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Model Wheat Genotypes as Tools to Uncover Effective Defense Mechanisms Against the Hemibiotrophic Fungus Bipolaris sorokiniana

May 2005 , Volume 95 , Number  5
Pages  528 - 532

Aloysius Ebelechukwu Ibeagha , Ralph Hückelhoven , Patrick Schäfer , Devendra Pal Singh , and Karl-Heinz Kogel

First, second, third, and fifth authors: Institute of Phytopathology and Applied Zoology, Interdisciplinary Research Centre for Environmental Sciences, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, D-35392, Giessen, Germany; and fourth author: Directorate of Wheat Research (DWR), Kunjpura Road, Karnal, Haryana, 132001, India

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Accepted for publication 11 January 2005.

We investigated the interaction of several differentially resistant wheatwith the hemibiotrophic phytopathogenic fungus Bipolaris sorokiniana (teleomorph Cochliobolus sativus). Wheat genotypes Yangmai, M 3 (W7976), Shanghai 4, and Chirya 7 showed higher levels of resistancewith cv. Sonalika, used as a susceptible control. In amicroscopic inspection, we found that fungal penetration intoepidermal layer failed mostly through a cell wall-associated defense. In cases where the fungus successfully overcame epidermal, its spread within the mesophyll tissue (necrotrophic phase) wasin the more resistant genotypes. Epidermal cell wall-associated, spreading as well as the extent of electrolyte leakage of infected, correlated well with field resistance. We propose that cellular hostsuch as formation of cell wall appositions as well as the degreeearly mesophyll spreading of fungal hyphae are indicative of thepotential of the respective host genotype and, therefore, could befor the characterization of new spot blotch resistance traits in cereals.

© 2005 The American Phytopathological Society