Hyphal Width Research Articles

Sclerotium rolfsii에 의한 윤판나물 흰비단병

2004과 2005년 2년간 경남농업기술원 함양 약초 전시포장에 재배중인 윤판나물에서 S. rolfsii에 의한 흰비단병이 발생되었다. 병징은 줄기와 지제부위가 수침상으로 물러지고 부패하면서 암갈색으로 되고 시들어 말라 죽는다. 병반부와 지제부위의 토양 표면에 흰색의 곰팡이가 솜털처럼 생기고 감자한천 배지에서 갈색의 둥근 균핵을 많이 형성하였으며 크기는 1<TEX>$\sim$</TEX>3mm였다. 균사의 폭은 <TEX>$3{\sim}10{\mu}m$</TEX>이며 균사생육 적온은 30<TEX>$^{\circ}C$</TEX>였으며 균사특유의 clamp connection이 관찰되었다. 윤판나물에서 발생한 병징과 균학적 특징 및 병원성을 검정한 결과, 이 병을 Sclerotium rolfsii Saccardo에 의한 윤판나물 흰비단병으로 명명하고자 한다. From 2004 to 2005, the stem rot of Disporum sessile D. <TEX>$D_{ON}$</TEX> caused by Sclerotium rolfsii occurred spoyadieally in an herbs exhibition farm of Hamyang, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptom is water-soaking, dark brown on the stem and rotting, wilting. The infected plants were mostly died. White mycelial mats were spread over lesions, and then sclerotia were formed on stems and near soil line. The sclerotia were globoid in shape, 1<TEX>$\sim$</TEX>3 mm in size and white to brown in color, The optimum temperature and sclerotia on PDA was 30<TEX>$^{\circ}C$</TEX> and the hyphal width was <TEX>$3{\sim}10{\mu]m$</TEX>. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. Pathogenicity of the causal organism was proved on D. sessile according to Koch's postulate. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the stem rot of D. sessile caused by S. rolfsii in Korea.

Sclerotium rolfsii에 의한 호박 흰비단병 발생

2004년과 2005년 2년간 경남농업기술원 시험포장내 울타리 부근에 재배중인 호박 과실에서 S. rolfsii에 의한 호박 흰비단병이 발생되었다. 병징은 과실이 수침상으로 물러지고 부패하면서 병반부위에 흰색의 곰팡이가 솜털처럼 생기고 갈색의 둥근 균핵을 많이 형성하였으며 크기는 1<TEX>$\sim$</TEX>3 mm였다. 이병과실이 지표면과 닿은 부위에도 흰색 균사와 갈색 균핵을 형성하였다 균사의 폭은 <TEX>$7{\sim}8{\mu}m$</TEX>이며, 균사생육적온과 균핵 형성은 30<TEX>$^{\circ}C$</TEX>에서 가장 좋았으며, 균사특유의 clamp connection이 관찰되었다. 호박 과실에서 발생한 병징과 균학적 특징 및 병원성을 검정한 결과, 이 병을 Sclerotium rolfsii Saccardo에 의한 호박 흰비단병으로 명명하고자 한다. The fruit rot of pumpkin caused by Sclerotium rolfsii occurred sporadically at Gyeongsangnam-do Agricultural Research and Extension Services, Korea in 2004 and 2005. The typical symptom of the disease included water-soaking, fruit rotting and wilting. White mycelial mats were spread over infected fruits and then sclerotia were formed on the lesions and near soil surface. The sclerotia were globoid in shape, 1<TEX>$\sim$</TEX>3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation was at <TEX>$30^{\circ}C$</TEX> on PDA and the hyphal width ranged from 4 to 8 <TEX>${\mu}m$</TEX>. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the fruit rot of Cucurbita spp. caused by S. rolfsii in Korea.

Sclerotium rolfsii에 의한 비비추 흰비단병

2004과 2005년 7월 경상남도 진주시 칠암동 남강변에 재배중인 비비추에서 S. rolfsii에 의한 흰비단병이 발생되었다. 병징은 잎자루, 줄기, 지제부위가 수침상으로 물러지고 부패하면서 암갈색으로 되고 시들어 말라 죽는다. 병반부와 지제부위의 토양 표면에 흰색의 곰팡이가 솜털처럼 생기고 갈색의 둥근 균핵을 많이 형성되었다. 감자한천 배지에서 갈색의 둥근 균핵을 많이 형성하였으며 크기는 <TEX>$1\~3$</TEX>mm였다. 균사의 폭은 <TEX>$4\~8{\mu}m$</TEX>이며, 균사생육 적온은 <TEX>$30^{\circ}C$</TEX>였다. 균사특유의 clamp connection이 관찰되었다. 비비추에서 발생한 병징과 균학적 특징 및 병원성을 검정한 결과, 이 병을 Sclerotium rolfsii Saccardo에 의한 비비추 흰비단병으로 명명하고자 한다. The stem rot disease was found on Hosta longipes that planted in the flower beds along the Namgang riverside in Jinju city, Korea. The disease occurred first time in July, 2004 and sporadically occurred in 2005. The typical symptom of the disease is water-soaking, dark brown spot on the stem, and getting wilt. The infected plants were mostly died. White mycelial mats were spread over lesions and sclerotia were formed on stems and near soil line. The sclerotia were globoid in shape, <TEX>$1\~3$</TEX> mm in diameter and white to brown in color, The optimum temperature for mycelial growth of the fungus on PDA was <TEX>$30^{\circ}C$</TEX> and the hyphal width was <TEX>$4\~8{\mu}m$</TEX>. Clamp connections were observed in the hyphae of the fungus grown on PDA. Pathogenicity of the causal organism was proved on Hosta longipes according to Koch,s postulate. On the basis of mycological characteristics and pathogenicity to host plants, the fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the stem rot of H. longipes caused by S. rolfsii in Korea.

Ultrastructure of theAspergillus nidulans hypA1restrictive phenotype shows defects in endomembrane arrays and polarized wall deposition

Aspergillus nidulans Eidam (G. Wint.) wild-type hyphal morphogenesis requires the hypA gene product. Like its homolog in Saccharomyces cerevisiae Meyen ex E.C. Hansen, TRS120, hypA encodes a cytoplasmic protein likely associated with endomem branes. hypA is not essential, but hypA1 temperature-sensitive strains grow poorly at restrictive temperatures. In younger cells, endomembrane arrays were aberrant, only sometimes resembling wild type. In older cells, Golgi equivalents were swollen, impacted with electron-dense granules. In hypA1 strains grown at 42 °C, the poorly polarized hyphae lack recognizable Spitzenkörper and have walls at least four-fold thicker than those of wild-type or hypA1 strains grown at 28 °C. At restrictive temperatures, both hyphal width and wall thickness increase markedly in basal regions, suggesting wall deposition is impaired. Septa are thicker than in wild type, but have medial pores and Woronin bodies. Individual nuclei and mitochondria are smaller at 42 °C than at 28 °C, but each collectively occupies similar proportions of the cytoplasm. Mitochondrial cristae are reduced in number and width at 42 °C, possibly compromising metabolic efficiency; in older cells, cristae are widely spaced and randomly inserted. If hypA1 cells grown at 42 °C are shifted to 28 °C, the thickened wall is precisely degraded for growth of wild-type branches, which form within 1 h, suggesting areas of nascent polarity formed at 42 °C require the hypA product for wild-type function.Key words: endomembrane, filamentous fungus, electron microscopy, cell wall, secretion, Saccharomyces TRS120.

Ultrastructural Cytochemistry of the Host-Fungus Interfaces in the Endornycorrhizal Association Glomus mosseae / Allium cepa

The structure of the host-fungus interface in the VA mycorrhizal association Glomus mosseae / Allium cepa has been investigated cytochemically (Thiery test; differential DMSO and EDTA extraction; phosphotungstic acid staining) and using different fixation procedures (glutaraldehyde and OsO4 post-fixation; simultaneous glutaraldehyde — OSO4 fixation). The continous, highly invaginated host plasmalemma surrounding the intracellular fungal structures retains its affinity for phosphotungstic acid and continues to produce polysaccharide fibrils, but in the presence of the endophyte it progressively loses the capacity to organise these into well-structured wall material. At the point of cell penetration and in the primary arbuscule branches the fungal wall, which is stained by the Thiery reaction and phosphotungstic acid but unaffected by DMSO or EDTA, is surrounded by a collar of host wall material which has the same cytochemical properties as the primary walls of the plant cell. The fine arbuscule branches are surrounded by a layer of condensed matrical fibrils. When the arbuscule branches senesce and collapse, they become encased by the polysaccharide fibrillar material derived from the host. The appearance of the interfacial matrix separating the host plasmalemma from the fungal wall is always the same, no matter which fixation procedure is used. It contains membranous vesicles and scattered polysaccharide fibrils, both of which are elaborated by the host plasmalemma. The importance of the host and endophyte plasmalemma formations is emphasised. The vesicles arising from the host plasmalemma are often in contact with the walls of the endophytic hyphae. In the fungus, these bulbous or tubular configurations of the plasmalemma can become very numerous and can occupy the whole hyphal width. Although these structures could be involved in host-fungus exchanges, their eventual participation in wall synthesis is also orooosed.

Some Properties of Anastomosis Group 6 and BI in Rhizoctonia solani Kühn

Morphological and physiological properties of AG-6 and AG-BI, new anastomosis groups in R. solani, and anastomosis frequency between AG-BI and other anastomosis groups were investigated.Metabasidia in AG-6 were barrel-shaped or obovate, 7.5-17.0×5.5-10.0μm and without a median constriction. The length of sterigmata was 4.5-18.8μm and numbers of sterigmata per metabasidium 3-(3.9)-5. Basidiospores were obovate to oblong-ellipsoid, hyaline, smooth, flattened on the inner side, with an apiculus, 5.0-10.0×2.8-5.2μm. They sometimes germinated by the repetition. The mean hyphal width was 8.6μm and the number of nuclei per cell was 3-15. Optimum temperature for growth was 25-30C. Thiamine was autotrophic. Metabasidia in AG-BI were barrel-shaped, short clavate or obovate, 8.8-19.0×7.0-11.3μm and without a median constric-tion. The length of sterigmata was 4.0-12.0μm and numbers of sterigmata per meta-basidium 3-(3.9)-5. Basidiospores were obovate to oblong-ellipsoid, hyaline, smooth, flattened on the inner side, with an apiculus, 5.0-10.0×3.7-6.7μm. They sometimes germinated by the repetition. The mean hyphal width was 10.2μm and the number of nuclei per cell was 5-23. Optimum temperature for growth was 23-25C. Thiamine was heterotrophic. Anastomosis frequency of AG-BI was highest with AG-2-2 and lower by degrees with AG-2-1, AG-3, and AG-6. Judging from their morphological properties of perfect stage, AG-6 and AG-BI are classified as Thanatephorus cucumeris (Frank) Donk.

THE PRODUCTION AND BEHAVIOR OF DIPLOIDS OF COPRINUS LAGOPUS.

Diploid strains ofCoprinus lagopushave been synthesized from commonAheterokaryons either as oidial colonies or sectors. The criteria of growth rate and colony morphology on selective medium were used to distinguish between diploid and heterokaryon colonies. The average oidial size and hyphal width of diploid strains was significantly greater than that of the haploid parental strains.Diploid monokaryons were very stable and only rarely produced haploid segregants. However, aneuploid intermediates in haploidization have been identified and these segregated further to give haploid monokaryons with recombinant genomes.Dikaryons formed from diploid and haploid strains produced fruiting bodies. Meiosis and basidiospore production were irregular owing to the formation of triploid or partially triploid fusion nuclei in the basidia. In contrast to their stability in monokaryons, diploid nuclei tended to be unstable when combined in a dikaryon with a haploid nucleus, and often underwent partial haploidization before fruiting. Segregation of genes in the basidiospore progeny reflected whether haploidization had occurred before or after the formation of the fruiting body. If the haploid nucleus had aBmating-type allele common to the diploid nucleus, haploidization effected loss of the common allele.