scholarly journals First Report of Fusarium avenaceum Causing Canker Disease on Kiwi Tree in China

Plant Disease ◽  
2022 ◽  
Author(s):  
Qing Sun ◽  
Yongjing Xie ◽  
Tangmin Chen ◽  
Jianping Zhang ◽  
Pedro Laborda ◽  
...  

In May 2021, canker symptoms were detected on ‘Xuxiang’ kiwi trees in southwestern Shaanxi (Hanzhong municipality; 107.27° E, 33.23° N) in China. Seven-year-old trees exhibited black necrotic lesions and cracked areas in the trunk (Figure 1). The symptoms were observed in approximately 10% of the trees in 6 orchards (31 ha in total). Application of commercial fungicides did not control the advancement of the pathogen, and infected trees were removed to control the spread. Three samples, approximately 1 cm2 in size, of symptomatic tissue were collected and surface sterilized in 2% NaOCl for 1 min, and washed with sterile ddH2O. Four isolates showing white mycelium with yellow pigmentation were obtained after 4 days of incubation on PDA, containing chloramphenicol (50 µg/mL), at 28 ºC. The pathogen was isolated from all collected samples. ITS, EF1-α, TUB2, RPB1 and RPB2 genes were amplified using ITS1/ITS4, EF1-728F/EF1-986R, T1/T22, RPB1-5F/RPB1-8R and RPB2-5F/RPB2-7cR (strain NJC06), or RPB2-c7F/RPB2-11aR (strains NJC07 and NJC08), primers, respectively. Two isolates shared the same sequences (strain NJC08). Obtained sequences were submitted to GenBank under accession numbers MZ669205 and OL347898-OL347899 (ITS), OL439731-OL439733 (EF1-α), OL439734-OL439736 (TUB2), OL439737-OL439739 (RPB1), and OL439740-OL439742 (RPB2). The sequences shared >99% (ITS; F. avenaceum CBS 128538, MH864972), >99% (EF1-α; F. avenaceum 55-2, MN473124), 100% (TUB2; F. avenaceum SICAUCC 18-0001, MK253102), >98% (RPB1; F. avenaceum NRRL 26911, MG282372), and >98% (RPB2; F. avenaceum SICAUCC 18-0001, MK396098; or F. avenaceum FRC R-09495, CQ915486) homology to multiple F. avenaceum strains. Molecular phylogenetic tree (Figure 2) was constructed using MEGA7 with Fusarium strains found causing rot in various hosts (Wang et al. 2015), and other fungal species, such as Cadophora nalorum, Diaporthe ambigua, D. australafricana, and Neofusicoccum parvum, which were reported to cause cordon dieback on kiwi tree in Chile (Diaz et al. 2021). Microscope observations after cultivation of all isolates on barley-honey-tryptone medium (Song et al. 2020) showed the presence of septate mycelium, fusiform microconidia (8-15 µm in length, containing between 0 and 3 septa; n = 77) and chlamydospores (n = 21), and agree with the morphology of F. avenaceum (Zhao et al. 2020). To confirm pathogenicity, a sterilized spatula was used to make wounds (3 mm diameter, 1 mm depth) on the trunk of 3-months-old ‘Xuxiang’ kiwi trees. Solutions containing 1 × 106 spores/mL (20 µL) of the isolates were injected in the wounds. Sterile ddH2O was used for the control experiment. Inoculated plants were maintained in a growth chamber at 28 °C and 80% relative humidity for 4 days. The pathogen was recovered from the canker lesions, which were similar to those observed in the orchards, and its identity was confirmed by sequence analysis. The pathogen only infected wounded trees, and probably invaded the orchards during the pruning in February 2021. F. avenaceum was reported to cause canker on almond tree (Stack et al. 2020), stem rot on Anthoxanthum aristatum and Polygonatum cyrtonema (Pieczul et al. 2018; Xu et al. 2019), and root rot on carrot, Coptis chinensis and wheat (Le Moullec-Rieu et al. 2020; Mei et al. 2020; Ozer et al. 2020). Recently, F. avenaceum was found causing fruit blotch in kiwi fruit in Anhui (China) (Zhao et al. 2020). Here, F. avenaceum was found causing canker disease in kiwi tree, demonstrating the host and tissue promiscuity of this pathogen. Kiwi is an important crop in China with nearly 1.5 million tons produced in 2019. This report will help to better understand the pathogens reducing kiwi production in China.

Plant Disease ◽  
2020 ◽  
Author(s):  
Xinchi Shi ◽  
Suyan Wang ◽  
Xuchu Duan ◽  
Xing Gao ◽  
Xinyu Zhu ◽  
...  

In March 2020, widespread anthracnose was observed on soybean (Glycine max) in southeastern Jiangsu (Nantong municipality; 120.53° E, 31.58° N) in China. Plants exhibited irregular brown necrotic lesions in stem and leaves, and pronounced wilting. The symptoms were detected in one soybean field, 0.42 ha, surrounded by healthy wheat fields. Approximately 65% of the soybean plants showed the disease symptoms, and crop yield was reduced by 28-35% with respect the yield achieved in previous years, when no symptoms were observed. The symptoms were consistent with those previously reported for anthracnose on soybean caused by Colletotrichum chlorophyti, C. cliviae and C. gloeosporioides (Barbieri et al. 2017; Mahmodi et al. 2013; Yang et al. 2012). Diseased, 3-week old plants were collected. Small pieces, approximately 1 cm2 in size, of symptomatic tissue were surface sterilized in 1.5% NaOCl for 1 min, and washed twice with sterile ddH2O. The pathogen was isolated and cultured on potato dextrose agar (Song et al. 2020), containing chloramphenicol (50 µg/mL), under darkness at 28 °C for 3 days. Sequence of internal transcribed spacer (ITS), actin (ACT), β-tubulin (TUB2) and glyceraldehyde 3-phosphate dehydrogenase (GAP/span>DH) genes was performed as reported by Yang et al. (2015). Sequences were submitted to GenBank under accession numbers MT361074 (ITS) and MT415548-MT415550 (ACT, TUB2 and GAPDH). Blast search revealed that the amplified sequences had 100% (ITS; C. brevisporum TCHD, MH883805), 97.66% (ACT; C. brevisporum S38, KY986905), 99.06% (TUB2; C. brevisporum PF-2, KY705061) and 100% (GAPDH; C. brevisporum LJTJ27, KP823797) matches to multiple C. brevisporum strains, whereas all reported C. chlorophyti, C. cliviae and C. gloeosporioides strains showed no similarity to at least 2 of the studied genes. Molecular phylogenetic tree constructed using MEGA7 confirmed the identity of the pathogen. ACT and ITS sequences were blasted separately in Muscle (https://www.ebi.ac.uk/Tools/msa/muscle/) and then combined together to make the phylogenetic tree. The evolutionary history was inferred by using the Maximum Likelihood method based on the Tamura 3-parameter model, and the tree with the highest log likelihood (-1749.2186) is shown in Figure 1. The Colletotrichum strains previously found causing anthracnoseon soybean, and other relevant strains used in taxonomic analyses were included in the phylogenetic tree. Microscope observations showed the presence of 15-µm-long cylindrical conidia and septate mycelium, and agree with those reported for the morphology of C. brevisporum by Damm et al. (2019). To confirm pathogenicity, the mycelia from a 2 day-old culture on PDA was collected and suspended in sterile ddH2O (≈ 106 cells/mL) to prepare the inoculum. The pathogen was sprayed-inoculated on stem and leaves of healthy soybean plants. In control plants, sterile ddH2O was used. Inoculated plants were maintained in growth chamber at 28 °C and 50% relative humidity. Typical anthracnose symptoms were obsered 20 days after inoculation (Figure 2). C. brevisporum was reported to produce anthracnose on pumpkin, papaya, mulberry, coffee, passion fruit and pepper in China (Liu et al. 2017; Liu et al. 2019; Xue et al. 2019). Here, we report for the first time C. brevisporum causing anthracnose on soybean, an economically-relevant crop in China.


Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 776-776 ◽  
Author(s):  
G. Granata ◽  
R. Faedda ◽  
A. Sidoti

The evergreen carob tree (Ceratonia siliqua L., Fabaceae), also called locust, is widespread in the Mediterranean Region. Carob pods have been traditionally consumed as animal and human food and seeds are mainly used in the pharmaceutical and cosmetic industries. In July 2009, symptoms of canker, branch dieback, and foliage reddening were observed on carob trees in several natural areas in the province of Ragusa, Italy. Disease incidence ranged from 5 to 80% across different sites and for most areas it was nearly 15%. All affected trees showed dark necrotic tissue in the bark, cambium, and sapwood of the trunk and branches. Cankers often girdled the stem or branch, causing wilting and death of the portions beyond the canker. Black, subepidermal pycnidia developed in and erupted through the dead bark. Fragments of discolored wood were collected from 36 symptomatic carob trees (12 trees for each area), transferred onto potato dextrose agar (PDA), and incubated for 5 days at 21°C in the dark. Fungal colonies were consistently obtained from these diseased tissues. They initially were pale, becoming gray-green and finally black. After 30 days of incubation at room temperature in the natural light, colonies produced pycnidia identical to those observed in nature. A total of 500 conidia on 10 isolates were examined with a compound microscope. Conidia were initially hyaline, smooth, oblong to ovoid, both ends rounded, and aseptate; at maturity they were pale brown, one-septate, and measured 24 to 28 × 10 to 13.5 μm (means ± S.D. = 24.3 ± 1.4 × 12.1 ± 1 μm, L/W = 2.0 ± 0.18). The nucleotide sequences of the β-tubulin (GenBank Accession No. HQ660080) and TE-1α (No. HQ660078) genes and ITS-rDNA region (No. HM028640) for a representative isolate (IMI 390972) from carob showed 100, 100, and 98% similarity, respectively, when compared with the sequences HQ660079, EU392279, and EU392302, respectively, of the ex-type isolate of Diplodia olivarum (strain CBS 121887). On the basis of morphological and molecular characters, the fungus was identified as D. olivarum A.J.L. Phillips, Frisullo & Lazzizera; teleomorph unknown (1). Two-year-old trees were wounded with a scalpel through the full thickness of the bark along 1-cm longitudinal direction and inoculated by applying a 5-mm-diameter plug of mycelial (isolate IMI 390972) on PDA to the wound site. Three control seedlings were similarly wounded and plugs of sterile PDA applied. Plugs were held in place by Parafilm. The inoculated seedlings were maintained at 20 to 22°C and a 12-h light/dark cycle. Sixty days after inoculation, all inoculated trees showed leaf chlorosis, sunken, necrotic bark at the inoculation sites and finally pycnidia of D. olivarum. All treated seedlings were killed within 6 months from the inoculation. No symptoms were observed in the control plants. The pathogen was consistently reisolated from all the inoculated trees, but not from the control plants. D. olivarum has been found on rotting olive drupes in Apulia (southern Italy) and was first described as a new species in 2008 (1). This fungal species could be phenotypically misidentified as the closely related species D. mutila, which differs by having larger mean dimensions of conidia. To our knowledge, this is the first report of D. olivarum inducing canker and dieback on carob tree. Reference: (1) C. Lazzizera et al. Fungal Divers. 31:63, 2008.


Plant Disease ◽  
2020 ◽  
Author(s):  
Tangmin Chen ◽  
Xinchi Shi ◽  
Suyan Wang ◽  
Pedro Laborda

In September 2020, widespread stem canker on soybean (Glycine max) was detected in southeastern Jiangsu (Nantong municipality; 120.76° E, 32.23° N) in China. Mature plants, 14 weeks of cultivation, exhibited brown necrotic lesions and dried-up stem. The symptoms were observed in eleven soybean fields, 1.6 ha in total, and approximately 80% of the plants were symptomatic. The symptoms were consistent with those previously reported for stem canker on soybean caused by Diaporthe aspalathi, D. caulivora and D. sojae (Ghimire et al. 2019; Mena et al. 2020). Small pieces, approximately 0.4 cm2 in size, of symptomatic tissue were surface sterilized in 1.5% NaOCl for 1 min, and washed twice with sterile ddH2O. The pathogen was isolated and cultured on potato dextrose agar (PDA), containing chloramphenicol (50 µg/mL), under darkness at 28 ºC for 7 days. Amplification of internal transcribed spacer (ITS), elongation factor 1-α (EF1-α) and β-tubulin (TUB2) genes was performed using ITS1/ITS4, EF1-728F/EF1-986R and Bt2a/Bt2b primers, respectively (Jia et al. 2019). Sequences were submitted to GenBank under accession numbers MW130133 (ITS), MW147481 (EF1-α) and MW147482 (TUB2). Blast search revealed that the amplified sequences had 99.65% (ITS; B. dothidea JZB310202, MN945381), 100% (EF1-α; B. dothidea ZB-77, MH726166) and 99.75% (TUB2; B. dothidea ZB-1, MN642587) matches to multiple B. dothidea strains, whereas all reported Diaporthe strains showed no nucleotide identity to the amplified sequences. Molecular phylogenetic tree was constructed using MEGA7 to confirm the identity of the pathogen. ITS, EF1-α and TUB2 sequences were blasted separately in Muscle (https://www.ebi.ac.uk/Tools/msa/muscle/) and then combined together to make the phylogenetic tree. The evolutionary history was inferred by using the Maximum Likelihood method based on the Tamura 3-parameter model, and the tree with the highest likelihood (-4291.3981) is shown in Figure 1. Diaporthe strains found causing stem canker on soybean, some Phytophthora sojae strains (which also cause dried-up stem on soybean) (Yang et al. 2019), and B. dothidea strains found in China in other hosts were included in the phylogenetic tree. To confirm pathogenicity, a sterilized spatula was used to make wounds (3 mm diameter, 1 mm depth) on the stem of 2-week old soybean plants. Mycelial plugs from a 7 day-old culture on PDA were placed on the wounds and covered with Parafilm. Sterilized PDA plugs were used as control. Inoculated plants were maintained in a growth chamber at 28 °C and 60% relative humidity. Typical stem canker symptoms were observed 5 days after inoculation (Figure 2). Microscope observations showed the presence of septate mycelium, fusiform conidia and round conidiomata, and agreed with those previously reported for the morphology of B. dothidea strains (Phillips et al. 2013). During recent months, B. dothidea was reported to cause stem canker and leave wilt on a number of plant species in China (Huang et al. 2020; Ju et al. 2020; Wang et al. 2020a, 2020b, 2020c), confirming the expansion and host promiscuity of this pathogen. Stem canker on soybean has been thoroughly associated to Diaporthe strains; however, this is the first report of B. dothidea causing this disease. We believe that our results will help to better understand the pathogens affecting soybean production in China.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1434
Author(s):  
Hiran A. Ariyawansa ◽  
Ichen Tsai ◽  
Jian-Yuan Wang ◽  
Patchareeya Withee ◽  
Medsaii Tanjira ◽  
...  

Camellia sinensis is one of the major crops grown in Taiwan and has been widely cultivated around the island. Tea leaves are prone to various fungal infections, and leaf spot is considered one of the major diseases in Taiwan tea fields. As part of a survey on fungal species causing leaf spots on tea leaves in Taiwan, 19 fungal strains morphologically similar to the genus Diaporthe were collected. ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), tub2 (beta-tubulin), and cal (calmodulin) gene regions were used to construct phylogenetic trees and determine the evolutionary relationships among the collected strains. In total, six Diaporthe species, including one new species, Diaporthe hsinchuensis, were identified as linked with leaf spot of C. sinensis in Taiwan based on both phenotypic characters and phylogeny. These species were further characterized in terms of their pathogenicity, temperature, and pH requirements under laboratory conditions. Diaporthe tulliensis, D. passiflorae, and D. perseae were isolated from C. sinensis for the first time. Furthermore, pathogenicity tests revealed that, with wound inoculation, only D. hongkongensis was pathogenic on tea leaves. This investigation delivers the first assessment of Diaporthe taxa related to leaf spots on tea in Taiwan.


2018 ◽  
Vol 63 (2) ◽  
pp. 45-64 ◽  
Author(s):  
Jolanta Miadlikowska ◽  
Nicolas Magain ◽  
Carlos J. Pardo-De la Hoz ◽  
Dongling Niu ◽  
Trevor Goward ◽  
...  

AbstractClosely related lichen-forming fungal species circumscribed using phenotypic traits (morphospecies) do not always align well with phylogenetic inferences based on molecular data. Using multilocus data obtained from a worldwide sampling, we inferred phylogenetic relationships among five currently accepted morphospecies of Peltigera section Peltidea (P. aphthosa group). Monophyletic circumscription of all currently recognized morphospecies (P. britannica, P. chionophila, P. frippii and P. malacea) except P. aphthosa, which contained P. britannica, was confirmed with high bootstrap support. Following their re-delimitation using bGMYC and Structurama, BPP validated 14 putative species including nine previously unrecognized potential species (five within P. malacea, five within P. aphthosa, and two within P. britannica). Because none of the undescribed potential species are corroborated morphologically, chemically, geographically or ecologically, we concluded that these monophyletic entities represent intraspecific phylogenetic structure, and, therefore, should not be recognized as new species. Cyanobionts associated with Peltidea mycobionts (51 individuals) represented 22 unique rbcLX haplotypes from five phylogroups in Clade II subclades 2 and 3. With rare exceptions, Nostoc taxa involved in trimembered and bimembered associations are phylogenetically closely related (subclade 2) or identical, suggesting a mostly shared cyanobiont pool with infrequent switches. Based on a broad geographical sampling, we confirm a high specificity of Nostoc subclade 2 with their mycobionts, including a mutualistically exclusive association between phylogroup III and specific lineages of P. malacea.


2020 ◽  
Vol 44 (1) ◽  
pp. 1-40
Author(s):  
W.M. Jaklitsch ◽  
H. Voglmayr

Fresh collections and their ascospore and conidial isolates backed up by type studies and molecular phylogenetic analyses of a multigene matrix of partial nuSSU-, complete ITS, partial LSU rDNA, rpb2, tef1 and tub2 sequences were used to evaluate the boundaries and species composition of Fenestella and related genera of the Cucurbitariaceae. Eight species, of which five are new, are recognised in Fenestella s.str., 13 in Parafenestella with eight new species and two in the new genus Synfenestella with one new species. Cucurbitaria crataegi is combined in Fenestella, C. sorbi in Synfenestella, Fenestella faberi and Thyridium salicis in Parafenestella. Cucurbitaria subcaespitosa is distinct from C. sorbi and combined in Neocucurbitaria. Fenestella minor is a synonym of Valsa tetratrupha, which is combined in Parafenestella. Cucurbitaria marchica is synonymous with Parafenestella salicis, Fenestella bavarica with S. sorbi, F. macrospora with F. media, and P. mackenziei is synonymous with P. faberi, and the latter is lectotypified. Cucurbitaria sorbi, C. subcaespitosa and Fenestella macrospora are lecto- and epitypified, Cucurbitaria crataegi, Fenestella media, F. minor and Valsa tetratrupha are epitypified in order to stabilise the names in their phylogenetic positions. A neotype is proposed for Thyridium salicis. A determinative key to species is given. Asexual morphs of fenestelloid fungi are phoma-like and do not differ from those of other representatives of the Cucurbitariaceae. The phylogenetic structure of the fenestelloid clades is complex and can only be resolved at the species level by protein-coding genes, such as rpb2, tef1 and tub2. All fungal species studied here occur, as far as has been possible to determine, on members of Diaporthales, most frequently on asexual and sexual morphs of Cytospora.


2021 ◽  
Vol 46 (1) ◽  
pp. 211-217
Author(s):  
Denise Monte Braz ◽  
Thomas F. Daniel ◽  
Carrie Kiel ◽  
Anna Gao ◽  
Sagrika Jawadi ◽  
...  

Abstract—A species previously treated in Staurogyne (S. nitida) is elevated to the category of a new genus of Acanthaceae, subfamily Nelsonioideae, based on morphological and molecular data. The sole species, Aymoreana nitida, occurs in the Atlantic Forest of eastern Brazil, from southern Bahia to northern Espírito Santo. Aymoreana differs from other genera of Nelsonioideae by the combination of the calyx with subequal segments, the slightly zygomorphic corolla, the four didynamous stamens, and the asymmetric gynoecium. Morphological information is accompanied by a molecular phylogenetic tree, ecological data, a preliminary conservation assessment, and illustrations.


2000 ◽  
Vol 66 (5) ◽  
pp. 1899-1904 ◽  
Author(s):  
Tapani Tuomi ◽  
Kari Reijula ◽  
Tom Johnsson ◽  
Kaisa Hemminki ◽  
Eeva-Liisa Hintikka ◽  
...  

ABSTRACT We analyzed 79 bulk samples of moldy interior finishes from Finnish buildings with moisture problems for 17 mycotoxins, as well as for fungi that could be isolated using one medium and one set of growth conditions. We found the aflatoxin precursor, sterigmatocystin, in 24% of the samples and trichothecenes in 19% of the samples. Trichothecenes found included satratoxin G or H in five samples; diacetoxyscirpenol in five samples; and 3-acetyl-deoxynivalenol, deoxynivalenol, verrucarol, or T-2-tetraol in an additional five samples. Citrinine was found in three samples. Aspergillus versicolor was present in most sterigmatocystin-containing samples, and Stachybotrys spp. were present in the samples where satratoxins were found. In many cases, however, the presence of fungi thought to produce the mycotoxins was not correlated with the presence of the expected compounds. However, when mycotoxins were found, some toxigenic fungi usually were present, even if the species originally responsible for producing the mycotoxin was not isolated. We conclude that the identification and enumeration of fungal species present in bulk materials are important to verify the severity of mold damage but that chemical analyses are necessary if the goal is to establish the presence of mycotoxins in moldy materials.


Phytotaxa ◽  
2018 ◽  
Vol 350 (1) ◽  
pp. 42 ◽  
Author(s):  
GALINA V. DEGTJAREVA ◽  
MICHAEL G. PIMENOV ◽  
TAHIR H. SAMIGULLIN

The systematic position of three Apiaceae-Apioideae taxa, Pinacantha porandica, Ladyginia bucharica and Peucedanum mogoltavicum, from Middle Asia and Afghanistan, is clarified based on nrITS DNA sequence data. In the molecular phylogenetic tree, the monotypic Pinacantha is placed in unresolved position within the Ferulinae. Although there is no morphological information on essential characters, we propose a new position of Pinacantha porandica within the genus Ferula. As a result a new combination Ferula porandica is proposed, with a new section Pinacantha to accommodate it. The attribution of Peucedanum mogoltavicum to Ferula has been confirmed, its correct name being Ferula lithophila. The genus Ladyginia should not be included in Ferula, its closest relatives being Mozaffariania and Glaucosciadium from the Glaucosciadium Clade.


2018 ◽  
Vol XI ◽  
pp. 1-10
Author(s):  
Andrzej Grzywacz ◽  
Ewa Referowska- Chodak

The paper presents the taxonomic status of fungi and species abundance of fungi and fungus-like organisms occurring in Poland. It provides the history of species conservation and discusses the level of threat posed to fungi. Tree nature monuments with particular emphasis put on old trees, as well as fungal species under the strict and partial legal protection that may inhabit such trees have also been characterized. The paper describes an ideological conflict concerning nature conservation that may arise in connection with the infestation of protected monument trees by fungi also protected by law. Although there is no legal conflict as regards the elimination of protected fungal species from monument trees, the practice shows that it is difficult to obtain permission for such actions in regional directorates of environmental protection. This is (wrongly) explained by the lack of derogations from the destruction of some fungal species and their habitats.


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