Possible roles and functions of LPL1 gene encoding lysophospholipase during early infection by Magnaporthe grisea

Abstract

The rice blast fungus Magnaporthe grisea differentiates appressoria, which are required to attack its rice plant host. Clone A26, tentatively named LPL1, was previously found to be homologous to the known lysophospholipase genes from our subtractive cDNA library. The LPL1 protein had a consensus motif (GxSxG) and a catalytic triad (S, D, H) of esterases in the deduced amino acid sequence, and the protein expressed in Escherichia coli had lysophospholipase activity. To clarify the functions and possible roles of LPL1, the gene was disrupted by targeted gene replacement. The DLPL1 mutants formed fewer appressoria on the hydrophobic surface of GelBond film, and the appressoria had reduced turgor pressure and penetration into cells of the leaf sheath. The DLPL1 mutants and wild-type differentiated normal appressoria on other artificial substrata such as polycarbonate plate and on rice leaf sheath. Cytological analysis of the appressoria indicated that DLPL1 mutants had a delay in the disappearance of lipid droplets. These findings imply that LPL1, phospholipid metabolism, or both are involved in glycerol biosynthesis and accumulation to generate turgor pressure in the appressorium. LPL1 was, however, dispensable for full pathogenicity, suggesting that other complementary pathways or similar genes related to phospholipid metabolism probably function in M. grisea.

A Conserved Carboxylesterase Is a SUPPRESSOR OF AVRBST-ELICITED RESISTANCE inArabidopsis

“…In addition to our study, there is one report of a cellular phenotype associated with an APT1/LysoPLA1 mutation. Gene replacement of the Magnaporthe grisea LPL1 gene caused defects in apressoria formation and penetration into leaf cells (Kanamori et al, 2005).…”

Effect of culture age on mepanipyrim-mediated inhibition of pectinase secretion in Botrytis cinerea

“…The biological and cytological properties of fungi change from the mycelial base to the top, 12,13) and different genes are expressed in the germ tube than in the vegetatively growing mycelium, 14,15) therefore, these differences can affect the activity of mepanipyrim. However, our results suggested that the differences in mepanipyrim activities on germ tubes and mycelia correlate with the age of the culture.…”

Molecular biological studies on appressorium formation in the rice blast fungus

“…Next, this gene expression was analyzed in more detail, and genes upregulated in appressorium-forming conditions compared with vegetatively growing mycelia were isolated as candidate genes related to appressorium formation. To elucidate the function of the isolated genes, we generated null mutants of each gene and characterized their phenotypes (Kamakura et al 2002;Saitoh et al 2003;Kanamori et al 2005). In addition, to enhance the analysis of the genes, we developed a GFP-tagging gene knockout (GGKO) method that enables expression and functional analysis of a gene simultaneously (Saitoh et al 2008) and devised a simple method to obtain fungal DNA for molecular biological analyses (Saitoh et al 2006).…”