Guorong Xin

NiFe-based layered double hydroxides (LDHs), as engineered nanomaterials (ENMs), are widely utilized in industrial applications, environmental remediation, and soil improvement. However, the biological impacts of such ENMs on plant-soil systems remain insufficiently explored. A 50-day soil cultivation experiment was conducted to assess the effects of two-dimensional and three-dimensional NiFe-based LDHs (2D NiFe-LDHs and 3D NiFeS-LDHs) on ryegrass growth and soil ecosystem. Generally, morphology and structure differences influence the biological effects of NiFe-based LDHs. 2D NiFe-LDHs promote ryegrass growth at specific concentrations, whereas 3D NiFeS-LDHs exhibit significant inhibitory effects on ryegrass growth. NiFe-based LDHs directly impacted soil geochemistry. 3D NiFeS-LDHs decreased soil pH while increasing electrical conductivity and soil organic carbon. 2D NiFe-LDHs inhibited soil sucrase (S-SC) activity, but enhanced soil urease (S-UE) activity. Conversely, NiFeS-LDHs inhibited catalase (S-CAT) activity and S-UE activity, while promoting neutral phosphatase (S-NP) activity However, as concentrations increased, the effects of 2D NiFe-LDHs and 3D NiFeS-LDHs on soil properties and enzyme activities became more similar. Both NiFe-based LDHs altered the diversity of soil bacterial and fungal communities, with 3D NiFeS-LDHs exerting a stronger inhibitory effect on fungal diversity at higher concentrations. The structural differences in NiFe-based LDHs exert a distinct and substantial impact on the composition of soil microbial communities and soil enzyme activities. The findings provide critical insights into bio-effects of NiFe-based LDHs, which provide a theoretical basis for the study of potential ecological risks in soil.

Soil structure is crucial for maintaining soil health and can be improved through winter cropping. This study evaluated the effects of winter cropping Italian ryegrass (WI), rye (WR), oat (WO), and winter fallow (CK) on soil aggregate structure and explored the role of soil-cementing materials and arbuscular mycorrhizal fungi (AMF) communities in regulating soil aggregate distribution and stability. Compared to CK, the WI and WR treatments increased the proportion of water-stable large macroaggregates (>2 mm diameter) by 45.7% and 41.5%, respectively. Both WI and WR treatments enhanced the mean weight diameter and geometric mean diameter of soil aggregates, while soil porosity increased by 15.7% and 21.7%, respectively. The contents of amorphous iron oxide, humic acid, and fulvic acid were significantly higher in the WI and WR treatments. The WR treatment improved the Shannon index of AMF communities by 14.6%, and the relative abundances of Claroideoglomus increased by 55.3%, 51.3%, and 43.5% in the WI, WR, and WO treatments, compared to CK, respectively. Dominant AMF genera had a substantial impact on soil aggregate distribution. The partial least squares path model indicated that distinct AMF communities contributed to variations in soil aggregate distribution following winter cropping forages. Both Italian ryegrass and rye showed the greatest potential for enhancing soil structure and are recommended for winter cropping in Southern China. These findings suggest that winter cropping forages can improve soil aggregate structure primarily by enhancing AMF communities, providing a promising strategy for improving soil health.

Rapid movements of plant structures triggered by mechanical force have been documented for centuries; however, how plant cells sense mechanical stimuli and generate rapid response remains unknown. Here we show the central role of a mechanosensitive channel gene in touch-triggered rapid stigma movement of Torenia fournieri. T. fournieri possesses a bilobed stigma sensitive to mechanical stimuli. Using live-cell calcium imaging, we detect that touch induces a wave of cytosolic calcium ([Ca²⁺]_cyt) essential for stigma movement. Transcriptomic analysis reveals distinct gene expression profiles between the stigma and style, leading to the identification of the MscS-like gene JUE1, predominantly expressed in stigmas. Stigmas of jue1 mutants exhibit complete loss of touch-triggered movement, confirming its role as a key regulator in sensitive stigma movement. JUE1 is required for rapid propagation of the touch-induced [Ca²⁺]_cyt, as cell-to-cell spreading of the [Ca²⁺]_cyt wave is impaired in the jue1. To conclude, we report a plant mechanosensitive ion channel involved in touch-triggered organ movement by modulating calcium dynamics.

Soil Cadmium (Cd) contamination is a worldwide problem with negative impacts on human health. Cultivating the Cd-Pollution Safety Cultivar (Cd-PSC) with lower Cd accumulation in edible parts of plants is an environmentally friendly approach to ensure food security with wide application prospects. Specialized mechanisms have been addressed for Cd accumulation in crops. This review provides an extensive generality of molecular regulation mechanisms involved in Cd absorption, transport, detoxification, and tolerance in plants, highlighting key aspects of rhizosphere, apoplast barrier, Cd uptake, transfer, and cellular repair strategies under Cd stress. Additionally, we summarize the possible approaches for lowering the Cd accumulation crops, including molecular-assistant breeding, applying chemical materials, and microbial strategy to decrease Cd content in edible parts and improve Cd tolerance of crops under Cd stress. This review would provide valuable insights for cultivating low Cd accumulated crop cultivars, ultimately contributing to food safety.

Rapid movements of plant structures triggered by mechanical force has been documented for centuries. Previous studies showed that cytosolic calcium ([Ca2+]cyt) acts as a key signal mediating touch response and leaf movement in Mimosa pudica and several carnivorous plants, however, how plant cells sense mechanical stimuli and thereby produce the Ca2+ signals to generate a rapid response remains an outstanding question. Here we show the central role of a mechanosensitive channel gene in touch-triggered rapid stigma movement of Torenia fournieri. T. fournieri possesses a bilobed stigma that is sensitive to mechanical stimuli and close rapidly within seconds. Using calcium imaging, we detected that touch triggers a rapid wave of [Ca2+]cyt that is necessary for stigma movement. Transcriptomic sequencing unveiled distinct transcriptional atlas between stigma and style tissues, and we further identified two mechanosensitive ion channel genes, JUE1/2, which are preferentially expressed in the stigmas. Stigmas of jue1 CRISPR mutants showed complete loss of response to mechanical stimuli, while stigmas of jue2 mutants were still mechanosensitive, supporting JUE1’s function as a mechanical sensor. We further demonstrated that JUE1 is required for generation of the touch-induced [Ca2+]cyt wave, since [Ca2+]cyt wave was not detected in the jue1 mutant. To conclude, we report a plant mechanical sensor involved in touch-triggered organ movement via manipulation of calcium signature.

Winter planting is promising for improving the utilization rate of fallow paddy fields in southern China by establishing arbuscular mycorrhizal fungi (AMF) communities. However, the effects of different winter forage crops on AMF community construction remain unknown. The AMF community establishment of different winter planting forage crops were conducted in oat, rye, Chinese milk vetch, and ryegrass, with winter fallow as a control. The AMF colonization rate, soil AMF spore density, community structure and diversity, and soil physicochemical properties were determined. The results showed that the total nitrogen and available nitrogen in winter Chinese milk vetch were 11.11% and 16.92% higher than those in winter fallow (P < 0.05). After planting winter forage crops, the AMF spore density in winter oat, rye, Chinese milk vetch, and ryegrass soil were 127.90%, 64.37%, 59.91%, and 73.62% higher than that before planting, respectively (P < 0.05). Claroideoglomus was the dominant AMF genus in the soil of winter planting oat, rye, and ryegrass. The average membership function value of winter Chinese milk vetch was the highest, indicating that it had the best comprehensive effect on soil physicochemical properties, AMF community structure and diversity, and fresh forage yield. Winter forage crops could increase the spore pool of soil AMF and improve the soil AMF community structure and diversity. Winter Chinese milk vetch in paddy field had the best comprehensive effect on soil physicochemical properties and soil AMF community according to the comprehensive evaluation. These findings provide a theoretical basis for sustainable development and utilization of the southern rice paddy ecosystem.

Climate change is one of the biggest challenges to the world at present. Tomato is also suffered from devastating yield loss due to climate change. The domesticated tomato (Solanum lycopersicum) is presumed to be originated from the wild tomato (S. pimpinellifolium). In this study, we compared the climate data of S. pimpinellifollium with the domesticated tomato, predicted the suitable regions of S. pimpinellifollium in China using MaxEnt model and assessed their tolerance to drought stress. We found that the predicted suitable regions of wild tomato are highly consistent with the current cultivated regions of domesticated tomato, suggesting that the habitat demand of domesticated tomato descended largely from its ancestor, hence the habitat information of wild tomato could provide a reference for tomato cultivation. We further predicted suitable regions of wild tomato in the future in China. Finally, we found that while average drought tolerance between wild and domesticated tomato accessions shows no difference, tolerance levels among wild tomato accessions exhibit higher variation, which could be used for future breeding to improve drought resistance. To summarize, our study shows that suitable regions of wild tomato provide insights into domesticated tomato cultivation in China.