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

Abstract

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.

Muerte descendente de Prunus sp. asociada a Armillaria spp. en huertas comerciales de Michoacán, México

“…For the phylogenetic analysis, all the sequences of Armillaria spp. isolates from Michoacan were grouped in a single consensus sequence, and sequences of isolates of 34 Armillaria species characterized worldwide were used, according to the method of Maphosa et al (2006), Hasegawa et al (2010), Ross-Davis et al (2012), Elías-Román et al (2013) and Guo et al (2016). Pleurotus ostreatus (NCBI accession number AY883432) was used as a root node outside the group.…”

“…En los últimos años, los datos moleculares, específi-camente las secuencias de ADN, se están utilizado para identificar las especies de hongos y realizar estudios filogenéticos (Cai et al, 2011;Guo et al, 2016;Koch et al, 2017). En la taxonomía contemporánea de este hongo, las comparaciones de secuencias de ADN han llevado al descubrimiento de una serie de nuevas especies que no están relacionadas con especies morfológicas (Maphosa et al, 2006), lo cual ha tenido implicaciones en la identificación de este organismo.…”

“…Aún con el desplante de árboles infectados, el micelio sobrevive como saprófito, las raíces residuales specifically DNA sequences, have been used to identify species of fungi and conduct phylogenetic studies (Cai et al, 2011;Guo et al, 2016;Koch et al, 2017). With the contemporary taxonomy of this fungus, comparing DNA sequences has led to the discovery of new species that are not related to morphological species (Maphosa et al, 2006), a fact that has had implications for identifying the fungus.…”

“…In Mexico, the fungus is distributed in the states of Baja California, Chiapas, Chihuahua, State of Mexico, Durango, Guanajuato, Guerrero, Jalisco, Michoacan, Morelos, Nuevo Leon, Oaxaca, Puebla, Queretaro, Veracruz and in forest areas of Mexico City (Valdés et al, 2004;Cibrián et al, 2007;Elías-Román et al, 2013;Klopfenstein et al, 2014;Fernández-Pavía, et al, 2015). The objective of this research was to identify and molecularly characterize the pathogen associated with dieback of peach and plum trees.…”

“…En México, este hongo se distribuye en los estados de Baja California, Chiapas, Chihuahua, Durango, Estado de México, Guanajuato, Guerrero, Jalisco, Michoacán, Morelos, Nuevo León, Oaxaca, Puebla, Querétaro, Veracruz y en áreas forestales de la Ciudad de México (Valdés et al, 2004;Cibrián et al, 2007;Elías-Román et al, 2013;Klopfenstein et al, 2014;Fernández-Pavía, et al, 2015). El objetivo de este trabajo fue la identificación y caracterización molecular del patógeno asociado a la muerte descendente de los árboles de durazno y ciruelo.…”