Effect of 2,6‐dichloroisonicotinic acid, its formulation materials and benzothiadiazole on systemic resistance to alternaria leaf spot in cotton

Abstract

A wettable powder (WP) formulation providing 5-25 g mL ¹1 of 2,6-dichloroisonicotinic acid (INA) and 15-75 g mL ¹1 of WP applied to cotton cotyledons significantly increased the resistance of the next two leaves to challenge inoculation by Alternaria macrospora. The wettable powder alone at 15-75 g mL ¹1 had a lesser effect. A wettable granule (WG) formulation supplying 35 g mL ¹1 of benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) and 35 g mL ¹1 of WG, applied as a cotyledonary treatment, significantly reduced the formation of lesions on the subsequent two leaves when challenged with A. macrospora. The WG control had no effect. Each treatment except for the WG control also raised the activities of ␤-1,3-glucanase in unchallenged leaf and stem tissue. Each of the components of the wettable powder without INA applied to cotyledons raised enzyme activities in the next leaves. Individual components, as suspensions of silicic acid and kaolin and solutions of the detergent Attisol II, the wetting agent Ultravon W300 and pure INA, applied to cotyledons increased the resistance of the next leaves to A. macrospora. The responsiveness of cotton to BTH and to each of the components of formulated INA is discussed in relation to knowledge of the effects of BTH and INA on other plants and to possible ways in which the other components of the wettable powder may affect the process of signalling for systemic resistance to disease.

Resistance against various fungal pathogens and reniform nematode in transgenic cotton plants expressing Arabidopsis NPR1

“…Thus, endogenous, basal SA levels may be an important consideration in selecting a crop species for the development of NPR1-mediated disease resistance. SA and its synthetic analog, BTH are known to induce SAR and SAR associated genes in various plant species (Ward et al 1991;Uknes et al 1992;Hudspeth et al 1996;Djonovic et al 2006;Gorlach et al 1996;Friedrich et al 1996;Nawrath and Metraux 1999;Colson-Hanks and Deverall 2000;Kohler et al 2002;Zhu et al 2003). In some of these studies, SAR was induced by direct bathing of the root or soil-drenching with the chemical.…”

Characterization of chitinase secreted by Bacillus cereus strain CH2 and evaluation of its efficacy against Verticillium wilt of eggplant

“…The disease is usually managed by using tolerant cultivars and cultural practices. No genetic sources of resistance can protect the vascular system from infection, although some cultivars are more tolerant than others (Colson-Hanks and Deverall 2000). Some chemical fungicides seem to be effective, but they are not environmentally friendly (Nannipieri et al 1984).…”

Vitamin B1 Functions as an Activator of Plant Disease Resistance

“…SAR could serve as a basis for novel disease control strategies involving genetically engineered plants with enhanced disease resistance and agrochemicals that induce the mimicry of incompatible interactions. To accomplish this goal, mutant lines, including the constitutive expression of PR genes (cpr; Bowling et al, 1994;Clarke et al, 2000) and constitutive immunity (cim) mutants of Arabidopsis (Arabidopsis thaliana; Maleck et al, 2002), and several chemicals, including BTH, dichloroisonicotinic acid (DCINA; Schweizer et al, 1997;Colson-Hanks and Deverall, 2000), and probenazole (Midoh and Iwata, 1996;Yoshioka et al, 2001), have been characterized and developed. Chemical plant defense activators have several advantages over disease control methods that depend on traditional fungicides or bactericides and breeding for resistance.…”