Abscisic Acid in Tobacco Plants

Abstract

In tobacco plants inoculated with The tobacco inhibitor was tentatively identified as abscisic acid, based on a comparison with authentic abscisic acid on paper, thin layer, column, and gas-liquid chromatography. On the basis of optical rotatory dispersion, circular dichroism, and ultraviolet spectra, the tobacco inhibitor was indistinguishable from abscisic acid. Increases in the inhibitor content of infected tissues are attributed primarily to abscisic acid although other substances, not separable from abscisic acid by the procedures used, could also play a role. The inhibitor was not found in P. solanacearum culture medium.Stunting is one of the earliest symptoms of many plant diseases caused by vascular wilt fungi and bacteria and by systemic viruses. Reduced growth of infected plants has generally been attributed to mechanical, nutritional, or toxic factors. Little effort has been directed toward determining the relationship of endogenous host growth regulators to this phenomenon. Numerous instances of reversal by gibberellic acid of the stunting which accompanise many virus infections of plants have been reported (7,11,16,18,25), which suggests that these pathogens interfere with synthesis of gibberellins. An increase in the growth inhibitor content of plants exhibiting stunting associated with infection by fungi, bacteria, or viruses has been reported (2,10,20, 23,24,26). In all

Biosynthesis and metabolism of abscisic acid in tomato leaves infected with Botrytis cinerea

“…Previous work (Kettner 1991) has shown that the effect of ABA is more pronounced when strains of the fungus with low to moderate virulence on tomato leaves are used. Combined with the observation of enhanced endogenous levels of ABA that have been found in a wide variety of plant species inoculated with fungi or bacteria (Steadman and Sequeira 1970;Pegg 1976;Kern 1985), or after viral infection (Mohanty et aI. 1979;Whenham and Fraser 1981;Wenham et al 1985), there is increasing evidence that ABA is implicated in the control of susceptibility of plants to microbial attack.…”

“…Although the role of ABA in plant diseases remains to be established, increasing evidence from studies on infected plants suggests that ABA is involved in the interaction between phytopathogenic microorganisms and their host plants. Increased levels of endogenous ABA have been reported from various plant species in response to infection with fungi, bacteria and viruses (Steadman and Sequeira 1970;Pegg 1976;Kern 1985;Whenham et al 1986;Tuomi et al 1993). Furthermore, ABA levels were found to increase in roots of maize colonized by vesicular arbuscular mycorrhizas (Danneberg et al 1992).…”

Levels of (±) Abscisic Acid and Xanthoxin in Spinach under Different Environmental Conditions

“…The level of ABA in leaves can be raised by a variety of conditions: wilting (10,11), waterlogging of the root system (10), low RH (4, 10), osmotic stress of the roots (5), lack of mineral nutrients (6), cold stress (3), and infection with the wilt-inducing bacterium Pseudomonas solanacearum (8). A common feature of these factors is that they affect the water balance of plants.…”

Antagonistic Interaction between Systemic Acquired Resistance and the Abscisic Acid–Mediated Abiotic Stress Response in Arabidopsis

“…Similarly, the involvement of ABA in plant-pathogen interactions is ambiguous. Increased endogenous levels of ABA were observed in response to infection by viruses, bacteria, and fungi (Steadman and Sequeira, 1970;Whenham et al, 1986;Kettner and Dorffling, 1995). The application of ABA induced callose deposition, resulting in resistance against necrotic fungi (Ton and Mauch-Mani, 2004;Mauch-Mani and Mauch, 2005).…”