First report of nut rot caused by Neofusicoccum parvum on hazelnut (Corylus avellana) in Italy

Hazelnut (Corylus avellana L.), which is native to Europe and Western Asia, is a widely distributed and economically important crop in Italy, cultivated on 82,104 ha and its production is 110,618 t (ISTAT 2021). A total of one hundred and eleven black rotted nuts (incidence: 41%) with sunken lesions from Lu and Cuccaro (45°00'21.8"N/8°28'59.6"E), north-western Italy, were collected during the ripening stage of hazelnuts during October-December 2020. Symptomatic half cut kernels were sterilized in 1% NaClO for 1 min, washed in sterile water twice, and dried on sterile filter paper. The fragments were placed onto potato dextrose agar (PDA) containing streptomycin. After 48 to 72 h of incubation at 25°C, fast-growing white colonies with abundant aerial mycelia were observed. On the opposite side of the plates, colonies were initially white, then turned to dark-grayish olive after one week of incubation. Dark colonies produced globose, hyaline, ellipsoidal, unicellular conidia ranging from 12.23-15 μm x 5-6.71 μm. Morphologically, the causal agent was identified as Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips (Crous et al. 2006; Zhang et al. 2021). The DNA from the isolates HMa-19-2 and Hwb-4b-2 was extracted with the E.Z.N.A. Fungal DNA mini kit (Omega Bio-tek) according to manufacturer instructions. Molecular identification was confirmed by sequencing of rDNA internal transcribed spacer (ITS) using primers ITS1/ITS4 (White et al. 1990) and translation elongation factor 1-alpha (tef-1α) gene by using the primers EF1-728F/EF1-986R (Carbone & Kohn, 1999). The sequences of both isolates were deposited in GenBank for ITS (accession numbers MZ848132 and MZ848133) and for tef-1α gene (accession numbers MZ913266 and MZ913267). The BLAST analysis showed 99% identity with ex-type strain of N. parvum (CMW9081) for ITS and tef-1α. Maximum likelihood method based on combined sequences of ITS and tef-1α genes was performed and the isolates of N. parvum clustered with ex-type strain of N. parvum (CMW9081; eXtra file). Pathogenicity of both isolates were tested on ripening hazelnuts (BBCH: 85) to evaluate Koch’s postulates. Three nuts per isolate, and per three replicates, were surface disinfected with 1% NaClO. A piece of shell (5 mm diameter) from nuts was removed with a sterile cork borer, then nuts were inoculated with PDA mycelium plugs of the same diameter cut from 7 days old PDA colony (Seddaiu et al. 2021). The control nuts were treated with sterilized PDA plugs. All inoculated nuts produced black lesions with softening pulp (eXtra file). Additionally, abundant white-gray mycelium developed on the inoculation sites. Control nuts showed no symptoms. Neofusicoccum parvuwas recently reported in Italy on chestnut (Seddaiu et al. 2021) and blueberry (Guarnaccia et al. 2021). The fungal pathogen was also reported as agent of grey necrosis of hazelnut in Chile (Duran et al. 2020). However, this is the first report of N. parvum on hazelnut nut in Italy. The findings suggest that N. parvum could severely affect hazelnut production in Italy. Accurate identification of the pathogen will support the growers to manage the disease.

Download Full-text

First report of Gibellulopsis nigrescens on peppermint in Germany

Journal of Plant Diseases and Protection ◽

10.1007/s41348-021-00540-0 ◽

2021 ◽

Author(s):

Elias Alisaac ◽

Monika Götz

Keyword(s):

Verticillium Wilt ◽

Elongation Factor ◽

Economic Losses ◽

Fungal Culture ◽

Translation Elongation ◽

First Report ◽

Regular Control ◽

Fungal Dna ◽

Elongation Factor 1 ◽

Important Medicinal Plant

AbstractPeppermint is an important medicinal plant, and it is known for its essential oils and phenolic acids. Verticillium wilt is a vascular disease resulted from several Verticillium spp. causing significant economic losses in peppermint cultivation. In this study, the fungus Gibellulopsis nigrescens (syn. Verticillium nigrescens) was isolated from symptomless peppermint plants during the regular control of Verticillium wilt on peppermint in Germany. A pure fungal culture was prepared, and fungal DNA was extracted. Ribosomal internal transcribed spacer (ITS), beta-tubulin (TUB), and translation elongation factor 1-α (TEF1-α) were amplified, sequenced, and deposited in the GenBank. These sequences are located within the Gibellulopsis nigrescens cluster. Koch’s postulate was fulfilled, and the fungus was re-isolated from the inoculated plants. Up to our knowledge, this is the first report of Gibellulopsis nigrescens on peppermint in Germany.

Download Full-text

Characterization of Botryosphaeriaceae Species as Causal Agents of Trunk Diseases on Grapevines

Plant Disease ◽

10.1094/pdis-03-15-0286-re ◽

2015 ◽

Vol 99 (12) ◽

pp. 1678-1688 ◽

Cited By ~ 16

Author(s):

Antonia Carlucci ◽

Francesca Cibelli ◽

Francesco Lops ◽

Maria Luisa Raimondo

Keyword(s):

Elongation Factor ◽

Phylogenetic Study ◽

Translation Elongation ◽

Neofusicoccum Parvum ◽

Grapevine Trunk Diseases ◽

General Decline ◽

Wide Range ◽

Trunk Diseases ◽

Pathogenicity Tests

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.

Download Full-text

First report of Nigrospora sphaerica causing fruit dried-shrink disease in Akebia trifoliata from China

Plant Disease ◽

10.1094/pdis-11-20-2471-pdn ◽

2021 ◽

Author(s):

Xiujing Hong ◽

Shijia Chen ◽

linchao Wang ◽

Bo Liu ◽

Yuruo Yang ◽

...

Keyword(s):

Elongation Factor ◽

Morphological Characteristics ◽

Its Region ◽

Average Diameter ◽

Ethanol Solution ◽

Likelihood Method ◽

Conidial Suspension ◽

Multiple Sequence ◽

First Report ◽

Pure Cultures

Akebia trifoliata, a recently domesticated horticultural crop, produces delicious fruits containing multiple nutritional metabolites and has been widely used as medicinal herb in China. In June 2020, symptoms of dried-shrink disease were first observed on fruits of A. trifoliata grown in Zhangjiajie, China (110.2°E, 29.4°N) with an incidence about 10%. The infected fruits were shrunken, colored in dark brown, and withered to death (Figure S1A, B). The symptomatic fruits tissues (6 × 6 mm) were excised from three individual plants, surface-disinfested in 1% NaOCl for 30s and 70% ethanol solution for 45s, washed, dried, and plated on potato dextrose agar (PDA) containing 50 mg/L streptomycin sulfate in the dark, and incubated at 25℃ for 3 days. Subsequently, hyphal tips were transferred to PDA to obtain pure cultures. After 7 days, five pure cultures were obtained, including two identical to previously reported Colletotrichum gloeosporioides causing leaf anthracnose in A. trifoliata (Pan et al. 2020) and three unknown isolates (ZJJ-C1-1, ZJJ-C1-2, and ZJJ-C1-3). The mycelia of ZJJ-C1-1, ZJJ-C1-2 and ZJJ-C1-3 were white, and formed colonies of approximate 70 mm (diameter) in size at 25℃ after 7 days on potato sucrose agar (PSA) plates (Figure S1C). After 25 days, conidia were formed, solitary, globose, black, shiny, smooth, and 16-21 μm in size (average diameter = 18.22 ± 1.00 μm, n = 20) (Figure S1D). These morphological characteristics were similar to those of N. sphaerica previously reported (Li et al. 2018). To identify species of ZJJ-C1-1, ZJJ-C1-2 and ZJJ-C1-3, the internal transcribed spacer (ITS) region, β-tubulin (TUB2), and the translation elongation factor 1-alpha (TEF1-α) were amplified using primer pairs including ITS1/ITS4 (Vilgalys and Hester 1990), Bt-2a/Bt-2b (Glass and Donaldson 1995), and EF1-728F/EF-2 (Zhou et al. 2015), respectively. Multiple sequence analyses showed no nucleotide difference was detected among genes tested except ITS that placed three isolates into two groups (Figure S2). BLAST analyses determined that ZJJ-C1-1, ZJJ-C1-2 and ZJJ-C1-3 had 99.73% to N. sphaerica strains LC2705 (KY019479), 100% to LC7294 (KY019397), and 99.79-100% to LC7294 (KX985932) or LC7294 (KX985932) based on sequences of TUB2 (MW252168, MW269660, MW269661), TEF-1α (MW252169, MW269662, MW269663), and ITS (MW250235, MW250236, MW192897), respectively. These indicated three isolates belong to the same species of N. sphaerica. Based on a combined dataset of ITS, TUB2 and TEF-1α sequences, a phylogenetic tree was constructed using Maximum likelihood method through IQ-TREE (Minh et al. 2020) and confirmed that three isolates were N. sphaerica (Figure S2). Further, pathogenicity tests were performed. Briefly, healthy unwounded fruits were surface-disinfected in 0.1% NaOCl for 30s, washed, dried and needling-wounded. Then, three fruits were inoculated with 10 μl of conidial suspension (1 × 106 conidia/ml) derived from three individual isolates, with another three fruits sprayed with 10 μl sterilized water as control. The treated fruits were incubated at 25℃ in 90% humidity. After 15 days, all the three fruits inoculated with conidia displayed typical dried-shrink symptoms as those observed in the farm field (Figure S1E). The decayed tissues with mycelium and spores could be observed on the skin or vertical split of the infected fruits after 15 days’ inoculation (Figure S1F-H). Comparably, in the three control fruits, there were no dried-shrink-related symptoms displayed. The experiment was repeated twice. The re-isolated pathogens were identical to N. sphaerica determined by sequencing the ITS, TUB2 and TEF-1α. Previous reports showed N. sphaerica could cause postharvest rot disease in kiwifruits (Li et al. 2018). To our knowledge, this is the first report of N. sphaerica causing fruits dried-shrink disease in A. trifoliata in China.

Download Full-text

First Report of Stem Dieback Caused by Lasiodiplodia parva on Styphnolobium japonicum in China

Plant Disease ◽

10.1094/pdis-08-21-1598-pdn ◽

2021 ◽

Author(s):

Ziwei Zhou ◽

Cuiping Wu ◽

Jing Yang ◽

Jieying Xu ◽

Zhenpeng Chen ◽

...

Keyword(s):

Robinia Pseudoacacia ◽

Elongation Factor ◽

Aerial Mycelium ◽

Random Trees ◽

Molecular Evidence ◽

Conidial Suspension ◽

Internal Transcribed Spacer Region ◽

Accurate Identification ◽

Individual Tree ◽

First Report

Styphnolobium japonicum (L.) Schott is a variant of Robinia pseudoacacia and is a popular Asian tree widely used in traditional medicine. From March 2019 to 2021, a disease was found on the campus of Nanjing Forestry University and several landscape sites of Xuanwuhu Park, causing dieback. Most of the trees (approximately 40%) have rotted branches. On average, 60% of the branches per individual tree were affected by this disease. The initial round lesions were grayish brown. In the later stage, the whole branch becomes black and produces spherical fruiting bodies . Twenty diseased branches were picked from three random trees. Small tissues (3-4mm²) were surface-sterilized in 75% ethanol for 30 s followed by 1% NaClO for 90 s and placed on potato dextrose agar (PDA), and incubated in the dark at 25°C for three days. Hyphae were visibly emerged from 70% of the samples. Three representative isolates (Lth-soj1, Lth-soj2, and Lth-soj3) were obtained and deposited in China’s Forestry Culture Collection Center (Lth-soj1: cfcc55896, Lth-soj2: cfcc55897, Lth-soj3: cfcc55898). The colonies of three isolates on PDA were fast growing and white, which turned grey to dark grey after 3 days of incubation in the dark at 28°C . Two-weeks old colonies were black and fluffy on PDA, with abundant aerial mycelium, and the reverse side too was black in color. The fungus usually grew well on PDA and produced pycnidia and conidia within 3–4 weeks. Conidia were initially hyaline and aseptate, ellipsoid to ovoid, with granular content, apex broadly rounded, remaining hyaline and later becoming dark brown, one septate, thick walled, base truncate or round and longitudinally striate. The conidia (n=30) of a representative isolate（Lth-soj1）, measured 24.3 ± 0.3 μm in length and 13.3 ± 0.5 μm in width . The morphological characters of the three isolates matched those of Lasiodiplodia parva(Alves et al. 2008). For accurate identification, the DNA of the three isolates was extracted. The internal transcribed spacer region (ITS), translation elongation factor (EF1-α), and β-tubulin 2 (TUB2) genes were amplified using the primer pairs ITS1/ITS4 , EF1-728F/EF1-986R, and Bt2a/Bt2b , respectively. The sequences were deposited in GenBank under accession numbers MZ613154, MZ643245 and MZ643242 for Lth-soj1, MZ613155, MZ643246 and MZ643244 for Lth-soj2, and MZ613157, MZ643247 and MZ643243 for Lth-soj3. The ITS, EF1-α, and TUB2 sequences of isolate Lth-soj1 (GenBank Acc. No. MZ613154, MZ643245, MZ643242) were 100% (519/519 nt), 99.34% (299/301 nt), and 99.77% (436/437 nt) identical to those of MZ182360, EF622063, and MK294119, respectively. Interspecific differences were observed in a maximum-likelihood tree of Lasiodiplodia species using the concatenated dataset. Based on the morphological and molecular evidence, the isolates were identified as L. parva. The pathogenicity of three isolates were tested on potted three-year-old seedlings (100-cm tall) of S. japonicum maintained in a greenhouse. Healthy stems were wounded with a sterile needle then inoculated with 10 µL of conidial suspension. Control plants were treated with ddH2O. In total, 12 seedlings were inoculated including three controls. Three seedlings per isolate and 10 stems per seedling were used for each treatment. The plants were kept inside sealed polythene bags for the first 24 h and sterilized H2O was sprayed into the bags twice a day to maintain humidity and kept in a greenhouse at the day/night temperatures at 25/16°C. Within seven days, all the inoculated points showed lesions similar to those observed in field and the conidiomatas growing on the surface of the branches, whereas controls were asymptomatic . The infection rate of each of the three isolates was 100%. The strain was re-isolated from the lesions and sequenced as L.parva, whereas not from control stems. This is the first report of L. parva causing rotten branches of S. japonicum in China and the worldwide. These data will help to develop effective strategies for managing this newly emerging disease.

Download Full-text

Identification of Neofusicoccum parvum causing canker and twig blight on Ficus carica in Italy

Phytopathologia Mediterranea ◽

10.36253/phyto-10798 ◽

2020 ◽

Vol 59 (1) ◽

pp. 213-218

Author(s):

Dalia AIELLO ◽

Giorgio GUSELLA ◽

Alberto FIORENZA ◽

Vladimiro GUARNACCIA ◽

Giancarlo POLIZZI

Keyword(s):

Sequence Data ◽

Elongation Factor ◽

Its Region ◽

Ficus Carica ◽

Translation Elongation ◽

Neofusicoccum Parvum ◽

Elongation Factor 1 Alpha ◽

Twig Blight ◽

Pathogenicity Tests ◽

Fungal Colony

During June 2018, several symptomatic fig (Ficus carica) cuttings, showing twig blight, subcortical discolouration and apical dieback were collected from a nursery in Catania province, Sicily (Italy). Isolations from diseased tissue consistently showed the presence of the same fungal colony. Morphology of the fungal isolates together with sequence data of the nuclear rDNA internal transcriber spacer (ITS) region, translation elongation factor 1-alpha (tef1) gene and partial beta-tubulin (tub2) gene of representatives isolates revealed the presence of the fungus Neofusicoccum parvum. Pathogenicity tests were conducted by inoculating fig cuttings with mycelial plugs. After 10 days, the inoculated plants developed cankers similar to those observed in the greenhouse and after 26 days all inoculated plants were dead. To the best of our knowledge, this is the first report worldwide of N. parvum causing disease on this host.

Download Full-text

First Report of Dieback Caused by Lasiodiplodia pseudotheobromae on Ormosia pinnata in China

Plant Disease ◽

10.1094/pdis-03-20-0647-re ◽

2020 ◽

Vol 104 (10) ◽

pp. 2551-2555

Author(s):

Luoye Li ◽

Mengying Lei ◽

Honghong Wang ◽

Xiaozhu Yang ◽

Mebeaselassie Andargie ◽

...

Keyword(s):

Elongation Factor ◽

Morphological Characteristics ◽

Type I ◽

Translation Elongation ◽

First Report ◽

Pathogenicity Tests ◽

Landscape Trees ◽

Eventual Death ◽

Internal Transcribed Spacer Rdna ◽

Translation Elongation Factor 1Α

Ormosia pinnata (Lour.) Merr. is an important tree used for landscape and plant recovery of barren slopes in China. During an investigation of plant disease on landscape trees in 2018, a dieback was observed on O. pinnata trees in Guangzhou, Guangdong Province, China. Symptoms were characterized by initial dryness of the twigs and eventual death of the whole branch of the tree. Isolations from symptomatic branches yielded 13 isolates including two main morphotypes. Pathogenicity tests showed that isolate GDOP1 from Type I caused dieback of O. pinnata. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA (ITS1-5.8S-ITS2) and partial sequence of the translation elongation factor 1α (EF1-α), the fungus causing dieback on O. pinnata was identified as Lasiodiplodia pseudotheobromae. This is the first report of L. pseudotheobromae infecting O. pinnata in the world.

Download Full-text

First report of Fusarium solani causing stem rot of Dracaena in Iran

Journal of Plant Protection Research ◽

10.1515/jppr-2016-0013 ◽

2016 ◽

Vol 56 (1) ◽

pp. 100-103 ◽

Cited By ~ 1

Author(s):

Mostafa Abedi-Tizaki ◽

Doustmorad Zafari ◽

Jamal Sadeghi

Keyword(s):

Fusarium Solani ◽

Elongation Factor ◽

Stem Rot ◽

Pathogenicity Test ◽

Translation Elongation Factor ◽

Translation Elongation ◽

First Report ◽

Brown Discoloration ◽

Elongation Factor 1 Alpha ◽

Elongation Factor 1

Abstract In July 2013, symptoms of stem rot were observed in the Dracaena sanderiana cuttings in greenhouses of Mahallat County, Markazi Province, Iran. The symptoms first appeared as severe wilting. Later, leaves became brown and necrotic. Symptoms on the cuttings were observed as rotted areas on the middle of the stems. The cortical tissues of the plants showed a distinct brown discoloration. Eventually, the infected plants died. The pathogen was isolated from Dracaena stems and identified as F. solani by a fragment of the translation elongation factor 1-alpha (EF-1α) gene. Fusarium solani was confirmed by a pathogenicity test, and the causal agent was re-isolated from infected D. sanderiana plants. To the best of our knowledge, this is the first report of stem rot caused by F. solani on the cuttings of D. sanderiana.

Download Full-text

Identification and pathogenicity of Diplodia, Neofusicoccum, Cadophora and Diaporthe species associated with cordon dieback in kiwifruit cv. Hayward in central Chile

Plant Disease ◽

10.1094/pdis-05-20-0988-re ◽

2020 ◽

Author(s):

Gonzalo A Díaz ◽

Juan Pablo Zoffoli ◽

Enrique Ferrada ◽

Mauricio A. Lolas

Keyword(s):

Elongation Factor ◽

Its Region ◽

Fruit Trees ◽

Economic Losses ◽

Translation Elongation ◽

Diplodia Seriata ◽

Neofusicoccum Parvum ◽

Central Chile ◽

Field Surveys ◽

Dieback Disease

Dieback symptoms associated with fungal trunk pathogens cause significant economic losses to kiwifruit and other woody fruit trees worldwide. This study represents the first attempt to identify and characterize the fungal trunk pathogens associated with cordon dieback disease of kiwifruit in central Chile. Field surveys were conducted throughout the main kiwifruit-growing regions in central Chile to determine the incidence and to characterize the fungal trunk pathogens associated with cordon dieback of kiwifruit cv. Hayward through morphological, molecular and pathogenicity studies. A total of 250 cordon samples were collected, and the isolations were performed on acidified potato dextrose agar (2%, APDA) plus antibiotics and Igepal. The incidence of kiwifruit cordon dieback ranged between 5 and 85% in all surveyed areas in central Chile. A total of 246 isolates were isolated and identified using culture and morphological features as belonging to three fungal taxa. Diaporthaceae spp. (Diaporthe ambigua and D. australafricana; n=133 isolates), Botryosphaeriaceae spp. (Diplodia seriata and Neofusicoccum parvum; n=89 isolates) and Ploettnerulaceae spp. (Cadophora luteo-olivacea and C. malorum; n=24 isolates) were identified using phylogenetics studies of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of the rDNA, part of the β-tubulin gene (tub2) and part of the translation elongation factor 1-α gene (tef1-α). Isolates of N. parvum and Di. seriata were the most virulent, causing internal brown lesion and dieback symptoms in attached green shoots, attached lignified canes and young inoculated kiwifruits. This report is the first to describe Di. seriata and C. luteo-olivacea associated with kiwifruit cordon dieback in Chile and presents the first description of N. parvum causing kiwifruit dieback worldwide.

Download Full-text

First Report of Fusarium Maize Ear Rot Caused by Fusarium meridionale in China

Plant Disease ◽

10.1094/pdis-01-14-0108-pdn ◽

2014 ◽

Vol 98 (8) ◽

pp. 1156-1156 ◽

Cited By ~ 4

Author(s):

H. Zhang ◽

W. Luo ◽

Y. Pan ◽

J. Xu ◽

J. S. Xu ◽

...

Keyword(s):

Fusarium Species ◽

Elongation Factor ◽

Morphological Characteristics ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Fusarium Ear Rot ◽

Ear Rot ◽

Translation Elongation Factor ◽

Translation Elongation ◽

First Report

Fusarium is an important genus of fungal pathogens that are responsible for devastating diseases, such as Fusarium ear rot on maize, which may result in yield losses and/or mycotoxin contamination. In September 2013, a survey to determine population composition of Fusarium species on maize was conducted at 22 fields in 18 counties in Gansu Province. Maize ears with clear symptoms (with a white to pink- or salmon-colored mold at the ear tip) were collected. Symptomatic seeds were surface-sterilized with 70% ethanol and 10% sodium hypochlorite and rinsed three times with sterile water to eliminate hypochlorite residues. After drying on sterile filter paper, the seeds were placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 3 days. Mycelium that was characteristic of Fusarium spp. (2) was purified by transferring single spores to fresh PDA. Fusarium species were identified by morphological characteristics (2), multilocus genotyping assay (MLGT) (3), and sequence analysis of the translation elongation factor-1α (TEF) gene. Several Fusarium species were identified and Fusarium verticillioides and F. proliferatum were the predominant species. Based on MLGT, two strains from Chenghong County were identified as F. meridionale with NIV chemotype, a species in F. graminearum species complex (FGSC). Morphological characteristics were also identical to FGSC. Colonies grew rapidly on PDA and produce relatively large amounts of dense mycelia and red pigments. Slender, thick-walled, and moderately curved or straight macroconidia were observed with 5- to 6-septate. Furthermore, conidia on SNA also showed typical characteristics of F. meridionale, as the dorsal and ventral lines were often parallel and gradually curved. Sequences comparison of the partial translation elongation factor (TEF-1α, 644 bp) gene (1) was used to validate these observations. BLASTn analysis with the FUSARIUM-ID database revealed 100% sequence identity to F. meridionale (GenBank Accession No. KJ137017). Thus, both morphological and molecular criteria supported identification of the strains as F. meridionale. A pathogenicity test was performed on Zhengdan958, the maize variety with the largest planted acreage in China. Four days after silk emergence, 2 ml conidial suspension (105 macroconidia/ml) of each isolate were injected into each of 10 maize ears through silk channel. Control plants were inoculated with sterile distilled water. Typical FER symptoms (reddish-white mold) was observed on inoculated ears and no symptoms were observed on water controls. Koch's postulates were fulfilled by re-isolating the same fungus from the infected seeds. F. meridionale was one of the pathogens causing Fusarium head blight on wheat and barley in China and produced nivalenol (4,5) and it also has been isolated from maize in Korea and Nepal. To our knowledge, this is the first report of F. meridionale causing Fusarium ear rot on maize in China. Further studies on biological characteristics such as temperature sensibility and fungicide resistance are needed to gain a better understanding of this new pathogen. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (3) T. J. Ward et al. Fungal Genet. Biol. 45:473, 2008. (4) L. Yang et al. Phytopathology 98:719, 2008. (5) H. Zhang et al. Plos one 7:e31722, 2012.

Download Full-text

First Report of Neofusicoccum parvum Associated with Dieback of Mango Trees in Peru

Plant Disease ◽

10.1094/pdis-93-4-0426b ◽

2009 ◽

Vol 93 (4) ◽

pp. 426-426 ◽

Cited By ~ 12

Author(s):

J. Javier-Alva ◽

D. Gramaje ◽

L. A. Alvarez ◽

J. Armengol

Keyword(s):

Dna Sequences ◽

Mangifera Indica ◽

Elongation Factor ◽

Tree Canopy ◽

Internal Transcribed Spacer Region ◽

Neofusicoccum Parvum ◽

First Report ◽

Early Maturation ◽

Mycelial Plug ◽

Stem Lesions

Mango (Mangifera indica L) is one of the most important cash crops of northern Peru. Since 2003, adult mango trees (cvs. Criollo and Kent) located in Piura Province developed symptoms of dieback characterized by the death of twigs and branches in the tree canopy. Additional disease symptoms involved darkened, elongated lesions on the peduncle, causing an early maturation of the fruit, and in advanced symptoms, stem-end rot of fruits. Symptoms were frequent in the spring months (September to November) when the lesions expand rapidly. Diseased tissues from branches and fruits were collected and small pieces of necrotic tissues were surface disinfected and plated onto potato dextrose agar (PDA) with 0.5 g L–1 streptomycin sulfate. Plates were incubated at 25°C in the dark. All affected tissues consistently developed colonies with a white mycelium, moderately dense, and becoming olivaceous gray after 5 to 6 days. Pycnidia were produced on sterile mango twigs placed on the surface of potato carrot agar (PCA) after 10 days. Conidia were hyaline, guttulate, aseptate, measuring (15-) 18.5 (-22.5) × (4-) 5.2 (-7.5) μm. Conidia became olivaceous and developed one or two septa before germination. Isolates were identified as Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers, & A.J.L. Phillips (1). DNA sequences of the rDNA internal transcribed spacer region (ITS) and part of the translation elongation factor 1-alpha (EF1-α) genes were used to confirm the identification through BLAST searches in GenBank (ITS: 99% identity to Accession No. EU080928; EF1-α: 98% identity to Accession No. AY343367). Representative sequences of the studied DNA regions were deposited at GenBank (ITS: Accession No. FJ528596; EF1-α: Accession No. FJ528597). Pathogenicity tests were conducted on 18-month-old potted mango plants cv. Kent with two N. parvum strains (A4 and A5). A mycelial plug (3 cm in diameter) taken from the margin of an actively growing colony of each isolate was put in a wound made with a cork borer of the same diameter on the stem of each plant. Inoculation wounds were wrapped with Parafilm. Controls were inoculated with sterile PDA plugs. Ten replicates for each isolate were used with an equal number of control plants. Plants were maintained in a greenhouse with a temperature range of 22 to 28°C. After 4 weeks, mango plants showed necrotic stem lesions originating from the inoculation point affecting also the branches of the inoculated plants. No differences in lesion area between strains were obtained. No lesions developed in the control plants. Reisolations from necrotic tissues were successful and both isolates were morphologically identical to those used for inoculations. N. parvum was isolated from all symptomatic trees in all surveyed areas. This pathogen has already been reported on mango (2) and currently represents a serious problem in the mango-producing areas of Peru. To our knowledge, this is the first report of N. parvum affecting mango in Peru. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) B. Slippers et al. Mycologia 97:99, 2005.

Download Full-text