple trees in apple orchards of Iran. Multigene phylogenetic inference based on combined sequence data of ITS, act, rpb2, and tef1-α loci, supplemented with morphological characteristics and pathogenicity assay revealed four novel Cytospora species which were described as C. avicennae, C. azerbaijanica, C. ershadii, and C. iranica, and four known species, namely C. chrysosperma, C. parasitica, C. paratranslucens, and C. sorbicola. Also, C. sorbicola is newly reported on apple trees worldwide. Koch's postulates were fulfilled to confirm that all eight species in this study were pathogenic on apple trees in Iran, among which C. sorbicola was the most intensive species. The results of this study further highlight rich diversity among Cytospora species occurring on apple trees, revealing several novel Cytospora species on this host. The host range, geographical distribution, and economic significance of novel species on apple industry remains to be studied.
... Thus far, about 24 species of Cytospora and their sexual allies have been reported from Malus spp. Worldwide [30][31][32][33] , of which 14 species recognized in Iran 32,34,35 . However, taxonomic status of most of these species has not been approved through molecular approaches. ...
... Thus far, about 24 species of Cytospora and their sexual allies have been reported from Malus spp. Worldwide [30][31][32][33] , of which 14 species recognized in Iran 32,34,35 . However, taxonomic status of most of these species has not been approved through molecular approaches. ...
... Apple is one of the main hosts that suffer severe damage from the Cytospora canker disease 31,55,56 . At present, 24 Cytospora species have been reported as causal agents of canker disease in apple trees worldwide and 14 species have been recorded in Iran 30,32,33,35 . The results of our study indicated that more extensive pathogen surveys of apple production regions should be undertaken. ...
Apple is the most important fruit tree in West Azarbaijan province of Iran. However, a disease with crown and collar canker and necrosis was observed in three young apple orchards in Urmia, affected 15% and 1% of ‘Red Delicious’ and ‘Golden Delicious’ cultivars, respectively. A fungus with typical characteristics of the asexual morph of Cytospora was regularly isolated from the diseased tissues. Morphological characteristics and phylogenetic analysis inferred from the combined dataset of the ITS–rDNA, parts of LSU, tef1-α, rpb2 and act1 genes revealed that the isolates represent a new species of Cytospora, described herein as Cytospora balanejica sp. nov.. Pathogenicity of all isolates was confirmed on the cv. ‘Red Delicious’ based on Koch’s postulates. Also, the reaction of 12 apple cultivars was assessed against five selected isolates with higher virulence. Results showed that except cv. ‘Braeburn’ which did not produce any symptoms of infection, the other 11 cultivars showed characteristic symptoms including sunken and discolored bark and wood. The mean length of discolored area was different among the 11 so-called susceptible cultivars, hence cvs. ‘M4’ and ‘Golden delicious’ had the highest and the lowest lesion length, respectively. Moreover, the aggressiveness of five tested isolates was varied and the isolates BA 2–4 and BA 3–1 had the highest and lowest aggressiveness, respectively. Based on our observations on the potential ability of the fungus in causing the disease on young and actively growing apple trees, it will be a serious threat to apple cultivation and industry.
Apple is the most important fruit tree in West Azarbaijan province of Iran. In a survey of apple orchards, a disease with crown and collar canker and necrosis symptoms was observed in three young apple orchards in Urmia, affecting 15% and 1% of ‘Red Delicious’ and ‘Golden Delicious’ cultivars, respectively. A fungus with typical characteristics of the asexual morph of Cytospora was regularly isolated from the diseased tissues. Morphological characteristics and phylogenetic analyses inferred from the combined dataset of the ITS-rDNA, parts of LSU, tef1-α, rpb2, and act1 genes revealed that the isolates represent a new species of Cytospora, described herein as Cytospora balanejica sp. nov.. The pathogenicity of all isolates was confirmed on apple cv. ‘Red Delicious’ based on Koch’s postulates. Also, the reaction of 12 other apple cultivars was assessed against five selected isolates with the highest virulence. The results showed that except for cv. ‘Braeburn’, which did not produce any symptoms of the disease, the other 11 cultivars showed characteristic disease symptoms including sunken and discolored bark and wood. The mean length of the discolored area was different among the 11 so-called susceptible cultivars, hence cvs. ‘M4’ and ‘Golden Delicious’ showed the highest and the lowest lesion length, respectively. Moreover, the aggressiveness of the five tested isolates was different, and the isolates BA 2-4 and BA 3-1 had the highest and lowest aggressiveness, respectively. Based on our observations on the potential ability of the fungus to cause disease on young and actively growing apple trees, it will be a serious threat to apple cultivation and industry.
Rapid apple decline (RAD) is a complex phenomenon affecting cultivated apple trees and particularly dwarf rootstocks on grafted young apple trees. Since its first appearance in the United States, RAD has been reported worldwide, for example in Canada, South America, Africa, and Asia. The phenomenon has also been observed in apple orchards in Korea, and it presented similar symptoms regardless of apple cultivar and cultivation period. Most previous reports have suggested that RAD may be associated with multiple factors, including plant pathogenic infections, abiotic stresses, environmental conditions, and the susceptibility of trees to cold injury during winter. However, RAD was observed to be more severe and affect more frequently apple trees on the Malling series dwarf rootstock. In this study, we reviewed the current status of RAD worldwide and surveyed biotic and abiotic factors that are potentially closely related to it in Korea.
