The circadian system of plants is a complex physiological mechanism, a biological process in which plants can adjust themselves according to the day and night cycle. To understand the effects of different photoperiods on the biological clock of tea plants, we analyzed the expression levels of core clock genes (CCA1, PRR9, TOC1, ELF4) and photosynthesis-related genes (Lhcb, RbcS, atpA) under normal light (light/dark = 12 h/12 h, 12L12D) and took the cost function defined by cycle and phase errors as the basic model parameter. In the continuous light environment (24 h light, 24L), the peak activity and cycle of key genes that control the biological clock and photosynthesis were delayed by 1–2 h. Under a skeleton photoperiod (6L6D, 3L3D), the expression profiles of clock genes and photosynthesis-related genes in tea plants were changed and stomatal opening showed a circadian rhythm. These observations suggest that a skeleton photoperiod may have an effect on the circadian rhythm, photosynthetic efficiency and stomatal regulation of tea plants. Our study and model analyzed the components of circadian rhythms under different photoperiodic pathways, and also revealed the underlying mechanisms of circadian regulation of photosynthesis in tea plants.

Celery (Apium graveolens L.) is a kind of green leaf vegetable with a large consumption demand in the food industry. It is a commonly used material in quick-frozen food stuffing such as dumplings and steamed stuffed. Fresh celery leaf blades and petioles are rich in photosynthetic pigments including chlorophyll and carotenoid, their contents are closely related to the quality of celery and its products. In order to explore the effects of freezing and thawing temperature and thawing time on the degradation of photosynthetic pigments in celery leaf blades and petioles, the changes in photosynthetic pigments during thawing storage were measured under different freezing and thawing temperatures. The results showed that lower freezing and thawing temperatures were beneficial to the preservation of photosynthetic pigments in celery leaf blades and petioles, and the loss of photosynthetic pigments enhanced with the increase in thawing temperature and thawing time. Under the cold storage condition of −80 °C, the loss rate of pigment substances can be reduced by nearly 20% compared with that of −18 °C, and −80 °C and 4 °C could be the best temperature combination of freezing and thawing. The content and degradation rate of photosynthetic pigments in celery leaf blades were higher than that in petioles during thawing, with a total chlorophyll loss rate reaching 35% during 6 to 12 h after thawing. The increase in temperature difference between freezing and thawing could aggravate the damage to the cell structure and the degradation of the pigment, as chlorophyll is more sensitive to temperature changes, and the degradation rate is significantly higher than that of carotenoids. From the perspective of delaying the degradation of photosynthetic pigments, the results of this study will provide potential references for the reasonable configuration of freezing and thawing temperatures in the process of storage and transportation of celery products.

Sweet potato (Ipomoea batatas L.) is an important food, feed, and industrial raw material and new energy crop. Its rich nutritional value and health effects are increasingly being recognized by consumers, and the demand is increasing. However, due to the continuous cultivation of sweet potato over many years, the degeneration of seedlings and the accumulation of viral diseases are important factors affecting the yield and quality of sweet potatoes. This article provides an overview and analysis of the types and hazards of sweet potato virus diseases, the advantages of virus-free sweet potatoes, the scale of virus-free sweet potato cultivation, sweet potato stem tip virus-free production technology, its development status, and the existing problems. Combined with the development of the sweet potato industry across China, relevant development suggestions are proposed to provide a reference for promoting the healthy, stable, sustainable, high-quality, and efficient development of the sweet potato industry.

Parsley [Petroselinum crispum (Mill.)] is a medicinal and edible vegetable of the Apiaceae family that is rich in apigenin. The Apiaceae family is well known for its diverse secondary metabolites. As a high-quality reference genome is lacking for parsley, the evolution and apigenin biosynthesis in Apiaceae have remained unexplored. Here, we report the chromosome-level genome sequence of parsley, consisting of 1.85 Gb that mainly arose from the expansion of long terminal repeats. Whole-genome bisulfite sequencing revealed a significantly higher number of hypermethylated differentially expressed genes in leaf blades and petioles than in root tissues. Moreover, we identified and characterized chalcone isomerase (CHI) genes, encoding key enzymes involved in apigenin biosynthesis in parsley. We also established that the APETALA2 family transcription factor Pcrispum_6.2855 (PcAP2) binds to the (Pcrispum_11.4764) PcCHI promoter and promotes apigenin accumulation. In conclusion, our work presents a multiomics data resource for understanding apigenin biosynthesis and its transcriptional regulation in parsley, in addition to shedding light on the evolution of parsley within the Apiaceae.

Tea plants are a perennial crop with significant economic value. Chlorophyll, a key factor in tea leaf color and photosynthetic efficiency, is affected by the photoperiod and usually exhibits diurnal and seasonal variations. In this study, high-throughput transcriptomic analysis was used to study the chlorophyll metabolism, under different photoperiods, of tea plants. We conducted a time-series sampling under a skeleton photoperiod (6L6D) and continuous light conditions (24 L), measuring the chlorophyll and carotenoid content at a photoperiod interval of 3 h (24 h). Transcriptome sequencing was performed at six time points across two light cycles, followed by bioinformatics analysis to identify and annotate the differentially expressed genes (DEGs) involved in chlorophyll metabolism. The results revealed distinct expression patterns of key genes in the chlorophyll biosynthetic pathway. The expression levels of CHLE (magnesium-protoporphyrin IX monomethyl ester cyclase gene), CHLP (geranylgeranyl reductase gene), CLH (chlorophyllase gene), and POR (cytochrome P450 oxidoreductase gene), encoding enzymes in chlorophyll synthesis, were increased under continuous light conditions (24 L). At 6L6D, the expression levels of CHLP1.1, POR1.1, and POR1.2 showed an oscillating trend. The expression levels of CHLP1.2 and CLH1.1 showed the same trend, they both decreased under light treatment and increased under dark treatment. Our findings provide potential insights into the molecular basis of how photoperiods regulate chlorophyll metabolism in tea plants.