Role of Ethylene in Fruit Ripening

Abstract

There have arisen two schools of thought concerning the role of ethylene in fruit maturation: the classic view of Kidd and West (26) and Hansen (22) that ethylene is a ripening hormone, and a recent interpretation by Biale et al. (7,3,4) that it is a by-product of the ripening process. The original presentation of the by-product theory in this journal (7) was tempered with the reminder that 0.1 ppm ethylene may stimulate ripening, so that "in the absence of any information correlating the internal ethylene content with the rate of ethylene production, one can advance the argument that small quantities sufficient to induce ripening are produced prior to the rise of respiration, but measurable amounts are detected only after the onset of the climacteric." The development of highly sensitive gas chromatographic instruments makes it feasible to appraise critically those instances in whiclh fruits have been reported to produce ethylene not at all or only after the climacteric has started, and also to determine the content of ethylene witllin a fruit at the onset of the rise in respiration. Results of such experiments are reported in this communication, and they have a direct bearing on the problem of whetlher or not ethylene is a natural ripening hormone. Materials.Mangoes (Magiiifera indica L., cv. Kent & Haden) were harvested in local orchards. The fruits used for each experiment were picked from the same tree on the same day and were all of about equal size and apparent maturity. Bananas (Miusa acuiiniata cv. Gros Mfichel) harvested at 34 fullness were shipped from Ecuador. Pineapples [Ananas comnosus (L.) AMerr.] at various stages of maturity were flown from Honduras; they arrived in very satisfactory condition w%ithin a day of picking. The Citrus Experiment Station at Tampa, Fla. provided oranges [Citrl(s sinensis (L.) Osbeck] and passion fruits (Passiflora eddlis,Sims); other fruits were purchased in local markets.

The draft genome of tropical fruit durian (Durio zibethinus)

“…Enrichment in gene sets related to sulfur comprised five clusters, of which acidthiol ligase enzymes (containing a number of key enzymes in carbon-sulfur reactions and flavonoid production) and methionine metabolic pathways (of which MGL is a key member) 28 contained the most significantly upregulated leading-edge genes. Ripening-related gene sets included genes regulated by the MADS-BOX transcription factor family 29,30 , SEPALLATA transcription factor family, and ethylene-related genes such as ACS (aminocyclopropane-1-carboxylic acid synthase), a key ethylene-production enzyme involved in ripening 31 . Other upregulated processes related to taste and odor included triterpenoid metabolism, which has been associated with the intensely bitter taste of Ganoderma lucidum (Lingzhi) 32 , and lipid-related genes involved in the production of C 6 volatile compounds (hexanal and hexanol), which have been associated with the green odor profiles of apples, tomatoes, and bananas, as well as undesirable rancid odors when present at high levels 33,34 .…”

The fading distinctions between classical patterns of ripening in climacteric and non-climacteric fruit and the ubiquity of ethylene—An overview

“…A substantial proportion of the rise in rates of respiration is reported to be contributed by cyanideinsensitive respiration in fruits like banana, mango and tomato (Kumar and Sinha 1992;Pandey et al 1995;Reddy and Srivastava 1998). Differences in the levels of ethylene for climacteric and non-climacteric fruits were reported by Burg and Burg (1962) during the process of ripening (Table 2). The data showed differences in endogenous levels of ethylene not only within the two categories of fruits (higher levels in climacteric fruits) but also for the fruits within a category.…”

Interaction between MYC2 and ETHYLENE INSENSITIVE3 Modulates Antagonism between Jasmonate and Ethylene Signaling inArabidopsis

“…Both ethylene (ET) and jasmonate (JA) are essential plant hormones that regulate various plant developmental processes and diverse defense responses (Kieber, 1997;Bleecker and Kende, 2000;Guo and Ecker, 2004;Broekaert et al, 2006;Howe and Jander, 2008;Browse, 2009;Shan et al, 2012;Wasternack and Hause, 2013). ET signal is perceived by its receptors ETHYLENE RESPONSE1 (ETR1), ETR2, ETHYLENE RESPONSE SENSOR1 (ERS1), ERS2, and ETHYLENE INSENSITIVE4 (EIN4) (Hua and Meyerowitz, 1998) to repress CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) (Kieber et al, 1993), which activates EIN2 (Alonso et al, 1999;Ju et al, 2012;Qiao et al, 2012;Wen et al, 2012) and subsequently stabilizes EIN3 and EIN3-LIKE1 (EIL1) (Chao et al, 1997;Guo and Ecker, 2003;Potuschak et al, 2003;Gagne et al, 2004) to mediate various ET responses, including hypocotyl growth (Zhong et al, 2012), apical hook formation (Knight et al, 1910;An et al, 2012), root growth (Ortega-Martínez et al, 2007;Růzicka et al, 2007), flowering (Ogawara et al, 2003;Achard et al, 2007), fruit ripening (Burg and Burg, 1962;Theologis et al, 1992), leaf senescence (Gepstein and Thimann, 1981;Li et al, 2013), freezing tolerance , and resistance against pathogen infection (Alonso et al, 2003;Chen et al, 2009).…”