Diaporthe species associated with the maritime grass Festuca rubra subsp. pruinosa

Rufin Marie Kouipou Toghueo; Beatriz R Vázquez de Aldana; Iñigo Zabalgogeazcoa

doi:10.3389/fmicb.2023.1105299

Diaporthe species associated with the maritime grass Festuca rubra subsp. pruinosa

Front Microbiol. 2023 Feb 16:14:1105299. doi: 10.3389/fmicb.2023.1105299. eCollection 2023.

Authors

Rufin Marie Kouipou Toghueo¹, Beatriz R Vázquez de Aldana¹, Iñigo Zabalgogeazcoa¹

Affiliation

¹ Plant-Microorganism Interaction Research Group, Institute of Natural Resources and Agrobiology of Salamanca, Consejo Superior de Investigaciones Científicas (IRNASA-CSIC), Salamanca, Spain.

Abstract

Festuca rubra subsp. pruinosa is a perennial grass growing in sea cliffs where plants are highly exposed to salinity and marine winds, and often grow in rock fissures where soil is absent. Diaporthe species are one of the most abundant components of the root microbiome of this grass and several Diaporthe isolates have been found to produce beneficial effects in their host and other plant species of agronomic importance. In this study, 22 strains of Diaporthe isolated as endophytes from roots of Festuca rubra subsp. pruinosa were characterized by molecular, morphological, and biochemical analyses. Sequences of the nuclear ribosomal internal transcribed spacers (ITS), translation elongation factor 1-α (TEF1), beta-tubulin (TUB), histone-3 (HIS), and calmodulin (CAL) genes were analyzed to identify the isolates. A multi-locus phylogenetic analysis of the combined five gene regions led to the identification of two new species named Diaporthe atlantica and Diaporthe iberica. Diaporthe atlantica is the most abundant Diaporthe species in its host plant, and Diaporthe iberica was also isolated from Celtica gigantea, another grass species growing in semiarid inland habitats. An in vitro biochemical characterization showed that all cultures of D. atlantica produced indole-3-acetic acid and ammonium, and the strains of D. iberica produced indole 3-acetic acid, ammonium, siderophores, and cellulase. Diaporthe atlantica is closely related to D. sclerotioides, a pathogen of cucurbits, and caused a growth reduction when inoculated in cucumber, melon, and watermelon.

Keywords: Diaporthe atlantica; Diaporthe iberica; Festuca rubra subsp. pruinosa; endophyte; grasses; multi-locus phylogeny.

Grants and funding

This research was supported by grant PID2019-109133RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by project “CLU2019-05–IRNASA/CSIC Unit of Excellence” funded by the Junta de Castilla y León and co-financed by EU (ERDF “Europe drives our growth”). RT was supported by grant FJC2018-03857-I funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your Future.”