Research revealed that the abaxial leafy supplemental lighting (AB) can significantly improve the net photosynthetic rate and stomatal conductance in the leaves of tomato plants compare to the adaxial leafy supplemental lighting (AD) method. However, the underlying regulatory mechanisms are still poorly understood. Here, we conducted AB and AD on tomato and assessed transcriptomic, and proteomic changes in leaves. The result showed that under the two supplemental lighting methods, a total of 7352 genes and 152 proteins were differentially expressed. Significant differences were observed in genes expression levels and proteins abundances across multiple pathways, mainly including cell process, metabolism process, biological regulation, environment information processing, genetic information processing, metabolism, and organismal systems. Additionally, we also found that some key genes that plant hormone signaling, light perception, photosynthesis, plant fitness, and promoting fruit ripening, have increased significantly, which can explain the effect of AB on plant growth and development. Finally, through the qPCR, we determined that AB mainly up-regulate a series of auxin-responsive genes or factors, auxin polarity transport genes, gibberellin synthesis genes, cell cycle regulator genes, sugar transporters, and fleshy fruit ripening genes. These results help us to understand plant light response mechanism and discover genes which contribute to efficient light energy utilization.

Plant seedlings are sensitive to cultivation environment factors and highly susceptible to pathogenic infections under adverse conditions such as inappropriate light environment. In this study, five kinds of LED lighting sources with different red (R) and blue (B) light combinations were set up: R10B0, R7B3, R5B5, R2B8 and R0B10 (with R:B ratios of 10:0, 7:3, 5:5, 2:8 and 0:10, respectively) to explore their effects on tomato seedlings’ growth, AsA-GSH cycle, endogenous hormones, and resistance to Phytophthora infestans, providing a basis for factory seedling light-quality selection. The results showed that with the increase in the proportion of blue light in the composite light, the growth indicators, photosynthetic characteristic parameters and enzyme activities of tomato seedlings generally increased. The contents of AsA, reduced glutathione, and oxidized glutathione all reached the maximum under high-proportion blue-light treatments (R2B8 and R0B10). The high-blue-light groups (R2B8 and R0B10) had the highest AsA and glutathione contents. The red–blue combinations reduced inhibitory ABA and increased growth-promoting hormones (e.g., melatonin), while monochromatic light increased ABA to inhibit growth. After inoculation with P. infestans, the apoplastic glucose content was the highest under the red–blue-combined treatments (R5B5 and R2B8), while the total glucose content in leaves was the highest under the combined light R2B8 treatment. In conclusion, high-proportion blue-light treatment can greatly promote the photosynthetic process of tomato, enhance the AsA-GSH cycle, and achieve the best effect in improving the resistance of tomatoes to P. infestans. Given these, the optimal light environment setting was R:B = 2:8.

ADP-glucose pyrophosphorylase (AGPase) is an important enzyme in the starch synthesis pathway. Its enzyme activity can determine the efficiency of starch biosynthesis. Cassava (Manihot esculenta Crantz) is the main staple crop worldwide and has a high starch content in its storage root. However, the inner regulatory mechanism of AGPase gene family is unclear. MePHD1; a plant homeodomain transcription factor; was isolated through a yeast one-hybrid screening using the promoter of ADP-glucose pyrophosphorylase small subunit1a (MeAGPS1a) as bait, and cassava storage root cDNA library as prey. This factor could bind to the MeAGPS1a promoter in vitro and in vivo, and its predicted binding region ranged from −400 bp to −201 bp, at the translation initiation site. The transcript level of MePHD1 could be induced by five plant hormones, and a temperature of 42 °C. This was down-regulated during the maturation process of the storage root. MePHD1 protein could repress the promoter activity of MeAGPS1a gene by a dual-luciferase assay; which indicated that MePHD1 is a negative regulator for the transcript level of MeAGPS1a gene.

Insufficient light supply for canopies is a constant issue during greenhouse production in most areas of Northern China. Applying supplemental lighting to plant canopies is an efficient method of solving this problem. Several studies were conducted to identify the optimal, economically efficient abaxial leafy supplemental lighting mode to produce high-quality greenhouse tomatoes. In this experiment, no supplemental treatment was used as a blank control (CK), while three supplemental lighting modes were used as treatments: T1, continuous supplemental lighting from 8:00–9:00 (at GMT+8, which is 6:00–7:00 local time, before the thermal insulation covers, abbreviated as TIC below, opening), and 20:00–22:00 (after TIC closing) with photosynthetic photon fluxion density (PPFD) of 200 μmol·m⁻²·s⁻¹; T2, dynamic altered supplemental lighting with PPFD rising from 100 μmol·m⁻²·s⁻¹ to 200 μmol·m⁻²·s⁻¹ before TIC opening and falling from 200 μmol·m⁻²·s⁻¹ to 100 μmol·m⁻²·s⁻¹ after TIC closing; and T3, intermittent supplemental lighting which was automatically conducted with PPFD of 100 μmol·m⁻²·s⁻¹ when indoor PPFD below 150 μmol·m⁻²·s⁻¹ from 8:00–22:00. The results demonstrated that abaxial leafy supplemental lighting treatment could improve both fruit yield and quality. The total yield in the T1 and T2 treatments was higher than in other treatments, though there was no significant difference. Differences in leaf carbon exportation showed the possibility of determining fruit yield from the 3rd leaf under the fruit. The overall appearance, flavor quality, nutrient indicators, and aroma of cherry tomato fruits under T1 and T2 treatments were generally higher than in other treatments. Correlation analysis of fruit yield and quality parameters suggested that they produce relatively high yield and fruit quality. Combined with a cost-performance analysis, dynamic altered supplemental lighting (T2) is more suitable for high-valued greenhouse cherry tomato production.

Background: Ethyl methyl sulfonate (EMS) mutagenesis is widely used because of its advantages of inducing point mutations and no need for genetic transformation. To identify germplasm resources of processed tomatoes with superior comprehensive traits suitable for cultivation in Xinjiang. Methods: In this study, tomato seeds were treated with 2% EMS reagent for 12 h, 21 quality traits and 20 quantitative traits of 33 processed tomatoes derived from EMS-mutagenized“M82”were evaluated. Results: The results indicated that for traits such as hypocotyl color, growth habit, plant type, leaf type, and leaf shape, the range of quantitative trait variation was 8.45–37.25%, with a genetic diversity index ranging from 1.25 to 2.07. Conclusions: Cluster analysis of quantitative traits categorized the 33 EMS-mutagenized “M82” processed tomato resources into five groups: Group I contained 22 robust germplasm samples; Group II consisted of a single potential high-quality germplasm; Group III comprised five germplasm with a small and extreme plant type; Group IV included four high-yield germplasm; and Group V represented one moderate, conventional germplasm. Raw data from 15 quantitative traits across the 33 accessions were standardized using the “extreme method” to extract six comprehensive factors. The top 10 germplasm resources based on the comprehensive score were 76, 137, 97, 102, 19, 104, 21, 108, 17, and 147. It provides some theoretical basis for realizing the high-yield and high-quality cultivation and variety breeding of processed tomatoes in Xinjiang.

Drought is one of the major abiotic stresses that inhibits plant growth and development. Therefore, it is critical to explore drought resistance genes in crops to obtain high-quality breeding materials. In this study, the drought-sensitive tomato line “FQ118” and the resistant line “FQ119” were treated with PEG-6000 and, at 0 h (CK), 6 h, 24 h, 36 h and 48 h, the plants were evaluated for growth and physiological indicators, and leaf tissues were collected for RNA-seq. The growth indicators (growth trend, dry and fresh weights above- and below-ground, etc.) and the antioxidant enzyme system reflect that “FQ119” has stronger drought tolerance. Through RNA-seq analysis, a total of 68,316 transcripts (37,908 genes) were obtained. The largest number of significant differentially expressed genes (DEGs) in the comparison of “FQ118” and “FQ119” was observed at 6 h and 48 h. KEGG analysis demonstrated the significant enrichment of certain pathways associated with drought stress, such as glycerolipid metabolism and galactose metabolism. Co-expression analysis revealed that 7 hub DEGs, including genes encoding a photosystem reaction center subunit protein, chlorophyll a-b binding protein, glyceraldehyde-3-phosphate dehydrogenase A (GAPDH), and others, were coenriched in both comparisons. In addition, three hub genes specific to the comparison during the 6-h processing stage, encoding oxygen-evolving enhancer protein 1, receptor-like serine/threonine-protein kinase and calcium-transporting ATPase, were identified. The above hub genes were related to plant resistance to drought stress, and RT‒qPCR verified that the overall magnitudes of the differences in expression between the two lines gradually increased over time. Virus-induced gene silencing (VIGS) experiments have demonstrated that GAPDH plays a relevant role in the drought resistance pathway. In addition, the differences in expression of 7 DEGs encoding transcription factors, including Dofs, WRKYs, MYBs, and MYCs, also tended to increase with increasing duration of drought treatment, as determined via qPCR. In summary, this study identified several valuable genes related to plant drought resistance by screening genes with differential transcription under drought stress. This in-depth gene mining may provide valuable references and resources for future breeding for drought resistance in tomato.