Abstract
The color of an apple is an important index of its appearance quality, which affects the fruit’s marketability and value. The green variety “Granny Smith” remains green when ripe, and the pigment in the peel is mainly chlorophyll. The chlorophyll in the peel of the yellow variety “Golden Delicious” degrades as the fruit ripens. To explore the different mechanisms of chlorophyll degradation in the “Golden Delicious” and “Granny Smith” varieties, transcriptomic analysis was performed on the mature peels of both cultivars. High-quality sequences totaling 48,206,940 and 48,796,646 raw bases, as well as 9632 differentially expressed genes (DEGs), were identified. A total of 1206 DEGs were classified in 118 KEGG metabolic pathways. Additionally, 3258 transcription factors from 428 gene families were predicted, and DEGs associated with chlorophyll degradation, including MdSGR2, MdNYC1 and MdHCAR, were identified. Subsequently, the MdSGR2 gene was isolated from the mature peel of “Granny Smith” apples. Subsequent subcellular localization analysis confirmed that MdSGR2 specifically targets chloroplasts. The transient overexpression of MdSGR2 was found to negatively regulate chlorophyll degradation, leading to the inhibition or deceleration of chlorophyll breakdown, thereby maintaining green coloration in the leaves and peel. Conversely, silencing MdSGR2 positively regulated chlorophyll degradation, resulting in chlorosis in the leaves and peel. These findings offer valuable insights into the regulatory mechanism governing apple fruit coloration and lays a solid foundation for further investigation in this field.
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Claims 8
Claim · model-written summary
The peel transcriptomes yielded 48,206,940 and 48,796,646 raw bases.
- Taxon
- Apple
Malus domesticat0 - Outcome
- High-quality sequencese0
- Value
- 48,206,940 and 48,796,646 raw basese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High-quality sequences totaling 48,206,940 and 48,796,646 raw bases”
t0“Apple”
Claim · model-written summary
The cultivar peel comparison identified 9632 differentially expressed genes.
- Taxon
- AppleMalus domesticat0
- Outcome
- differentially expressed genese0
- Value
- 9632e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“9632 differentially expressed genes (DEGs), were identified”
t0“Apple”
Claim · model-written summary
A total of 1206 differentially expressed genes were classified in 118 KEGG pathways.
- Taxon
- AppleMalus domesticat0
- Outcome
- DEGs were classified in 118 KEGG metabolic pathwayse0
- Value
- 1206 DEGse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A total of 1206 DEGs were classified in 118 KEGG metabolic pathways”
t0“Apple”
Claim · model-written summary
The analysis predicted 3258 transcription factors from 428 gene families.
- Taxon
- AppleMalus domesticat0
- Outcome
- transcription factorse0
- Value
- 3258e0
- Qualifier
- 428 gene familiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3258 transcription factors from 428 gene families were predicted”
t0“Apple”
Claim · model-written summary
The study identified MdSGR2, MdNYC1 and MdHCAR among genes associated with chlorophyll degradation.
- Taxon
- AppleMalus domesticat0
- Gene
- MdSGR2, MdNYC1 and MdHCARe0
- Outcome
- DEGs associated with chlorophyll degradatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DEGs associated with chlorophyll degradation, including MdSGR2, MdNYC1 and MdHCAR, were identified”
t0“Apple”
Claim · model-written summary
MdSGR2 localized specifically to chloroplasts.
- Taxon
- AppleMalus domesticat0
- Gene
- MdSGR2e0
- Outcome
- targets chloroplastse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MdSGR2 specifically targets chloroplasts”
t0“Apple”
Claim · model-written summary
Transient MdSGR2 overexpression inhibited or slowed chlorophyll breakdown and maintained green leaf and peel coloration.
- Taxon
- AppleMalus domesticat0
- Organ / stage
- leaves and peele0
- Treatment
- transient overexpression of MdSGR2e0
- Gene
- MdSGR2e0
- Outcome
- chlorophyll degradatione0
- Direction
- negatively regulatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The transient overexpression of MdSGR2 was found to negatively regulate chlorophyll degradation, leading to the inhibition or deceleration of chlorophyll breakdown, thereby maintaining green coloration in the leaves and peel”
t0“Apple”
Claim · model-written summary
Silencing MdSGR2 promoted chlorophyll degradation and caused chlorosis in leaves and peel.
- Taxon
- AppleMalus domesticat0
- Organ / stage
- leaves and peele0
- Treatment
- silencing MdSGR2e0
- Gene
- MdSGR2e0
- Outcome
- chlorophyll degradatione0
- Direction
- positively regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing MdSGR2 positively regulated chlorophyll degradation, resulting in chlorosis in the leaves and peel”
t0“Apple”
The same questions in other papers
loss of function · physiology: pigments · Malus domestica (apple)Results agree
1 paper in the same direction as this paper
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.