scholarly journals First Report of the Armillaria Root-Disease Pathogen, Armillaria gallica, Associated with Several Woody Hosts in Three States of Mexico

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1280-1280 ◽  
Author(s):  
N. B. Klopfenstein ◽  
J. W. Hanna ◽  
P. G. Cannon ◽  
R. Medel-Ortiz ◽  
D. Alvarado-Rosales ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Cloud Forest ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Root Disease ◽  
Ecological Impacts ◽  
Eriobotrya Japonica ◽  
Armillaria Gallica ◽  
Armillaria Root Disease ◽  
Ecological Behavior

In September 2007, rhizomorphs with morphological characteristics of Armillaria were collected from woody hosts in forests of Mexico State, Veracruz, and Oaxaca, Mexico. Based on pairing tests, isolates were assigned to five somatically compatible genets or clones (MEX7R, MEX11R, MEX23R, MEX28R, and MEX30R). These genets were all identified as Armillaria gallica based on somatic pairing tests against known tester isolates and nucleotide sequences of the translation elongation factor 1α (tef-1α; GenBank Accession Nos. KF156772 to 76). Sequences of tef-1α for all genets showed a max identity of 97 to 99% to A. gallica (ST23, JF313125) (3,4). However, A. gallica comprises a genetically diverse complex that likely represents multiple cryptic species (3). In Mexico, this species has been previously reported in northeastern Morelos on Quercus sp., eastern Mexico State on Pinus hartwegii, and southwestern Mexico State on Prunus persica (1,2). This study identified associations with 10 new hosts within three states of Mexico, but only five hosts were diseased. Genet MEX7R comprised seven isolates collected in the University of Chapingo forest near Texcoco, Mexico State (19°18′10.764″ N, 98°42′14.147″ W, elevation 3441 m). Four MEX7R isolates were collected from diseased Alnus sp. including the root ball of a 130 cm dbh, root-disease killed tree, one isolate from a symptomless Senecio sp. s.l. (Roldana sp.) shrub and two isolates from symptomless Abies religiosa. Genet MEX11R comprised four isolates from a cloud forest near Xalapa, Veracruz (19°31′14.628″ N, 96°59′22.812″ W, elevation 1496 m). MEX11R isolates were collected from the roots of a root-disease killed Carpinus caroliniana, and from trees with no obvious symptoms (Miconia mexicana, Quercus xalapensis, and Liquidambar styraciflua). Two isolates of genet MEX23R were collected from the Jardin Botanico Francisco Javier Clavijero, Instituto de Ecologia, A.C., Xalapa, Veracruz (19°30′49.067″ N, 96°56′32.999″ W, elevation 1344 m). These isolates were from root-diseased Eriobotrya japonica (non-native fruit tree) that showed obvious symptoms (flaccid, chlorotic, and senescing leaves) and from an adjacent, infected Platanus mexicana that did not show readily observable symptoms. Two collections near Oaxaca, Oaxaca, included a single isolate MEX28R from the root ball of a recently root disease-killed Arbutus xalapensis within a small root disease center at Peña Prieta, in Parque La Cumbre, near Ixtepeji (17°09′42.084″ N, 96°38′15.936″ W, elevation 2853 m) and a single isolate MEX30R from the base of an asymptomatic Alnus acuminata near the El Carrizal fish hatchery 10 km northeast of San Miguel del Valle (17°06′45.036″ N, 96°24′03.743″ W, elevation 2594 m). Armillaria gallica has a circumpolar distribution with an extremely wide host range, and its ecological behavior varies greatly. Continued surveys are needed to better understand the distribution and ecological impacts of this pathogen in relation to Armillaria root disease in Mexico and the potential influences of climate change. Although A. gallica displays diverse ecological behavior, trees infected with A. gallica are less likely to survive the stresses of human activity and a changing climate (4). References: (1) D. Alvarado-Rosales and R. A. Blanchette. Phytopathology 84:1106, 1994. (2) R. D. Elias-Roman et al. For. Pathol. 43:390, 2013. (3) M.-S. Kim et al. Phytopathology 102:S4.63, 2012. (4) B. Marcais and N. Breda. J. Ecol. 94:1214, 2006.

scholarly journals First Report of an Armillaria Root Disease Pathogen, Armillaria gallica, Associated with Several New Hosts in Hawaii

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1503-1503 ◽  
Author(s):  
M.-S. Kim ◽  
J. W. Hanna ◽  
N. B. Klopfenstein
Keyword(s):  
Loblolly Pine ◽  
Tree Species ◽  
Forest Decline ◽  
Plant Pathogens ◽  
Root Disease ◽  
Native Forest ◽  
Monterey Pine ◽  
Armillaria Gallica ◽  
Armillaria Root Disease ◽  
Apparently Healthy

The loss and decline of native tree species caused by invasive plant pathogens is a major threat to the endangered endemic forests of the Hawaiian Islands (3). Thus, it is critical to characterize existing pathogens to evaluate potential invasiveness. In August 2005, rhizomorphs and mycelial bark fans of genet HI-4 were collected from dead/declining, mature trees of introduced Monterey pine (Pinus radiata) on the southern flank of Mauna Kea, Hawaii (approximately 19°42′55″N, 155°26′48″W, elevation 2,175 m). In March of 2008, three additional genets (HI-11, HI-13, and HI-16) were collected as rhizomorphs at a site named Pu'u La'au (west slope of the Mauna Kea Forest Reserve area, approximately 19°50′00″N, 155°35′35″W, elevation 2,275 to 2,550 m), approximately 20 km west-northwest of the HI-4 collection. These genets were collected from apparently healthy loblolly pine (Pinus taeda) that were introduced, apparently healthy māmane (Sophora chrysophylla; an endemic tree species of Hawaii), dead and dying māmane, and apparently healthy Methley plum (Prunus cerasifera × Prunus salicina) that was planted. All isolates were determined to have identical sequences in the intergenic spacer-1 rDNA region (GenBank Accession No. DQ995357). On the basis of somatic paring tests against North American Armillaria tester strains and 99% nucleotide sequence identities to GenBank Accession Nos. AY190245 and AY190246, these isolates were identified as Armillaria gallica. Past surveys have noted A. mellea sensu lato and A. nabsnona on numerous hosts in Hawaii, including māmane (3,4). However, to our knowledge, this is the first confirmed report of A. gallica in Hawaii, where it was found on māmane, Monterey pine, loblolly pine, and Methley plum. A. gallica has been widely categorized as a beneficial saprophyte, an opportunistic pathogen, or an aggressive pathogen (2). A recent study suggests that A. gallica can be highly pathogenic in some areas of the eastern United States and it is an important component of forest decline (2), especially under increasing stressors such as climate change. The isolation of A. gallica from declining stands on both introduced and endemic hosts under drought conditions suggests this pathogen is a contributing factor to forest decline on the island of Hawaii. Because the māmane tree is an important component of the native forest stands and essential to the endangered palila bird (Loxioides bailleui), which feeds almost exclusively on its green seeds (1), continued monitoring of Armillaria root disease is warranted. References: (1) P. C. Banko et al. J. Chem. Ecol. 28:1393, 2002. (2) N. J. Brazee and R. L. Wick. For. Ecol. Manage. 258:1605, 2009. (3) R. E. Burgan and R. E. Nelson. USDA For. Serv. Tech. Rep. PSW-3, 1972. (4) J. W. Hanna et al. Plant Dis. 91:634, 2007.

scholarly journals First Report of Armillaria Root Disease Pathogen, Armillaria gallica, on Rhododendron and Quercus rubra in Georgia, USA

Plant Disease ◽  
2020 ◽  
Author(s):  
John W. Hanna ◽  
Ned B. Klopfenstein ◽  
Michelle M. Cram ◽  
Rabiu O. Olatinwo ◽  
Stephen W Fraedrich ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Quercus Rubra ◽  
The State ◽  
Root Disease ◽  
Malt Extract ◽  
Southeastern Usa ◽  
First Report ◽  
Botanical Gardens ◽  
Armillaria Gallica ◽  
Armillaria Root Disease

Armillaria root and butt diseases, which are a global issue, can be influenced by changing environmental conditions. Armillaria gallica is a well-known pathogen of diverse trees worldwide (Brazee and Wick 2009). Besides A. gallica causing root rot of Hemerocallis sp. and Cornus sp. in South Carolina (Schnabel et al. 2005), little is reported on the distribution and host range of A. gallica in the southeastern USA. In July 2017, three Armillaria isolates were obtained from two naturally occurring hosts in Georgia, USA and cultured on malt extract medium (3% malt extract, 3% dextrose, 1% peptone, and 1.5% agar). One isolate (GA3) was obtained in Unicoi State Park near Helen, Georgia (Lat. 34.712275, Long. -83.727765, elev. 498 m) from the basal portion of Rhododendron sp. with extensive root/butt decay, but no crown symptoms were evident (Supplementary Figure 1). GA4 and GA5 (Lat. 33.902433, Long. -83.382453, elev. 215 m) were isolated from wind-felled Quercus rubra (red oak) with root disease at the State Botanical Gardens in Athens, Georgia. GA4 was associated with a large root ball (ca. 4-m diameter) (Supplementary Figure 2), and GA5 was obtained from a mature tree with infected roots, with characteristic spongy rot of Armillaria root disease. Crown symptoms could not be evaluated because the crowns had been removed before the collections. Several other oaks with Armillaria root disease were noted throughout the State Botanical Gardens. Pairing tests reduced these three isolates (whiteish mycelia with a dark, brownish crust and rhizomorphs), to two genets with GA4 = GA5. Both genets (GA3 and GA4) were identified as A. gallica using translation elongation factor 1α (tef1) sequences (Genbank Nos. MT761697 and MT761698, respectively) that showed ≥ 97% identity (≥ 98% coverage) with A. gallica sequences (KF156772, KF156775). Also, nine replications of somatic pairing tests showed 33 – 67% compatibility with A. gallica (occurs in southeastern USA), compared with 0 – 22% for A. mexicana, A. mellea (occurs in southeastern USA), A. solidipes, and Desarmillaria tabescens (occurs in southeastern USA). To our knowledge, this note represents the first report of A. gallica on Rhododendron and Q. rubra in Georgia, USA, which has experienced severe drought in recent decades (e.g., Park Williams et al. 2017) that could predispose trees to Armillaria infection (e.g., Wargo 1996). Quercus rubra was previously reported as a host of A. gallica in Arkansas (Kelley et al. 2009) and Massachusetts (Brazee and Wick 2009), USA. In Missouri, USA, A. gallica has been reported as a weak pathogen with potential biological control against A. mellea (Bruhn et al. 2000). Other reports from several regions on various hosts suggest pathogenicity of A. gallica is associated with changing climate (Nelson et al. 2013, Kim et al. 2017, Kubiak et al. 2017). Wide genetic variation and/or cryptic speciation within A. gallica may account for differences in ecological behavior (Klopfenstein et al. 2017), but this is difficult to evaluate because Armillaria pathogenicity tests cannot be used on most forest tree seedlings. This study suggests that A. gallica is more widespread than previously known and its adverse impacts on woody plants may intensify over time, depending on the environmental conditions. Further studies are needed to determine environmental influences on A. gallica, the full distribution of A. gallica, and its effects in forests of the southeastern USA.

scholarly journals Screening Almond Rootstocks for Sources of Resistance to Armillaria Root Disease

HortScience ◽  
2018 ◽  
Vol 53 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Kendra Baumgartner ◽  
Phillip Fujiyoshi ◽  
Craig Ledbetter ◽  
Roger Duncan ◽  
Daniel A. Kluepfel
Keyword(s):  
Culture Medium ◽  
Prunus Persica ◽  
Abiotic Factors ◽  
Prunus Dulcis ◽  
Root Disease ◽  
Growth Chamber ◽  
Sources Of Resistance ◽  
Horticultural Crops ◽  
Armillaria Root Disease

Prunus dulcis (almond) is one of the most susceptible horticultural crops to Armillaria root disease. Resistance to Armillaria mellea and Armillaria tabescens, the geographically isolated causal fungi that attack almond and closely related Prunus persica (peach), has been evaluated in studies of almond, peach, and other Prunus rootstocks, but not in one comprehensive study. We evaluated the relative resistance to A. mellea and A. tabescens of six clonally propagated almond and peach rootstocks (Bright’s 5, Empyrean 1, Hansen 536, Krymsk 1, Krymsk 86, and Lovell) in comparison with that of clonally propagated Marianna 2624 rootstock (resistant control) and clonally propagated Nemaguard rootstock (susceptible control). Replicate clones used in the growth chamber assay were micropropagated and rooted in vitro before inoculating the culture medium with Armillaria spp. At 2 months, the most resistant and susceptible rootstocks were Krymsk 86 and Hansen 536, respectively, with 27% vs. 89% mortality. This finding was consistent among two isolates of A. mellea and one isolate of A. tabescens in three replicate experiments. Our finding of low mortality among Krymsk 86, Krymsk 1, and Marianna 2624, which all share Prunus cerasifera (Myrobalan plum) parentage, is consistent with past reports of resistance in the field to A. mellea, but conflicts with reports of susceptibility to A. tabescens. Resistance to A. tabescens of genotypes with Myrobalan plum parentage in our assay may reflect the simplified rooting environment of tissue culture medium, which does not perfectly mimic a field trial, in which biotic and abiotic factors may affect host resistance. Nonetheless, our growth chamber assay may provide a more rapid alternative to identify sources of resistance for breeding and to screen progeny of such crosses.

scholarly journals Identification of Lasiodiplodia pseudotheobromae Causing Fruit Rot of Citrus in China

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Jianghua Chen ◽  
Zihang Zhu ◽  
Yanping Fu ◽  
Jiasen Cheng ◽  
Jiatao Xie ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Citrus Fruit ◽  
Economic Loss ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Citrus Reticulata ◽  
Postharvest Diseases ◽  
Citrus Reticulata Blanco

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China.

scholarly journals New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María del Carmen H. Rodríguez ◽  
Harry C. Evans ◽  
Lucas M. de Abreu ◽  
Davi M. de Macedo ◽  
Miraine K. Ndacnou ◽  
...  
Keyword(s):  
New Species ◽  
Cloud Forest ◽  
Elongation Factor ◽  
Classical Biological Control ◽  
Hemileia Vastatrix ◽  
Translation Elongation ◽  
Coffee Leaf Rust ◽  
Novel Taxa ◽  
Coffee Plants ◽  
Wild Coffee

AbstractA survey for species of the genus Trichoderma occurring as endophytes of Coffea, and as mycoparasites of coffee rusts (Hemileia), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of Trichoderma were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (tef1), rpb2 and cal for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of Trichoderma species endophytic in both wild and cultivated Coffea, and mycoparasitic on Hemileia rusts. Sixteen species were delimited, including four novel taxa which are described herein: T. botryosum, T. caeruloviride, T. lentissimum and T. pseudopyramidale. Two of these new species, T. botryosum and T. pseudopyramidale, constituted over 60% of the total isolations, predominantly from wild C. arabica in Ethiopian cloud forest. In sharp contrast, not a single isolate of Trichoderma was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘Trichoderma void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African Trichoderma isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from Hemileia vastatrix, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.

scholarly journals A review ethnopharmacology of Rosaceae fruit species

2020 ◽  
Vol 9 (10) ◽  
pp. e3409108596
Author(s):  
Letícia Barela Barbosa ◽  
Camila Palma Nunes ◽  
Joice Karina Otênio ◽  
Rosselyn Gimenes Baisch ◽  
Heris Lorenzi dos Santos Perfeito ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Eriobotrya Japonica ◽  
Fragaria Vesca ◽  
Scientific Journals ◽  
Prunus Domestica ◽  
Scientific Investigations ◽  
Fruit Species ◽  
Rosaceae Species ◽  
Effective Use ◽  
Phytochemical Studies

This study aims to carry out a bibliographic survey on ethnobotanical, ethnopharmacological and pharmacological information on Rosaceae species. The species addressed were Eriobotrya japonica (yellow-plum), Fragaria vesca (strawberry), Malus domestica (apple), Prunus domestica (plum), Prunus persica (peach), Pyrus communis (pear) and Rubus brasiliensis (raspberry) grown in the garden Medicinal of Universidade Paranaense (UNIPAR) - Campus 2. For this study, the databases were taken from national and international scientific journals without restriction of year of publication. As a result, a category of use was identified, part used, form of preparation, popular use, pharmacological and phytochemical studies for each species. Thus, it is observed that all fruit species are popularly used a medicinal, with records of ethnopharmacological, pharmacological and phytochemical studies. Medicinal plants are very widespread and used, being considered as an important therapeutic resource. However, despite the pharmacological records found, new scientific investigations are still needed to ensure the safer and more effective use of these species by the population.

scholarly journals First report of Diaporthe ueckerae causing stem canker on soybean (Glycine max L.) in Colombia

Plant Disease ◽  
2021 ◽  
Author(s):  
Nathali López-Cardona ◽  
YUDY ALEJANDRA GUEVARA ◽  
Lederson Gañán-Betancur ◽  
Carol Viviana Amaya Gomez
Keyword(s):  
Management Strategies ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Aerial Mycelium ◽  
Stem Canker ◽  
Growth Stages ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Glycine Max L ◽  
Soybean Plants

In October 2018, soybean plants displaying elongated black to reddish-brown lesions on stems were observed in a field planted to the cv. BRS Serena in the locality of Puerto López (Meta, Colombia), with 20% incidence of diseased plants. Symptomatic stems were collected from five plants, and small pieces (∼5 mm2) were surface sterilized, plated on potato dextrose agar (PDA) and incubated for 2 weeks at 25°C in darkness. Three fungal isolates with similar morphology were obtained, i.e., by subculturing single hyphal tips, and their colonies on PDA were grayish-white, fluffy, with aerial mycelium, dark colored substrate mycelium, and produced circular black stroma. Pycnidia were globose, black, occurred as clusters, embedded in tissue, erumpent at maturity, with an elongated neck, and often had yellowish conidial cirrus extruding from the ostiole. Alpha conidia were observed for all isolates after 30 days growth on sterile soybean stem pieces (5 cm) on water agar, under 25ºC and 12 h light/12h darkness photoperiod. Alpha conidia (n = 50) measured 6.0 – 7.0 µm (6.4 ± 0.4 µm) × 2.0 – 3.0 µm (2.5± 0.4 µm), were aseptate, hyaline, smooth, ellipsoidal, often biguttulate, with subtruncate base. Beta conidia were not observed. Observed morphological characteristics of these isolates were similar to those reported in Diaporthe spp. by Udayanga et al. (2015). DNA from each fungal isolate was used to sequence the internal transcribed spacer region (ITS), and the translation elongation factor 1-α (TEF1) gene, using the primer pairs ITS5/ITS4 (White et al. 1990) and EF1-728F/EF1- 986R (Carbone & Kohn, 1999), respectively. Results from an NCBI-BLASTn, revealed that the ITS sequences of the three isolates (GenBank accessions MW566593 to MW566595) had 98% (581/584 bp) identity with D. miriciae strain BRIP 54736j (NR_147535.1), whereas the TEF1 sequences (GenBank accessions MW597410 to MW597412) had 97 to 100% (330-339/339 bp) identity with D. ueckerae strain FAU656 (KJ590747). The species Diaporthe miriciae R.G. Shivas, S.M. Thomps. & Y.P. Tan, and Diaporthe ueckerae Udayanga & Castl. are synonymous, with the latter taking the nomenclature priority (Gao et al. 2016). According to a multilocus phylogenetic analysis, by maximum likelihood, the three isolates clustered together in a clade with reference type strains of D. ueckerae (Udayanga et al. 2015). Soybean plants cv. BRS Serena (growth stages V3 to V4) were used to verify the pathogenicity of each isolate using a toothpick inoculation method (Mena et al. 2020). A single toothpick colonized by D. ueckerae was inserted directly into the stem of each plant (10 plants per isolate) approximately 1 cm below the first trifoliate node. Noncolonized sterile toothpicks, inserted in 10 soybean plants served as the non-inoculated control. Plants were arbitrarily distributed inside a glasshouse, and incubated at high relative humidity (>90% HR). After 15 days, inoculated plants showed elongated reddish-brown necrosis at the inoculated sites, that were similar to symptoms observed in the field. Non-inoculated control plants were asymptomatic. Fungal cultures recovered from symptomatic stems were morphologically identical to the original isolates. This is the first report of soybean stem canker caused by D. ueckerae in Colombia. Due to the economic importance of this disease elsewhere (Backman et al. 1985; Mena et al. 2020), further research on disease management strategies to mitigate potential crop losses is warranted.

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