TY - JOUR
T1 - Colletotrichum gloeosporioides pelB is an important virulence factor in avocado fruit-fungus interaction
AU - Yakoby, N.
AU - Beno-Moualem, D.
AU - Keen, N. T.
AU - Dinoor, A.
AU - Pines, O.
AU - Prusky, D.
PY - 2001
Y1 - 2001
N2 - Colletotrichum gloeosporioides is an important pathogen of tropical and subtropical fruits. The C. gloeosporioides pelB gene was disrupted in the fungus via homologous recombination. Three independent isolates, GD-14, GD-23, and GD-29, did not produce or secrete pectate lyase B (PLB) and exhibited 25% lower pectate lyase (PL) and pectin lyase (PNL) activities and 15% higher polygalacturonase (PG) activity than the wild type. The PLB mutants exhibited no growth reduction on glucose, Na polypectate, or pectin as the sole carbon source at pH 3.8 or 6.0, except for a 15% reduction on pectin at pH 6.0. When pelB mutants were inoculated onto avocado fruits, however, a 36 to 45% reduction in estimated decay diameter was observed compared with the two controls, the wild type and undisrupted transformed isolate. In addition, these pelB mutants induced a significantly higher host phenylalanine ammonia lyase activity as well as the antifungal diene, which is indicative of higher host resistance. These results suggest that PLB is an important factor in the attack of C. gloeosporioides on avocado fruit, probably as a result of its virulence factor and role in the induction of host defense mechanisms.
AB - Colletotrichum gloeosporioides is an important pathogen of tropical and subtropical fruits. The C. gloeosporioides pelB gene was disrupted in the fungus via homologous recombination. Three independent isolates, GD-14, GD-23, and GD-29, did not produce or secrete pectate lyase B (PLB) and exhibited 25% lower pectate lyase (PL) and pectin lyase (PNL) activities and 15% higher polygalacturonase (PG) activity than the wild type. The PLB mutants exhibited no growth reduction on glucose, Na polypectate, or pectin as the sole carbon source at pH 3.8 or 6.0, except for a 15% reduction on pectin at pH 6.0. When pelB mutants were inoculated onto avocado fruits, however, a 36 to 45% reduction in estimated decay diameter was observed compared with the two controls, the wild type and undisrupted transformed isolate. In addition, these pelB mutants induced a significantly higher host phenylalanine ammonia lyase activity as well as the antifungal diene, which is indicative of higher host resistance. These results suggest that PLB is an important factor in the attack of C. gloeosporioides on avocado fruit, probably as a result of its virulence factor and role in the induction of host defense mechanisms.
KW - Gene knockout
KW - Induced resistance
KW - Pectolytic enzymes
UR - http://www.scopus.com/inward/record.url?scp=0034921938&partnerID=8YFLogxK
U2 - 10.1094/MPMI.2001.14.8.988
DO - 10.1094/MPMI.2001.14.8.988
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C2 - 11497471
AN - SCOPUS:0034921938
SN - 0894-0282
VL - 14
SP - 988
EP - 995
JO - Molecular Plant-Microbe Interactions
JF - Molecular Plant-Microbe Interactions
IS - 8
ER -