scholarly journals Comparison of Sapwood Discoloration in Fagaceae Trees After Inoculation with Isolates of Raffaelea quercivora, Cause of Mass Mortality of Japanese Oak Trees

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Dai Kusumoto ◽  
Hayato Masuya ◽  
Toshihide Hirao ◽  
Hideaki Goto ◽  
Keiko Hamaguchi ◽  
...  
Keyword(s):  
Mortality Rates ◽  
Mass Mortality ◽  
Platypus Quercivorus ◽  
Oak Trees ◽  
High Virulence ◽  
Standing Trees ◽  
Fagus Japonica ◽  
Raffaelea Quercivora ◽  
Species Specific ◽  
Highly Virulent

The mass mortality of oak trees has been prevalent in Japan since the late 1980s. The fungus Raffaelea quercivora is transmitted by an ambrosia beetle, Platypus quercivorus, which causes mortality. The beetle is able to bore galleries into the sapwood of most Fagaceae trees in Japan; however, the level of mortality caused by R. quercivora and P. quercivorus differs greatly among tree species. Previous studies by our research group have demonstrated that the virulence of R. quercivora differs among isolates when inoculated into Quercus serrata logs. However, interactions between the virulence of R. quercivora isolates and the susceptibility of other fagaceous species have yet to be elucidated. In this study, we inoculated the fresh logs of 11 fagaceous species with isolates of low and high virulence, and measured the tangential widths of discolored sapwoods 3 weeks after inoculation. Although the discoloration widths of Q. crispula sapwood were similar among all isolates, those of Q. serrata and Q. acutissima tended to increase with the more virulent isolates. Sapwood discoloration in Q. glauca, Q. acuta, Q. salicina, Lethocarpus edulis, and Castanopsis sieboldii was greatly increased by highly virulent isolates. Discoloration in Fagus japonica was not influenced by any of the isolates. The logs of Q. crispula and Q. serrata but not Q. glauca were significantly more discolored by a low-virulence isolate compared with standing trees. The various virulent isolates induced unique sapwood discoloration characteristics in each species, which may explain species-specific differences in mortality rates.

Taxonomic reevaluation of Raffaelea quercivora isolates collected from mass mortality of oak trees in Japan

Mycoscience ◽  
2012 ◽  
Vol 53 (3) ◽  
pp. 211-219 ◽  
Author(s):  
Min Young Seo ◽  
Yosuke Matsuda ◽  
Chiharu Nakashima ◽  
Shin-ichiro Ito
Keyword(s):  
Mass Mortality ◽  
Oak Trees ◽  
Raffaelea Quercivora Isolates ◽  
Raffaelea Quercivora

scholarly journals Draft Genome Sequence of Raffaelea quercivora JCM 11526, a Japanese Oak Wilt Pathogen Associated with the Platypodid Beetle, Platypus quercivorus

2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Hayato Masuya ◽  
Ri-ichiroh Manabe ◽  
Moriya Ohkuma ◽  
Rikiya Endoh
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Mass Mortality ◽  
Ambrosia Beetle ◽  
Draft Genome Sequence ◽  
Oak Wilt ◽  
Platypus Quercivorus ◽  
Japanese Oak Wilt ◽  
Raffaelea Quercivora

The Japanese oak wilt pathogen Raffaelea quercivora and the platypodid beetle, Platypus quercivorus , cause serious mass mortality of Quercus spp. in Japan. Here, we present the first draft genome sequence of R. quercivora JCM 11526 to increase our understanding of the mechanism of pathogenicity and symbiosis with the ambrosia beetle.

Neomisticius platypi n. sp. and N. variabilis n. sp. (Tylenchomorpha: Anguinidae) from dead oak trees in Japan

Nematology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Natsumi Kanzaki ◽  
Hayato Masuya ◽  
Keiko Hamaguchi
Keyword(s):  
New Species ◽  
Vas Deferens ◽  
Morphological Characteristics ◽  
Platypus Quercivorus ◽  
Oak Trees ◽  
Two New Species ◽  
Previous Definition ◽  
Rectal Glands ◽  
Stylet Length ◽  
Definition Of

Summary Two new Neomisticius species, typologically and phylogenetically close to each other, are described and illustrated from dead Quercus trees and an ambrosia beetle, Platypus quercivorus. The two species share some stylet morphological characteristics, namely, they both possess a long conus occupying more than half of the total stylet length, a long crustaformeria composed of more than 160 cells (eight rows of more than 20 cells each), and a short and broad female tail with a digitate tip. They are distinguished from each other by N. variabilis n. sp. having a wide, spindle-shaped male bursa with a blunt terminus and N. platypi n. sp. having an oval bursa with a rounded terminus. In addition, the males and females of both species have three large rectal glands and the posterior end of the male testis (distal end of the vas deferens) bears three cells that seemingly function as a valve between the vas deferens and the cloacal tube. These characteristics have not been reported in other tylenchids. Currently, the genus contains only three species: the two new species and N. rhizomorphoides, which has a normal stylet with a short conus, a short crustaformeria, and lacks rectal glands and valve cells in the vas deferens. Therefore, the two new species are readily distinguished from N. rhizomorphoides and, based on the previous definition, may even represent a new genus. However, considering their phylogenetic closeness and biological similarities (e.g., association with ambrosia beetles), the generic definition of Neomisticius was emended to include these new species.

scholarly journals A New Cytosporone Derivative from the Endophytic Fungus Cytospora sp

2014 ◽  
Vol 9 (7) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Tomoya Takano ◽  
Takuya Koseki ◽  
Hiromasa Koyama ◽  
Yoshihito Shiono
Keyword(s):  
Antimicrobial Activity ◽  
Endophytic Fungus ◽  
2D Nmr ◽  
Ambrosia Beetle ◽  
Oak Wilt ◽  
Tree Disease ◽  
Platypus Quercivorus ◽  
Mass Spectral ◽  
Screening Study ◽  
Raffaelea Quercivora

Japanese oak wilt (JOW) is a tree disease caused by the fungus Raffaelea quercivora, which is vectored by the ambrosia beetle, Platypus quercivorus. In a screening study of the inhibitory active compounds from fungi, a new cytosporone analogue, compound 1, was isolated from the endophytic fungus Cytospora sp. TT-10 isolated from Japanese oak, together with the known compounds, integracin A (2), cytosporones N (3) and A (4). Their structures were determined by extensive 1D– and 2D–NMR spectroscopic and mass spectral analyses. Compound 1 was identified as 4,5-dihydroxy-3-heptylphthalide and named cytosporone E. Compounds 2 and 3 showed antimicrobial activity against Raffaelea quercivora.

scholarly journals IMMUNIZATION OF GUINEA PIGS WITH A MODIFIED STRAIN OF LYMPHOCYTIC CHORIOMENINGITIS VIRUS

1937 ◽  
Vol 66 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Erich Traub
Keyword(s):  
Guinea Pigs ◽  
Serial Passage ◽  
Lymphocytic Choriomeningitis ◽  
White Mouse ◽  
Lymphocytic Choriomeningitis Virus ◽  
High Virulence ◽  
Different Strains ◽  
Highly Virulent

A strain of choriomeningitis virus which was highly virulent for guinea pigs, as isolated from a naturally infected white mouse, has been markedly attenuated for guinea pigs by serial intracerebral passage through white mice. The change of virulence occurred before the 8th serial passage. The modified virus as a rule produces fever in guinea pigs but no other symptoms, and the infection is followed by a very solid immunity. Parallel passages of the same strain through guinea pigs have maintained its high virulence for this species but slightly reduced its pathogenicity for mice. These observations indicate that the differences in virulence for guinea pigs noted before (1, 2) with different strains of choriomeningitis virus obtained from infected stock mice may be due not only to differences in the susceptibility of guinea pigs but also to variations in the virulence of the virus. A marked degree of resistance was demonstrable in several guinea pigs on the 4th, 8th, and 10th day after injection with modified virus, when antivirus could not yet be detected in the serum. Circulating antivirus appears therefore to play a secondary part in their immunity, which seems to be closely associated with the tissues as in mice.

scholarly journals Transient virulence of emerging pathogens

2009 ◽  
Vol 7 (46) ◽  
pp. 811-822 ◽  
Author(s):  
Benjamin M. Bolker ◽  
Arjun Nanda ◽  
Dharmini Shah
Keyword(s):  
Genetic Variance ◽  
Evolutionary Dynamics ◽  
Growth Conditions ◽  
Emerging Pathogens ◽  
Potential Significance ◽  
Phase Selection ◽  
Transmission Rates ◽  
Virulence Evolution ◽  
High Virulence ◽  
Highly Virulent

Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia ) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

scholarly journals Spatial Distribution of Raffaelea quercivora in Xylem of Naturally Infested and Inoculated Oak Trees

2010 ◽  
Vol 100 (8) ◽  
pp. 747-755 ◽  
Author(s):  
Yukiko Takahashi ◽  
Norihisa Matsushita ◽  
Taizo Hogetsu
Keyword(s):  
Small Area ◽  
Fluorescent Substance ◽  
Oak Wilt ◽  
Conduction Loss ◽  
Conductive Zone ◽  
Inoculation Site ◽  
Oak Trees ◽  
Water Conduction ◽  
Raffaelea Quercivora ◽  
Distribution Water

Mass mortality of Japanese oak caused by Raffaelea quercivora due to Japanese oak wilt (JOW) has been tremendous since the late 1980s in Japan. We investigated detailed distribution of R. quercivora hyphae in a naturally infected Quercus serrata tree using fluorescein-conjugated wheat germ agglutinin and also examined spatial relationships between hyphal distribution, water conduction loss, and host reactions in xylem in inoculated Q. crispula saplings. Hyphae of R. quercivora elongated longitudinally in vessels and transversely in ray tissues in both naturally infected and inoculated Quercus trees. Hyphae were confined within a relatively small area near the inoculation site. Vessel dysfunction was also confined and overlapped with hyphal distribution. The reaction zone consisting of two types of fluorescent substance was formed surrounding the outside of the hyphal area in xylem and was always found in non-water-conductive zone. These results suggest that wilting of Quercus trees caused by JOW may not be induced by dysfunction of a small number of vessels, but by that of many vessels, and it requires that R. quercivora hyphae spread from many galleries bored by beetles during mass attacks.

Sign in / Sign up

Export Citation Format

Share Document