The Tobacco Trichome Exudate Z-abienol and Its Relationship With Plant Resistance to Phytophthora nicotianae
| Autor: | David P. Eickholt, Justin M Ma, William T. Steede, Sheri P. Kernodle, Katherine E Drake-Stowe, Ramsey S. Lewis, H. David Shew, David A. Danehower |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine Hyphal growth Exudate Population Plant Science Secondary metabolite Quantitative trait locus 01 natural sciences 03 medical and health sciences Pleiotropy Botany medicine education education.field_of_study biology fungi food and beverages Phytophthora nicotianae biology.organism_classification Trichome 030104 developmental biology medicine.symptom Agronomy and Crop Science 010606 plant biology & botany medicine.drug |
| Zdroj: | Plant disease. 101(7) |
| ISSN: | 0191-2917 |
| Popis: | In previous research, we discovered a favorable quantitative trait locus (QTL) in cigar tobacco cultivar ‘Beinhart 1000’ designated as Phn15.1, which provides a high level of partial resistance to the black shank disease caused by Phytophthora nicotianae. A very close genetic association was also found between Phn15.1 and the ability to biosynthesize Z-abienol, a labdanoid diterpene exuded by the trichomes onto above-ground plant parts, and that imparts flavor and aroma characteristics to Oriental and some cigar tobacco types. Because accumulation of Z-abienol is considered to be undesirable for cultivars of other tobacco types, we herein describe a series of experiments to gain insight on whether this close association is due to genetic linkage or pleiotropy. First, in an in vitro bioassay, we observed Z-abienol and related diterpenes to inhibit hyphal growth of P. nicotianae at concentrations between 0.01 and 100 ppm. Secondly, we field-tested transgenic versions of Beinhart 1000 carrying RNAi constructs for downregulating NtCPS2 or NtABS, two genes involved in the biosynthesis of Z-abienol. Thirdly, we also field tested a recombinant inbred line population segregating for a truncation mutation in NtCPS2 leading to an interrupted Z-abienol pathway. We observed no correlation between field resistance to P. nicotianae and the ability to accumulate Z-abienol in either the transgenic materials or the mapping population. Results suggest that, although Z-abienol may affect P. nicotianae when applied at high concentrations in in vitro assays, the compound has little effect on black shank disease development under natural field conditions. Thus, it should be possible to disassociate Phn15.1-mediated black shank resistance identified in cigar tobacco cultivar Beinhart 1000 from the ability to accumulate Z-abienol, an undesirable secondary metabolite for burley and flue-cured tobacco cultivars. |
| Databáze: | OpenAIRE |
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