ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

A nonpathogenic mutant of Colletotrichum magna is deficient in extracellular secretion of pectate lyase.

Wattad, C.; Freeman, S.; Dinoor, A.; Prusky, D.;

Molecular Plant-Microbe Interactions Year: 1995 Vol: 8 Issue: 4 Pages: 621-626 Ref: 26 ref.

1995

บทคัดย่อ

A nonpathogenic mutant strain (path-1) of C. magna was isolated and grew endophytically in cucurbit seedlings. Decay development on the pericarp of avocado fruits was significantly delayed in the wild-type (wt) isolate of C. magna compared with C. gloeosporioides [Glomerella cingulata] isolate Cg-14, but both isolates colonized mesocarp tissue equally well. However, path 1 did not cause disease symptoms in either the pericarp or the mesocarp. Electrofocussing of culture filtrates of Colletotrichum strains revealed the presence of pectate lyase (PL) and polygalacturonase (PG) at pIs of 7.9 and 4.8, respectively, but no significant activity from path-1 was detected. Western blots detected PL in avocado fruit tissue infected by Cg-14 and wild-type C. magna. DNA of the 3 Colletotrichum isolates hybridized to a pel probe from G. cingulata suggesting that at the DNA level no deletion in the pel gene was evident in path-1. Similar levels of pel mRNA expression were also found for wild type and path-1 o

f C. magna, and Cg-14 of G. cingulata. However, when PL antibodies were cross-reacted with cell lysate of Colletotrichum strains, PL accumulated in the hyphae of path-1 of C. magna, but was not detected in Cg-14 cell lysate. It is suggested that the malfunction in extracellular secretion of PL proteins results in differential pathogenicity of path-1 isolate on avocado.