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

Scientia Agricola

Walter Maccheroni Jr.²  Welington Luiz Araújo¹  João Lúcio Azevedo¹ 

[1] ,Allelyx Applied GenomicsCampinas SP ,Brasil

关键词: Glomerella;    enzyme secretion;    endophytes;    pathogenic fungi;    pacC;    Glomerella;    secreção enzimática;    endófitos;    fungo patogênico;    pacC;   

DOI  :  10.1590/S0103-90162004000300010

来源: SciELO

【 摘 要 】

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.

【 授权许可】

CC BY   
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