Fruit ripening ethylene synthesis

The synthesis of endo-PG occurs in the ripening stage after an increase of ethylene production [21] and its appearance has been correlated with an increase in soluble pectin and softening [22]. Exo-PG is suggested to participate in the initiation of climacteric ethylene production [23]. Strawberry fruit has been accepted to be a non-climacteric fruit and ethylene... 

Delayed fruit ripening due to reduced ethylene synthesis... 

Tomato Agritrope/1996 5-Adenosylmethionine hydrolase Escherichia coli bacteriophage T3 Delayed fruit ripening due to reduced ethylene synthesis... 

Saltveit ME and Mencarelli F. 1988. Inhibition of ethylene synthesis and action in ripening tomato fruit by ethanol vapors. J Am Soc Hort Sci 113 572—576. 

Synthesis of ethylene, a gaseous plant hormone involved in fruit ripening and flower senescence. 

Fruit tissues respond to ethylene by exhibiting increases in the activities of enzymes that catalyze ripening reactions, and in some cases, the increases in enzyme activity probably are the result of de novo synthesis, rather than activation of preexisting enzymes. Other target tissues respond similarly to ethylene. But it is not known whether ethylene acts directly to evoke new enzyme production. Interpretation of results with inhibitors of RNA and protein synthesis is inconclusive, because it could be merely that RNA and protein synthesis are essential to maintain the cells in a state competent to respond to ethylene. Moreover, there are some responses to ethylene, besides fruit ripening, which occur under conditions which apparently do not directly involve RNA and protein synthesis (e.g., membrane permeability changes). It has been proposed that the in vivo ethylene receptor site contains a metal such as copper (34,35). 

We noted earlier in this chapter (Section II.C.3) the pyridoxal-phosphate-linked enzymatic route of synthesis of ACPC (9) from the a-aminobutyryl moiety of S-adenosylmethionine (99). ACPC (9) undergoes further metabolic processing by two distinct fragmentation routes, to a-ketobutyrate (138) and ammonia (equation 21) in bacteria and yeast or to ethylene (139) in fruit and other plant tissues (equation 22) where ethylene (139) is a potent hormone for fruit-ripening or wound-healing The bacterial enzyme, ACPC deaminase is much better characterized and is taken up first. 

If the endogenous material is a participant in the initiation of ripening, however, it is unlikely the fruit PG is responsible for its origin. Several studies (e.g. 8, 20) have shown that tomato fruit synthesis of PG follows (by as much as a day or more) the increase in fruit ethylene production that is accepted as a marker of ripening s onset. Of course, ripening is not a simultaneous, whole fruit phenomenon. It is a developmental event the passes through the fruit (its different tissue areas, perhaps even from cell to... 

Previous publications reported that ethanol treatment retarded ripening of several fruits, including whole tomatoes and tomato slices (Saltveit and Mencarelli 1988). Also, ethanol can slow down tomato ripening by inhibiting synthesis and action of ethylene,... 

The ripening of nonclimacteric fruits is usually considered as a process that as a whole does not require ethylene. Nevertheless, endogenous ethylene is involved at some steps of development of these fruits. In general, chlorophyll degradation in nonclimacteric fruits is believed to be ethylene stimulated, whereas the synthesis of pigments can depend on ethylene action or not. ... 

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