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Abstract

Arbuscular mycorrhiza activates the expression of a metallothionein-encoding plant gene in Pisum sativum L.

In order to analyze expression of a metallothionein (MT) encoding plant gene in the arbuscular mycorrhizal symbiosis, transcript quantification was carried out using wild-type Pisum sativum (cv. Finale) and a defective myc genotype mutated for the sym36 gene (RisNod24), where the fungal partner is not able to form functional arbuscules. Roots of G. intraradices-inoculated cv. Finale were colonized by the mycorrhizal fungus but not nodulated and all stages of fungal development were present three to five weeks after inoculation. Only appressoria and hyphae were present in roots of the mutant RisNod24, but no arbuscules. After three and five week’s development, the intensity of root cortex colonization in cv. Finale plants was 61% and 50%, respectively, while roots of the mutant RisNod24 exhibited 7% and 5%, respectively. The expression profile of the MT-encoding gene in roots of both pea genotypes was similar after one week development. However, in three and five week-old cv. Finale accumulation of the PsMT(A) transcripts was ten and two-fold higher, respectively, than in the mutant RisNod24. The protein encoded by the PsMT(A) gene could be involved in metal transport and/or homeostasis as well as in strategies of tolerance of heavy metal toxicity in the mycorrhizal symbiosis.



Rivera-Becerril, F.; Franken, P.; Gianinazzi, S.; Gianinazzi-Pearson, V. 2006. Arbuscular mycorrhiza activates the expression of a metallothionein-encoding plant gene in Pisum sativum L. Revista Mexicana de Micologia 22, 1-6.