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Brazilian Journal of Biology

Print version ISSN 1519-6984

Abstract

SANTOS, B. A. et al. Effect of arbuscular mycorrhizal fungi and  soil phosphorus level on expression of protein and activity of peroxidase on passion fruit roots. Braz. J. Biol. [online]. 2001, vol.61, n.4, pp. 693-700. ISSN 1519-6984.  http://dx.doi.org/10.1590/S1519-69842001000400021.

The effects of mycorrhizal inoculation and increasing soil P levels on the expression of total proteins and peroxidase activity on passion fruit roots were evaluated. The experimental design was entirely at random, with four treatments of inoculation (a - control; b - Gigaspora albida; c - Scutellospora heterogama; d - mixture of G. albida, G. margarita, S. heterogama, and Glomus clarum) × three levels of soil P (4, 11, and 30 mg/dm3 of soil), each with three replicates. Plants were harvested 70 days after inoculation, when root colonization, shoot P level, protein content, and enzymatic activity of peroxidase (PAGE - 7%) on root extract were evaluated. Regarding protein, there was no significant difference among the treatments, except between those roots receiving mixed inoculum and 11 mg P/dm3 of soil. Effect of P on protein concentration, when compared with the inoculation effect was observed. For peroxidase, there was an eletrophoretic band common to all treatments (rf: 0.43) and another that was absent only in noncolonized plants, grown in soil with lower P (rf: 0.46). Mycorrhizal specific bands were not present but a small decrease of intensity of bands in noncolonized plants was observed. Conversely, the control roots presented a single band (rf: 0.33) not observed in the other extracts, that may demonstrate an inhibitory effect of AMF on some host activities. The data showed the influence of P level in soil on the protein expression of roots, suggesting the influence of this nutrient on root genetic expression as well as on the mechanisms of symbiotic control/recognition.

Keywords : mycorrhiza; root proteins; peroxidase; passion fruit.

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