David, R., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Itzhaki, H., Department of Plant Genetics, Weizmann Institute of Science, Rehovot 76100, Israel, Institute for Applied Research, Ben Gurion University of the Negev, Beer-Sheva, Israel Ginzberg, I., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Gafni, Y., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Galili, G., Department of Plant Genetics, Weizmann Institute of Science, Rehovot 76100, Israel Kapulnik, Y., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel
A differentially displayed cDNA clone (MD17) was isolated from tobacco roots (Nicotiana tabacum cv. Xanthi-nc) infected with the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The isolated DNA fragment exhibited a reduced level of expression in response to AM establishment and 90% identity with the 3' noncoding sequence of two basic chitinases (EC 3.2.1.14) from N. tabacum. Northern (RNA) blots and Western blots (immunoblots), probed with tobacco basic chitinase gene-specific probe and polyclonal antibodies raised against the chitinase enzyme, yielded hybridization patterns similar to those of MD17. Moreover, the up-regulation of the 32-kDa basic chitinase gene expression in tobacco roots by (1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) was less effective in mycorrhizal roots than in nonmycorrhizal controls. Suppression of endogenous basic chitinase (32-kDa) expression was also observed in transgenic mycorrhizal plants that constitutively express the 34-kDa basic chitinase A isoform. When plants were grown with an increased phosphate supply, no suppression of the 32-kDa basic chitinase was obtained. These findings indicate that during the colonization and establishment of G. intraradices in tobacco roots, expression of the basic chitinase gene is down-regulated at the mRNA level.
Suppression of tobacco basic chitinase gene expression in response to colonization by the arbuscular mycorrhizal fungus Glomus intraradices
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David, R., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Itzhaki, H., Department of Plant Genetics, Weizmann Institute of Science, Rehovot 76100, Israel, Institute for Applied Research, Ben Gurion University of the Negev, Beer-Sheva, Israel Ginzberg, I., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Gafni, Y., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel Galili, G., Department of Plant Genetics, Weizmann Institute of Science, Rehovot 76100, Israel Kapulnik, Y., Institute of Field and Garden Crops, ARO, Volcani Center, Bet Dagan 50250, Israel
Suppression of tobacco basic chitinase gene expression in response to colonization by the arbuscular mycorrhizal fungus Glomus intraradices
A differentially displayed cDNA clone (MD17) was isolated from tobacco roots (Nicotiana tabacum cv. Xanthi-nc) infected with the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The isolated DNA fragment exhibited a reduced level of expression in response to AM establishment and 90% identity with the 3' noncoding sequence of two basic chitinases (EC 3.2.1.14) from N. tabacum. Northern (RNA) blots and Western blots (immunoblots), probed with tobacco basic chitinase gene-specific probe and polyclonal antibodies raised against the chitinase enzyme, yielded hybridization patterns similar to those of MD17. Moreover, the up-regulation of the 32-kDa basic chitinase gene expression in tobacco roots by (1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) was less effective in mycorrhizal roots than in nonmycorrhizal controls. Suppression of endogenous basic chitinase (32-kDa) expression was also observed in transgenic mycorrhizal plants that constitutively express the 34-kDa basic chitinase A isoform. When plants were grown with an increased phosphate supply, no suppression of the 32-kDa basic chitinase was obtained. These findings indicate that during the colonization and establishment of G. intraradices in tobacco roots, expression of the basic chitinase gene is down-regulated at the mRNA level.