查看更多>>摘要：Abstract Powdery mildew on oak, caused by Erysiphe spp., has been shown to have serious ecological consequences on a range of Quercus hosts. Erysiphe alphitoides and E. quercicola are two of the most heavily studied and common powdery mildews known to occur on Quercus species. In recent years, these species have been noted throughout the world on a range of hosts within and outside the Quercus genus. Reports that E. alphitoides was absent in European herbaria before 1921 and the discovery of the holotype of E. alphitoides from 1911 in an American herbarium (FH) led to the current study in which we genetically analysed six specimens of E. alphitoides s. lat including, most importantly, the holotype of E. alphitoides from France collected in 1911. The results of our analyses revealed that: (1) The sequence of the E. alphitoides holotype falls within the E. quercicola clade, confirming that E. alphitoides did not spread to Europe until ~1921. (2) E. alphitoides var. chenii forms a monophyletic clade with E. epigena and should be reduced to synonymy with that species and (3) through sequence analyses E. alphitoides and E. quercicola are confirmed to have spread to North America. The sequencing results of the E. alphitoides holotype have severe nomenclatural‐taxonomic consequences. A proposal was submitted simultaneously with the present manuscript to conserve the name E. alphitoides so that the traditional usage of the names E. alphitoides and E. quercicola could be maintained. The sequences obtained for the current study provide new insight into the taxonomy and spread of these ecologically significant, globally distributed species. The present study highlights the importance of sequencing specimens from type material, above all when morphological similar species are involved.
查看更多>>摘要：Abstract Pine wilt disease is a devastating forest disease worldwide caused by the pinewood nematode (PWN; Bursaphelenchus xylophilus). Esteya vermicola is widely recognized as a promising bio‐control agent effective against PWN. During a survey of associated microorganisms of Pinus yunnanensis in Southwest China, a novel isolate of E. vermicola was obtained. This isolate produced two types of conidia. One type of conidia was hyaline, unicellular, bacilloid, and non‐adhesive. The second type of conidia is solitary, hyaline, unicellular asymmetric elliptic or lunate, concave inward, ending slightly apiculate, adhesive on the concave surface, and contained an ovoid endospore‐like structure. Only the lunate conidia showed infection activity against PWN. This novel isolate produced a high proportion of infective lunate conidia and exhibited high adhesion and infection activity against PWN by adhering to the nematode within 48?h and killing 74.5% of the tested PWN individuals within 4?days. Given that the isolate was obtained from P. yunnanensis, it may be well adapted to the endogenous environment of pine trees. The isolate shows potential as a bio‐control agent against a plant‐parasitic nematode in the field.
查看更多>>摘要：Abstract Eucalypts are cultivated in many regions of the world because of their amenability to intensive plantation forestry (environmental adaptability and plasticity of clones, fast growth, easiness of rooting and strong re‐sprouting after coppicing), quality of the timber for multiple uses and high economic performance. Symptomatic Eucalyptus camaldulensis trees were sampled at two sites in the Mazandaran province of Iran. Plants showed trunk bark cracking and cankers accompanied by dark‐brown watery exudation from damaged tissues. Isolation, purification along with phenotypic and genotypic characterization of isolates were performed using routine bacteriological methods. Finally, the bacterial isolates obtained from cankers on symptomatic eucalyptus plants were identified as Rahnella victoriana based on results of biochemical tests in combination with analyses of partial sequences of the 16S rRNA, gyrB,rpoB, and atpD gene regions. When representative isolates were inoculated into the stem of 1‐year‐old E. camaldulensis saplings, necrotic lesions were visible in external and internal bark tissues 30?days after inoculation. The bacteria were re‐isolated from lesions up to 2?months post‐inoculation. This is the first report of bacterial canker of Eucalyptus caused by R. victoriana in Iran and in the world.
查看更多>>摘要：Abstract In July 2017, hundreds of Ribes fasciculatum var. chinense plants were found infected with powdery mildew for the first time in Korea. Further field surveys resulted in collecting anamorphs and teleomorphs of the powdery mildew at three additional locations in Korea. Morphological characterization of the holomorph and molecular sequence analyses of the ITS regions and 28S rDNA gene confirmed the identification of this fungus as Podosphaera mors‐uvae, which is already known for a long time on Ribes spp. in Europe and North America. Previous records of P. mors‐uvae on Ribes grossularia in Japan and China are also discussed. This is the first report of P. mors‐uvae from Korea.
查看更多>>摘要：Abstract The aim of the present study was to identify the pathogen responsible for anthracnose observed in Ligustrum japonicum Thunb ‘Howardii’ in the Anqing area of China. Three representative isolates of the pathogen were collected from the leaves of infected plants at different locations, using a tissue isolation method and then identified based on colony characteristics, morphology, multi‐locus phylogenetic analysis and pathogenicity tests. All three representative isolates formed a phylogenetic clade with reference sequences of Colletotrichum siamense. This is the first study to report C.?siamense as a causative agent of anthracnose on L.?japonicum in Anqing, China.
Rodrigo HakamadaRenato Meulman Leite SilvaGabriela Gon?alves MoreiraJosé Da Silva Teixeira...
9页
查看更多>>摘要：Abstract Austropuccinia psidii Winter, causal agent of myrtle rust, is one of the main pathogens in Eucalyptus plantations in Brazil. We investigated the effects of the pathogen on wood yield and light use efficiency (LUE) in a Eucalyptus grandis x Eucalyptus urophylla clone in a field trial at the end of a five‐year rotation. The study comprised two treatments that are commonly adopted by managers. One treatment with curative fungicide spray (Triadimenol 250?g l?1) seven months after planting and another with five preventive sprays of the same fungicide, from the 1st to 7th month age of saplings. At 5?years old, the control plots attained a mean annual increment of 35?m3 ha?1?yr?1, the curative and preventive treatments were 39 and 47?m3 ha?1?yr?1 (11% and 34% higher, respectively). LUE was also higher when fungicides were applied, 8% and 26% higher in curative and preventive treatments (1.06 and 1.24?g MJ?1) compared with the control plots (0.98?g MJ?1). To confirm the negative effect of rust at a larger scale, we tracked 102 inventory plots (from 1,234?ha) from 2 to 6?years old with the same clone, half infected and half with rust corrective control. Growth difference decreased with time, from an average of 41% at age 2%–5% at age 6. These results highlight the importance of managing myrtle rust in Eucalyptus plantations by selecting a disease‐tolerant genotype or adopting other strategies for disease control.
查看更多>>摘要：Abstract Zonate leaf spot of Ailanthus altissima presumed to be associated with an Ascochyta sp. has been observed in Korea where the species is naturalized. Using microscopic examinations of 22 specimens, deposited in the Korea University herbarium since 1989, and molecular phylogenetic analyses of three monoconidial isolates, we identified the isolates as Boeremia exigua. Pathogenicity of the fungus was confirmed by fulfilling Koch's postulates. These results indicated that the previous records of Ascochyta ailanthi and Ascochyta sp. on A.?altissima should be re‐evaluated to confirm the identity of the species.
查看更多>>摘要：Abstract Species of Ceratocystis and allied genera are pathogens of many trees, including Cunninghamia lanceolata. During a survey of 2020, we found a serious wilt disease of C. lanceolata in Yunnan Province, China. Three different fungi resembling Ceratocystis and allied genera were consistently isolated from discoloured foliage and stems on C. lanceolata. Morphological and DNA sequence comparisons based on 60S and LSU gene regions showed that the pathogens were Ceratocystis and related species. We included 4 isolates identified as C. acaciivora?=?C. manginecans, 10 isolates identified as Berkeleyomyces basicola ≡ Thielaviopsis basicola, and 1 isolate identified as Chalaropsis sp., from 3 geographical locations. Pathogenicity tests on potted plants showed that all three species were pathogenic. To our knowledge, this is the first report Ceratocystis acaciivora,B. basicola and Chalaropsis sp. causing C. lanceolata wilt in China.
查看更多>>摘要：Abstract The genus Colletotrichum comprises an important and diverse group of endophytes, saprophytes and plant pathogens, many of which cause a syndrome known as anthracnose, on a wide range of hosts, mainly in tropical and subtropical regions. Since most of the accumulated research on the genus focuses on cultivated plants of commercial interest, the aim of this review was to explore how the genus has been studied in native woody plants in natural ecosystems. Following the PRISMA protocol for systematic reviews, we identified 52 original scientific publications that recorded Colletotrichum species associated with native woody hosts in natural environments in a taxonomic, ecological or phytosanitary context. Here, we conclude that research in natural ecosystems is scarce, mostly carried out in tropical areas and mainly focused on aspects of community ecology. We also observed the cosmopolitan nature of the genus, associated with many hosts, mostly as endophytes. The species most frequently recorded were in the ‘gloeosporioides’ complex, although due to the limitations in identification methods used in the studies, a large proportion of records could not be identified or verified at the species level.
NSTL
Wiley