Abstract
Despite a range of initiatives to reduce global carbon emission, the mean global temperature is increasing due to climate change. Since rising temperature poses a serious threat of food insecurity, it is important to further explore important biological molecules that can confer thermotolerance to plants. Recently, melatonin has emerged as a universal abiotic stress regulator that can enhance plant tolerance to high temperature. Nonetheless, such regulatory roles of melatonin were unraveled mainly by assessing the effect of exogenous melatonin on plant tolerance to abiotic stress. Here, we generated melatonin deficient tomato plants by silencing of a melatonin biosynthetic gene, CAFFEIC ACID O- METHYLTRANSFERASE 1 (COMT1), to unveil the role of endogenous melatonin in photosynthesis under heat stress. We examined photosynthetic pigment content, leaf gas exchange and a range of chlorophyll fluorescence parameters. The results showed that silencing of COMT1 aggravated heat stress by inhibiting both the light reactions and the carbon fixation reactions of photosynthesis. The photosynthetic pigment content, light absorption flux, trapped energy flux, energy dissipation, density of active reaction centre per PSII cross section, the photosynthetic electron transport rate, the maximum photochemical efficiency of PSII photochemistry and the rate of CO2 assimilation all decreased in COMT1-silenced plants compared with that of non-silenced plants particularly under heat stress. However, exogenous melatonin alleviated heat-induced photosynthetic inhibition in both genotypes, indicating that melatonin is essential for maintaining photosynthetic capacity under stressful conditions. These findings provide genetic evidence on the vital role of melatonin in photosynthesis and thus may have useful implication in horticultural crop management in the face of climate change.
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Claims 4
Claim · model-written summary
COMT1 silencing aggravated heat stress by inhibiting light and carbon fixation reactions.
- Taxon
- Tomato
Solanum lycopersicumt0 - Treatment
- silencing of COMT1e0
- Gene
- COMT1e0
- Outcome
- light reactions and the carbon fixation reactions of photosynthesise0
- Direction
- inhibitinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing of COMT1 aggravated heat stress by inhibiting both the light reactions and the carbon fixation reactions of photosynthesis”
t0“Tomato”
Claim · model-written summary
Photosynthetic pigments and PSII light and electron transport measures decreased in COMT1-silenced plants under heat stress.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- COMT1-silenced plantse0
- Outcome
- photosynthetic pigment content, light absorption flux, trapped energy flux, energy dissipation, density of active reaction centre per PSII cross section, the photosynthetic electron transport rate, the maximum photochemical efficiency of PSII photochemistrye0
- Direction
- decreasede0
- Qualifier
- heat stresse0
- Comparator
- non-silenced plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic pigment content, light absorption flux, trapped energy flux, energy dissipation, density of active reaction centre per PSII cross section, the photosynthetic electron transport rate, the maximum photochemical efficiency of PSII photochemistry and the rate of CO2 assimilation all decreased in COMT1-silenced plants compared with that of non-silenced plants particularly under heat stress”
t0“Tomato”
Claim · model-written summary
CO2 assimilation decreased in COMT1-silenced plants relative to non-silenced plants, especially under heat stress.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- COMT1-silenced plantse0
- Outcome
- rate of CO2 assimilatione0
- Direction
- decreasede0
- Qualifier
- heat stresse0
- Comparator
- non-silenced plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the rate of CO2 assimilation all decreased in COMT1-silenced plants compared with that of non-silenced plants particularly under heat stress”
t0“Tomato”
Claim · model-written summary
Exogenous melatonin alleviated heat-induced photosynthetic inhibition in both genotypes.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- exogenous melatonine0
- Outcome
- heat-induced photosynthetic inhibitione0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous melatonin alleviated heat-induced photosynthetic inhibition in both genotypes”
t0“Tomato”
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