Stem rust

Wheat leaf Wheat protein Wheat stem rust Wheatstone bridgf Wheel-balancing weight ... 

Pectins and pectinases in stem rust-infected wheat... 

Pesticides affect the content of microelements and other substances in plants, thus changing their nutritive value, as well as their ability to be stored. This was detected for OCPs in grain and legume harvests. For example, wheat crops treated with some fungicides (zineb, bayleton, and propicanazol) to fight stem rust (Puccirda) produce a lower quality of bread [3]. 

United States Department of Agriculture. Office of Pest Management National Plant Disease Recovery System. "Recovery Plan for Leaf Rust, Stem Rust, and Stripe Rust of Wheat Caused by Puccinia triticina, Puccinia graminis, and Puccinia striiformis, Respectively." August 28,2006. 

OA Sulfur Mustard and Arsine Oil Mixture 0-Aethyl-S-(2-dimethylaminoaethyl)-methylphosphonothioat Oat Stem Rust... 

Macek, K.J., M.A. Lindberg, S. Sauter, K.S. Buxton, and P.A. Costa. 1976. Toxicity of Four Pesticides to Water Fleas and Fathead Minnows. U.S. Environ. Protection Agen. Rep EPA-600/3-76-099. 57 pp. Macko, V., J.A.A. Renwick, and J.F. Rissler. 1978. Acrolein induces differentiation of infection structures in the wheat stem rust fungus. Science 199 442-443. 

Wheat stem rust Fewer infections by urediospores 0.06 ppm 6 h 177... 

Some pathogens, such as the stem rust pathogen Puccinia graminis... 

Lignin Biosynthesis in Stem Rust Infected Wheat... 

Highly resistant wheat varieties exhibit a typical hypersensitive response when infected with an avirulent race of the stem rust fungus. Host cells which are penetrated by a fungal haustorium undergo rapid necrotization, thus depriving the biotrophic parasite of its nutritional basis. 

We will now consider the evidence that has accumulated to show the participation of lignification in the hypersensitive resistance of wheat to the wheat stem rust fungus, Puccinia graminis f. sp. tritici. 

When highly resistant wheat varieties are inoculated with an avirulent race of the stem rust fungus, fungal growth is arrested by the hypersensitive death of the first penetrated host cells (30,31.) Even in very densely inoculated leaves, the reaction of less than one percent of the host cells is sufficient to stop further development of the parasite. This small percentage may be the reason, why no increased content of biochemically determined lignin was measured in infected hypersensitive wheat leaves (60,61). 

However, when an elicitor (see below), isolated from the stem rust fungus (62), is injected into the intercellular spaces of wheat leaves almost every cell in the infiltrated area exhibits a hypersensitive-like reaction (62-65). In the elicitor treated leaves, lignin content as determined by the thioglycolic acid procedure clearly increased (66). 

The second step of the proposed chain of events, resistance as a direct consequence of cell death, is still controversial (82-86). In the wheat-stem rust system, evidence favouring the idea of hypersensitive cell death as the cause of resistance (30,31,87-90) contrasts to results suggesting cell collapse as being a mere consequence of a yet unknown preceding resistance mechanism (90-97). 

Our recent observation (Moerschbacher Noll, unpublished) that a different PAL inhibitor, (l-amino-2-phenylethyl) phosphonic acid (APEP), is equally active in preventing hypersensitive cell death and partially lowering resistance of wheat to stem rust strongly suggest that the effects of both inhibitors is via their inhibitory action against PAL. 

The application of two of these inhibitors, N(O-hydroxyphenyl) sulfi-namoyl-tertiobutyl acetate and N(O-aminophenyl) sulfinamoyl-tertiobutyl acetate, to highly resistant wheat leaves infected with an avirulent strain of stem rust resulted in decreased lignification and decreased necrosis of penetrated host cells and concomitantly led to increased fungal development, occasionally even allowing some sporulation to occur (60). 

When injected into primary leaves of different cereals, the stem rust elicitor causes symptoms which closely resemble the respective resistance reactions of these species against the attack by stem rust of wheat, i.e., lignification in barley and rye, brown spots in oat, and no visible symptoms in maize (66). 

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