scholarly journals Molecular Identification of a Sexual Interloper: The Pear Pathogen, Venturia pirina, has Sex on Apple

2001 ◽  
Vol 91 (7) ◽  
pp. 633-641 ◽  
Author(s):  
Christiane Stehmann ◽  
Shaun Pennycook ◽  
Kim M. Plummer

Venturia pirina (the pear scab pathogen) and V. inaequalis (the apple scab pathogen) were detected as ascospores discharged from apple leaf litter in New Zealand (spring 1998). Pseudothecia of both species were located on dead apple leaves; however, only those of V. inaequalis were associated with scab lesions. V. pirina was identified by rDNA sequence analyses, because morphological characters could not distinguish this fungus from V. asperata (a rare saprophyte on apple) and other Venturia spp. pathogenic on rosaceous fruit trees. Species-specific polymerase chain reaction primers designed to the 18S end of the internal transcribed spacer 1 region differentiated Venturia fruit tree pathogens reliably. V. pirina field isolates were pathogenic on pear, but only weak saprophytes on apple. In rare instances, when appressoria of V. pirina appeared to penetrate the cuticle of apple leaves, epidermal cells responded with a localized hypersensitive response (HR). To our knowledge, this is the first report of induction of HR-like events by V. pirina on its nonhost, apple, and also the first record of sexual reproduction of V. pirina on apple. It is assumed that V. pirina pseudothecia formed from saprophytic lesions in senescing apple leaves when active defense mechanisms such as HR were no longer induced.

Zootaxa ◽  
2015 ◽  
Vol 3919 (1) ◽  
pp. 192
Author(s):  
M. VALOIS ◽  
F. SILVA

Golinca trevisani Valois & Silva, new species (Coleoptera: Scarabaeidae: Cetoniinae: Trichiini: Incina) from Ouro Preto do Oeste, Rondônia, and Amazonas, Brazil is described, representing the first record of the genus Golinca for Brazil. Diagnosis, illustrations of key morphological characters, the first male genitalia description in the genus, and a key for identification of four species of Golinca are provided. 


Author(s):  
A. Sivanesan

Abstract A description is provided for Venturia pirina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Principally on pear (Pyrus communis) and other Pyrus spp., also recorded from Eriobotrya japonica (loquat) (Herb. IMI). DISEASE: Causes scab or black spot of pear, which results in loss of quantity and quality of fruit. The disease attacks shoots, buds, leaves and fruit, symptoms and aetiology being very similar to those of apple scab caused by V. inaequalis on Malus spp. (CMI Descript. 401). Dark, more or less circular scabs are produced on leaves and fruit, often with some growth distortion. Infection of young wood is more common than with apple scab and causes pale brown blister-like lesions which burst to release conidia in the following year. GEOGRAPHICAL DISTRIBUTION: Worldwide in temperate and subtropical regions wherever pears are grown (see CMI Map 367, ed. 2, 1968). TRANSMISSION: Epidemiology is similar to that of apple scab. The overwintering saprophytic perithecial stage on leaf litter releases airborne ascospores in spring which infect young growth, and secondary infection by conidia dispersed during wet summer weather also occurs. Overwintering lesions on young wood are more frequent than with apple scab and conidia produced by these in the spring can be an important source of primary infection (46, 2061; 47, 849).


Zootaxa ◽  
2018 ◽  
Vol 4527 (1) ◽  
pp. 75
Author(s):  
LUCIANA MARTINS

The genus Thyonella currently comprises four species which occur in the Atlantic and Pacific Oceans. Thyonella mexicana is the only species known to occur in the Pacific Ocean. The main morphological characters used to distinguish Thyonella species are their dermal ossicles. Since the differences among these characters are subtle, this contribution provides a detailed description and comparison of the ossicle assemblage of the concerned taxa. In addition, description of the internal morphology of three of the concerned species is also provided. Further, this study reports on the first record of Thyonella sabanillaensis for the Southwestern Atlantic. A worldwide revision of the distributional records of Thyonella species is presented and their taxonomy is discussed, concluding that some traditional taxonomic characters should be used cautiously. A brief discussion about the importance of SEM analysis is also provided. 


2021 ◽  
Vol 32 (2) ◽  
pp. 293-301
Author(s):  
MD JAYEDUL ISLAM ◽  
SHARMIN AKTER ◽  
PROVAKOR SARKAR ◽  
MOHAMMAD RASHED ◽  
IREEN PARVIN ◽  
...  

A new record of Plectropomus pessuliferus (Serranidae: Epinephelinae) wasdocumented based on morphological characters and DNA barcoding. The species was collectedduring a regular survey for making an inventory of reef associated fishes in Saint Martin`sIsland, Bangladesh. This is the first report of roving coral grouper from the marine waters ofBangladesh validated by morpho-meristic analysis and DNA barcoding. This is also the firstreport from the northern Bay of Bengal.


Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1055-1055 ◽  
Author(s):  
R. Metzger ◽  
L. Belbahri ◽  
G. Calmin ◽  
N. Badin ◽  
F. Lefort

Old cultivars of roses (Rosa spp.) established on Rosa canina as rootstock are grown in field collections in the repository at Gaillard in eastern France, close to the Swiss border. During June 2005 and July 2006, several rose plants in full vegetation were severely wilted, leading ultimately to plant death. Necrotic lesions were present on the roots, and marginal tissue was excised and incubated in the dark at 20°C on PARP V8 agar plates (1). Similar isolates were obtained in both years, which were inoculated within 4 days on V8 agar medium and incubated at 25°C. The pathogen colonies grew approximately 30 mm daily on V8 agar. Colonies on corn meal agar (CMA) (1) were submerged, with or without a vague radiate pattern on potato carrot agar. Main hyphae were as much as 7 μm wide. Sporangia and zoospores were not produced. Hyphal swellings as much as 25 μm in diameter were abundant, terminal, and sometimes intercalary, often forming regular, dense chains in basipetal succession at hyphal tips and readily liberated. The morphological characters matched those described for Pythium intermedium (2). DNA sequencing of the ITS rDNA (ITS1, ITS2, and 5.8S rDNA) was generated using primers ITS5 and ITS4 in primary PCR (35 cycles: 96°C for 1 min, 55°C for 1 min, and 72°C for 2 min) and sequencing reactions (1). All isolates yielded identical ITS sequences, which were identical to the ex-type strain of P. intermedium, CBS 266.38 (GenBank Accession No. AY598647). The ITS sequence was deposited as GenBank Accession No. EF078693 (National Center for Biotechnology Information, NCBI, Bethesda, MD). Pathogenicity testing was performed on 3-year-old Rosa canina rootstocks from clonal propagation in 25 cm in diameter and 40 cm deep pots of compost 297 (Ricoter, Aarberg, Switzerland). Five-day-old mycelial plugs of our isolates grown on CMA (1) were inoculated in two pots, and roots were mechanically wounded. Sterile plugs were used on two control plants set aside. All plants were kept for 2 weeks at 20°C in a glasshouse with sufficient watering. Extensive necrotic lesions developed on inoculated roots, and severe wilting and leaves drying out were also observed. The controls showed no symptoms. P. intermedium was reisolated from margins of root lesions, thus fulfilling the postulates of Koch. P. intermedium was originally isolated from dead plant material (2) but is known as a typical soil inhabitant. It also has been isolated from water and living material from numerous plant species, but never from the genus Rosa until now. To our knowledge, this is the first record of P. intermedium on Rosa spp. grafted on Rosa canina in France. References: (1) L. Belbahri et al. FEMS Microbiol Lett 255:209, 2006. (2) A. J. van der Plaats-Niterink. Stud. Mycol. 21:1, 1981.


2020 ◽  
Vol 36 (1) ◽  
pp. 33-36
Author(s):  
Luis F. Hernández-Guevara ◽  
Francisco J. Sánchez-Rámos ◽  
Rahuel J. Chan-Chable ◽  
Luis M. Hernández-Triana ◽  
Ma. Teresa Valdés-Perezgasga ◽  
...  

ABSTRACT Collections of mosquitoes were conducted for the surveillance of species of medical importance in the state of Morelos, Mexico, in June 2017. Species collected included Mansonia (Mansonia) dyari, which was identified using morphological characters and cytochrome c oxidase I DNA barcoding. Although 3 species of genus Mansonia have been previously reported in Mexico, this is the 1st confirmed record of Ma. dyari in Morelos State, where no Mansonia species had been recorded. Historical records of Ma. dyari and Ma. indubitans in Mexico were reviewed. Therefore, this record increases the number of mosquito species occurring in Morelos to 46. The specimens collected in this study were deposited in the Culicidae collection of the Universidad Autónoma Agraria Antonio Narro, Unidad Laguna.


2021 ◽  
Vol 4 ◽  
Author(s):  
Christina Wiebe ◽  
Petra Nowak ◽  
Hendrik Schubert

Assessing the biodiversity of an ecosystem plays a major role in ecosystem management. However, proper determination on species-level is often tricky when morphological features are scarce and especially rare species require huge sampling efforts to be detected in the aquatic realm. As an alternative to conventional methods, environmental samples can be examined via the eDNA method, allowing for large-scale integration as well as taxa resolution independent from expression of morphological characters. However, to apply this technique genetic markers that are specific to a species or at least a genus are required. Such markers until now have been successfully developed only for a few well studied taxonomic groups like, e.g., fishes and amphibians, but are still missing for others, especially plants and algae (e.g. Bista et al. 2017). This project focusses on the development of species-specific markers for the macrophytic green algae Tolypella canadensis (Characeae, Charophyta), a rare alga preferring deep water and known so far mainly from remote places. Tolypella canadensis is a circumpolar species and prefers oligotrophic lakes, where it grows in depths up to 13 m (Langangen 2002; Romanov and Kopyrina 2016). In addition, proper determination of Tolypella-species is a field of a few specialists, further complicating monitoring or even detection of this rare species. The design of the species-specific primers was based on reference nucleotide sequences of the chloroplast genes rbcL, psbC and atpB and of the ribosomal internal transcribed spacer regions ITS1 and ITS2, obtained from GenBank (Perez et al. 2017). To determine the specificity of the newly designed primers, DNA isolates obtained from T. canadensis specimens collected from the Torneträsk (Sweden, 2018) and other charophyte species were prepared in different proportions. The sensitivity of the primers was experimentally assayed by using serial dilutions of T. canadensis DNA. Additionally, a mock test comprised of a sample with the DNA of several charophyte species was conducted and finally, the markers were tested on environmental samples from the Torneträsk. Tolypella canadensis-specific primers of the ITS2 region yielded positive PCR amplifications of one single band when T. canadensis was present in a sample. Cross-amplification was not found during the mock test; other charophyte species did not yield positive amplification. The eDNA samples from the Torneträsk validated the performance of the ITS2 marker. The T. canadensis-specific marker designed in this project was proven to be sensitive and accurate. It could be recommended as a useful tool to detect the presence of T. canadensis DNA, even at low concentration and in complex samples containing other charophyte species.


Check List ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 705-712
Author(s):  
Leila B. Guzmán ◽  
Enzo N. Serniotti ◽  
Roberto E. Vogler ◽  
Ariel A. Beltramino ◽  
Alejandra Rumi ◽  
...  

Omalonyx unguis (d’Orbigny, 1837) is a semi-slug inhabiting the Paraná river basin. This species belongs to Succineidae, a family comprising a few representatives in South America. In this work, we provide the first record for the species from Misiones Province, Argentina. Previous records available for Omalonyx in Misiones were identified to the genus level. We examined morphological characteristics of the reproductive system and used DNA sequences from cytochrome oxidase subunit I (COI) gene for species-specific identification. These new distributional data contribute to consolidate the knowledge of the molluscan fauna in northeastern Argentina.


2019 ◽  
Vol 78 (1) ◽  
pp. 91-94
Author(s):  
Duilio Iamonico ◽  
Ridha El Mokni

Abstract Amaranthus spinosus L. (Amaranthaceae s.l.), a species native to the Neotropics, has been found in four localities (Bizerta, Bir Bouregba, Hammamet, and Nabeul) of N. Tunisia. Our discovery represents the first record at national level, and the second one for N. Africa. Morphological characters and ecological data are given. Nomenclatural notes are provided for the name A. diacanthus, which was regarded by some authors as heterotypic synonym of A. spinosus. A neotype is designated in the present paper based on a specimen preserved at LSU.


Zootaxa ◽  
2018 ◽  
Vol 4496 (1) ◽  
pp. 562 ◽  
Author(s):  
GERUSA PAULI KIST STEFFEN ◽  
RICARDO BEMFICA STEFFEN ◽  
MARIE LUISE CAROLINA BARTZ ◽  
SAMUEL WOOSTER JAMES ◽  
RODRIGO JOSEMAR SEMINOTTI JACQUES ◽  
...  

The knowledge regarding earthworm species richness in subtropical Brazil is limited, particularly in the state of Rio Grande do Sul (RS), where only a few sites have been sampled. In this study we assessed earthworm richness in different ecosystems of RS, prioritizing un-sampled regions. Fifteen ecosystems, including native vegetation and other ecosystems with variable levels of disturbance were sampled in 30 counties in RS, totaling 77 sampling points, mainly in the Pampa biome. Qualitative sampling was performed by handsorting soil monoliths and fixing the earthworms in 4% formalin solution. Species identification was based on morphological characters, and species richness and Shannon (H) and McIntosh (U) diversity indices were calculated for each ecosystem. Twenty-one earthworm species were identified, belonging to seven families: Glossoscolecidae (8), Rhinodrilidae (2), Ocnerodrilidae (4), Megascolecidae (4), Acanthodrilidae (1), Lumbricidae (1) and Criodrilidae (1). From these, ten are new species belonging to the genera: Glossoscolex (6), Fimoscolex (1), Kerriona (1), Eukerria (1), and one aquatic species of the Criodrilidae family, belonging to a new genus. Most of the native species (Urobenus brasiliensis, Fimoscolex n.sp.1 and the Glossoscolex spp.) predominated in ecosystems little altered by human activity, while exotic (Amynthas gracilis, Amynthas rodericensis, Metaphire californica, Aporrectodea trapezoides) and peregrine species (Pontoscolex corethrurus) predominated in areas with more human disturbance. Native ecosystems with lower disturbance, particularly forests and native pastures had higher diversity than disturbed sites. This is the first record of A. rodericencis for Brazil and most sites represent new collection records for the known species in RS.


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