Two pectin lyase genes, pnl-1 and pnl-2, from Colletotrichum gloeosporioides f. sp. malvae differ in a cellulose-binding domain and in their expression during infection of Malva pusilla.

Microbiology (Reading) 2002 Jul;148(Pt 7):2149-2157

Department of Environmental Biology, University of Guelph, Guelph, Ontario, , Canada N1G 2W11.

Two pectin lyase genes, designated pnl-1 and pnl-2, were cloned from Colletotrichum gloeosporioides f. sp. malvae, a pathogen of round-leaved mallow (Malva pusilla). pnl-1 was isolated using cDNA from infected plant material; pnl-2 was isolated using cDNA from 3-day-old mycelia grown in mallow-cell-wall extract (MCWE) broth. pnl-1 is the first pectinase gene described thus far to encode a cellulose-binding domain (CBD), which is common in cellulases and xylanases, whereas pnl-2 encodes a pectin lyase that lacks a CBD. In pure culture, pnl-1 expression could be detected when purified pectin or glucose was the sole carbon source, but not when MCWE was the sole carbon source. The lack of pnl-1 expression appeared to be due to gene repression by some unknown factor(s) in the cell-wall extract. In contrast, expression of pnl-2 was detected in cultures when MCWE, but not when purified pectin or glucose, was the sole carbon source. In infected tissue, detection of pnl-1 expression by Northern-blot hybridization and by RT-PCR began with the onset of the necrotrophic phase of infection. Expression ofpnl-2 was not detectable by Northern-blot hybridization, but was observed byRT-PCR in both the biotrophic and necrotrophic phases of infection. The differences between pnl-1 and pnl-2 (i.e. pnl-1 encoding a CBD and differences in the expression patterns of both genes) may be related to the requirements of C. gloeosporioides f. sp. malvae to be able to grow in host tissue under the different conditions present during the biotrophic and necrotrophic phases of infection.

Download full-text PDF

Source
http://dx.doi.org/10.1099/00221287-148-7-2149DOI Listing
July 2002
7 Reads

Publication Analysis

Top Keywords

pnl-1 expression
12
sole carbon
12
gloeosporioides malvae
12
carbon source
12
pnl-1 pnl-2
12
pectin lyase
12
pnl-1
9
pectin glucose
8
purified pectin
8
cellulose-binding domain
8
isolated cdna
8
phases infection
8
biotrophic necrotrophic
8
northern-blot hybridization
8
necrotrophic phases
8
malva pusilla
8
glucose sole
8
lyase genes
8
colletotrichum gloeosporioides
8
expression
7

Similar Publications