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|Title:||Application of in vitro methods to improve soybean resistance to Fusarium solani, the causal agent of sudden death syndrome|
|Doctoral Committee Chair(s):||Hartman, Glen L.|
|Department / Program:||Crop Sciences|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Plant Culture
Agriculture, Plant Pathology
|Abstract:||Sudden death syndrome (SDS) of soybean (Glycine max (L.) Merr.) is caused by the soilborne fungus, Fusarium solani. Calli reactions of five soybean cultivars grown on culture medium amended with fungal culture filtrate were compared to the reactions of the same five cultivars inoculated with the fungus under greenhouse conditions. A significant positive correlation was found between sensitivity of calli to the fungal culture filtrates and SDS ratings of inoculated plants. Culture filtrates of F. solani isolates which did not cause SDS of soybean, had significantly lower toxicity to soybean calli than that of SDS-causing isolates.
Culture filtrate of a F. solani SDS-causing isolate was applied as a selection agent to soybean embryogenic suspension cultures. One plant of each of the cvs. Asgrow A3427, Chamberlain, and Spencer, and 69 plants of cv. Jack were regenerated (R$\sb0$ plants) from toxin-resistant embryogenic cultures. The R$\sb1$ (185) (first-selfed generation) and R$\sb2$ (225) (second-selfed generation) plants of cv. Jack regenerants were inoculated with F. solani SDS isolates. Thirty-four days after inoculating the R$\sb1$ and R$\sb2$ regenerants: 1% were without foliar symptoms; 29 and 26.2%, respectively, had symptoms only on the unifoliolate leaves or had mild symptoms on both the unifoliolate and trifoliolate leaves; and 70 and 72%, respectively, had severe foliar symptoms. All parental cv. Jack plants had foliar symptoms (11% being mild and 89% severe).
A phytotoxic polypeptide with an estimated molecular weight of 17 kD was identified in culture filtrates of a SDS-causing isolate by using the calli assay. Fifteen amino acids were sequenced from the N-terminal end. The toxin caused browning on soybean calli; necrosis on detached cotyledons and leaves; and yellowing, curling, and drying of attached soybean cotyledons and leaves.
|Rights Information:||Copyright 1995 Jin, Hua|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9543614|