C. A. Pérez

Endophytic and canker-associated Botryosphaeriaceae occurring on non-native Eucalyptus and native Myrtaceae trees in Uruguay

Species of the Botryosphaeriaceae are important pathogens causing cankers and die-back on many woody plants. In Uruguay, Neofusicoccum eucalyptorum, N. ribis and B. dothidea have previously been associated with stem cankers on plantation-grown Eucalyptus globulus. However, very little is known regarding the occurrence and species diversity of Botryosphaeriaceae in native Myrtaceae forests or what their relationship is to those species infecting Eucalyptus in plantations. The objectives of this study were to identify the Botryosphaeriaceae species present as endophytes or associated with cankers in both introduced and native tree hosts in Uruguay, and to test the pathogenicity of selected isolates obtained from native trees on Eucalyptus. Symptomatic and asymptomatic material was collected countrywide from Eucalyptus plantations and native Myrtaceae trees. Single spore cultures were identified based on conidial morphology and comparisons of DNA sequences of the ITS and EF1-α regions. Six Botryosphaeriaceae species were identified. Botryosphaeria dothidea, N. eucalyptorum and specimens residing in the N. parvum-N. ribis complex were isolated from both introduced Eucalyptus and native Myrtaceae trees, whereas Lasiodiplodia pseudotheobromae was found only on Myrcianthes pungens. Diplodia pseudoseriata sp. nov. and Spencermartinsia uruguayensis sp. nov. are novel species found only on native myrtaceous hosts. Pathogenicity tests showed that isolates obtained from native trees and identified as L. pseudotheobromae, N. eucalyptorum and the N. parvum-N.ribis complex are pathogenic to E. grandis. Interestingly, Lasiodiplodia pseudotheobromae has not previously been found on Eucalyptus in Uruguay and represents a potential threat to this host.

Fungal Planet description sheets: 154–213

Novel species of microfungi described in the present study include the following from South Africa: Camarosporium aloes, Phaeococcomyces aloes and Phoma aloes from Aloe, C. psoraleae, Diaporthe psoraleae and D. psoraleae-pinnatae from Psoralea, Colletotrichum euphorbiae from Euphorbia, Coniothyrium prosopidis and Peyronellaea prosopidis from Prosopis, Diaporthe cassines from Cassine, D. diospyricola from Diospyros, Diaporthe maytenicola from Maytenus, Harknessia proteae from Protea, Neofusicoccum ursorum and N. cryptoaustrale from Eucalyptus, Ochrocladosporium adansoniae from Adansonia, Pilidium pseudoconcavum from Greyia radlkoferi, Stagonospora pseudopaludosa from Phragmites and Toxicocladosporium ficiniae from Ficinia. Several species were also described from Thailand, namely: Chaetopsina pini and C. pinicola from Pinus spp., Myrmecridium thailandicum from reed litter, Passalora pseudotithoniae from Tithonia, Pallidocercospora ventilago from Ventilago, Pyricularia bothriochloae from Bothriochloa and Sphaerulina rhododendricola from Rhododendron. Novelties from Spain include Cladophialophora multiseptata, Knufia tsunedae and Pleuroascus rectipilus from soil and Cyphellophora catalaunica from river sediments. Species from the USA include Bipolaris drechsleri from Microstegium, Calonectria blephiliae from Blephilia, Kellermania macrospora (epitype) and K. pseudoyuccigena from Yucca. Three new species are described from Mexico, namely Neophaeosphaeria agaves and K. agaves from Agave and Phytophthora ipomoeae from Ipomoea. Other African species include Calonectria mossambicensis from Eucalyptus (Mozambique), Harzia cameroonensis from an unknown creeper (Cameroon), Mastigosporella anisophylleae from Anisophyllea (Zambia) and Teratosphaeria terminaliae from Terminalia (Zimbabwe). Species from Europe include Auxarthron longisporum from forest soil (Portugal), Discosia pseudoartocreas from Tilia (Austria), Paraconiothyrium polonense and P. lycopodinum from Lycopodium (Poland) and Stachybotrys oleronensis from Iris (France). Two species of Chrysosporium are described from Antarctica, namely C. magnasporum and C. oceanitesii. Finally, Licea xanthospora is described from Australia, Hypochnicium huinayensis from Chile and Custingophora blanchettei from Uruguay. Novel genera of Ascomycetes include Neomycosphaerella from Pseudopentameris macrantha (South Africa), and Paramycosphaerella from Brachystegia sp. (Zimbabwe). Novel hyphomycete genera include Pseudocatenomycopsis from Rothmannia (Zambia), Neopseudocercospora from Terminalia (Zambia) and Neodeightoniella from Phragmites (South Africa), while Dimorphiopsis from Brachystegia (Zambia) represents a novel coelomycetous genus. Furthermore, Alanphillipsia is introduced as a new genus in the Botryosphaeriaceae with four species, A. aloes, A. aloeigena and A. aloetica from Aloe spp. and A. euphorbiae from Euphorbia sp. (South Africa). A new combination is also proposed for Brachysporium torulosum (Deightoniella black tip of banana) as Corynespora torulosa. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Fungal Planet description sheets: 214-280

Novel species of microfungi described in the present study include the following from South Africa: Cercosporella dolichandrae from Dolichandra unguiscati, Seiridium podocarpi from Podocarpus latifolius, Pseudocercospora parapseudarthriae from Pseudarthria hookeri, Neodevriesia coryneliae from Corynelia uberata on leaves of Afrocarpus falcatus, Ramichloridium eucleae from Euclea undulata and Stachybotrys aloeticola from Aloe sp. (South Africa), as novel member of the Stachybotriaceae fam. nov. Several species were also described from Zambia, and these include Chaetomella zambiensis on unknown Fabaceae, Schizoparme pseudogranati from Terminalia stuhlmannii, Diaporthe isoberliniae from Isoberlinia angolensis, Peyronellaea combreti from Combretum mossambiciensis, Zasmidium rothmanniae and Phaeococcomyces rothmanniae from Rothmannia engleriana, Diaporthe vangueriae from Vangueria infausta and Diaporthe parapterocarpi from Pterocarpus brenanii. Novel species from the Netherlands include: Stagonospora trichophoricola, Keissleriella trichophoricola and Dinemasporium trichophoricola from Trichophorum cespitosum, Phaeosphaeria poae, Keissleriella poagena, Phaeosphaeria poagena, Parastagonospora poagena and Pyrenochaetopsis poae from Poa sp., Septoriella oudemansii from Phragmites australis and Dendryphion europaeum from Hedera helix (Germany) and Heracleum sphondylium (the Netherlands). Novel species from Australia include: Anungitea eucalyptorum from Eucalyptus leaf litter, Beltraniopsis neolitseae and Acrodontium neolitseae from Neolitsea australiensis, Beltraniella endiandrae from Endiandra introrsa, Phaeophleospora parsoniae from Parsonia straminea, Penicillifer martinii from Cynodon dactylon, Ochroconis macrozamiae from Macrozamia leaf litter, Triposporium cycadicola, Circinotrichum cycadis, Cladosporium cycadicola and Acrocalymma cycadis from Cycas spp. Furthermore, Vermiculariopsiella dichapetali is described from Dichapetalum rhodesicum (Botswana), Ophiognomonia acadiensis from Picea rubens (Canada), Setophoma vernoniae from Vernonia polyanthes and Penicillium restingae from soil (Brazil), Pseudolachnella guaviyunis from Myrcianthes pungens (Uruguay) and Pseudocercospora neriicola from Nerium oleander (Italy). Novelties from Spain include: Dendryphiella eucalyptorum from Eucalyptus globulus, Conioscypha minutispora from dead wood, Diplogelasinospora moalensis and Pseudoneurospora canariensis from soil and Inocybe lanatopurpurea from reforested woodland of Pinus spp. Novelties from France include: Kellermania triseptata from Agave angustifolia, Zetiasplozna acaciae from Acacia melanoxylon, Pyrenochaeta pinicola from Pinus sp. and Pseudonectria rusci from Ruscus aculeatus. New species from China include: Dematiocladium celtidicola from Celtis bungeana, Beltrania pseudorhombica, Chaetopsina beijingensis and Toxicocladosporium pini from Pinus spp. and Setophaeosphaeria badalingensis from Hemerocallis fulva. Novel genera of Ascomycetes include Alfaria from Cyperus esculentus (Spain), Rinaldiella from a contaminated human lesion (Georgia), Hyalocladosporiella from Tectona grandis (Brazil), Pseudoacremonium from Saccharum spontaneum and Melnikomyces from leaf litter (Vietnam), Annellosympodiella from Juniperus procera (Ethiopia), Neoceratosperma from Eucalyptus leaves (Thailand), Ramopenidiella from Cycas calcicola (Australia), Cephalotrichiella from air in the Netherlands, Neocamarosporium from Mesembryanthemum sp. and Acervuloseptoria from Ziziphus mucronata (South Africa) and Setophaeosphaeria from Hemerocallis fulva (China). Several novel combinations are also introduced, namely for Phaeosphaeria setosa as Setophaeosphaeria setosa, Phoma heteroderae as Peyronellaea heteroderae and Phyllosticta maydis as Peyronellaea maydis. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Teratosphaeria (Mycosphaerella) nubilosa, the causal agent of Mycosphaerella leaf disease (MLD), recently introduced into Uruguay

Mycosphaerella leaf disease on Eucalyptus is well known in Uruguay but none of the more serious Mycosphaerella spp. and Teratosphaeria spp. causing this disease have yet been found. In the autumn of 2007, more severe defoliation than has been known in the past and associated with symptoms resembling Mycosphaerella infections was observed on Eucalyptus globulus. Isolations and identifications based on morphology and DNA sequence comparisons showed that the causal agent of the defoliation is the well known and serious pathogen Teratosphaeria nubilosa (=Mycosphaerella nubilosa). This is the first record of the pathogen in South America. Using ten microsatellite loci previously developed for T. nubilosa, only one multilocus haplotype was found from 46 T. nubilosa collected isolates. Interestingly, this haplotype was the same as one previously found in Portugal and Spain. The results suggest that T. nubilosa has recently been introduced into Uruguay and that it most likely originated from the Iberian Peninsula where E. globulus is widely planted.

Puccinia psidii infecting cultivated Eucalyptus and native myrtaceae in Uruguay

Eucalyptus or guava rust caused by Puccinia psidii is a serious disease of Eucalyptus and other Myrtaceae. In Uruguay, it has been previously found on Eucalyptus globulus and Psidium brasiliensis. Almost nothing is known regarding the occurrence of this pathogen on other Eucalyptus species or native Myrtaceae in that country. In this study, we determined the presence of P. psidii on Eucalyptus species and native Myrtaceae trees in Uruguay and evaluated the pathogenicity of specimens from native myrtaceous hosts on E. globulus and E. grandis. Phylogenetic analyses based on the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA operon were used to confirm pathogen identity. Comparisons of ITS sequences confirmed the identity of P. psidii on Eucalyptus globulus, E. grandis, Myrcianthes pungens, and Myrrhinium atropurpureum var. octandrum. This is the first report of P. psidii on M. atropurpureum var. octandrum. Pathogenicity tests showed that isolates from native Myrtaceae could infect both Eucalyptus species tested, indicating a strong biological relationship between both introduced and native Myrtaceae. This study supplies relevant field data, morphological information, molecular phylogenetic analyses and infection studies that contribute to a better understanding of an important and little studied pathogen.

Species of Mycosphaerellaceae and Teratosphaeriaceae on native Myrtaceae in Uruguay: evidence of fungal host jumps

Mycosphaerella species are well-known causal agents of leaf diseases on many economically and ecologically important plant species. In Uruguay, a relatively large number of Mycosphaerellaceae and Teratosphaeriaceae are found on Eucalyptus, but nothing is known of these fungi on native Myrtaceae. The aim of this study was to identify Mycosphaerellaceae and Teratosphaeriaceae species associated with leaf diseases on native Myrtaceae in Uruguay and to consider whether host jumps by the pathogen from introduced Eucalyptus to native Myrtaceae have occurred. Several native forests throughout the country were surveyed with special attention given to those located close to Eucalyptus plantations. Five species belonging to the Mycosphaerellaceae and Teratosphaeriaceae clades were found on native Myrtaceous trees and three of these had previously been reported on Eucalyptus in Uruguay. Those occurring both on Eucalyptus and native Myrtaceae included Pallidocercospora heimii, Pseudocercospora norchiensis, and Teratosphaeria aurantia. In addition, Mycosphaerella yunnanensis, a species known to occur on Eucalyptus but not previously recorded in Uruguay, was found on leaves of two native Myrtaceous hosts. Because most of these species occur on Eucalyptus in countries other than Uruguay, it appears that they were introduced in this country and have adapted to be able to infect native Myrtaceae. These apparent host jumps have the potential to result in serious disease problems and they should be carefully monitored.

Discovery of the eucalypt pathogen Quambalaria eucalypti infecting a non-Eucalyptus host in Uruguay

Quambalaria eucalypti, a serious pathogen of Eucalyptus, is believed to be native to Australia and introduced into various southern hemisphere countries, including Uruguay. In this study we record the discovery of Q. eucalypti causing leaf lesions on Myrceugenia glaucescens, a tree native to Uruguay. The identity of the pathogen was confirmed using DNA sequence comparisons of the internal transcribed spacer (ITS) region of the rDNA operon, as well as morphological characteristics. This is the first record of the pathogen on a host other than Eucalyptus. It clearly indicates a disturbing example of an alien invasive pathogen having undergone a host-shift from non-native Eucalyptus to a native tree in Uruguay.

Genome-Wide Association Mapping Identifies Disease-Resistance QTLs in Barley Germplasm from Latin America

Diseases are the main problem for barley in Latin America. Spot blotch (caused by Cochliobolus sativus), stripe rust (caused by Puccinia striiformis f. sp. hordei), and leaf rust (caused by Puccinia hordei) are three of the most important diseases that attack the crop in the region. Chemical control of those diseases is both economically and environmentally inappropriate, making the development of durable resistant varieties a priority for breeding programs. However, the availability of new resistance sources is a limiting factor. The objective of this work was to detect genomic regions associated to durable resistance to spot blotch, stripe rust, and leaf rust in Latin American germplasm. Associations between disease severities measured in several environments across the Americas and 1,536 SNPs (belonging to the barley OPA1) in a population of 360 genotypes were used to identify genomic regions associated with disease. Several models for association mapping with mixed models were compared. These models considered either the structure of the population (Q) through PCA analysis, the identity by descent through coancestry information (K), or both. Results show significant marker-trait associations for spot blotch and leaf and stripe rust. Associations are environment specific.

Root Nodule and Rhizosphere Bacteria for Forage Legume Growth Promotion and Disease Management

Forage legumes are essential for an efficient animal-based agriculture. This chapter describes microbial-based strategies for improving legume establishment. It focuses on the use of root nodule bacteria for growth promotion and rhizosphere pseudomonads for disease management. The technological system for biological nitrogen fixation deployed in Uruguay is discussed as a model. We analyze the significance of the characterization of rhizobial strains, selection and culture collection, as well as inoculant production and quality control. Knowledge of the biodiversity of introduced and local populations of rhizobia is discussed for the design of successful inoculation strategies. On the other hand, the exploitation of the highly diverse genus Pseudomonas is considered for the biological control of Pythium seedling diseases. By testing large local collections of fluorescent Pseudomonas, strains can be selected with enhanced disease-suppressing and plant growth-promoting abilities to develop bacterial inoculants. The ecology of forage legume microbes is recognized as a key tool for developing sustainable agricultural systems.

Enfermedades bacterianas de eucaliptos: Estado actual del conocimiento

En los ultimos anos se ha observado un aumento sustantivo de las problematicas sanitarias en las plantaciones de Eucalyptus spp. (eucalipto) Diversas enfermedades afectan actualmente a este cultivo, predominando aquellas causadas por hongos. Sin embargo, las enfermedades de origen bacteriano han aumentado su importancia a nivel mundial. Las bacterias fitopatogenas en eucalipto pueden causar: i) manchas foliares, ii) tizon apical y iii) marchitamiento vascular. En el mundo, las manchas foliares bacterianas han sido asociadas a los generos Xanthomonas, Pseudomonas, Erwinia, Pantoea y Rhizobiaceae, siendo Xanthomonas axonopodis la especie predominante. El tizon bacteriano puede ser causado por distintas especies bacterianas, Erwinia psidii, Pantoea ananatis, Enterobacter cowanii, Xanthomonas campestris y X. vasicola. Mientras que el marchitamiento vascular ha sido asociado a Ralstonia solanacearum y Erwinia psidii. Estas enfermedades representan un potencial riesgo para la produccion forestal, ya que han sido reportadas en diversas zonas climaticas del mundo ocasionando graves perdidas economicas, tanto en vivero como en campo, pudiendo afectar un amplio rango de hospederos dentro del genero Eucalyptus, como tambien algunas especies del genero Psidium. Sumado a esto, las bacterias se diseminan con facilidad dificultando su control, por lo que la principal medida de manejo es la utilizacion de germoplasma con mejor comportamiento sanitario