Acibenzolar-S-methyl induces resistance to Colletotrichum lagenarium and cucumber mosaic virus in cantaloupe

Efficacy of acibenzolar-S-methyl (Bion®) treatment of Australian commercial passionfruit, Passiflora edulis f. sp. flavicarpa, on resistance to Passionfruit woodiness virus (PWV) and activities of chitinase & β-1,3-glucanase

“…At 30 dpi plants treated with Bion® at 0.05 g a.i./l had significantly higher activities of both enzymes, compared with untreated controls or Bion® at 0.1 g a.i./l. Studies of the effects of acibenzolar-Smethyl (ASM) in tobacco against Tomato spotted wilt virus (Mandal et al 2008) and in cantaloupe against Cucumber mosaic virus (Smith-Becker et al 2003), found an increase for PR protein gene, PR-3, other classes of PR proteins such as PR-1 and PR-5 (Mandal et al 2008) and for chitinase (Smith-Becker et al 2003). Both studies found an effective reduction in systemic spread of the viruses.…”

“…The activities of PR proteins β-1,3-glucanase and chitinase were measured because they are useful markers of SAR induction (Loebenstein 2009;Smith-Becker et al 2003); elevated PR protein activity is correlated with stronger SAR induction (Smith-Becker et al 2003). The current study indicated an association between reduced virus titre and increased PR protein activity, however, there is no prior evidence suggesting that β-1,3-glucanase or chitinase have direct antiviral activity in virus-induced SAR (Loebenstein 2009).…”

“…The current study indicated an association between reduced virus titre and increased PR protein activity, however, there is no prior evidence suggesting that β-1,3-glucanase or chitinase have direct antiviral activity in virus-induced SAR (Loebenstein 2009). Little is known of how ASM induces SAR under virus attack, although previous studies demonstrated that exogenous application of salicylic acid (SA), a plant defence hormone analogous to ASM (Smith-Becker et al 2003), can trigger two anti-viral defence mechanisms; inhibition of viral replication at the site of inoculation or delaying movement of the virus out of the inoculation site to distal parts of the plant (Naylor et al 1998;Murphy and Carr 2002). Viral replication at the inoculation site was inhibited in tobacco plants treated with SA and inoculated with Tobacco mosaic virus (TMV) (Chivasa et al 1997), whereas after SA treatment and inoculation with Cucumber mosaic virus (CMV) (Naylor et al 1998), movement of the virus out of the inoculation site was inhibited resulting in delayed CMV symptom development.…”

“…PR proteins are useful molecular markers of SAR as their accumulation is directly correlated to the level of SAR in uninfected tissue (Smith-Becker et al 2003;Ryals et al 1996). β-1,3-glucanase and chitinase are glycosyl hydrolases which respectively catalyse cleavage of the (1,3)-β-D-glucosidic linkages in (1,3)-β-glucans (Gupta et al 2013) and degradation of the unbranched linear chain of β-1,4-linked N-acetyl D-glucosamine residues which make up chitin (Das et al 2012).…”

“…Thus, induction of the PR proteins β-1,3-glucanase and chitinase results in the breakdown of glucans and chitin in the fungal cell wall (Gupta et al 2013;Das et al 2012). β-1,3-glucanase and chitinase activity is conserved in a broad spectrum of host plant species and these proteins have been used as effective markers in various research regarding host response to pathogen attack and the efficacy of plant inducing chemicals in activating SAR (Whan et al 2009;Smith-Becker et al 2003;Dann and Deverall 2000;Colson-Hanks and Deverall 2000). The efficacy of Bion® in reducing passionfruit woodiness disease caused by PWV and enhancing activities of PR proteins in passionfruit has not been investigated.…”