Effect of abnormal metabolites isolated from nematode-infected pine on pine seedlings and pine wood nematodes.

Oku, Hachiro; Yamamoto, Hiromi; Ohta, Hiroshi; Shiraishi, Takeshi

doi:10.3186/jjphytopath.51.303

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…The toxic substances found in PWN-infected pine tissue (Ueda et al, 1984;Oku et al, 1985) cannot explain the results of this study. The PWN-induced toxic substances have low molecular weights and can diffuse throughout the area occupied by several pine cells.…”

Section: Discussioncontrasting

confidence: 66%

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The process of epithelial cell death in Pinus thunbergii caused by the pine wood nematode, Bursaphelenchus xylophilus

Son

Hogetsu²,

Moon

2014

Nematol

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This study describes a new technique to investigate how the pine wood nematode (PWN), Bursaphelenchus xylophilus, kills pine epithelial cells. After inoculating PWN into 20-cm-long Pinus thunbergii stem cuttings and incubating for 1, 3 or 7 days, the cuttings were split into 2.5 cm segments. The segments were tangentially cut so that the epithelia of several cortical resin canals were exposed, and these were stained with Evans Blue for the detection of dead epithelial cells. While almost no dead epithelial cells were found in the cortical resin canals of non-PWN-inoculated control cuttings up to day 7 of the experiment, dead epithelial cells were distributed sparsely in the epithelium of cortical resin canals throughout pine cuttings inoculated with PWN 1, 3 and 7 days after inoculation. The sparse and sporadic distribution of dead pine cells in the epithelium suggested that individual PWN attacked one epithelial cell at a time with its stylet and migrated between attacks.

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Section: Discussioncontrasting

confidence: 66%

“…It is known that benzoic acid and several other toxic substances accumulate in PWN-infected pine tissue (Ueda et al, 1984;Oku et al, 1985). Because these substances have low molecular weights, they can diffuse and kill pine cells in an area containing several tissue cells.…”

Section: J a S O N Et Almentioning

confidence: 99%

The process of epithelial cell death in Pinus thunbergii caused by the pine wood nematode, Bursaphelenchus xylophilus

Son

Hogetsu²,

Moon

2014

Nematol

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“…Physiological changes in symptom development of pine wilt disease have been dealt with in many papers; decrease in photosynthesis (Fukuda et al, 1992a;Kaneko, 1989;Masuda, 1976;Ohyama and Kaminaka, 1975), denaturation of xylem and cortex parenchyma cells (Fukuda et al, 1992b;Ikeda, 1996a, Ikeda andKiyohara, 1995;Ikeda and Suzaki, 1984;Ikeda et al, 1994;Ishida et at., 1993;Kuroda et al, 1988;Mamiya, 1975Mamiya, , 1980Mamiya, , 1984Mamiya, , 1985Nobuchi et al, 1984;Sugawa, 1978Sugawa, , 1982, traumatic resin canal formation (Sugawa, 1978(Sugawa, , 1982, cambium destruction (Fukuda et al, 1992b;Ikeda, 1996a;lkeda et al, 1994;Myers, 1986;Sasaki et al, 1984), production of phytotoxic substances Kawazu et al, 1996a, b;Oku, 1988;Oku et al, 1980Oku et al, , 1985Shaheen et al, 1984;Ueda et aL, 1984), enhanced respiration (Mori and Inoue, 1983;Ohyama and Kaminaka, 1975) and ethylene production (Fukuda et al, 1994, Mori andInoue, 1986), water potential and transpiration of leaves and heat pulse velocity (Fukuda et al, 1988a(Fukuda et al, , b, c, 1992aIkeda and Kiyohara, 1995;Ikeda and Suzaki, 1984;…”

mentioning

confidence: 99%

Physiological Process of the Symptom Development and Resistance Mechanism in Pine Wilt Disease

Fukuda

1997

Journal of Forest Research

141

112

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Pathophysiological changes during the symptom development of pine wilt disease are reconsidered from recent investigations. The symptom development is divided into two stages: the early and the advanced stages. In the early stage, small number of nematodes migrate in cortex, then in xylem of the stem, and induce denaturation and necrosis of parenchyma cells. These changes in parenchyma are regarded as defense reactions of pines which result in terpene synthesis in xylem cells and embolism in tracheids. Such changes in the early stage can be induced in both susceptible and resistant pine species by either virulent or avirulent isolates of pinewood nematode (Bursaphelenchus xylophilus), or by B. mucronatus. No change occur in physiological status of leaves, and nematode reproduction is suppressed during this stage. Pine trees can survive if symptom does not progress from this stage. The symptoms of the advanced stage usually occur only in susceptible pines infected by virulent nematode isolates. At the beginning of the advanced stage, enhanced ethylene production by stem which coincides with cambial destruction occurs, and results in embolism of the outermost xylem in the portion. The embolism causes decrease in leaf water potential and cessation of photosynthesis. After cessation of photosynthesis, symptoms develop drastically with a burst of nematode population. There seems to be some unknown mechanism which suppress nematode reproduction and invasion to the cambial zone. This mechanism is thought to be photosynthesis-dependent, so that in photosynthesis-decreased conditions, even avirulent nematodes can multiply and invade cambium to induce tree death. Water stress in hot and dry summer should accelerates symptom development from the early to the advanced stage through such decrease of photosynthesis-dependent "cambial resistance."

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“…iii) After the abrupt decrease, virulent PWN gathering at the inoculation site kill pine cells by physical damage, cellulase or toxin, etc. (Mamiya, 1975;Odani et al, 1985b;Oku et al, 1985;Yamamoto et al, 1986;Kojima et al, 1994). iv) Thereafter, host defence responses decline and the environment becomes favourable for fungal growth.…”

Section: Discussionmentioning

confidence: 91%

Influence of fungi on multiplication and distribution of the pine wood nematode, Bursaphelenchus xylophilus, in axenized Pinus thunbergii cuttings

Wang¹,

Yamada²,

Sakaue³

et al. 2005

Nematol

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Influence of fungi on multiplication and distribution of the pine wood nematode (PWN), Bursaphelenchus xylophilus, was investigated in Pinus thunbergii cuttings. Axenized nematodes and/or one of two fungi isolated from healthy and PWN-killed P. thunbergii were inoculated together into autoclaved cuttings. A close relationship between the existence and distribution of fungal hyphae, and the multiplication and distribution of PWN was observed. The PWN did not multiply when only axenized nematodes were inoculated in the absence of fungi. When fungi were present, PWN population size increased markedly. The number of nematodes was high at sites where fungal hyphae were distributed. It is suggested that the restriction of a large portion of the nematode population near the inoculation site during the early stage of disease development is closely related to restricted distribution of fungal hyphae.

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Effect of abnormal metabolites isolated from nematode-infected pine on pine seedlings and pine wood nematodes.

Cited by 9 publications

References 3 publications

The process of epithelial cell death in Pinus thunbergii caused by the pine wood nematode, Bursaphelenchus xylophilus

The process of epithelial cell death in Pinus thunbergii caused by the pine wood nematode, Bursaphelenchus xylophilus

Physiological Process of the Symptom Development and Resistance Mechanism in Pine Wilt Disease

Influence of fungi on multiplication and distribution of the pine wood nematode, Bursaphelenchus xylophilus, in axenized Pinus thunbergii cuttings

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