Work

The development of Alternaria alternata is prevented by chitinases and ß-1,3- glucanases from Citrus limon seedlings

Year: 2003

Type: article

Abstract: In addition to phytoalexin synthesis, the defense response of intact Citrus limon seedlings against Alternaria alternata involves both constitutive and induced enzyme activities such as chitinases (Ch) and beta-1,3-glucanases (Glu). A alternata conidial germination was prevented by protein extracts from inoculated lemon seedlings, but also by extracts from mock-inoculated specimens. On the other hand, degradation of mycelia was accomplished only by protein extracts from inoculated seedlings. The presence of six Ch isoenzymes and of four Glu isoenzymes was detected in protein extracts from mock-inoculated seedlings. As a result of fungal inoculation, the isoenzyme pattern of Ch and Glu changed, making possible the detection of a new Ch isoenzyme and of three new Glu. Also, some constitutive Ch and Glu increased their enzyme activity, and those Ch that increased their activity also showed a broadening of their substrate specificity. These changes were prevented by alpha-amanitin and cycloheximide, suggesting that the presence of new Ch and Glu isoenzymes was due to de novo synthesis of proteins. Results suggest that constitutive Ch and Glu could act as pre-formed defense molecules in Citrus limon preventing A. alternata germination, while those induced after fungal inoculation of lemon seedlings could act along with the former, to produce lysis of fungal mycelia, resulting in a more efficient control of A. alternata development.

Source: Biological Research

DOI: 10.4067/s0716-97602003000300012

Authors: NORA FANTA, XIMENA ORTEGA, LUZ M PÉREZ

Institutions: University of Chile, Universidad Andrés Bello

Language: English

Topic: Plant-Microbe Interactions and Immunity

Subfield: Plant Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: hybrid

Estimated APC paid: $2,790