Regional Distribution of Two Races of Phialophora gregata f. sp. adzukicola, Causal Agent of Brown Stem Rot of Adzuki Bean, and Their Genetic Diversity on Hokkaido, Northernmost Island of Japan

2002 ◽  
Vol 68 (4) ◽  
pp. 284-291 ◽  
Author(s):  
Norio KONDO ◽  
Yuki KOBAYASHI ◽  
Futoshi SAKUMA ◽  
Shohei FUJITA ◽  
Kippei MURATA
Keyword(s):  
Genetic Diversity ◽  
Regional Distribution ◽  
Causal Agent ◽  
Stem Rot ◽  
Adzuki Bean ◽  
Brown Stem Rot ◽  
Phialophora Gregata

scholarly journals Re-evaluation and Selection of Adzuki Beans to Breed Cultivars Resistant to New Race of Phialophora gregata f. sp. adzukicola, the Causal Agent of Adzuki Bean Brown Stem Rot (BSR)

2007 ◽  
Vol 9 (3) ◽  
pp. 87-95 ◽  
Author(s):  
Shohei Fujita ◽  
Norio Kondo ◽  
Hisanori Shimada ◽  
Kippei Murata ◽  
Shigeo Naito
Keyword(s):  
Causal Agent ◽  
Stem Rot ◽  
Adzuki Bean ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
New Race ◽  
Selection Of

scholarly journals Detection of Two Races of Phialophora gregata f. sp. adzukicola, the Causal Agent of Adzuki Bean Brown Stem Rot

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 928-930 ◽  
Author(s):  
N. Kondo ◽  
S. Fujita ◽  
K. Murata ◽  
A. Ogoshi
Keyword(s):  
Stem Rot ◽  
Adzuki Bean ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Field Soils ◽  
Infested Field ◽  
Race 1 ◽  
Pathogenic Races ◽  
Race 2 ◽  
Hokkaido Island

Adzuki bean brown stem rot (BSR) is endemic on Hokkaido Island and has been controlled since 1985 by using resistant cultivars. BSR was reported on the resistant cultivar Kita-no-otome in a field near Memuro-cho, and this study was undertaken to determine if pathogenic races were present. The existence of avirulent and virulent isolates of the pathogen to cultivar Kita-no-otome was shown by comparing the virulence among six isolates (T96-1, T96-2, T96-3, T96-4, T96-5, and S95-1) obtained from diseased plants or naturally infested field soils. Three out of six isolates caused no disease on Kita-no-otome (DSI = 0), whereas the other three isolates were virulent on this cultivar (DSI = 1.2 to 2.6). In additional experiments, another three lines, Toiku No. 125, Toiku No. 132, and Toiku No. 140, derived from various gene sources, also revealed the same response to two representative isolates (T96-1 and T96-5) tested as with Kita-no-otome. Consequently, two races of Phialophora gregata f. sp. adzukicola, race 1 and race 2, can be distinguished by avirulence or virulence to Kita-no-otome, respectively.

scholarly journals Brown Stem Rot Resistance in Soybean Germ Plasm from Central China

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 953-956 ◽  
Author(s):  
M. S. Bachman ◽  
C. D. Nickell ◽  
P. A. Stephens ◽  
A. D. Nickell
Keyword(s):  
Germplasm Collection ◽  
Central China ◽  
Stem Rot ◽  
Disease Assessment ◽  
Sources Of Resistance ◽  
University Of Illinois ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Foliar Symptoms ◽  
Resistant Lines

Soybean accessions from China were screened in an attempt to identify unique sources of resistance to Phialophora gregata, the cause of brown stem rot. In 1994, over 500 accessions from the USDA Soybean Germplasm Collection, University of Illinois, Urbana-Champaign, were evaluated in the field at Urbana, IL, for reaction to brown stem rot. The accessions originated from nine provinces in central China and ranged in maturity from groups II to IV. Disease assessment was based on incidence of foliar symptoms and severity of stem symptoms produced by infection with natural inoculum. Based on field results, 64 putatively resistant lines were selected and evaluated in the greenhouse by a root-dip inoculation method. Thirteen accessions with levels of resistance equal to those of resistant standards were identified from five provinces. These lines may have value as donors of unique sources of resistance to brown stem rot.

scholarly journals Characterization and Distribution of Two Races of Phialophora gregata in the North-Central United States

2003 ◽  
Vol 93 (7) ◽  
pp. 901-912 ◽  
Author(s):  
T. C. Harrington ◽  
J. Steimel ◽  
F. Workneh ◽  
X. B. Yang
Keyword(s):  
Genetic Variation ◽  
Stem Rot ◽  
North Central ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
The North ◽  
Foliar Symptoms ◽  
Central United States ◽  
Soybean Plants ◽  
Xylem Discoloration

Genetic variation and variation in aggressiveness in Phialophora gregata f. sp. sojae, the cause of brown stem rot of soybean, was characterized in a sample of 209 isolates from the north-central region. The isolates were collected from soybean plants without regard to symptoms from randomly selected soybean fields. Seven genotypes (A1, A2, A4, A5, A6, M1, and M2) were distinguished based on DNA fingerprinting with microsatellite probes (CAT)5 and (CAC)5, with only minor genetic variation within the A or M genotypes. Only the A1, A2, and M1 genotypes were represented by more than one isolate. The A genotypes dominated in the eastern Iowa, Illinois, and Ohio samples, whereas the M genotypes were dominant in samples from western Iowa, Minnesota, and Missouri. In growth chamber experiments, isolates segregated into two pathogenicity groups based on their aggressiveness toward soybean cvs. Kenwood and BSR101, which are relatively susceptible and resistant, respectively, to brown stem rot. In both root dip inoculation and inoculation by injecting spores into the stem near the ground line (stab inoculations), isolates of the A genotypes caused greater foliar symptoms and more vascular discoloration than isolates of the M genotypes on both cultivars of soybean. All isolates caused foliar symptoms in both cultivars and in three additional cultivars of soybean with resistance to brown stem rot. Greater differences between the A and M genotypes were seen in foliar symptoms than in the linear extent of xylem discoloration, and greater differences were seen in Kenwood than in BSR101. Inoculation of these genotypes into five cultivars of soybean with different resistance genes to brown stem rot showed a genotype × cultivar interaction. A similar distinction was found in an earlier study of the adzuki bean pathogen, P. gregata f. sp. adzukicola, and consistent with the nomenclature of that pathogen, the soybean pathogens are named the aggressive race (race A) and the mild race (race M) of P. gregata f. sp. sojae.

scholarly journals A Molecular Marker Identifying Subspecific Populations of the Soybean Brown Stem Rot Pathogen, Phialophora gregata

2000 ◽  
Vol 90 (8) ◽  
pp. 875-883 ◽  
Author(s):  
Weidong Chen ◽  
Craig R. Grau ◽  
Eric A. Adee ◽  
Xiangqi Meng
Keyword(s):  
Molecular Marker ◽  
Direct Detection ◽  
Point Mutations ◽  
Variable Region ◽  
Stem Rot ◽  
Specific Primers ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Genotype C ◽  
Genotype A

A molecular marker was developed to separate and identify subspecific populations of Phialophora gregata, the causal agent of soybean brown stem rot. A variable DNA region in the intergenic spacer of the nuclear rDNA was identified. Two specific primers flanking the variable region were developed for easy identification of the genotypes using polymerase chain reaction (PCR). These two specific primers amplified three DNA products. The three PCR products were used to separate isolates of P. gregata into distinct genotypes: A (1,020 bp), B (830 bp), and C (660 bp). Genotype C was found in isolates obtained from Adzuki beans from Japan, whereas all 292 isolates obtained from soybean and the 8 isolates from mung bean belonged to either genotype A or B. The original nondefoliating (type II) strain ATCC 11073 (type culture of P. gregata) belonged to genotype B. The difference between genotypes A and B was due only to an 188-bp insertion or deletion; genotype C, however, differs from genotypes A and B at 58 point mutations, in addition to the length difference. Isolates of both genotypes A and B were widespread in seven Midwestern states. Genotype A was found mostly in certain susceptible soybean cultivars like Sturdy and Pioneer 9305, whereas genotype B was found predominately in brown stem rot-resistant soybean cvs. Bell, IA 3003, and Seiben SS282N. The specific primers were also used to directly detect cultivar-preferential infection by the two genotypes in infected soybean stems growing in the same field. Data from direct detection in soybean stems showed that cultivar-preferential infection by the two genotypes of P. gregata was significant.

scholarly journals Soybean Stem Colonization by Genotypes A and B of Cadophora gregata Increases with Increasing Population Densities of Heterodera glycines

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1297-1301 ◽  
Author(s):  
G. M. Tabor ◽  
G. L. Tylka ◽  
C. R. Bronson
Keyword(s):  
Population Density ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Population Densities ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Soybean Genotypes ◽  
Genotype A

Growth chamber experiments were conducted to investigate whether parasitism by increasing population densities of Heterodera glycines, the soybean cyst nematode, increases the incidence and severity of stem colonization by the aggressive genotype A and the mild genotype B of Cadophora gregata (Phialophora gregata), causal agents of brown stem rot of soybeans. Soybean genotypes with three combinations of resistance and susceptibility to H. glycines and genotype A of C. gregata were inoculated with each genotype of C. gregata alone or each genotype with two population densities of H. glycines eggs, 1,500 or 10,000 per 100 cm3 of soil. Stems of two H. glycines-susceptible soybeans were more colonized by both aggressive and mild genotypes of C. gregata in the presence of high than in the presence of low H. glycines population density.

Detecting Orobanche minor Seeds in Soil Using PCR

2003 ◽  
Vol 4 (1) ◽  
pp. 4 ◽  
Author(s):  
Megan E. Patzoldt ◽  
Weidong Chen ◽  
Brian W. Diers
Keyword(s):  
Southern China ◽  
Germplasm Collection ◽  
Central China ◽  
Stem Rot ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
South Central ◽  
Resistant Sources ◽  
Preliminary Study ◽  
Orobanche Minor

A new set of soybean accessions from south-central China were added to the USDA germplasm collection in 1996. Previous studies have shown that accessions with high levels of resistance to brown stem rot (BSR) can be found in germplasm collected from central and southern China. The objective of this study was to screen these accessions and identify those with resistance to BSR. In a preliminary study, 85 of 623 accessions tested were identified as resistant to BSR. In the second study, these 85 accessions were challenged with multiple biotypes of Phialophora gregata f. sp. sojae to identify those accessions with the strongest resistance. From these two studies, ten accessions were identified that had BSR resistance equal to or greater than the current resistant sources. Accepted for publication 10 June 2003. Published 1 July 2003.

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