Manipulation of light quality is an effective tool to regulate photosynthetic capacity and fruit antioxidant properties of Solanum lycopersicum L. cv. ‘Microtom’ in a controlled environment

Abstract

Light quality plays an essential role in setting plant structural and functional traits, including antioxidant compounds. This paper aimed to assess how manipulating the light spectrum during growth may regulate the photosynthetic activity and fruit bioactive compound synthesis in Solanum lycopersicum L. cv. ‘Microtom’ to improve plant physiological performance and fruit nutritional value. Plants were cultivated under three light quality regimes: red-green-blue LEDs (RGB), red-blue LEDs (RB) and white fluorescent lamps (FL), from sowing to fruit ripening. Leaf functional traits, photosynthetic efficiency, Rubisco and D1 protein expression, and antioxidant production in fruits were analyzed. Compared to FL, RGB and RB regimes reduced height and increased leaf number and specific leaf area, enhancing plant dwarf growth. The RGB regime improved photosynthesis and stomatal conductance despite lower biomass, favoring Rubisco synthesis and carboxylation rate than RB and FL regimes. The RB light produced plants with fewer flowers and fruits with a lower ascorbic acid amount but the highest polyphenol content, antioxidant capacity and SOD and CAT activities. Our data indicate that the high percentage of the green wavelength in the RGB regime promoted photosynthesis and reduced plant reproductive capacity compared to FL and RB. Conversely, the RB regime was the best in favoring the production of health-promoting compounds in tomato berries.

Blue spectral quality contributes to yield and ascorbic acid content in ‘Micro Tom’ tomato under sole-source lighting

“…Adding blue to a red light background increased leaf number and leaf area in several tomato cultivars and species (Hernández et al, 2016; Ouzounis et al, 2016), whereas another analysis (of young plants) showed that only dry weight partitioning to the leaf, compared to stem, was increased (Kalaitzoglou et al, 2021). For ‘Micro Tom’ in particular, in one case, a higher blue proportion resulted in increased SLA, not leaf number and area (Ke et al, 2022), in another case, a low leaf number and small leaf area (Vitale et al, 2022) – a discrepancy likely caused by different light recipes used (specifically, the quantities of green and far-red light). The variation in phenotypes observed are likely due to the large natural variation in tomato.…”

“…Tomato-specific blue light benefits include prevention of grey mold disease and reduction of intumescence injury (Imada et al, 2014; Retana-Cordero et al, 2022). In addition, blue light affects tomato nutritional quality (He et al, 2022; Ntagkas et al, 2020; Vitale et al, 2022; Wang et al, 2022).…”

Tissue culture coupled with a gas exchange system offers new perspectives on phenotyping the developmental biology of Solanum lycopersicum L. cv. ‘MicroTom’

“…A significant area of focus in the field of tomato production is yield and fruit quality in response to light ( Vitale et al., 2022 ). Since major categories of secondary plant metabolites are present in tomato fruit ( Li et al., 2020 ), the rapid cycling MicroTom is an ideal candidate to study fruit quality in response to different abiotic factors.…”

“…Since major categories of secondary plant metabolites are present in tomato fruit ( Li et al., 2020 ), the rapid cycling MicroTom is an ideal candidate to study fruit quality in response to different abiotic factors. Although light quality can significantly impact the nutritional value of growth chamber produced MicroTom fruit by increasing antioxidant levels ( Vitale et al., 2022 ), it is unknown if the secondary metabolite activities of in vitro MicroTom fruit mimic their ex vitro counterparts. This represents an important area of focus for fruit production and quality in response to light, and a research area perfectly suited for the tissue culture approach.…”

“…‘Microtom’ (MicroTom) is a miniature, herbaceous tomato cultivar, with a relatively rapid life cycle from seed germination to seed set. Like Arabidopsis , MicroTom is a model organism with a well annotated genome and extensive mutant seedbank for studying plant-pathogen interactions ( Takahashi et al., 2005 ) as well as genetic ( Dan et al., 2006 ), molecular ( Park et al., 2007 ), and physiological ( Vitale et al., 2022 ) aspects of vegetative growth, flowering, and fruiting stages of the plant’s life cycle. Despite the miniature growth form of this cultivar, MicroTom experiments often rely on conventional cultivation methods that require expansive bench space and/or expensive growth cabinets to create replicated environments.…”