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#delayed ripening

2 public questions tagged with this topic.

Transgenic Plant -2

Endless Summer tomatoes show delayed ripening due to inhibition of:

Endless Summer tomatoes achieve delayed ripening by targeting ethylene production rather than downstream wall enzymes, contrasting with Flavr Savr. Endless Summer line carries antisense copy of ACC synthase gene LE-ACS2 expressed under constitutive promoter, reducing endogenous ACS mRNA through complementary base pairing and RNA interference mediated degradation. Since SAM to ACC conversion is rate-limiting and ACS activity determines ethylene evolution rate, silencing lowers ACC concentration, thereby reducing substrate for ACC oxidase that requires Fe2+, ascorbate, bicarbonate and oxygen to

Ref: Oeller et al. Science 1991 254:437 Antisense ACS tomato; Fluhr Plant Mol Biol Review ACS inhibition.

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Transgenic Plant -2

Delayed ripening in Flavr Savr tomato leads to:

Delayed ripening engineered in Flavr Savr tomato illustrates antisense RNA interference applied to post-harvest biology. Normal vine-ripened tomatoes accumulate high levels of polygalacturonase mRNA, producing abundant PG enzyme that depolymerizes pectic polysaccharides, causing rapid loss of firmness within days after harvest, requiring early picking of green mature fruit and artificial ethylene treatment for color development, sacrificing flavor volatiles. Calgene introduced an additional PG gene in reverse orientation driven by CaMV 35S promoter into cultivar via Agrobacterium binary vector

Ref: FDA Consumer Report Flavr Savr 1994; Giovannoni Annu Rev Plant Biol 2001 Tomato ripening; PMC5033183.

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