X-Message-Number: 24126 Date: Fri, 21 May 2004 20:29:09 -0700 (PDT) From: Doug Skrecky <> Subject: methyl jasmonate versus chilling injury (A potential additive to vitrification solutions?) Biochem Biophys Res Commun. 2004 Jan 16;313(3):694-701. Methyl jasmonate treatments reduce chilling injury and activate the defense response of guava fruits. Tropical fruits cannot be stored at low temperatures due to the chilling injury phenomena. With the goal of reducing the chilling injury, we tested 10(-4) and 10(-5) M of methyl jasmonate (MJ) treatment before the storage of red and white cultivars of guava fruits at 5 degrees C for up to 15 days plus two days at 20 degrees C. Every five days, we evaluated chilling injury index, ion leakage percentage, vitamin C, sugars, total phenols, and the activity of the enzymes lipoxygenase (LOX) and phenylalanine-ammonia lyase (PAL). We found that methyl jasmonate treatments reduce the chilling injury index and the ion leakage percentage. Furthermore, MJ did not affect vitamin C, chlorophyll, and total phenols. MJ increased sugar content, PAL, and LOX activities. We concluded that MJ reduces chilling injury and activates the fruit defense response as indicated by the behavior of total phenols and the increase in sugar content, PAL, and LOX activities. Planta. 2002 Apr;214(6):895-901. Epub 2001 Dec 12. Jasmonate and salicylate induce the expression of pathogene sis-related-protein genes and increase resistance to chilling injury in tomato fruit. Treatment of tomato (Lycopersicon esculentum L. cv. Beefstake) fruit with low concentrations of (0.01 mM) methyl jasmonate (MeJA) or methyl salicylate (MeSA) substantially enhanced their resistance to chilling temperature and decreased the incidence of decay during low-temperature storage. While studying the expression of pathogenesis-related (PR) protein genes, different accumulation patterns of PR-protein mRNAs in tomato fruit were observed. MeJA substantially increased the accumulation of PR-2b transcripts encoding intracellular beta-1,3-glucanase and enhanced the mRNA levels of PR-2a and PR-3b encoding extracellular beta-1,3-glucanase and intracellular chitinase, respectively. MeSA substantially increased accumulation of PR-2b and PR-3a mRNAs and slightly increased PR-3b mRNA accumulation. Chilling temperature did not appreciably enhance the accumulation of PR-protein mRNAs in untreated fruit. However, the accumulation of PR-3b mRNAs in MeSA-treated fruit was enhanced following low-temperature storage. Transcript abundance of catalase genes also was investigated in different pretreated tomatoes. The accumulation of cat1 mRNA was increased substantially by MeJA, while it was reduced by MeSA treatment. These results suggest that the pre-treatment of tomato fruit with MeSA or MeJA induces the synthesis of some stress proteins, such as PR proteins, which leads to increased chilling tolerance and resistance to pathogens, thereby decreasing the incidence of decay. J Agric Food Chem. 2000 Feb;48(2):515-9. Methyl jasmonate reduces chilling injury and maintains postharvest quality of mango fruit. Exposure of mango (Mangifera indica cv. Tommy Atkins) fruit to methyl jasmonate (MJ) vapors (10(-)(4) M) for 24 h at 25 degrees C reduced chilling injury during subsequent storage for 21 days at 7 degrees C and after 5 days of shelf life at 20 degrees C. The chilling tolerance induced by MJ was positively correlated with the reduction in the percent ion leakage of mango tissue. The overall quality of MJ-treated fruit was also better than that of control fruit. MJ treatment increased the total soluble solids but did not affect titratable acidity or pH. MJ also did not change the normal climacteric rise in respiration, water loss, and softening rates. The efficacy of MJ to reduce chilling injury and decay of mango could be related to the tolerance induced at low temperature. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24126