Soil cadmium (Cd) contamination severely threatens human health. Therefore, screening and breeding low-Cd absorption cultivars of cherry tomato (Solanum lycopersicum L.) is essential to restrict human Cd intake. In this study, a hydroponic experiment was conducted to perform a comparative transcriptome analysis of the leaves of two cherry tomato cultivars with different Cd contents under different Cd stress (0, 10, and 50 μM), for the purpose of exploring the differences in the transcriptional responses to Cd stress between the two cultivars. Our results revealed that the Cd content in the leaves of HLZ (Hanluzhe; a low-Cd accumulation cultivar) was significantly lower than that in the leaves of LFC (Lvfeicui; a high-Cd accumulation cultivar). Transcriptome analysis showed that the different expression genes (DEGs) were mainly involved in plant hormone signal transduction, antioxidant enzymes, cell wall biosynthesis, and metal transportation. In the LFC leaves, DEGs in the IAA signal transduction and antioxidant enzymes exhibited higher transcription levels. However, the DEGs in the ETH signal transduction demonstrated a lower transcription level compared to that of HLZ. Over-expressed genes in the pectin biosynthesis and pectin methylesterase (PME) of the LFC leaves might result in the trapping of Cd by increased levels of low-methylated pectin around the cell wall. Furthermore, Cd transporter genes, such as HMA5, NRAMP6, CAX3, ABCC3, and PDR1, were up-regulated in the HLZ leaves, indicating that the HLZ cultivar comprised an active Cd transport capacity from apoplast to vacuolar. This may contribute to the low Cd concentration observed in the HLZ leaves. Overall, our study provides a molecular basis for tomato screening and breeding.

Phedimus aizoon L. is a drought-resistant Chinese herbal medicine and vegetable. However, its drought tolerant limit and the mechanism of drought tolerance are unknown, which restricts the promotion of water-saving cultivation of Phedimus aizoon L. in arid areas. To solve the above problem, we carried out a 30-day-long drought stress experiment in pots that presented different soil water contents and were divided into four groups: control check, 75–80% of the maximum water-holding capacity (MWHC); mild drought, 55–60%; moderate drought, 40–45%; and severe drought, 20–25%. The dynamic changes in both plant physiological indexes from 10 to 30 days and leaf anatomical structure on the 30th day of stress were recorded. The results show that Phedimus aizoon L. grew normally under mild drought stress for 30 days, but the growth of the plants became inhibited after 20 days of severe drought and after 30 days of moderate drought. At the same time, Phedimus aizoon L. physiologically responded to cope with drought stress: the growth of the root system accelerated, the waxy layer of the leaves thickened, and the dark reactions of the plants transformed from those of the C3 cycle to CAM. The activity of antioxidant enzymes (SOD, POD and CAT) continuously increased to alleviate the damage caused by drought stress. To ensure the relative stability of the osmotic potential, the contents of osmoregulatory substances such as proline, soluble sugars, soluble protein and trehalose increased correspondingly. Although Phedimus aizoon L. has strong drought stress resistance, our experimental results show that the soil available water content should not be less than 27% during cultivation.

The purpose of this study is to explore the physiological mechanisms underlying the attenuation of Cd toxicity using Se in two cherry tomato cultivars ‘Hanluzhe’ (HLZ) and ‘Lvfeicui’ (LFC), with low and high Cd accumulation rates, respectively. Hydroponic experiments were conducted and 2.5 μmol L⁻¹ Se was applied to hydroponic solution with 50 μmol L⁻¹ Cd. The photosynthetic parameter, antioxidant enzyme activities, non-enzymatic antioxidants, mineral elements, phytochelatins, and Cd contents of two cherry tomatoes were detected. Exogenous Se reduced Cd assimilation and altered its chemical form and subcellular distribution in both cultivars. Exogenous Se mitigated Cd-induced oxidative stress by enhancing the activity of superoxide dismutase (37.0% in HLZ and 48.9% in LFC), peroxidase (50.6% in HLZ and 30.4% in LFC), catalase (18.5% in HLZ and 28.6% in LFC), ascorbate peroxidase (26.6% in HLZ and 47.4% in LFC), and glutathione peroxidase (28.3% in HLZ and 30.4% in LFC). Although Se significantly increased the photosynthetic rate (Pn) of HLZ, it exhibited no significant effect on the Pn of LFC under Cd stress. Se improved the phytochelatin (15.1% in HLZ and 42.4% in LFC) content, which accelerated Cd chelation in both cultivars. Further, Se alleviated nutrient (Ca, Mg, Fe, Zn, and Cu) assimilation or transportation in both cultivars to varying degrees. The efficiency of Cd toxicity alleviation using Se was higher in the high Cd-accumulating cultivar LFC than in the low Cd-accumulating cultivar HLZ. Screening low Cd-accumulating cultivars with exogenous Se is a promising method to manage Cd accumulation in cherry tomatoes.

Background: Chayote is an underutilized species of Cucurbitaceae. It is rich in nutrients such as protein, minerals, phenols and its extracts have anti-cardiovascular and anti-cancer effects, making it a versatile plant for both medicinal and culinary purposes. Although research on its root tuber is limited, they are rich in starch and have a structure similar to that of potatoes, cassava, and sweet potatoes. Therefore, they can serve as potential substitutes for potatoes and offer promising prospects as agricultural and industrial resources. However, the physiological and cellular mechanisms of chayote root tuber formation and development are still unclear. Results: In this study, we observed the growth habit of ‘Tuershao’ (high yield of root tuber). The results revealed that the tuber enlargement period of ‘Tuershao’ lasts approximately 120 days, with the early enlargement phase occurring during 0–30 days, rapid enlargement phase during 30–90 days, and maturation phase during 90–120 days. Physiological indicators demonstrated a gradual increase in starch content as the tuber developed. The activities of sucrose synthase (SUS) and invertase (VIN) showed a consistent trend, reaching the highest level in the rapid expansion period, which was the key enzyme affecting tuber expansion. Moreover, the special petal like structure formed by the secondary phloem and secondary xylem of the tuber resulted in its enlargement, facilitating the accumulation of abundant starch within the thin-walled cells of this structure. Principal component analysis further confirmed that starch content, SUS and VIN activities, as well as the concentrations of calcium (Ca), iron (Fe), and selenium (Se), were the major factors influencing tuber development. Moreover, the low temperature environment not only promoted the growth of ‘Tuershao’ tubers but also enhanced the accumulation of nutritional substances. Conclusions: These findings contribute to a deeper understanding of the formation and developmental mechanisms of ‘Tuershao’ tubers, providing valuable guidance for cultivation practices aimed at improving crop yield.

Three different photoperiod treatments (8 h/16 h, 12 h/12 h, and 16 h/8 h of light/dark) were implemented to investigate the impact of growth, biomass, and phytochemical accumulation in two celery cultivars, namely ‘Zhangqiubaoqin’ (BQ) and ‘Hongchenghongqin’ (HQ), within a plant factory setting. The findings demonstrated that the 12 h/12 h photoperiod stimulated the growth of both celery varieties, while the 16 h/8 h photoperiod hindered their growth. Notably, the root length, shoot fresh and dry weight, plant height, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid content of both celery cultivars exhibited the highest values under the 12 h/12 h light and dark photoperiod. Furthermore, the effective quantum yields of the electron transfer ratio (ETR) and the photochemical quenching coefficient (qP) displayed superior value under the 12 h/12 h light and dark photoperiod. With the exception of cellulose, the levels of soluble sugar, soluble protein, total phenol, and vitamin C were also highest under the 12 h/12 h photoperiod for both cultivars. BQ demonstrated the highest total apigenin content under the 12 h/12 h (light and dark) photoperiod, whereas HQ exhibited the highest content under the 16 h/8 h (light and dark) photoperiod. In summary, celery plants exhibited optimal performance and biomass production when subjected to the 12 h/12 h (light and dark) photoperiod treatment.

Chayote (Sechium edule) produces edible tubers with high starch content after 1 year of growth but the mechanism of chayote tuberization remains unknown. ‘Tuershao’, a chayote cultivar lacking edible fruits but showing higher tuber yield than traditional chayote cultivars, was used to study tuber formation through integrative analysis of the metabolome and transcriptome profiles at three tuber-growth stages. Starch biosynthesis- and galactose metabolism-related genes and metabolites were significantly upregulated during tuber bulking, whereas genes encoding sugars will eventually be exported transporter (SWEET) and sugar transporter (SUT) were highly expressed during tuber formation. Auxin precursor (indole-3-acetamide) and ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, were upregulated, suggesting that both hormones play pivotal roles in tuber development and maturation. Our data revealed a similar tuber-formation signaling pathway in chayote as in potatoes, including complexes BEL1/KNOX and SP6A/14-3-3/FDL. Down-regulation of the BEL1/KNOX complex and upregulation of 14-3-3 protein implied that these two complexes might have distinct functions in tuber formation. Finally, gene expression and microscopic analysis indicated active cell division during the initial stages of tuber formation. Altogether, the integration of transcriptome and metabolome analyses unraveled an overall molecular network of chayote tuberization that might facilitate its utilization.