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Maina AW, Oerke EC. Hyperspectral imaging for quantifying Magnaporthe oryzae sporulation on rice genotypes. PLANT METHODS 2024; 20:87. [PMID: 38849955 PMCID: PMC11161989 DOI: 10.1186/s13007-024-01215-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 05/29/2024] [Indexed: 06/09/2024]
Abstract
BACKGROUND Precise evaluation of fungal conidia production may facilitate studies on resistance mechanisms and plant breeding for disease resistance. In this study, hyperspectral imaging (HSI) was used to quantify the sporulation of Magnaporthe oryzae on the leaves of rice cultivars grown under controlled conditions. Three rice genotypes (CO 39, Nipponbare, IR64) differing in susceptibility to blast were inoculated with M. oryzae isolates Guy 11 and Li1497. Spectral information (450-850 nm, 140 wavebands) of typical leaf blast symptoms was recorded before and after induction of sporulation of the pathogen. RESULTS M. oryzae produced more conidia on the highly susceptible genotype than on the moderately susceptible genotype, whereas the resistant genotype resulted in no sporulation. Changes in reflectance spectra recorded before and after induction of sporulation were significantly higher in genotype CO 39 than in Nipponbare. The spectral angle mapper algorithm for supervised classification allowed for the classification of blast symptom subareas and the quantification of lesion areas with M. oryzae sporulation. The correlation between the area under the difference spectrum (viz. spectral difference without and with sporulation) and the number of conidia per lesion and the number of conidia per lesion area was positive and count-based differences in rice - M. oryzae interaction could be reproduced in the spectral data. CONCLUSIONS HSI provided a precise and objective method of assessing M. oryzae conidia production on infected rice plants, revealing differences that could not be detected visually.
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Affiliation(s)
- Angeline Wanjiku Maina
- Institute for Crop Science and Resource Conservation (INRES) - Plant Pathology, Rheinische Friedrich-Wilhelms University of Bonn, Bonn, Germany.
| | - Erich-Christian Oerke
- Institute for Crop Science and Resource Conservation (INRES) - Plant Pathology, Rheinische Friedrich-Wilhelms University of Bonn, Bonn, Germany
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Lu K, Chen R, Yang Y, Xu H, Jiang J, Li L. Involvement of the Cell Wall-Integrity Pathway in Signal Recognition, Cell-Wall Biosynthesis, and Virulence in Magnaporthe oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:608-622. [PMID: 37140471 DOI: 10.1094/mpmi-11-22-0231-cr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The fungal cell wall is the first layer exposed to the external environment. The cell wall has key roles in regulating cell functions, such as cellular stability, permeability, and protection against stress. Understanding the structure of the cell wall and the mechanism of its biogenesis is important for the study of fungi. Highly conserved in fungi, including Magnaporthe oryzae, the cell wall-integrity (CWI) pathway is the primary signaling cascade regulating cell-wall structure and function. The CWI pathway has been demonstrated to correlate with pathogenicity in many phytopathogenic fungi. In the synthesis of the cell wall, the CWI pathway cooperates with multiple signaling pathways to regulate cell morphogenesis and secondary metabolism. Many questions have arisen regarding the cooperation of different signaling pathways with the CWI pathway in regulating cell-wall synthesis and pathogenicity. In this review, we summarized the latest advances in the M. oryzae CWI pathway and cell-wall structure. We discussed the CWI pathway components and their involvement in different aspects, such as virulence factors, the possibility of the pathway as a target for antifungal therapies, and crosstalk with other signaling pathways. This information will aid in better understanding the universal functions of the CWI pathway in regulating cell-wall synthesis and pathogenicity in M. oryzae. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Kailun Lu
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Rangrang Chen
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Yi Yang
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Hui Xu
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Jihong Jiang
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Lianwei Li
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Guegan H, Poirier W, Ravenel K, Dion S, Delabarre A, Desvillechabrol D, Pinson X, Sergent O, Gallais I, Gangneux JP, Giraud S, Gastebois A. Deciphering the Role of PIG1 and DHN-Melanin in Scedosporium apiospermum Conidia. J Fungi (Basel) 2023; 9:jof9020134. [PMID: 36836250 PMCID: PMC9965090 DOI: 10.3390/jof9020134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
Scedosporium apiospermum is a saprophytic filamentous fungus involved in human infections, of which the virulence factors that contribute to pathogenesis are still poorly characterized. In particular, little is known about the specific role of dihydroxynaphtalene (DHN)-melanin, located on the external layer of the conidia cell wall. We previously identified a transcription factor, PIG1, which may be involved in DHN-melanin biosynthesis. To elucidate the role of PIG1 and DHN-melanin in S. apiospermum, a CRISPR-Cas9-mediated PIG1 deletion was carried out from two parental strains to evaluate its impact on melanin biosynthesis, conidia cell-wall assembly, and resistance to stress, including the ability to survive macrophage engulfment. ΔPIG1 mutants did not produce melanin and showed a disorganized and thinner cell wall, resulting in a lower survival rate when exposed to oxidizing conditions, or high temperature. The absence of melanin increased the exposure of antigenic patterns on the conidia surface. PIG1 regulates the melanization of S. apiospermum conidia, and is involved in the survival to environmental injuries and to the host immune response, that might participate in virulence. Moreover, a transcriptomic analysis was performed to explain the observed aberrant septate conidia morphology and found differentially expressed genes, underlining the pleiotropic function of PIG1.
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Affiliation(s)
- Hélène Guegan
- CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
- Correspondence: ; Tel.: +33-223233496
| | - Wilfried Poirier
- University of Angers, University of Brest, IRF, SFR ICAT, 49000 Angers, France
| | - Kevin Ravenel
- University of Angers, University of Brest, IRF, SFR ICAT, 49000 Angers, France
| | - Sarah Dion
- INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
| | - Aymeric Delabarre
- INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
| | - Dimitri Desvillechabrol
- Institut Pasteur, Université Paris Cité, Plate-Forme Technologique Biomics, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Xavier Pinson
- CNRS, INSERM, Biosit UAR 3480 US_S 018, MRic Core Facility, 35000 Rennes, France
| | - Odile Sergent
- INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
| | - Isabelle Gallais
- INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
| | - Jean-Pierre Gangneux
- CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail)—UMR_S 1085, 35000 Rennes, France
| | - Sandrine Giraud
- University of Angers, University of Brest, IRF, SFR ICAT, 49000 Angers, France
| | - Amandine Gastebois
- University of Angers, University of Brest, IRF, SFR ICAT, 49000 Angers, France
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The Plant Homeodomain Protein Clp1 Regulates Fungal Development, Virulence, and Autophagy Homeostasis in Magnaporthe oryzae. Microbiol Spectr 2022; 10:e0102122. [PMID: 36036638 PMCID: PMC9602895 DOI: 10.1128/spectrum.01021-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rice blast disease caused by Magnaporthe oryzae is a serious threat to global grain yield and food security. Cti6 is a nuclear protein containing a plant homeodomain (PHD) that is involved in transcriptional regulation in Saccharomyces cerevisiae. The biological function of its homologous protein in M. oryzae has been elusive. Here, we report Clp1 with a PHD domain in M. oryzae, a homologous protein of the yeast Cti6. Clp1 was mainly located in the nucleus and partly in the vesicles. Clp1 colocalized and interacted with the autophagy-related proteins Atg5, Atg7, Atg16, Atg24, and Atg28 at preautophagosomal structures (PAS) and autophagosomes, and the loss of Clp1 increased the fungal background autophagy level. Δclp1 displayed reduced hyphal growth and hyperbranching, abnormal fungal morphology (including colony, spore, and appressorium), hindered appressorial glycogen metabolism and turgor production, weakened plant infection, and decreased virulence. The PHD is indispensable for the function of Clp1. Therefore, this study revealed that Clp1 regulates development and pathogenicity by maintaining autophagy homeostasis and affecting gene transcription in M. oryzae. IMPORTANCE The fungal pathogen Magnaporthe oryzae causes serious diseases of grasses such as rice and wheat. Autophagy plays an indispensable role in the pathogenic process of M. oryzae. Here, we report a Cti6-like protein, Clp1, that is involved in fungal development and infection of plants through controlling autophagy homeostasis in the cytoplasm and gene transcription in the nucleus in M. oryzae. This study will help us to understand an elaborated molecular mechanism of autophagy, gene transcription, and virulence in the rice blast fungus.
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Nucleosome Assembly Protein 1, Nap1, Is Required for the Growth, Development, and Pathogenicity of Magnaporthe oryzae. Int J Mol Sci 2022; 23:ijms23147662. [PMID: 35887015 PMCID: PMC9316785 DOI: 10.3390/ijms23147662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 02/06/2023] Open
Abstract
Magnaporthe oryzae is the causal agent of rice blast, leading to significant reductions in rice and wheat productivity. Nap1 is a conserved protein in eukaryotes involved in diverse physiological processes, such as nucleosome assembly, histone shuttling between the nucleus and cytoplasm, transcriptional regulation, and the cell cycle. Here, we identified Nap1 and characterized its roles in fungal development and virulence in M. oryzae. MoNap1 is involved in aerial hyphal and conidiophore differentiation, sporulation, appressorium formation, plant penetration, and virulence. ΔMonap1 generated a small, elongated, and malformed appressorium with an abnormally organized septin ring on hydrophobic surfaces. ΔMonap1 was more sensitive to cell wall integrity stresses but more resistant to microtubule stresses. MoNap1 interacted with histones H2A and H2B and the B-type cyclin (Cyc1). Moreover, a nuclear export signal (NES) domain is necessary for Nap1’s roles in the regulation of the growth and pathogenicity of M. oryzae. In summary, NAP1 is essential for the growth, appressorium formation, and pathogenicity of M. oryzae.
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