Anatomical and histochemical characteristics of Japanese birch (Tohoku) plantlets infected with the Inonotus obliquus IO-U1 strain

Abstract

Host-pathogen interactions were investigated on a Japanese birch (Betula platyphylla var. japonica, Tohoku) plantlet after infection with a canker-rot fungus, the Inonotus obliquus IO-U1 strain. For a time-course study, intact, wounded, and infected plantlets were collected from 2 h to 30 days after treatment. Notable changes were observed morphologically in the treated portion of wounded and infected plantlets. Phenolics first deposited at the cut margin and subsequently in vessels after 4 h of infection. Their deposition extended to other xylem elements, the cortex, and the pith with an increase in the infection period. Phenolics deposition was extensive at 10 days post-inoculation (dpi), when most of the cells were entirely filled with phenolics. A necrophylactic periderm (NP) was formed at the junction of the original periderm with a layer of 2-4 new phellem cells at 30 dpi. Based on the results obtained, phenolics deposition and NP formation are considered to occur as infection-induced responses in Tohoku birch plantlets infected with I. obliquus IO-U1.

Cationic peroxidase related to basal resistance of Betula platyphylla var. japonica plantlet No.^|^#8201;8 against canker-rot fungus Inonotus obliquus strain IO-U1

“…In our previous study, host-pathogen interactions were investigated using the Betula platyphylla var. japonica plantlet Tohoku infected with a canker-rot fungus, I. obliquus strain IO-U1 (Rahman et al 2008). We found that phenolic deposition and necrophylactic periderm formation occur as infection-induced responses in B. platyphylla var.…”

“…japonica plantlet Tohoku infected with I. obliquus strain IO-U1. In that study, the fungal hyphae were detected at 10 dpi in cortex, xylem ray, and pith area, although the hyphae did not detected at 2 dpi (Rahman et al 2008 isozymes in the C1, C2, and T plantlets at 2, 10, and 30 d after treatment are shown in Figure 4. Clear isozyme bands were observed in the basic region (pI>8.5), and three POD isozymes (pI 8.5, pI 9.1, and pI 9.3) were induced by wounding and fungal infection.…”

“…These sections were mounted with 75% glycerin and observed using optical light microscopy (BX 51, Olympus, Japan). The evaluation of phenolic compound accumulation by observation using fluorescence microscopy and optical light microscopy was performed by the methods described in our previous paper (Rahman et al 2008).…”

“…8 plantlets and I. obliquus strain IO-U1 were used for the experiments. The preparation of the plantlets and fungus and the treatments of intact (C1), wounded (C2), and infected (T) plantlets were performed according to the methods of our previous report (Rahman et al 2008). After the treatments, the plantlets were grown for 2, 4, 6, and 12 h and 2, 10, and 30 d. Stem samples (1 cm in length) were collected from the third internode or treated position in the C1, C2, and T plantlets to observe the in situ POD activity and phenolic compound accumulation.…”

Proteome analysis of infection-specific proteins from Japanese birch (Betula platyphylla var. japonica) plantlet No.8 infected with Inonotus obliquus strain IO-U1

“…We previously investigated the anatomical and histochemical characteristics of living B. platyphylla var. japonica (Tohoku) plantlets infected with the I. obliquus strain IO-U1 for clarifying the host-pathogen interactions (Rahman et al 2008). Our research clarified that phenolics were first deposited at the cut margin tissues and subsequently in the vessels after 4 h of infection; thereafter, their deposition extended to the other xylem elements, cortex, and pith.…”