Open AccessMycorrhiza-Induced Changes in Disease Severity and PR Protein Expression in Tobacco Leaves
Author(s) -
Orna Shaul,
Shmuel Galili,
Hanne Volpin,
Idit Ginzberg,
Y. Elad,
I. Chet,
Yoram Kapulnik
Publication year - 1999
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.1999.12.11.1000
Subject(s) - nicotiana tabacum , biology , botrytis cinerea , salicylic acid , mutant , pathogenesis related protein , mycorrhiza , glomus , arbuscular mycorrhiza , botany , fungus , gene expression , plant disease resistance , symbiosis , horticulture , microbiology and biotechnology , gene , bacteria , spore , biochemistry , genetics
The development of leaf disease symptoms and the accumulation of pathogenesis-related (PR) proteins were monitored in leaves of tobacco (Nicotiana tabacum cv. Xanthinc) plants colonized by the arbuscular mycorrhizal fungus Glomus intraradices. Leaves of mycorrhizal plants infected with the leaf pathogens Botrytis cinerea or tobacco mosaic virus showed a higher incidence and severity of necrotic lesions than those of nonmycorrhizal controls. Similar plant responses were obtained at both low (0.1 mM) and high (1.0 mM) nutritional P levels and with mutant plants (NahG) that are unable to accumulate salicylic acid. Application of PR-protein activators induced PR-1 and PR-3 expression in leaves of both nonmycorrhizal and mycorrhizal plants; however, accumulation and mRNA steady-state levels of these proteins were lower, and their appearance delayed, in leaves of the mycorrhizal plants. Application of 0.3 mM phosphate to the plants did not mimic the delay in PR expression observed in the mycorrhizal tobacco. Together, these data strongly support the existence of regulatory processes, initiated in the roots of mycorrhizal plants, that modify disease-symptom development and gene expression in their leaves.