Postharvest Biology and Technology 65 (2012) 1–4 Contents lists available at SciVerse ScienceDirect Postharvest Biology and Technology jou rnal h omepa g e: www.elsevier.com/locate/postharvbio Postharvest jasmonic acid treatment of sugarbeet roots reduces rot due to Botrytis cinerea, Penicillium claviforme, and Phoma betae Karen Klotz Fugate a,∗ , Jocleita Peruzzo Ferrareze b , Melvin D. Bolton a , Edward L. Deckard c , Larry G. Campbell a a USDA-ARS, Northern Crop Science Laboratory, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA b Departamento de Biologia Vegetal, Universidade Federal de Vic ¸ osa, 36571-000 Vic ¸ osa, MG, Brazil c Department of Plant Sciences, North Dakota State University, P.O. Box 6050, Fargo, ND 58108-6050, USA a r t i c l e i n f o Article history: Received 21 June 2011 Accepted 11 October 2011 Keywords: Beta vulgaris Botryotinia fuckeliana (de Bary) Whetz. Jasmonate Pleospora bjorlingii Byford Storage rot a b s t r a c t Although jasmonic acid (JA) and JA derivatives are known to activate plant defense mechanisms and provide protection against postharvest fungal diseases for several horticultural crops, JA’s ability to pro- tect sugarbeet (Beta vulgaris L.) roots against common causal organisms of storage rot is unknown. To determine the potential of JA to reduce rot due to three common sugarbeet storage pathogens, harvested roots were treated with JA concentrations of 0.01, 0.1, 1, 10, or 100 M, inoculated with Botrytis cinerea, Penicillium claviforme, or Phoma betae, and evaluated for the severity of rot symptoms after incubation at 20 ◦ C and 90% relative humidity. JA concentrations of 0.01–100 M significantly reduced rot due to all three pathogens. All concentrations of JA provided statistically equivalent control against B. cinerea and P. betae, and reduced the amount of rotted tissue due to these pathogens by an average of 51 and 71%, respectively. Against P. claviforme, JA concentrations of 0.01–10 M were equally effective and reduced rot by an average of 44%, while an increase in JA concentration to 100 M reduced rot by 65%. Against all three pathogens, JA treatment did not affect the incidence of infection, but reduced rot by reducing the progression of disease symptoms in root storage tissue. Published by Elsevier B.V. 1. Introduction Storage rots of sugarbeet root consume sucrose and produce sucrose- and cell wall-degrading enzymes whose reaction prod- ucts impair juice purification and sucrose crystallization operations and decrease sucrose recovery during processing (Buchholz et al., 1998; Tungland et al., 1998; Dutton and Huijbregts, 2006). Storage rots also increase root respiration rate, a process that metabolizes sucrose and generates heat, creating additional storage losses and contributing to the warming of storage piles (Mumford and Wyse, 1976; Kays and Paull, 2004). As storage piles warm, the respiration of both healthy and diseased roots and the incidence and severity of storage rots increase (Campbell and Klotz, 2006). Storage rots, therefore, increase storage and processing losses and initiate events that escalate the rate of storage losses. Botrytis cinerea Pers. ex Fr. (teleomorph: Botryotinia fucke- liana [de Bary] Whetz.), Penicillium claviforme Bainier and Phoma betae Frank (teleomorph: Pleospora bjorlingii Byford) are known ∗ Corresponding author. Tel.: +1 701 239 1356; fax: +1 701 239 1349. E-mail address: karen.fugate@ars.usda.gov (K.K. Fugate). storage rot pathogens of sugarbeet (Bugbee, 1986). B. cinerea is an aggressive rot-causing organism that is characterized by gray spore masses, active over a wide range of temperatures, and widely distributed in sugarbeet growing regions throughout the world (Gaskill and Seliskar, 1952; Campbell and Klotz, 2006; Fugate and Campbell, 2009). P. claviforme is generally less aggressive than B. cinerea, produces stalked fruiting bodies with green spore masses, and is prevalent in U.S. storage piles (Bugbee, 1975; Bugbee and Cole, 1976; Fugate and Campbell, 2009). P. betae causes a rot that begins in the central pith tissue of the root crown and develops downward and outward into the taproot and surrounding crown tissue (Bugbee and Cole, 1976). Rot due to P. betae typically develops after roots have been stored in excess of 80 d, although the organ- ism is capable of rotting tissue at any time after harvest (Bugbee, 1982). Rot of postharvest sugarbeet roots is controlled primarily by maintaining cool temperatures in storage piles since low tem- perature reduces the growth rate of many rot-causing organisms (Campbell and Klotz, 2006). Roots are harvested in late autumn when temperatures are low, and the large outdoor piles in which sugarbeet roots are stored are cooled using ambient winter air. The control of storage rots, therefore, is dependent on weather con- ditions and is limitedly effective against fungal organisms that are 0925-5214/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.postharvbio.2011.10.005