A carnitine–acylcarnitine carrier protein, MoCrc1, is essential for pathogenicity in Magnaporthe oryzae

Abstract

The rice blast fungus Magnaporthe oryzae forms a specialized infection structure called an appressorium to breach the host-plant epidermis for successful infection. In this study, a mutant defective in appressorial penetration was isolated by a mutagenesis approach, in which an exogenous DNA fragment was found to be inserted into the first exon of MoCRC1. This gene encodes a putative carnitine-acylcarnitine carrier protein that is widely conserved among eukaryotic organisms. Deletion of MoCRC1 severely reduces appressorium turgor generation, appressorial penetration, and development of infection hyphae. The null mutant of MoCRC1 lost pathogenicity on intact and abraded host leaves. MoCRC1 was also found to be required for growth on minimal medium containing sodium acetate or olive oil. Moreover, the transformed MoCrc1-eGFP fusion protein was expressed throughout the infection process. Our results suggest that the carnitine-acylcarnitine carrier protein plays vital roles in appressorium-mediated infection and is essential for pathogenesis of M. oryzae and perhaps other phytopathogenic fungi.

Glutamate synthase MoGlt1‐mediated glutamate homeostasis is important for autophagy, virulence and conidiation in the rice blast fungus

“…The 1.42‐kb upstream and 1.48‐kb downstream fragments of MoGLT1 were amplified with primers upf/upr and downf/downr. The resulting PCR products were cloned into the Cla I/ Kpn I and Bam HI/ Eco RI sites of pKOV21 to generate pKGLT1, and the vector was then introduced into the wild‐type strain P131 (Yang et al ., ). The putative MoGLT1 deletion mutants were screened by PCR with the primer pairs out1/hu and out2/hd, and then confirmed by DNA gel blot hybridizations using the 1.42‐kb upstream fragments as a probe.…”

“…The putative MoGLT1 deletion mutants were screened by PCR with the primer pairs out1/hu and out2/hd, and then confirmed by DNA gel blot hybridizations using the 1.42‐kb upstream fragments as a probe. For complementation assay, MoGLT1 , together with its 1.5‐kb upstream and 0.5‐kb downstream sequences, was amplified with the primer pair hbup/hbdown, and cloned into the Eco RI and Sma I sites in pKN harbouring the NPTII gene (Yang et al ., ) as pCGLT1. After linearization, pCGLT1 was transformed into the ΔMoglt1 mutant.…”

Crosstalk between SNF1 Pathway and the Peroxisome-Mediated Lipid Metabolism in Magnaporthe oryzae

“…The fatty acid β-oxidation, occurred predominantly in peroxisome, leads to the generation of acetyl-CoA pool, which is available for melanin biosynthesis pathway and also fuels fungal cell wall biosynthesis via the glyoxylate bypass and gluconeogenesis during plant infection [30], [31], [32]. The importance of such process is highlighted by the fact that mutants impaired in peroxisome biosynthesis [30], [33], [34], β-oxidation [35], carnitine acetyl transfer system [31], [36], or glyoxylate cycle [29] are non-pathogenic. Meanwhile, recent transcriptomic analysis independently confirms the pivotal role of peroxisomal acetyl-CoA production during appressorial development [37].…”

Roles of Peroxisomes in the Rice Blast Fungus

“…The M. oryzae MoCRC1 deletion mutant is severely reduced in appressorial penetration and invasive growth. MoCRC1 is also needed for utilization of olive oil [49]. …”

“…The Δ mocrc1 deletion mutant is severely reduced in penetration and invasive growth. The β -oxidation can also occur in mitochondria [49]. However, it seems like that the peroxisomal β -oxidation is important for appressoria-mediated penetration, while the mitochondrial β -oxidation functions in conidial viability and keeping redox homeostasis during host colonization.…”