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Joined 2026-09-21 Message
Incoming links: Ripening
Bart J. Janssen 2026-11-05
Bart J. Janssen studies the molecular control of plant development. A 2008 study led by Janssen followed gene expression as apple fruits developed, linking molecular measurements to recognizable changes in anatomy and growth.
The investigators collected samples at eight developmental times and used a DNA microarray representing approximately 13000 genes. Four broad temporal patterns distinguished flower stages, early cell division, growth with starch accumulation, and ripening. Selected measurements were checked using Quantitative PCR.[ref]
An apple is a pome, with both an ovary-derived core and surrounding hypanthium tissue. Comparing stages therefore asks how growth of a composite fruit is coordinated. A gene whose expression peaks during cell division becomes a candidate for further investigation; matching the timing does not alone demonstrate that the gene causes that developmental change.[ref]
Global gene expression analysis of apple fruit development from the floral bud to ripe fruit by Bart J. Janssen and others. Background, core/cortex distinction; Results, coordinated expression patterns
Pome 2026-11-05
A pome is a fleshy accessory fruit developing from an inferior ovary, with an enlarged hypanthium surrounding the central fruit tissues. An apple is a familiar example. Much of its edible flesh comes from tissue around the ovary, whereas the central core corresponds to the developed ovary. Thus the fleshy part of a pome cannot simply be identified with the pericarp, the wall derived from the ovary.[ref]
To see the distinction, cut an apple lengthwise through its stalk and centre: locate the seeds, the enclosing core and the surrounding flesh. The fruit integrates structures with different developmental origins.
In a 2008 study, Bart J. Janssen and colleagues sampled developing apple fruits at eight times and used a DNA microarray representing roughly 13000 genes. They identified coordinated gene expression patterns associated with early cell division, later growth and starch accumulation, and ripening. The experiment illustrates how the anatomy of a pome motivates a molecular question: how are growth and maturation of its different tissues coordinated?[ref]
Global gene expression analysis of apple fruit development from the floral bud to ripe fruit by Bart J. Janssen and others. Background; Results, Microarray analysis of apple fruit development and Four major groups of co-ordinately expressed genes
P. W. Oeller 2026-11-05
P. W. Oeller investigated molecular control of plant development, including the role of Ethylene in fruit ripening. A 1991 study with colleagues used Antisense RNA to reduce production of 1-aminocyclopropane-1-carboxylate synthase, an enzyme in Ethylene biosynthesis, in tomato plants.[ref]
Reversible inhibition of tomato fruit senescence by antisense RNA by P. W. Oeller and others. Science 254, pp. 437–439; primary byline and abstract
The modified tomatoes showed inhibited ripening, and supplying Ethylene externally reversed the inhibition. This paired intervention and rescue connected a molecular perturbation to a developmental process: reducing the signal delayed the process, while restoring the signal restored it. The result supplied causal evidence for Ethylene control in this experimental system, beyond a correlation between rising Ethylene and maturing fruit.[ref]
Reversible inhibition of tomato fruit senescence by antisense RNA by P. W. Oeller and others. Abstract; antisense inhibition and rescue by exogenous ethylene or propylene
Ripening 2026-11-05
Ripening is the coordinated set of developmental changes that brings a fruit toward its mature dispersal or eating state. Depending on the fruit, these changes can include altered pigmentation, softening, changes in sugars and acids, and the production of volatile compounds. They need not all occur at the same rate, so colour alone is an incomplete measure of ripening.
A particularly clear experiment established a role for Ethylene in tomato ripening. In 1991, P. W. Oeller and colleagues expressed Antisense RNA directed against 1-aminocyclopropane-1-carboxylate synthase, an enzyme required for Ethylene production. Ripening was inhibited. Supplying Ethylene from outside the plant reversed that inhibition.[ref]
Reversible inhibition of tomato fruit senescence by antisense RNA by P. W. Oeller and others. Science 254, pp. 437–439; abstract, antisense inhibition and rescue by supplied ethylene
The intervention and rescue distinguish a regulating signal from a substance that merely accumulates while ripening happens. Suppressing production delays the process, while restoring the signal restores it. This establishes a causal role for Ethylene in that tomato system; the precise control of ripening must still be investigated for other fruits.
S. F. Yang 2026-11-05
S. F. Yang studied the biosynthesis of Ethylene, a plant hormone involved in fruit ripening. A 1979 study with D. O. Adams established 1-aminocyclopropane-1-carboxylate as an intermediate between methionine and Ethylene.[ref]
In apple tissue, labelled methionine produced Ethylene in air but accumulated the cyclic intermediate under nitrogen. Supplying labelled 1-aminocyclopropane-1-carboxylate and comparing responses to an inhibitor helped establish the order of the reactions. The design used both precursor tracing and bypass of a blocked upstream step, rather than assuming that correlated concentrations reveal pathway order.[ref]
