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Chitinase Activity in Stylosanthes guianensis Systemically Protected Against Colletotricbum gloeosporioides
Author(s) -
Brown AverilE.,
Davis RobertD.
Publication year - 1992
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1992.tb01304.x
Subject(s) - chitinase , biology , inoculation , mycelium , virulence , microbiology and biotechnology , glucanase , pathogen , botany , fungi imperfecti , colletotrichum gloeosporioides , hypha , horticulture , enzyme , biochemistry , gene
Three‐ and four‐fold increases in chitinase activity were detected in the youngest, fully expanded leaf (L 1 ) of Stylosanthes guianensis cv. Endeavour following inoculation of the second youngest, fully expanded leaf (L 2 ) with virulent Type B and Type A isolates of Colletotrichum gloeosporioides compared with chitinase activity in L 1 leaves of uninoculated plants. Only small increases in β‐1,3‐glucanase were detected in L 1 leaves of systemically protected plants. Chitinase activity was maximal in leaf L 1 36 to 48 h after inoculation of leaf L 2 , and this was coincident with the onset of resistance to anthracnose in L 1 leaves. Chitinase activity also increased in L 1 leaves inoculated with a weakly pathogenic isolate of C. gloeosporioides . Resistance developed in these L 1 leaves to subsequent infection by a virulent isolate of the pathogen approximately 36 h after protective‐inoculation with the weakly pathogenic isolate. Two chitinase isozymes, with molecular weights of 65,000 daltons (pI 3.1) and 54,000 daltons (pI 4.0), were separated from extracts of C. gloeosporioides ‐challenged S. guianensis cv. Endeavour leaves. S. guianensis chitinase caused death of C. gloeosporioides hyphae, particularly in the presence of β‐1,3‐glucanase. Mycelial viability declined as activity of chitinase was increased in mixtures containing a fixed activity of β‐l,3‐glucanase.