Functional Validation of Phytoene Synthase and Lycopene ε-Cyclase Genes for High Lycopene Content in Autumn Olive Fruit (Elaeagnus umbellata)

Optimization of the method of ultrasonic extraction of lycopene with a green extract from the fruit of Elaeagnus umbellata, common in Western Georgia

The study determined the content of lycopene in the fruits of the Elaeagnus umbellata (35.25-60.21 mg/100 g), common at different heights above sea level in Western Georgia. For the effective extraction of lycopene as a biologically active substance, the optimal conditions for ultrasonic extraction were selected: sunflower oil was used as a "green solvent"; the ratio of solid mass and solvent was 1:50; temperature 30°C; ultrasound amplitude 40%; power 85 W; and extraction time 10 min. FTIR spectra revealed the characteristic functional groups of lycopene exhibiting two characteristic peaks at 2920 and 2950 cm-1. To explore the effect of lycopene on oil quality, the acid value, peroxide value, and p-anisidine were determined in each oil sample. The antioxidant determination by inhibition of DPPH radicals showed significant differences in native oils and oils with lycopene.

Chromosome Doubling Enhances Biomass and Carotenoid Content in Lycium chinense

Lycium chinense, a type of medicinal and edible plant, is rich in bioactive compounds beneficial to human health. In order to meet the market requirements for the yield and quality of L. chinense, polyploid induction is usually an effective way to increase plant biomass and improve the content of bioactive components. This study established the most effective tetraploid induction protocol by assessing various preculture durations, colchicine concentrations, and exposure times. The peak tetraploid induction efficacy, 18.2%, was achieved with a 12-day preculture and 24-h exposure to 50 mg L-1 colchicine. Compared to diploids, tetraploids exhibited potentially advantageous characteristics such as larger leaves, more robust stems, and faster growth rates. Physiologically, tetraploids demonstrated increased stomatal size and chloroplast count in stomata but reduced stomatal density. Nutrient analysis revealed a substantial increase in polysaccharides, calcium, iron, and zinc in tetraploid leaves. In addition, seventeen carotenoids were identified in the leaves of L. chinense. Compared to the diploid, lutein, β-carotene, neoxanthin, violaxanthin, and (E/Z)-phytoene exhibited higher levels in tetraploid strains T39 and T1, with T39 demonstrating a greater accumulation than T1. The findings suggest that the generated tetraploids harbor potential for further exploitation and lay the foundation for the selection and breeding of novel genetic resources of Lycium.

Recent Advances in Studying the Regulation of Fruit Ripening in Tomato Using Genetic Engineering Approaches

Tomato (Solanum lycopersicum L.) is one of the most commercially essential vegetable crops cultivated worldwide. In addition to the nutritional value, tomato is an excellent model for studying climacteric fruits' ripening processes. Despite this, the available natural pool of genes that allows expanding phenotypic diversity is limited, and the difficulties of crossing using classical selection methods when stacking traits increase proportionally with each additional feature. Modern methods of the genetic engineering of tomatoes have extensive potential applications, such as enhancing the expression of existing gene(s), integrating artificial and heterologous gene(s), pointing changes in target gene sequences while keeping allelic combinations characteristic of successful commercial varieties, and many others. However, it is necessary to understand the fundamental principles of the gene molecular regulation involved in tomato fruit ripening for its successful use in creating new varieties. Although the candidate genes mediate ripening have been identified, a complete picture of their relationship has yet to be formed. This review summarizes the latest (2017-2023) achievements related to studying the ripening processes of tomato fruits. This work attempts to systematize the results of various research articles and display the interaction pattern of genes regulating the process of tomato fruit ripening.

Transcriptome analyses reveal photosynthesis-related genes involved in photosynthetic regulation under low temperature stress in Lavandula angustifolia Mill

In order to reveal the mechanisms of photosynthetic regulation of Lavandula angustifolia Mill. under low temperature stress, photosynthesis-related genes were screened and the molecular mechanism were analyzed for this species growing in Harbin, northeast of China. RNA-seq technique and photosynthetic physiology measurement were performed under 20°C, 10°C, and 0°C in this study. The results showed that the observing modified rectangular hyperbola mode could accurately reflect the light-response processes under low temperature stress and the low temperature reduced the light energy utilization of L. angustifolia. The stomatal conductance decreased with the temperature dropping, which was associated with the up-regulation of LaBAM1s, LaMPK4-1 and LaMMK2. The up-regulation of LaMPK4-1 and LaMMK2 was beneficial for ROS scavenging. The improvement of cold resistance in L. angustifolia was related to the up-regulated expression of LaFBA and LaOMTs and down-regulated expression of LaGAPAs, LaGOX, and LaTKL1s with the temperature decreasing. The up-expression of LaPSY at 10°C than it at 20°C could protect the photosynthetic organs from oxidative damage. Moreover, the photosynthetic rates at 10°C and 0°C were close to the measured values, which was related to the interactions of RCA with SBPase and Rubisco with SBPase. These findings could provide a theoretical reference for further exploring the cold tolerance mechanism of L. angustifolia, as an important aromatic plant resource, and promoting its cultivation and distribution in the northeast of China.

Lycopene ε-cyclase mediated transition of α-carotene and β-carotene metabolic flow in carrot fleshy root

The accumulation of carotenoids, such as xanthophylls, lycopene, and carotenes, is responsible for the color of carrot (Daucus carota subsp. sativus) fleshy roots. The potential role of DcLCYE, encoding a lycopene ε-cyclase associated with carrot root color, was investigated using cultivars with orange and red roots. The expression of DcLCYE in red carrot varieties was significantly lower than that in orange carrots at the mature stage. Furthermore, red carrots accumulated larger amounts of lycopene and lower levels of α-carotene. Sequence comparison and prokaryotic expression analysis revealed that amino acid differences in red carrots did not affect the cyclization function of DcLCYE. Analysis of the catalytic activity of DcLCYE revealed that it mainly formed ε-carotene, while a side activity on α-carotene and γ-carotene was also observed. Comparative analysis of the promoter region sequences indicated that differences in the promoter region may affect the transcription of DcLCYE. DcLCYE was overexpressed in the red carrot 'Benhongjinshi' under the control of the CaMV35S promoter. Lycopene in transgenic carrot roots was cyclized, resulting in the accumulation of higher levels of α-carotene and xanthophylls, while the β-carotene content was significantly decreased. The expression levels of other genes in the carotenoid pathway were simultaneously upregulated. Knockout of DcLCYE in the orange carrot 'Kurodagosun' by CRISPR/Cas9 technology resulted in a decrease in the α-carotene and xanthophyll contents. The relative expression levels of DcPSY1, DcPSY2, and DcCHXE were sharply increased in DcLCYE knockout mutants. The results of this study provide insights into the function of DcLCYE in carrots, which could serve as a basis for creating colorful carrot germplasms.

Advances in engineering the production of the natural red pigment lycopene: A systematic review from a biotechnology perspective

BACKGROUND

Lycopene is a natural red compound with potent antioxidant activity that can be utilized both as pigment and as a raw material in functional food, and so possesses good commercial prospects. The biosynthetic pathway has already been documented, which provides the foundation for lycopene production using biotechnology.

AIM OF REVIEW

Although lycopene production has begun to take shape, there is still an urgent need to alleviate the yield of lycopene. Progress in this area can provide useful reference for metabolic engineering of lycopene production utilizing multiple approaches.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Using conventional microbial fermentation approaches, biotechnologists have enhanced the yield of lycopene by selecting suitable host strains, utilizing various additives, and optimizing culture conditions. With the development of modern biotechnology, genetic engineering, protein engineering, and metabolic engineering have been applied for lycopene production. Extraction from natural plants is the main way for lycopene production at present. Based on the molecular mechanism of lycopene accumulation, the production of lycopene by plant bioreactor through genetic engineering has a good prospect. Here we summarized common strategies for optimizing lycopene production engineering from a biotechnology perspective, which are mainly carried out by microbial cultivation. We reviewed the challenges and limitations of this approach, summarized the critical aspects, and provided suggestions with the aim of potential future breakthroughs for lycopene production in plants.

Expression of ZjPSY, a Phytoene Synthase Gene from Zoysia japonica Affects Plant Height and Photosynthetic Pigment Contents

Phytoene synthase (PSY) is a key limiting enzyme in the carotenoid biosynthesis pathway for regulating phytoene synthesis. In this study, ZjPSY was isolated and identified from Zoysia japonica, an important lawn grass species. ZjPSY cDNA was 1230 bp in length, corresponding to 409 amino acids. ZjPSY showed higher expression in young leaves and was downregulated after GA₃, ABA, SA, and MeJA treatments, exhibiting a sensitivity to plant hormones. Regulatory elements of light and plant hormone were found in the upstream of ZjPSY CDS. Expression of ZjPSY in Arabidopsis thaliana protein led to carotenoid accumulation and altered expression of genes involved in the carotenoid pathway. Under no-treatment condition, salt treatment, and drought treatment, transgenic plants exhibited yellowing, dwarfing phenotypes. The carotenoid content of transgenic plants was significantly higher than that of wild-type under salt stress and no-treatment condition. Yeast two-hybrid screening identified a novel interacting partner ZjJ2 (DNAJ homologue 2), which encodes heat-shock protein 40 (HSP40). Taken together, this study suggested that ZjPSY may affect plant height and play an important role in carotenoid synthesis. These results broadened the understanding of carotenoid synthesis pathways and laid a foundation for the exploration and utilization of the PSY gene.

Integrating Omics and Gene Editing Tools for Rapid Improvement of Traditional Food Plants for Diversified and Sustainable Food Security

Indigenous communities across the globe, especially in rural areas, consume locally available plants known as Traditional Food Plants (TFPs) for their nutritional and health-related needs. Recent research shows that many TFPs are highly nutritious as they contain health beneficial metabolites, vitamins, mineral elements and other nutrients. Excessive reliance on the mainstream staple crops has its own disadvantages. Traditional food plants are nowadays considered important crops of the future and can act as supplementary foods for the burgeoning global population. They can also act as emergency foods in situations such as COVID-19 and in times of other pandemics. The current situation necessitates locally available alternative nutritious TFPs for sustainable food production. To increase the cultivation or improve the traits in TFPs, it is essential to understand the molecular basis of the genes that regulate some important traits such as nutritional components and resilience to biotic and abiotic stresses. The integrated use of modern omics and gene editing technologies provide great opportunities to better understand the genetic and molecular basis of superior nutrient content, climate-resilient traits and adaptation to local agroclimatic zones. Recently, realizing the importance and benefits of TFPs, scientists have shown interest in the prospection and sequencing of TFPs for their improvements, cultivation and mainstreaming. Integrated omics such as genomics, transcriptomics, proteomics, metabolomics and ionomics are successfully used in plants and have provided a comprehensive understanding of gene-protein-metabolite networks. Combined use of omics and editing tools has led to successful editing of beneficial traits in several TFPs. This suggests that there is ample scope for improvement of TFPs for sustainable food production. In this article, we highlight the importance, scope and progress towards improvement of TFPs for valuable traits by integrated use of omics and gene editing techniques.