Journal of General Plant Pathology (2010) 76, 161-167

Miyuki Kusajima, Michiko Yasuda, Akiko Kawashima, Hideaki Nojiri, Hisakazu Yamane, Masami Nakajima, Katsumi Akutsu and Hideo Nakashita (2010)
Suppressive effect of abscisic acid on systemic acquired resistance in tobacco plants
Journal of General Plant Pathology 76 (2), 161-167
Abstract: Recent studies have indicated that the phytohormone abscisic acid (ABA), induced in response to a variety of environmental stresses, plays an important role in modulating diverse plant-pathogen interactions. In Arabidopsis thaliana, we previously clarified that ABA suppressed the induction of systemic acquired resistance (SAR), a plant defense system induced by pathogen infection through salicylic acid (SA) accumulation. We investigated the generality of this suppressive effect by ABA on SAR using tobacco plants. For SAR induction, we used 1,2-benzisothiazole-3(2H)-one 1,1-dioxide (BIT) and benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) that activate upstream and downstream of SA in the SAR signaling pathway, respectively. Wild-type tobacco plants treated with BIT or BTH exhibited enhanced disease resistance against Tobacco mosaic virus (TMV) and tobacco wildfire bacterium, Pseudomonas syringae pv. tabaci (Pst), however, which was suppressed by pretreatment of plants with ABA. Pretreatment with ABA also suppressed the expression of SAR-marker genes by BIT and BTH, indicating that ABA suppressed the induction of SAR. ABA suppressed BTH-induced disease resistance and pathogenesis-related (PR) gene expression in NahG-transgenic plants that are unable to accumulate SA. The accumulation of SA in wild-type plants after BIT treatment was also suppressed by pretreatment with ABA. These data suggest that ABA suppresses both upstream and downstream of SA in the SAR signaling pathway in tobacco.
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Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tobacco mosaic virus	Tobacco (Nicotiana tabacum)
	Pseudomonas syringae pv. tabaci	Tobacco (Nicotiana tabacum)
	Pseudomonas syringae