المؤلفون: Elise J. Gay, Noémie Jacques, Nicolas Lapalu, Corinne Cruaud, Valerie Laval, Marie-Hélène Balesdent, Thierry Rouxel

المصدر: BMC Biology, Vol 21, Iss 1, Pp 1-20 (2023)

مصطلحات موضوعية: Leptosphaeria maculans, Leptosphaeria biglobosa, Brassica napus, Fungal biology, Transcriptomics, Tripartite interactions, Biology (General), QH301-705.5

الوصف: Abstract Background Leptosphaeria maculans “brassicae” (Lmb) and Leptosphaeria biglobosa “brassicae” (Lbb) make up a species complex involved in the stem canker (blackleg) disease of rapeseed (Brassica napus). They coinfect rapeseed together, from the early stage of infection on leaves to the final necrotic stage at the stem base, and both perform sexual crossings on plant residues. L. biglobosa is suggested to be a potential biocontrol agent against Lmb, but there has been no mechanistic investigation of the different types of interactions that may occur between the plant and the two fungal species. Results We investigated the bi- or tripartite interaction mechanisms by (i) confronting Lmb and Lbb in culture conditions or during cotyledon infection, with different timing and/or spore concentration regimes, (ii) performing RNA-Seq experiments in vitro or on the kinetics of infection of cotyledons infected by Lmb and/or Lbb to evaluate the transcriptomic activity and the plant response when both fungal species are inoculated together. Lbb infection of B. napus cotyledons was typical of a necrotrophic behavior, with a very early setup of one pathogenicity program and very limited colonization of tissues. This contrasted with the complex succession of pathogenicity programs of the hemibiotroph Lmb. During simultaneous co-infection by both species, Lmb was strongly impacted in its growth and transcriptomic dynamics both in vitro and in planta, while Lbb was unaffected by the presence of Lmb. However, the drastic inhibition of Lmb growth by Lbb was ineffective in the case of delayed inoculation with Lbb or a lower amount of spores of Lbb compared to Lmb. Conclusions Our data suggest that Lmb growth inhibition by Lbb is the result of a combination of factors that may include competition for trophic resources, the generation by Lbb of an environment unsuitable for the lifecycle of Lmb or/and the effect on Lmb of plant defense responses induced by Lbb. It indicates that growth inhibition occurs in very specific conditions (i.e., co-inoculation at the same place of an equal amount of inoculum) that are unlikely to occur in the field where their coexistence does not prevent any species from completing their life cycle.

وصف الملف: electronic resource

Relation: https://doaj.org/toc/1741-7007

URL الوصول: https://doaj.org/article/fb2036cc7a9640ef96c4932db1111d0d

المؤلفون: Gay, Elise J., Jacques, Noémie, Lapalu, Nicolas, Cruaud, Corinne, Laval, Valerie, Balesdent, Marie-Hélène, Rouxel, Thierry^{Aff1, IDs12915023017268_cor7}

المصدر: BMC Biology. 21(1)

المؤلفون: Junyu Cheng, Tao Luo, Mingde Wu, Long Yang, Weidong Chen, Guoqing Li, Jing Zhang

المصدر: Journal of Fungi, Vol 9, Iss 12, p 1167 (2023)

مصطلحات موضوعية: rapeseed, Leptosphaeria biglobosa, Didymella macrostoma, penicillither, biological control, Biology (General), QH301-705.5

الوصف: Eight fungal strains (P1 to P8) were isolated from rapeseed stems (Brassica napus) infected with the blackleg pathogen Leptosphaeria biglobosa (Lb). They formed pycnidia with similar morphology to those of Lb, and thus were considered as Lb relatives (LbRs). The species-level identification of these strains was performed. Their virulence on rapeseed and efficacy in the suppression of Lb infection were determined, and the biocontrol potential and biocontrol mechanisms of strain P2 were investigated. The results showed that the LbRs belong to two teleomorphic genera in the family Didymellaceae, Didymella for P1 to P7 and Boeremia for P8. Pathogenicity tests on rapeseed cotyledons and stems indicated the LbRs were weakly virulent compared to L. biglobosa. Co-inoculation assays on rapeseed cotyledons demonstrated that P1 to P7 (especially P1 to P4) had a suppressive effect on Lb infection, whereas P8 had a marginal effect on infection by L. biglobosa. Moreover, D. macrostoma P2 displayed a more aggressive behavior than L. biglobosa in the endophytic colonization of healthy rapeseed cotyledons. Cultures of P2 in potato dextrose broth (PDB) and pycnidiospore mucilages exuded from P2 pycnidia showed antifungal activity to L. biglobosa. Further leaf assays revealed that antifungal metabolites (AM) of strain P2 from PDB cultures effectively suppressed infection by L. biglobosa, Botrytis cinerea (gray mold), and Sclerotinia sclerotiorum (white mold). An antifungal metabolite, namely penicillither, was purified and identified from PDB cultures and detected in pycnidiospore mucilages of strain P2. This study suggests that the LbRs are a repertoire for screening biocontrol agents (BCAs) against rapeseed diseases, and D. macrostoma P2 is a multi-functional BCA, a penicillither producer, and an endophyte.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/2309-608X/9/12/1167; https://doaj.org/toc/2309-608X

URL الوصول: https://doaj.org/article/481b10ca00d2459a9fb5f9dd65184de7

المؤلفون: Kang Zhou, Jing Zhang, Long Yang, Guoqing Li, Mingde Wu

المصدر: Journal of Fungi, Vol 9, Iss 11, p 1092 (2023)

مصطلحات موضوعية: blackleg, Leptosphaeria biglobosa, genetic diversity, population structure, pathogenicity, Biology (General), QH301-705.5

الوصف: Phoma stem canker (blackleg), caused by the fungi Leptosphaeria maculans (anamorph Phoma lingam) and L. biglobosa, is one of the most devastating diseases in oilseed rape (Brassica napus L.) production worldwide. However, the population structure and genetic variation of L. biglobosa populations in China have rarely been investigated. Here, a collection of 214 fungal strains of blackleg from China (including Shaanxi, Jiangxi, Hubei, Jiangsu, Chongqing, Sichuan, Guangxi, Guizhou, Hunan, and Henan) and Europe (France and Ukraine) was identified as L. biglobosa. Three simple sequence repeat (SSR) markers were developed to characterize their population structure. The results showed that the Nei’s average gene diversity ranged from 0.6771 for the population from Jiangsu to 0.3009 for the population from Hunan. In addition, most of the genetic variability (96%) occurred within groups and there were only relatively small amounts among groups (4.0%) (FST = 0.043, p = 0.042 < 0.05). Pairwise population differentiation (FST) suggested that significant genetic differentiation was observed between different L. biglobosa populations. Bayesian and unweighted average method analysis revealed that these L. biglobosa strains were clustered into three branches, and three European strains were similar to those from eastern China. The pathogenicity assay showed that those in Group III were significantly more virulent than those in Group I (t = 2.69, p = 0.016). The study also showed that Group III was dominant in Chinese L. biglobosa populations, which provides new insights for the further study of population evolution and the management of this pathogen.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/2309-608X/9/11/1092; https://doaj.org/toc/2309-608X

URL الوصول: https://doaj.org/article/253579e0fcde434b9c5fa07b4ca85952

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المؤلفون: Kevin M. King, Gail Canning, Kang Zhou, Zekuan Liu, Mingde Wu, Jonathan S. West

المصدر: Pathogens, Vol 12, Iss 1, p 3 (2022)

مصطلحات موضوعية: blackleg, epidemiology, heterothallic, Leptosphaeria biglobosa, mating type, oilseed rape, Medicine

الوصف: Blackleg (Phoma) disease, caused by the ascomycete fungi Plenodomus biglobosus and P. lingam, threatens oilseed rape (OSR; Brassica napus) crops internationally. In many parts of the world, both species co-occur, but in China only P. biglobosus has so far been reported. Plenodomus biglobosus reproduces asexually (pycnidiospores), but also sexually (pseudothecia-yielding ascospores), via a heterothallic mating system requiring MAT1-1 and MAT1-2 genotypes. However, the roles of airborne ascospore inoculum in driving blackleg disease outbreaks in China are less well understood compared to elsewhere in the world. This is despite the very different agronomic cropping practices in parts of China, in which paddy rice and OSR are often grown in rotation; OSR stubble is often submerged under water for long periods potentially affecting pseudothecial development. Here, we indirectly investigate the potential role of sexual reproduction by developing new polymerase chain reaction (PCR) -based mating-type diagnostics for P. biglobosus and subsequently screening an international collection of 59 European and 157 Chinese isolates. Overall, in both Europe and China, P. biglobosus mating types did not deviate from a 1:1 ratio, such as is generally thought to occur under frequency-dependent selection in sexually reproducing pathogen populations. Both mating types were balanced in all the individual European countries tested (Austria, France, Poland, UK). Conversely, in China, mating types were only balanced in the eastern region; in the northern and southwestern regions there were skewed ratios, more typical of predominantly asexual reproduction, towards MAT1-1 and MAT1-2, respectively. The implications of these findings and future research directions for improved understanding of P. biglobosus epidemiology on OSR, particularly in China, are considered.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/2076-0817/12/1/3; https://doaj.org/toc/2076-0817

URL الوصول: https://doaj.org/article/d9956e4d8bd2438fab2f66b339f7622b

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المؤلفون: Omer, Zahra Saad^Aff1, Wallenhammar, Ann-Charlotte^{Aff2, Aff3}

المصدر: European Journal of Plant Pathology: Published in cooperation with the European Foundation for Plant Pathology. 157(2):353-365

المؤلفون: Kaluhannadige Rasanie Eranka Padmathilake, Wannakuwattewaduge Gerard Dilantha Fernando

المصدر: Plants, Vol 11, Iss 7, p 996 (2022)

مصطلحات موضوعية: Brassica napus, Leptosphaeria maculans, Leptosphaeria biglobosa, biological control, Botany, QK1-989

الوصف: Leptosphaeria biglobosa is a less virulent Leptosphaeria spp. that causes blackleg disease in canola. Previous studies from our lab have shown that inoculation with the less virulent L. biglobosa can boost the resistance of canola plants against the highly virulent L. maculans. The objective of this study was to confirm the effectiveness of L. biglobosa as a biocontrol agent against L. maculans utilizing morphology, fluorescence microscopy, gene quantification, and transcriptomic analysis. The in planta development of two Leptosphaeria species inoculated at different time points was assessed using fluorescent protein-tagged isolates which are GFP-tagged L. maculans and DsRed-tagged L. biglobosa. The growth inhibition of L. maculans by pre-and co-inoculated L. biglobosa was supported by no lesion development on cotyledons and no or weak fluorescence protein-tagged mycelia under the confocal microscope. The host defense-related genes, WRKY33, PR1, APX6, and CHI, were upregulated in L. biglobosa inoculated Westar cotyledons compared to L. maculans inoculated cotyledons. The quantification of each pathogen through qPCR assay and gene expressions analysis on host defense-related genes by RT-qPCR confirmed the potential of L. biglobosa “brassicae’ in the management of the blackleg disease pathogen, L. maculans ‘brassicae’, in canola.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/2223-7747/11/7/996; https://doaj.org/toc/2223-7747

URL الوصول: https://doaj.org/article/1815e824d7ec4d17b7b9d0949a2623cc