Ambient pH-regulated enzime secretion in endophytic and pathogenic isolates of the fungal genus Colletotrichum

Authors

  • Walter Maccheroni Jr. Allelyx Applied Genomics
  • Welington Luiz Araújo Universidade de São Paulo; Escola Superior de Agronomia Luiz de Queiroz; Depto. de Genética
  • João Lúcio Azevedo UMC; Núcleo Integrado de Biotecnologia

DOI:

https://doi.org/10.1590/S0103-90162004000300010

Keywords:

Glomerella, enzyme secretion, endophytes, pathogenic fungi, pacC

Abstract

In fungi a genetic system ensures that enzymes are secreted mainly at ambient pH values corresponding to their optima of activity. Although a great deal of information has been obtained concerning this environmental response, there is a lack of studies involving phytopathogenic, endophytic and entomopathogenic fungi as well as different aspects of fungus-host interactions. This study compares in a plate-clearing assays, the effect of ambient pH in the secretion of amylase, cellulase, lipase, pectinase and protease by endophytic, phytopathogenic, and entomopathogenic isolates belonging to several species of Colletotrichum. All enzymes were secreted in a pH-dependent manner by all isolates. Endophytes and pathogens showed distinct patterns of protease secretion, with optima at alkaline and acid growth conditions, respectively. In liquid medium, a Pi-repressible acid phosphatase of an endophytic isolate responded to ambient pH, having a 14-fold increase in secreted specific activity at acid pH, as compared to alkaline pH. Furthermore, part of a Colletotrichum pacC homologue gene, coding for a transcriptional factor responsible for pH-regulated gene expression, was cloned. Ambient pH seems to be a general factor controlling enzyme secretion in fungus-host interactions through a conserved genetic circuit.

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Published

2004-06-01

Issue

Section

Genetics and Plant Breeding

How to Cite

Ambient pH-regulated enzime secretion in endophytic and pathogenic isolates of the fungal genus Colletotrichum . (2004). Scientia Agricola, 61(3), 298-302. https://doi.org/10.1590/S0103-90162004000300010