Effects of postharvest methyl jasmonate treatments against Botrytis cinerea on Geraldton waxflower (Chamelaucium uncinatum)

Abstract

Cut Geraldton waxflower (Chamelaucium uncinatum Schauer) flowers are often infected with Botrytis cinerea. Release of infection from quiescence can cause ethylene production by invaded host tissues and result in flower abscission. Postharvest floral organ abscission is a major problem for the commercial waxflower industry. Methyl jasmonate (MeJA) occurs naturally in plant tissue and has a signalling role in eliciting induced systemic resistance against disease. MeJA treatments have been shown to suppress B. cinerea infecting cut rose flowers. The present experiments investigated the potential of exogenous MeJA treatments for B. cinerea management on harvested waxflower. MeJA treatments of 10 and 100 µL liquid MeJA/L of air applied to cv. Purple Pride and 1 µL MeJA/L to cv. Mullering Brook gave reductions in disease severity for uninoculated stems. However, concentrations of 100 µL MeJA/L applied to Purple Pride in addition to 1 and 10 µL MeJA/L applied to Mullering Brook increased the incidence of floral organ fall. Flower abscission upon treatment with MeJA may be due to induced systemic resistance-associated upregulation of ethylene biosynthesis. MeJA treatments had no direct effect on B. cinerea hyphal elongation in vitro. Collectively, these results show that while MeJA treatment may elicit defence in waxflower against Botrytis, the chemical also causes floral organ fall. Thus, exogenous MeJA treatments do not have potential for B. cinerea management on harvested waxflower.

Novel Elicitors Induce Defense Responses in Cut Flowers

“…Our findings are in agreement with those by Meir et al (1998) that disease severity in both artificially inoculated and naturally infected rose flowers was reduced by a MeJA pulse at 0.2 mM at 20°C. On cut Geraldton waxflower 'Purple Pride' and 'Mullering Brook' sprigs, 1-100 μL L -1 MeJA postharvest vapour treatment significantly reduced the development of B. cinerea (Eyre et al, 2006). However, it also induced flower fall incidence, which was correlated with a systemic resistance-associated up-regulation of ethylene biosynthesis.…”

“…Gaseous MeJA might have induced a range of defence mechanisms to halt infection development. MeJA applied postharvest as vapour at 1-100 μL L -1 significantly reduced the development of B. cinerea on cut Geraldton waxflower 'Purple Pride' and 'Mullering Brook' sprigs (Eyre et al, 2006). In a very recent study, Darras et al (2011) demonstrated that gaseous MeJA at 0.1 μL L -1 significantly increased polythenol oxidase (PPO) activities 24 and 36 h post-treatment.…”

“…Similarly, a postharvest pulse, spray, or vapour treatment with MeJA 200 μΜ, 600 μΜ or 1 μL L -1 , respectively, significantly reduced petal specking by B. cinerea on cut inflorescences of Freesia hybrida 'Cote d'Azur' (Darras et al, 2005;. Moreover, 1-100 μL L -1 MeJA postharvest vapour treatment reduced B. cinerea development on cut Geraldton waxflower 'Purple Pride' and 'Mullering Brook' sprigs (Eyre et al, 2006). Application of gaseous MeJA to fresh cut peonies resulted in the lowest disease severity and in an improvement of vase life compared to the untreated controls (Gast, 2001).…”

Impact of abiotic stresses on the protection efficacy of defence elicitors and on metabolic regulation in tomato leaves infected by Botrytis cinerea

“…Under controlled conditions, a protective effect against was already demonstrated using BABA on Cohen et al 1994 ), Bion 50WG® on both and tomato (Azami-Sardooei et al 2013 ;Audenaert et al 2002 ;Zimmerli et al 2001 ), Chitosan on vine (Amborabe et al 2004 ) and MeJA on tomato fruit (Zhu and Tian 2012 ;Eyre et al 2006 ). To the exception of Chitosan which partly inhibited fungal germination (Fig.…”

“…Based on literature, four agents for which the ability to induce plant defence mechanisms has been previously demonstrated were used here as positive "PDE controls": Bion 50WG®, BABA, Chitosan and methyl jasmonate (MeJA) (Amborabe et al 2004 ;Azami-Sardooei et al 2013 ;Dufour et al 2013 ;Eyre et al 2006 ;Zhu and Tian 2012 ). In addition to those "PDE controls", the protection efficacy against of seven potential PDE were investigated (coded A to G; Table 1 ).…”