关键词: 柑橘, 胶孢炭疽菌, 细胞壁降解酶, 细胞壁成分, 防御酶

Abstract:

Objective: To examine dynamic changes in the activities of various cell wall-degrading enzymes (CWDEs),
the contents of cell wall components and the activities of defense-related enzymes in citrus pericarp tissues infected with
Colletotrichum gloeosporioides, aiming to gain more knowledge on the interaction between C. gloeosporioides and citrus
fruits. Methods: Chemical components of the pericarp of citrus fruit inoculated with C. gloeosporioides were detected and
comparatively analyzed during different sampling periods. Results: The activities of CWDEs including polygalacturonase
(PG), polymethyl-galacturonase (PMG), carboxymethyl cellulose (Cx) and β-glucosidase (β-Glu) were detected in the
infected tissue. The activities of CWDEs and cutinase remained at higher levels during the early infection period (day one
to three post infection). The cell wall components including cellulose, hemicellulose and pectin showed a declining trend,
but lignin content showed a rising trend during the infection of C. gloeosporioides. The activities of peroxidase (POD)
and catalase (CAT) and the content of malonaldehyde (MDA) showed a rising trend in the citrus pericarp tissues infected
with C. gloeosporioides. Conclusion: The CWDEs and cutinase play an important pathogenic role during the early stage
of anthracnose, which accelerates the infection of pathogenic fungi by degrading the cell wall components. In addition, the
infection of C. gloeosporioides accelerates membrane lipid peroxidation in host cells.

Key words: citrus, Colletotrichum gloeosporioides, cell wall-degrading enzymes, cell wall components, defense-related enzymes