Metabolites produced by Gnomoniopsis castanea associated with necrosis of chestnut galls
© Vinale 2014
Received: 7 April 2014
Accepted: 12 July 2014
Published: 15 August 2014
In this manuscript, we report the isolation and characterization of two secondary metabolites produced by a Gnomoniopsis castanea strain isolated in the Campania region (Italy) from chestnut galls infested with Dryocosmus kuriphilus. The compounds, purified from the fungal culture filtrate by using preparative HPLC-DAD, showed the same spectroscopic data of abscisic acid and 1′,4′-diol of abscisic acid. Phytotoxic activity of the isolated metabolites on chestnut leaves has been also observed.
KeywordsDryocosmus kuriphilus Gnomoniopsis castanea Abscisic acid 1′,4′-Diol of abscisic acid Fungal secondary metabolites
Many cultivated varieties of chestnut (Castanea spp.) are subjected to severe infestations caused by the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), which can disrupt the fruiting process and reduce a tree's yield by up to 70%. In addition to pest infestation, necrotic symptoms on leaves and galls are often observed due to the development of a gall colonizer identified as the fungus Gnomoniopsis sp. . The new species Gnomoniopsis castanea has been recently described, based on the association with Castanea sativa, the morphology and the phylogenetic analysis of the internal transcribed spacer (ITS) regions of ribosomal DNA and the EF1-a locus. The fungus has been associated with nut rot and caused disease symptoms when artificially inoculated on fruits or flowers .
Many fungi exert their effects on plant synthesizing secondary metabolites that alone reproduce some or even all of the symptoms of the disease caused by the producer organism. Moreover, some fungi interfere with the physiology of the plants by producing hormones, such as gibberellin, gibberellic acid, or indole-3-acetic acid .
Here, we report the isolation and characterization of the major secondary metabolites produced in liquid culture by a Gnomoniopsis strain isolated in the Campania region (Italy) from chestnut galls infested with D. kuriphilus. Sequence analysis of the ITS rDNA region indicated 99% similarity with GenBank sequences of G. castanea confirming the identity of this species characterized as the main causal agent of rot of the ripe nuts, both before and after picking .
Hormones or hormone-like molecules typically have an optimum activity in terms of plant growth regulation between 10−5 and 10−6 M while having a toxic effect at higher concentrations .
ABA has been considered a negative regulator of disease resistance. This effect is due to the interference of ABA with biotic stress signalling that is regulated by salicylic acid, jasmonic acid, and ethylene, and to an additional effect on shared components of stress signalling . The production of ABA by fungi may interfere with the normal physiology of the plant and could explain why phytopathogens secrete this metabolite to plants exogenously.
- Maresi G, Oliveira Longa CM, Turchetti T: Brown rot on nuts of Castanea sativa Mill: an emerging disease and its causal agent. iForest. 2013, 6: 294-301. 10.3832/ifor0952-006.View ArticleGoogle Scholar
- Visentin I, Gentile S, Valentino D, Gonthier P, Tamietti G, Cardinale F: Gnomoniopsis castanea sp. nov. (Gnomoniaceae, Diaporthales) as a causal agent of nut rot in sweet chestnut. J Plant Pathol. 2012, 94: 411-419.Google Scholar
- Möbius N, Hertweck C: Fungal phytotoxins as mediators of virulence. Curr Opin Plant Biol. 2009, 12: 390-398. 10.1016/j.pbi.2009.06.004.View ArticlePubMedGoogle Scholar
- Assante G, Merlini L, Nasini G: (+)-Abscisic acid, a metabolite of the fungus Cercospora rosicola. Cell Mol Life Sci. 1977, 33: 1556-1557. 10.1007/BF01933993.View ArticleGoogle Scholar
- Hirai N, Okamoto M, Koshimizu K: The 1′,4′-trans-diol of abscisic acid, a possible precursor of abscisic acid in Botrytis cinerea. Phytochemistry. 1986, 25: 1865-1868. 10.1016/S0031-9422(00)81164-4.View ArticleGoogle Scholar
- Vinale F, Sivasithamparam K, Ghisalberti EL, Marra R, Woo SL, Lorito M: Trichoderma–plant–pathogen interactions. Soil Biol Biochem. 2008, 40: 1-10. 10.1016/j.soilbio.2007.07.002.View ArticleGoogle Scholar
- Oritani T, Kiyota : Biosynthesis and metabolism of abscisic acid and related compounds. Nat Prod Rep. 2003, 20: 414-425. 10.1039/b109859b.View ArticlePubMedGoogle Scholar
- Arai K, Shimizu S, Miyajima H, Yamamoto Y: Castaneiolide, abscisic acid and monorden, phytotoxic compounds isolated from fungi (Macrophoma castaneicola) and (Didymosporium radicicola) cause “black root rot disease” in chestnut trees. Chem Pharm Bull. 1989, 37: 2870-2872. 10.1248/cpb.37.2870.View ArticleGoogle Scholar
- Mauch-Mani B, Mauch F: The role of abscisic acid in plant-pathogen interactions. Curr Opin Plant Biol. 2005, 8: 409-414. 10.1016/j.pbi.2005.05.015.View ArticlePubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.