Title |
Gene deletion and constitutive expression of the pectate lyase gene 1 (MoPL1) lead to diminished virulence of Magnaporthe oryzae |
Author |
Alex Wegner1†, Florencia Casanova1†, Marco Loehrer1, Angelina Jordine1, Stefan Bohnert1, Xinyu Liu2, Zhengguang Zhang2, and Ulrich Schaffrath1* |
Address |
1Department of Plant Physiology, RWTH Aachen University, Aachen 52056, Germany, 2Department of Plant Pathology, Nanjing Agricultural University, Jiangsu 210095, P. R. China |
Bibliography |
Journal of Microbiology, 60(1),79-88, 2022,
|
DOI |
10.1007/s12275-022-1074-7
|
Key Words |
Pyricularia oryzae, rice blast fungus, cell wall degrading
enzyme (CWDE), pectate lyase, MoPL1, virulence
factor, DAMP |
Abstract |
Phytopathogenic fungi are known to secrete specific proteins
which act as virulence factors and promote host colonization.
Some of them are enzymes with plant cell wall degradation capability,
like pectate lyases (Pls). In this work, we examined the
involvement of Pls in the infection process of Magnaporthe
oryzae, the causal agent of rice blast disease. From three Plgenes
annotated in the M. oryzae genome, only transcripts of
MoPL1 considerably accumulated during the infection process
with a peak at 72 h post inoculation. Both, gene deletion and
a constitutive expression of MoPL1 in M. oryzae led to a significant
reduction in virulence. By contrast, mutants that constitutively
expressed an enzymatic inactive version of MoPl1
did not differ in virulence compared to the wild type isolate.
This indicates that the enzymatic activity of MoPl1 is responsible
for diminished virulence, which is presumably due to
degradation products recognized as danger associated molecular
patterns (DAMPs), which strengthen the plant immune
response. Microscopic analysis of infection sites pointed to an
increased plant defense response. Additionally, MoPl1 tagged
with mRFP, and not the enzymatic inactive version, focally
accumulated in attacked plant cells beneath appressoria and
at sites where fungal hyphae transverse from one to another
cell. These findings shed new light on the role of pectate lyases
during tissue colonization in the necrotrophic stage of M.
oryzae's life cycle. |