Abstract
Softening characteristics were investigated in three types of pear fruit, namely, European pear 'La France', Chinese pear 'Yali', and Japanese pear 'Nijisseiki'. 'La France' fruit softened dramatically and developed a melting texture during ripening, while 'Yali' fruit with and without propylene treatment showed no change in flesh firmness and texture during ripening. Non-treated 'Nijisseiki' did not show a detectable decrease in flesh firmness, whereas continuous propylene treatment caused a gradual decrease in firmness resulting in a mealy texture. In 'La France', the analysis of cell wall polysaccharides revealed distinct solubilization and depolymerization of pectin and hemicellulose during fruit softening. In 'Nijisseiki', propylene treatment led to the solubilization and depolymerization of pectic polysaccharides to a limited extent, but not of hemicellulose. In 'Yali', hemicellulose polysaccharides were depolymerized during ripening, but there was hardly any change in pectic polysaccharides except in the water-soluble fraction. PC-PG1 and PC-PG2, two polygalacturonase (PG) genes, were expressed in 'La France' fruit during ripening, while only PC-PG2 was expressed in 'Nijisseiki' and neither PC-PG1 or PC-PG2 was expressed in 'Yali'. The expression pattern of PC-XET1 was constitutive during ripening in all three pear types. PG activity measured by the reducing sugar assay increased in all three pears during ripening. However, viscometric measurements showed that the levels of endo-PG activity were high in 'La France', low in 'Nijisseiki', and undetectable in 'Yali' fruits. These results suggest that, in pears, cell wall degradation is correlated with a decrease in firmness during ripening and the modification of both pectin and hemicellulose are essential for the development of a melting texture. Furthermore, the data suggest that different softening behaviours during ripening among the three pear fruits may be caused by different endo-PG activity and different expression of PG genes.
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Claims 20
Claim · model-written summary
'La France' fruit softened and developed melting texture during ripening.
- Taxon
- pear
_Poirier_Fleurs_et_feuilles.jpg?width=60)
Pyrus communist0 - Material
- 'La France'e0
- Outcome
- fruit softened dramatically and developed a melting texturee0
- Direction
- softenede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Poirier_Fleurs_et_feuilles.jpg?width=500)
Verbatim
e0“'La France' fruit softened dramatically and developed a melting texture during ripening”
t0“pear fruits”
Claim · model-written summary
'Yali' firmness and texture did not change during ripening with or without propylene.
- Taxon
- pearPyrus communist0
- Material
- 'Yali'e0
- Treatment
- with and without propylene treatmente0
- Outcome
- flesh firmness and texturee0
- Direction
- no changee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“'Yali' fruit with and without propylene treatment showed no change in flesh firmness and texture during ripening”
t0“pear fruits”
Claim · model-written summary
Untreated 'Nijisseiki' did not show a detectable firmness decrease.
- Taxon
- pearPyrus communist0
- Material
- 'Nijisseiki'e0
- Treatment
- Non-treatede0
- Outcome
- flesh firmnesse0
- Direction
- did not show a detectable decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Non-treated 'Nijisseiki' did not show a detectable decrease in flesh firmness”
t0“pear fruits”
Claim · model-written summary
Continuous propylene gradually decreased 'Nijisseiki' firmness and produced a mealy texture.
- Taxon
- pearPyrus communist0
- Material
- 'Nijisseiki'e0
- Treatment
- continuous propylene treatmente0
- Outcome
- firmnesse0
- Direction
- decreasee0
- Comparator
- Non-treated 'Nijisseiki'e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Non-treated 'Nijisseiki' did not show a detectable decrease in flesh firmness, whereas continuous propylene treatment caused a gradual decrease in firmness resulting in a mealy texture”
t0“pear fruits”
Claim · model-written summary
'La France' pectin and hemicellulose solubilized and depolymerized during softening.
- Taxon
- pearPyrus communist0
- Material
- 'La France'e0
- Outcome
- solubilization and depolymerization of pectin and hemicellulosee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 'La France', the analysis of cell wall polysaccharides revealed distinct solubilization and depolymerization of pectin and hemicellulose during fruit softening”
t0“pear fruits”
Claim · model-written summary
Propylene caused limited pectic polysaccharide solubilization and depolymerization in 'Nijisseiki'.
- Taxon
- pearPyrus communist0
- Material
- 'Nijisseiki'e0
- Treatment
- propylene treatmente0
- Outcome
- solubilization and depolymerization of pectic polysaccharidese0
- Qualifier
- to a limited extente0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 'Nijisseiki', propylene treatment led to the solubilization and depolymerization of pectic polysaccharides to a limited extent”
t0“pear fruits”
Claim · model-written summary
Propylene did not cause hemicellulose solubilization or depolymerization in 'Nijisseiki'.
- Taxon
- pearPyrus communist0
- Material
- 'Nijisseiki'e0
- Treatment
- propylene treatmente0
- Outcome
- hemicellulosee0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 'Nijisseiki', propylene treatment led to the solubilization and depolymerization of pectic polysaccharides to a limited extent, but not of hemicellulose”
t0“pear fruits”
Claim · model-written summary
'Yali' hemicellulose polysaccharides depolymerized during ripening.
- Taxon
- pearPyrus communist0
- Material
- 'Yali'e0
- Outcome
- hemicellulose polysaccharidese0
- Direction
- depolymerizede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 'Yali', hemicellulose polysaccharides were depolymerized during ripening”
t0“pear fruits”
Claim · model-written summary
'Yali' pectic polysaccharides hardly changed except in the water-soluble fraction.
- Taxon
- pearPyrus communist0
- Material
- 'Yali'e0
- Outcome
- pectic polysaccharidese0
- Direction
- hardly any changee0
- Qualifier
- except in the water-soluble fractione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 'Yali', hemicellulose polysaccharides were depolymerized during ripening, but there was hardly any change in pectic polysaccharides except in the water-soluble fraction”
t0“pear fruits”
Claim · model-written summary
PC-PG1 and PC-PG2 were expressed in 'La France' fruit during ripening.
- Taxon
- pearPyrus communist0
- Material
- 'La France'e0
- Gene
- PC-PG1 and PC-PG2e0
- Outcome
- were expressede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PC-PG1 and PC-PG2, two polygalacturonase (PG) genes, were expressed in 'La France' fruit during ripening”
t0“pear fruits”
Claim · model-written summary
Only PC-PG2 was expressed in 'Nijisseiki'.
- Taxon
- pearPyrus communist0
- Material
- 'Nijisseiki'e0
- Gene
- PC-PG2e0
- Outcome
- was expressede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“only PC-PG2 was expressed in 'Nijisseiki'”
t0“pear fruits”
Claim · model-written summary
Neither PC-PG1 nor PC-PG2 was expressed in 'Yali'.
- Taxon
- pearPyrus communist0
- Material
- 'Yali'e0
- Gene
- PC-PG1 or PC-PG2e0
- Outcome
- neither PC-PG1 or PC-PG2 was expressede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“neither PC-PG1 or PC-PG2 was expressed in 'Yali'”
t0“pear fruits”
Claim · model-written summary
PC-XET1 expression was constitutive during ripening in all three pear types.
- Taxon
- pearPyrus communise0
- Gene
- PC-XET1e0
- Outcome
- expression patterne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The expression pattern of PC-XET1 was constitutive during ripening in all three pear types”
Claim · model-written summary
PG activity by reducing sugar assay increased in all three pears during ripening.
PyrusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PG activity measured by the reducing sugar assay increased in all three pears during ripening”
Claim · model-written summary
Endo-PG activity was high in 'La France'.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“levels of endo-PG activity were high in 'La France'”
t0“pear fruits”
Claim · model-written summary
Endo-PG activity was low in 'Nijisseiki'.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low in 'Nijisseiki'”
t0“pear fruits”
Claim · model-written summary
Endo-PG activity was undetectable in 'Yali'.
- Taxon
- pearPyrus communist0
- Material
- 'Yali'e0
- Outcome
- undetectablee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“undetectable in 'Yali' fruits”
t0“pear fruits”
Claim · model-written summary
Cell wall degradation correlated with decreasing pear firmness during ripening.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in pears, cell wall degradation is correlated with a decrease in firmness during ripening”
Claim · model-written summary
Modification of pectin and hemicellulose is suggested as essential for melting texture in pears.
- Taxon
- pearPyrus communist0
- Outcome
- melting texturee0
- Qualifier
- modification of both pectin and hemicellulosee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the modification of both pectin and hemicellulose are essential for the development of a melting texture”
t0“pear fruits”
Claim · model-written summary
Different endo-PG activity and PG gene expression may explain different pear softening behaviors.
- Taxon
- pearPyrus communise0
- Gene
- PG genese0
- Outcome
- softening behaviourse0
- Qualifier
- different endo-PG activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“different softening behaviours during ripening among the three pear fruits may be caused by different endo-PG activity and different expression of PG genes”