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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #344347
Title: Novel Seimatosporium species from grapevine in northern California and their interactions with fungal pathogens involved in the trunk-disease complex

Author
item LAWRENCE, DANIEL - University Of California
item TRAVADON, RENAUD - University Of California
item Baumgartner, Kendra

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2017
Publication Date: 7/16/2018
Citation: Lawrence, D.P., Travadon, R., Baumgartner, K. 2018. Novel Seimatosporium species from grapevine in northern California and their interactions with fungal pathogens involved in the trunk-disease complex. Plant Disease. 102(6):1081-1092. https://doi.org/10.1094/PDIS-08-17-1247-RE.
DOI: https://doi.org/10.1094/PDIS-08-17-1247-RE

Interpretive Summary: Seimatosporium species and closely related fungi (so-named ‘pestalotioid fungi’ because of their spores, which are shaped like insects) have been isolated from the woody structure of grapevines showing symptoms of grapevine trunk diseases, namely the internal wood cankers. To determine whether they are pathogens, we tested the pathogenicity of California isolates from vines with general symptoms of the dieback-type trunk diseases, Botryosphaeria-, Eutypa-, and Phomopsis diebacks. Phylogenetic analyses of DNA sequences (specifically the ITS and LSU gene regions) revealed three species: Seimatosporium vitis and two newly described and typified species, Seimatosporium luteosporum sp. nov. and Seimatosporium vitifusiforme sp. nov. Both isolates of S. vitis and one isolate of S. vitifusiforme were pathogenic; S. luteosporum was not. To determine whether infeciton by a Seimatosporium species worsens infection by another pathogen, we co-inoculated the woody stems of potted grapevines with a Seimatosporium isolate and a known pathogen causing Botryosphaeria dieback (Diplodia seriata), Eutypa dieback (Diatrypella verruciformis, Cryptovalsa ampelina, Eutypa lata), or Phomopsis dieback (Diaporthe ambigua). Pairs of isolates were originally isolated from the same wood cankers. We found synergistic interactions between S. vitifusiforme and Dip. seriata, based on larger lesions in dual inoculated versus single-inoculated plants. In contrast, antagonistic interactions were revealed between S. vitis and Diat. verruciformis, based on smaller stems lesions in dual inoculated versus single-inoculated plants. Our findings suggest S. vitis and S. vitifusiforme are involved in the grapevine trunk-disease complex, and that they may interact with other trunk pathogens (e.g., Dip. seriata) to exacerbate symptoms.

Technical Abstract: Seimatosporium species and closely related ‘pestalotioid fungi’ have been isolated from vineyards around the world, but their ecological status in grapevine wood is not equivocal. To determine their involvement in the grapevine trunk-disease complex, we tested the pathogenicity of California isolates from vines with general symptoms of Botryosphaeria-, Eutypa-, and Phomopsis dieback. Phylogenetic analyses of ITS and LSU gene regions revealed three species: Seimatosporium vitis and two newly described and typified species, Seimatosporium luteosporum sp. nov. and Seimatosporium vitifusiforme sp. nov. Both isolates of S. vitis and one isolate of S. vitifusiforme were pathogenic; S. luteosporum was not. In co-inoculations with known trunk pathogens (Cryptovalsa ampelina, Diaporthe ambigua, Diatrypella verruciformis, Diplodia seriata, and Eutypa lata), which were originally isolated from the same wood cankers, synergistic interactions were revealed between S. vitifusiforme and Dip. seriata, based on larger stem lesions in dual inoculated versus single-inoculated plants. In contrast, antagonistic interactions were revealed between S. vitis and Diat. verruciformis, based on smaller stems lesions in dual inoculated versus single-inoculated plants. Our findings suggest S. vitis and S. vitifusiforme are involved in the grapevine trunk-disease complex, and that they may interact with other trunk pathogens (e.g., Dip. seriata) to exacerbate symptoms.