scholarly journals Use of Aeroponic Chambers and Grafting to Study Partial Resistance to Fusarium solani f. sp. glycines in Soybean

Plant Disease ◽  
2002 ◽  
Vol 86 (11) ◽  
pp. 1223-1226 ◽  
Author(s):  
D. S. Mueller ◽  
S. Li ◽  
G. L. Hartman ◽  
W. L. Pedersen

Several plant introductions (PIs) and cultivars have been classified as partially resistant (PR) to sudden death syndrome. However, little is known about the nature of resistance to this disease. Seedlings of two PR PIs and two susceptible cultivars were inoculated with Fusarium solani f. sp. glycines in aeroponic chambers. Plants were inoculated by taping two sorghum seeds infested with F. solani f. sp. glycines to the main root. Foliar symptoms of the susceptible cultivars were higher than those on the PR PIs and were associated with lower root and plant dry weight. Root lesion lengths of the four soybean lines differed (P < 0.05), but did not correlate with foliar disease or any other variable. To better understand the resistance mechanism by distinguishing between root and plant resistance, three partially resistant PIs (PI 520.733, PI 567.374, and PI 567.650B) and one susceptible soybean cultivar (GL3302) were compared using different grafting combinations in aeroponic chambers. Results of sudden death syndrome evaluation indicated that resistance is conditioned by both the scion and the rootstock. All three PIs evaluated had resistance associated with the scion; resistance in PI 567.650B also was associated with the rootstock. Although the PR PIs used appear to have little or no root resistance, an aeroponic system and grafting may help identify new sources of resistance to F. solani f. sp. glycines with root- or whole-plant resistance.

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 515-518 ◽  
Author(s):  
G. L. Hartman ◽  
Y. H. Huang ◽  
R. L. Nelson ◽  
G. R. Noel

Sudden death syndrome (SDS) is an important soybean disease that potentially can be controlled by host plant resistance. In this study, over 800 soybean plant introductions (PIs), lines, and cultivars were screened for resistance to Fusarium solani. Of 728 PIs from China, PI 567.374 had mean foliar SDS severities significantly (P = 0.05) lower than PI 520.733 (resistant check) in both growth-chamber and greenhouse tests. In addition, PIs 567.315, 567.441C, 567.650B, and 567.664 had mean SDS severity ratings significantly (P = 0.05) lower than PI 520.733 in a growth-chamber test. Of 16 soybean cyst nematode-resistant entries tested, 5 had values lower than the resistant check, PI 520.733, with cv. Hartwig significantly lower in the first trial. In trial two, no entries were lower than the resistant check, although cvs. Bell and Hartwig were not significantly different from PI 520.733. In another experiment, few soybean cultivars or experimental lines had SDS severity ratings lower than PI 520.733 in any one of three trials. Some of the newly acquired PIs from China that exhibited low foliar SDS severity ratings may provide the sources of resistance needed to develop new SDS-resistant soybean breeding lines and cultivars.


Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 741-746 ◽  
Author(s):  
D. S. Mueller ◽  
G. L. Hartman ◽  
R. L. Nelson ◽  
W. L. Pedersen

Sudden death syndrome, caused by Fusarium solani f. sp. glycines, has caused increased losses in soybean production in recent years. This study was done to identify potential sources of resistance to sudden death syndrome. Using a greenhouse screening procedure, 6,037 soybean plant introductions (PIs) were compared with a susceptible check, Great Lakes 3302, and two moderately resistant checks, PI 520.733 and PI 567.374, for resistance to sudden death syndrome. Only 57 PIs had foliar disease ratings that were not significantly different from PI 567.374 (P ≤ 0.05) 3 weeks after inoculation. Six PIs had lower ratings than PI 567.374 at 4 weeks after inoculation, while none had lower area under the disease progress curve (AUDPC) values. When comparing the PIs to PI 520.733, 209 PIs had foliar disease ratings not significantly different from PI 520.733 (P ≤ 0.05) 3 weeks after inoculation. Eight PIs had significantly lower disease severity ratings 4 weeks after inoculation, and 38 PIs had significantly lower AUDPC values than PI 520.733. Additionally, root lesion lengths were measured 4 weeks after inoculation and ranged from 25.2 to 41.5 mm for all the PIs; none of the entries had smaller lesion lengths than the susceptible check Great Lakes 3302. The correlation between lesion length and disease foliar severity rating was not significant. There also were no plant morphological characteristics (i.e., flower color or seed coat color) associated with higher sudden death syndrome foliar symptoms. Eighteen PIs previously identified as moderately resistant with differing agronomic traits were inoculated with five different isolates of Fusarium solani f. sp. glycines. Results indicated that resistance in these 18 PIs was effective against all five isolates of Fusarium solani f. sp. glycines. Isolate Mont-1 caused the greatest disease severity ratings. These PIs that exhibited low foliar severity ratings may provide new sources of resistance for the development of new sudden death syndrome-resistant lines and cultivars.


Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 566-569 ◽  
Author(s):  
K. W. Roy

Production of macroconidia by the causal agent of sudden death syndrome, Fusarium solani f. sp. glycines, occurred on lower stems and roots of soybean plants symptomatic for the disease in Illinois, Indiana, Kentucky, Mississippi, and Tennessee. Most of the sporulation was light to dark blue to blue-green in color. Microscopically (15×) visible sporulation occurred on plants in 26, and macroscopically visible sporulation occurred on plants in 15, of 32 fields inspected. In some fields, the incidence of plants with microscopically visible sporulation was as high as 70%, and the incidence of plants with macroscopically visible sporulation reached 50%. Sporulation varied from pinpoint microscopic areas to macroscopically visible masses 4 to 6 cm2 or larger. Areas of microscopically visible sporulation occurred on lower stems and roots within 2.5 cm above and below the soil line on about 50% of the plants, and areas of macroscopically visible sporulation occurred within the same region on about 60% of the plants. Both microscopic and macroscopic sporulation also occurred on taproots as far as 10 cm or more below the soil line. Severe foliar symptoms and root decay were associated with a greater incidence of plants with sporulation. The occurrence of sporulation should help distinguish sudden death syndrome from other diseases of like foliar symptomatology and help confirm its diagnosis. It is presumed from the results that sporulation eventually contributes to the inoculum density of F. solani f. sp. glycines in soybean fields.


Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 448-448 ◽  
Author(s):  
T. R. Anderson ◽  
A. U. Tenuta

Sudden death syndrome (SDS), caused by Fusarium solani (Mart.) Sacc. f. sp. glycines, is a disease of soybean (Glycine max (L.) Merr.) in several central and southern states of the United States. In Ontario, Canada, individual soybean plants with typical foliar symptoms of SDS (1) have been observed annually in Kent County since 1993 but the causal organism was not isolated or identified. In 1996, plants with symptoms of SDS were observed in six fields located in Essex, Kent, and Lambton counties. Interveinal chlorosis and necrosis occurred on top leaves of affected plants and a pale brown discoloration occurred in the vascular system in lower stems and upper tap roots. Slow-growing isolates of F. solani f. sp. glycines with typical blue sporodochia were isolated from symptomatic plants on acidified potato dextrose agar (1). Root inoculation of 15 2-week-old seedlings with colonized oat kernals with each of five single-spore isolates caused typical SDS symptoms on 5-week-old soybean plants of cvs. Conrad, A2540, S19-90, and Ripley in the greenhouse. The severity and incidence of symptoms varied with cultivar and isolate. Of 125 plants inoculated, 6% of Conrad, 10% of A2540, 14% of S19-90, and 17% of Ripley plants developed foliar symptoms. Symptoms did not develop on noninoculated controls. F. solani f. sp. glycines was reisolated from roots of symptomatic plants. Although Ripley is known to have resistance to SDS (2), foliar and root symptoms developed following inoculation with each Ontario isolate of F. solani f. sp. glycines. Yield losses in 1996 were difficult to assess because of the scattered distribution of diseased plants in most fields. Diseased plants had few and poorly filled pods. In two fields, soybean growth was severely restricted in large areas covering 2 ha each; however, soybean cyst nematode (SCN) was present in both fields. SCN was present at all locations. Although total yield losses are currently low, it is evident that F. solani f. sp. glycines causing SDS has become widely distributed in southwest Ontario and disease severity is increasing. References: (1) K. W. Roy et al. Phytopathology 79:191, 1989. (2) P. A. Stevens et al. Crop Sci. 33:929, 1993.


Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 827-831 ◽  
Author(s):  
D. S. Mueller ◽  
R. L. Nelson ◽  
G. L. Hartman ◽  
W. L. Pedersen

Sudden death syndrome, caused by Fusarium solani f. sp. glycines, has caused severe damage to soybean production in recent years. One way to control sudden death syndrome is with resistant cultivars. Over a 3-year period, 2,335 publicly and privately developed soybean entries were inoculated and evaluated for their response to F. solani f. sp. glycines under greenhouse conditions. The entries were compared with the susceptible check, Great Lakes 3302 (GL3302), and the moderately resistant checks, plant introductions (PIs) 520733 and 567374. Thirty-eight entries were identified with moderate levels of resistance. Based on foliar ratings, there were no differences (P < 0.05) between the Roundup Ready and conventional cultivars. In all, 90 ancestral lines that represent 99% of the genes in modern U.S. cultivars and 55 lines found in the pedigrees of public cultivars reported to have some resistance were evaluated for their response to F. solani f. sp. glycines. Nine ancestral lines (Aoda, Kim, Jackson, Sioux, Mammoth Yellow, T117, PI 171450, PI 54615-1, and PI 71506) and 12 cultivars or experimental lines (Ina, D83-3349, LN98-4340, LN83-2356, Hartwig, Harosoy, Bedford, Merit, Cutler, Calland, Hill, and Evans) had disease ratings not significantly different (P < 0.05) from PI 520733 or PI 567374. PI 54610, a putative ancestral line, also was found to be moderately resistant.


Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 879-879 ◽  
Author(s):  
B. W. Pennypacker

A small, circular patch of soybean (Glycine max) showing symptoms consistent with sudden death syndrome (SDS) (2) was noted on July 25, 1998, in a producer's field in Jersey Shore, PA. Foliar symptoms included interveinal chlorosis and necrosis, leaf cupping, and leaf abscission. The vascular cylinder of roots and stems had areas of reddish-brown discoloration. A slow-growing Fusarium sp., which produced a bluish-purple color on potato dextrose agar, was isolated from the roots of several symptomatic plants. The fungus was identified as Fusarium solani by The Fusarium Research Center, The Pennsylvania State University. Koch's postulates were tested on soybean cultivars A2506, Stine 3171, Pioneer 9305 and 9306, and Jack. Five plants per cultivar were inoculated at growth stage V1 by pouring 35 ml of a 4 × 107 spores per ml suspension on the growth mix in each pot. Five plants per cultivar were treated similarly with sterile water. Foliar symptoms of SDS began to appear 3 weeks after inoculation. Seven weeks after inoculation, symptoms of interveinal chlorosis and/or necrosis, leaf cupping, and occasional leaf abscission were apparent on the inoculated plants and on several noninoculated plants. The percentage of the plant showing symptoms was recorded and converted to the 0 to 5 scale (in which 0 = 0%, 1 = 1–10%, 2 = 11–30%, 3 = 31–40%, 4 = 41–90%, and 5= 91–100% of the leaf area affected) used by Rupe (3). Regardless of the rating method, there was a significant difference (P = 0.0001) between inoculated and noninoculated plants. There were no significant differences among cultivars. Roots of the inoculated plants were frequently discolored, in contrast to those of the noninoculated plants. F. solani was isolated from the roots of 97% of the inoculated plants and 23% of the noninoculated plants. Fungus gnats were suspected of spreading the pathogen to the noninoculated plants (1). F. solani f. sp. glycines causes SDS in soybean and its identity is confirmed by the symptoms produced on soybean (2). The symptoms produced when soybean plants were inoculated in the greenhouse were consistent with those of SDS (2) and indicate that the F. solani isolate recovered from symptomatic plants in the field was F. solani f. sp. glycines. This is the first documented occurrence of SDS on soybean in Pennsylvania. References: (1) D. W. Kalb and R. L. Millar. Plant Dis. 70:752, 1986. (2) K. W. Roy et al. Plant Dis. 81:1100, 1997. (3) J. C. Rupe. Plant Dis. 73:581, 1989.


Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 449-449 ◽  
Author(s):  
J. E. Kurle ◽  
S. L. Gould ◽  
S. M. Lewandowski ◽  
S. Li ◽  
X. B. Yang

In August 2002, soybean (Glycine max (L.) Merr.) plants exhibiting foliar and root symptoms typical of sudden death syndrome were observed in Blue Earth and Steele counties in south-central Minnesota. Leaf symptoms ranging from small chlorotic spots to prominent interveinal necrosis were present on soybean plants at the R6 to R7 growth stage. As plants matured, complete defoliation took place with only petioles remaining. Symptomatic plants had necrotic secondary roots, truncated taproots, and discolored cortical tissue at the soil line. Blue sporodochia containing macroconidia were observed on the taproot of affected plants at both locations (3,4). Multiple cultures from both locations were obtained by transferring macroconidia from the sporodochia to potato dextrose agar (PDA) and modified Nash-Snyder Medium (NSM) (3). After 14 days, isolations were made from fungal colonies exhibiting bluish pigmentation and masses of bluish macroconidia (4). The isolates grew slowly, developed a bluish color, and formed sporodochia containing abundant macroconidia on NSM. These isolates were identified as Fusarium solani (Mart.) Sacc. f. sp. glycines based on colony characteristics and morphology of macroconidia (2). Pathogenicity tests were conducted with a single isolate from each location. The isolate from Blue Earth County was inoculated as mycelia in a plug of media onto taproots of plants of susceptible cvs. Williams 82 and Spencer at the V2 growth stage. Chlorotic spots appeared on leaves after 12 days of growth at 22 to 25°C in the greenhouse. Interveinal necrosis appeared after 15 days (4). The isolate from Steele County was used to inoculate the susceptible cv. Great Lakes 3202. Sorghum seed (3 cm3) infested with mycelia of the isolate were placed 2 to 3 cm below soybean seed planted in Cone-Tainers. Noninfested sorghum seed was used as a control. Plants were maintained for 21 days at 22 to 28°C in the greenhouse. Chlorotic spots appeared on leaves of inoculated plants within 21 days after planting followed by the development of interveinal chlorosis and necrosis (1). Molecular analysis further supported the identification of the Steele County isolate as F. solani f. sp. glycines. Polymerase chain reaction with specific primers Fsg1 and Fsg2 of total genomic DNA extracted from the Steele County isolate amplified a 438-bp DNA fragment identical with that extracted from previously identified isolates of F. solani f. sp. glycines (1). In 2002, symptoms of sudden death syndrome were also reported in Olmsted, Freeborn, and Mower counties. Although studies are needed to determine the distribution of sudden death syndrome in the state, the occurrence of the symptoms at multiple locations suggests that F. solani f. sp. glycines is widely distributed in southeast and south-central Minnesota. The counties where sudden death syndrome symptoms were reported are located in the most productive soybean-growing region of Minnesota. Sudden death syndrome could be a serious threat to soybean production in this area since poorly drained, heavy, clay soils are common, and soil temperatures 18°C or less are normal before the end of May. References: (1) S. Li et al. Phytopathology 90:491, 2000. (2) K. W. Roy. Plant Dis. 81:566, 1997. (3) K. W. Roy et al. Plant Dis. 81:1100, 1997. (4) K. W. Roy. Plant Dis. 81:259, 1997.


Crop Science ◽  
1998 ◽  
Vol 38 (2) ◽  
pp. 472-477 ◽  
Author(s):  
V. N. Njiti ◽  
T. W. Doubler ◽  
R. J. Suttner ◽  
L. E. Gray ◽  
P. T. Gibson ◽  
...  

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 773-779 ◽  
Author(s):  
S. Sanogo ◽  
X. B. Yang ◽  
P. Lundeen

Three-year field experiments were conducted to assess the development of sudden death syndrome (caused by Fusarium solani f. sp. glycines) in three soybean cultivars, tolerant (P9344 and A3071) and nontolerant (BSR101), to glyphosate following foliar application of four herbicides (acifluorfen, glyphosate, imazethapyr, and lactofen) commonly applied to soybeans in the north-central region of the United States. Cultivar A3071 is resistant to sudden death syndrome, whereas cultivars P9344 and BSR101 are susceptible to this disease. There was no statistically significant cultivar-herbicide interaction with respect to the severity of foliar symptoms of the disease and the frequency of isolation of F. solani f. sp. glycines from roots of soybean plants. Across all herbicide treatments, the level of sudden death syndrome was lower in the disease-resistant cultivar than in the susceptible ones. There was an increase in the disease levels under application of acifluorfen, glyphosate, and imazethapyr compared with nontreated or lactofen-treated plants. The results obtained indicate that the response of glyphosate-tolerant soybeans to sudden death syndrome is not different from the response of conventional soybeans to this disease following application of the selected herbicides, and the resistance of soybean to sudden death syndrome was not changed with application of glyphosate.


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