Abstract
Torreya grandis is a widely cultivated fruit species in China that is valued for its significant economic and agricultural importance. The molecular mechanisms underlying pigment formation and photosynthetic performance in Torreya leaf color mutants remain to be fully elucidated. In this study, we performed transcriptome sequencing and measured photosynthetic performance indicators to compare mutant and normal green leaves. The research results indicate that the identified Torreya mutant differs from previously reported mutants, exhibiting a weakened photoprotection mechanism and a significant reduction in carotenoid content of approximately 33%. Photosynthetic indicators, including the potential maximum photosynthetic capacity (Fv/Fm) and electron transport efficiency (Ψo, φEo), decreased significantly by 32%, 52%, and 49%, respectively. While the quantum yield for energy dissipation (φDo) increased by 31%, this increase was not statistically significant, which may further reduce PSII activity. A transcriptome analysis revealed that the up-regulation of chlorophyll degradation-related genes—HCAR and NOL—accelerates chlorophyll breakdown in the Torreya mutant. The down-regulation of carotenoid biosynthesis genes, such as LCY1 and ZEP, is strongly associated with compromised photoprotective mechanisms and the reduced stability of Photosystem II. Additionally, the reduced expression of the photoprotective gene psbS weakened the mutant’s tolerance to photoinhibition, increasing its susceptibility to photodamage. These changes in gene expression accelerate chlorophyll degradation and reduce carotenoid synthesis, which may be the primary cause of the yellowing in Torreya. Meanwhile, the weakening of photoprotective mechanisms further impairs photosynthetic efficiency, limiting the growth and adaptability of the mutants. This study emphasizes the crucial roles of photosynthetic pigments and photosystem structures in regulating the yellowing phenotype and the environmental adaptability of Torreya. It also provides important insights into the genetic regulation of leaf color in relation to photosynthesis and breeding.
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Claims 14
Claim · model-written summary
The identified Torreya mutant differs from previously reported mutants and shows a weakened photoprotection mechanism.
TorreyaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the identified Torreya mutant differs from previously reported mutants, exhibiting a weakened photoprotection mechanism”
Claim · model-written summary
Carotenoid content of the Torreya leaf color mutant was significantly reduced by approximately 33% relative to normal green leaves.
- Material
- Torreya mutante1
- Organ / stage
- green leavese2
- Outcome
- carotenoid contente1
- Direction
- reductione1
- Value
- approximately 33%e1
- Comparator
- normal green leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the identified Torreya mutant differs from previously reported mutants, exhibiting a weakened photoprotection mechanism and a significant reduction in carotenoid content of approximately 33%”
e2“to compare mutant and normal green leaves”
Claim · model-written summary
Potential maximum photosynthetic capacity (Fv/Fm) decreased significantly by 32% in the Torreya grandis leaf color mutant relative to normal green leaves.
- Taxon
- Torreya grandis
Torreya grandist0 - Outcome
- potential maximum photosynthetic capacity (Fv/Fm)e3
- Direction
- decreasede3
- Value
- 32%e3
- Comparator
- normal green leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e2“to compare mutant and normal green leaves”
e3“the potential maximum photosynthetic capacity (Fv/Fm) and electron transport efficiency (Ψo, φEo), decreased significantly by 32%, 52%, and 49%, respectively”
Claim · model-written summary
Electron transport efficiency (Ψo) decreased significantly by 52% in the Torreya grandis leaf color mutant relative to normal green leaves.
- Taxon
- Torreya grandisTorreya grandist0
- Outcome
- electron transport efficiencye3
- Direction
- decreasede3
- Value
- 52%e3
- Comparator
- normal green leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e2“to compare mutant and normal green leaves”
e3“the potential maximum photosynthetic capacity (Fv/Fm) and electron transport efficiency (Ψo, φEo), decreased significantly by 32%, 52%, and 49%, respectively”
Claim · model-written summary
Electron transport efficiency (φEo) decreased significantly by 49% in the Torreya grandis leaf color mutant relative to normal green leaves.
- Taxon
- Torreya grandisTorreya grandist0
- Outcome
- electron transport efficiencye3
- Direction
- decreasede3
- Value
- 49%e3
- Comparator
- normal green leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e2“to compare mutant and normal green leaves”
e3“the potential maximum photosynthetic capacity (Fv/Fm) and electron transport efficiency (Ψo, φEo), decreased significantly by 32%, 52%, and 49%, respectively”
Claim · model-written summary
Quantum yield for energy dissipation (φDo) rose by 31% in the mutant, but this increase was not statistically significant.
- Taxon
- Torreya grandisTorreya grandist0
- Outcome
- quantum yield for energy dissipatione4
- Direction
- increasede4
- Value
- 31%e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e4“While the quantum yield for energy dissipation (φDo) increased by 31%, this increase was not statistically significant”
Claim · model-written summary
Chlorophyll degradation-related genes HCAR and NOL are up-regulated in the Torreya mutant.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e5“the up-regulation of chlorophyll degradation-related genes—HCAR and NOL—accelerates chlorophyll breakdown in the Torreya mutant”
Claim · model-written summary
Up-regulation of HCAR and NOL is asserted to accelerate chlorophyll breakdown in the Torreya mutant.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e5“the up-regulation of chlorophyll degradation-related genes—HCAR and NOL—accelerates chlorophyll breakdown in the Torreya mutant”
Claim · model-written summary
Carotenoid biosynthesis genes LCY1 and ZEP are down-regulated in the Torreya mutant.
- Taxon
- Torreya grandisTorreya grandist0
- Gene
- LCY1 and ZEPe6
- Outcome
- carotenoid biosynthesis genese6
- Direction
- down-regulatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e6“The down-regulation of carotenoid biosynthesis genes, such as LCY1 and ZEP, is strongly associated with compromised photoprotective mechanisms and the reduced stability of Photosystem II”
Claim · model-written summary
Down-regulation of LCY1 and ZEP is strongly associated with compromised photoprotective mechanisms and reduced stability of Photosystem II.
- Taxon
- Torreya grandisTorreya grandist0
- Gene
- LCY1 and ZEPe6
- Outcome
- photoprotective mechanismse6
- Qualifier
- reduced stability of Photosystem IIe6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e6“The down-regulation of carotenoid biosynthesis genes, such as LCY1 and ZEP, is strongly associated with compromised photoprotective mechanisms and the reduced stability of Photosystem II”
Claim · model-written summary
Reduced expression of the photoprotective gene psbS in the Torreya mutant.
- Taxon
- Torreya grandisTorreya grandist0
- Gene
- psbSe7
- Outcome
- expressione7
- Direction
- reducede7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e7“the reduced expression of the photoprotective gene psbS weakened the mutant’s tolerance to photoinhibition, increasing its susceptibility to photodamage”
Claim · model-written summary
Reduced psbS expression is asserted to weaken the mutant tolerance to photoinhibition, increasing its susceptibility to photodamage.
- Taxon
- Torreya grandisTorreya grandist0
- Gene
- psbSe7
- Outcome
- tolerance to photoinhibitione7
- Qualifier
- increasing its susceptibility to photodamagee7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e7“the reduced expression of the photoprotective gene psbS weakened the mutant’s tolerance to photoinhibition, increasing its susceptibility to photodamage”
Claim · model-written summary
Changes in gene expression may be the primary cause of the yellowing in Torreya.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e1“These changes in gene expression accelerate chlorophyll degradation and reduce carotenoid synthesis, which may be the primary cause of the yellowing in Torreya”
Claim · model-written summary
Weakened photoprotection is asserted to further impair photosynthetic efficiency and limit the growth and adaptability of the mutants.
- Taxon
- Torreya grandisTorreya grandist0
- Outcome
- growth and adaptabilitye1
- Qualifier
- the weakening of photoprotective mechanisms further impairs photosynthetic efficiencye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Torreya grandis with Leaf Color Mutations”
e1“the weakening of photoprotective mechanisms further impairs photosynthetic efficiency, limiting the growth and adaptability of the mutants”