An activatable fluorescence probe for rapid detection and in situ imaging of β-galactosidase activity in cabbage roots under heavy metal stress

β-Galactosidase (β-gal), an enzyme related to cell wall degradation, plays an important role in regulating cell wall metabolism and reconstruction. However, activatable fluorescence probes for the detection and imaging of β-gal fluctuations in plants have been less exploited. Herein, we report an activatable fluorescent probe based on intramolecular charge transfer (ICT), benzothiazole coumarin-bearing β-galactoside (BC-βgal), to achieve distinct in situ imaging of β-gal in plant cells. It exhibits high sensitivity and selectivity to β-gal with a fast response (8 min). BC-βgal can be used to efficiently detect the alternations of intracellular β-gal levels in cabbage root cells with considerable imaging integrity and imaging contrast. Significantly, BC-βgal can assess β-gal activity in cabbage roots under heavy metal stress (Cd2+, Cu2+, and Pb2+), revealing that β-gal activity is negatively correlated with the severity of heavy metal stress. Our work thus facilitates the study of β-gal biological mechanisms.

Bioaccumulation of PFASs in cabbage collected near a landfill site in China: Laboratory and field investigations

Previous studies found that the bioaccumulation of PFASs in vegetables poses potential risks to the health of residents in local areas near landfills in China. Therefore, our study investigated the uptake of perfluoroalkyl and polyfluoroalkyl substances (PFASs) and their accumulation and distribution in cabbage roots, stems, and leaves under both field and laboratory hydroponic conditions. It was found that the sum of concentration of 15 PFASs (designated as Σ15PFASs) in roots, stems, and leaves ranged from 24.8 to 365 ng/g, 49.2 to 204 ng/g, 11.9 to 115 ng/g, respectively, in the order of roots > stems > leaves, which were generally higher than the range in soil samples (6.07-63.91 ng/g). The dominant compounds in cabbage were PFBA and PFDA in field and hydroponic samples, respectively. The hydroponic experimental results revealed that the sum concentration of 10 PFASs (designated as Σ10PFASs) was the highest in roots, and PFDA was the dominant compound in different cabbage fractions. Bioconcentration factors of short-chain PFBA, PFPeA, and PFBS in hydroponics followed the trend of leaves > stems > roots, indicating that they were readily transported from roots to stems, and then to leaves, with the majority stored in leaves at abundance levels of 53 %, 71 %, and 60 %, respectively. Additionally, the much higher concentration factor for 6:2 FTS in leaves suggested a higher potential health risk than PFOS in terms of dietary consumption of cabbage leaves.

A turn-on NIR fluorescent probe for risk-assessing oxidative stress in cabbage roots under abiotic stress

Oxidative stress is closely related to the crop health status under stress conditions. H₂O₂ is an important signaling molecule in plants under stress. Therefore, monitoring H₂O₂ fluctuations is of great significance when risk-assessing oxidative stress. However, few fluorescent probes have been reported for the in situ tracking of H₂O₂ fluctuations in crops. Herein, we designed a "turn-on" NIR fluorescent probe (DRP-B) to detect and in situ-image H₂O₂ in living cells and crops. DRP-B exhibited good detection performance for H₂O₂ and could image endogenous H₂O₂ in living cells. More importantly, it could semi-quantitatively visualize H₂O₂ in cabbage roots under abiotic stress. Visualization of H₂O₂ in cabbage roots revealed H₂O₂ upregulation in response to adverse environments (metals, flood, and drought). This study provides a new method for risk-assessing oxidative stress in plants under abiotic stress and is expected to provide guidance for the development of new antioxidant defense strategies to enhance plant resistance and crop productivity.