Enhancement of Populus alba tolerance to Venturia tremulae upon inoculation with endophytes showing in vitro biocontrol potential
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Several studies have provided evidence that endophytes of forest trees can provide the trees with protection against pests and pathogens, but more experimental evidence is still needed to better understand if endophytes could be utilized in biocontrol of forest diseases. Here, we tested the hypothesis that fungal endophytes of Populus alba L. contribute to tree tolerance to Venturia tremulae Aderh., causal agent of shoot dieback in trees within Populus section. Fungal endophytes were isolated from twigs of two healthy P. alba trees, and classified according to their morphology and ITS sequence. Pleosporales, Dothideales and Eurotiales were the main fungal orders represented. Twelve isolates were challenged by the pathogen in in vitro dual assays and 10 of them reduced the growth rate of the pathogen. A mixed cell suspension from these endophytes was applied as a preventive treatment to P. alba seedlings growing in the greenhouse with the exception of positive control plants. Fifteen days later, plants were treated with a V. tremulae spore suspension. An additional control group of Populus x canescens (Aiton) Sm. seedlings were also inoculated with V. tremulae. Although the overall incidence of symptoms was low, both the incidence and severity of damages were lower in P. alba plants pretreated with endophytes than in controls (43.18 and 12.16% of incidence and severity reduction, respectively). Incidence of symptoms was higher in P. x canescens than in P. alba seedlings, evidencing the higher tolerance of P. alba to Venturia shoot blight. The results suggest that P. alba endophyte community may reinforce the host’s tolerance to the pathogen.
KeywordsEndophytic fungi Biological control Populus (Salicaceae) Venturia tremulae (Pleosporales, Venturiaceae)
We are very grateful to Dr. Hugo Mas i Gisbert (Laboratori de Sanitat Forestal, CIEF, Generalitat Valenciana) for providing plant material.
This study was funded by Ministerio de Ciencia e Innovación, Spain (CTQ2011–28503-C02–02).
Compliance with ethical standards
Conflict of interest
Author Clara Martínez-Arias declares that she has no conflict of interest.
Author David Macaya-Sanz declares that he has no conflict of interest.
Author Johanna Witzell declares that she has no conflict of interest.
Author Juan A. Martín declares that he has no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Bailey, B. A., Bae, H., Strem, M. D., Roberts, D. P., Thomas, S. E., Crozier, J., Samuels, G. J., Choi, I. Y., & Holmes, K. A. (2006). Fungal and plant gene expression during the colonization of cacao seedlings by endophytic isolates of four Trichoderma species. Planta, 224(6), 1449–1464.CrossRefGoogle Scholar
- Blenis, P. V. (2007). Impact of simulated aspen shoot blight on trembling aspen. Canadian Journal of Plant Pathology-Revue Canadienne De Phytopathologie, 37, 719–725.Google Scholar
- Crous, P. W., Schubert, K., Braun, U., de Hoog, G. S., Hocking, A. D., Shin, H. D., & Groenewald, J. Z. (2007). Opportunistic human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae. Studies in Mycology, 58, 185–217.CrossRefGoogle Scholar
- Gao, F., Dai, C., & Liu, X. (2010). Mechanisms of fungal endophytes in plant protection against pathogens. African Journal of Microbiology Research, 4(13), 1346–1351.Google Scholar
- Guyon, J. (2004). Management guide for Venturia leaf and shoot blight. Forest Health Protection and State Forestry Organizations. Available via https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5191787.pdf. Accessed 15 Dec 2016.
- Hanada, R. E., Pomella, A. W. V., Costa, H. S., Bezerra, J. L., Loguercio, L. L., & Pereira, J. O. (2010). Endophytic fungal diversity in Theobroma cacao (cacao) and T. grandiflorum (cupuacu) trees and their potential for growth promotion and biocontrol of black-pod disease. Fungal Biology, 114(11–12), 901–910.CrossRefGoogle Scholar
- Martín, J. A., Witzell, J., Blumenstein, K., Rozpedowska, E., Helander, M., Sieber, T. N., & Gil, L. (2013). Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in elms (Ulmus spp.). PLoS One, 8(2), 13.Google Scholar
- Martín, J. A., Macaya-Sanz, D., Witzell, J., Blumenstein, K., & Gil, L. (2015). Strong in vitro antagonism by elm xylem endophytes is not accompanied by temporally stable in planta protection against a vascular pathogen under field conditions. European Journal of Plant Pathology, 142(1), 185–196.CrossRefGoogle Scholar
- Morelet, M. (1985). The genus Venturia on Populus species of section Leuce: 1. Taxonomy. Cryptogamie Mycologie, 6(2), 101–117.Google Scholar
- Schubert, K., Ritschel, A., & Braun, U. (2003). A monograph of Fusicladium (Hyphomycetes). Schlechtendalia, 9, 1–132.Google Scholar
- Sinclair, W.A. & Lyon, H.H. (2005). Shoot blights and twig diebacks. In: Diseases of Trees and Shrubs (pp. 90-91). 2nd edition. Ithaca: Cornell University Press.Google Scholar
- White, T., Bruns, T., Lee, S., & Taylor, J. W. (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In M. A. Innis, D. H. Gelfand, J. J. Sninsky, & T. J. White (Eds.), PCR protocols: A guide to methods and applications (pp. 315–322). New York: Academic Press.Google Scholar