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Nowadays, there are many critical concerns in the agricultural sector, including reduced productivity of plants due to various environmental factors. Hence, a continuous innovation of existing technologies is necessary. Among the available technologies for sustainable agriculture, nanotechnology is one of the more promising technologies and has a great scope for development in agriculture. Zinc oxide nanoparticles (ZnO NPs) have attracted much attention due to their good properties and can be put into agriculture as nano-fertilizers, nano-growth regulators and nano-pesticides, although much remains to be explored about their mechanisms. Here, we review the literature on the interaction of ZnO NPs with plants through (i) uptake and transport pathways of ZnO NPs in plants. (ii) The mechanisms involved in improving growth, development and resistance. (iii) their effects on the rhizospheric environment. (iv) The toxic effects and mechanisms in plants. Our major conclusions are as follows: (1) they can be absorbed by the plant through the roots and leaves, with subsequent transformation. (2) moderate application can promote plant growth and mitigate stress, while excessive application can produce toxic effects. (3) the effects of them on the rhizospheric environment cannot be ignored. This study may provide a reference for the safe and effective use of ZnO NPs in agricultural production. • A wide range of mechanisms drive ZnO NPs to promote plant growth and alleviate stress. • ZnO NPs trigger the function of relevant regulatory genes involved in nutrient elements. • It provides new insights into the interactions between NPs and microorganisms/enzymes. • ZnO NPs can be a novel alternative for sustainable agricultural development. [ABSTRACT FROM AUTHOR]

Small peptides produced by plants (SPPs) and microbes (SPMs) function as crucial mediators in plant–rhizosphere microbe interactions, with SPPs facilitating long-distance signaling through extracellular vesicles and SPMs modulating plant immunity and hormone signaling to enhance communication. SPPs may directly alter the rhizosphere microbiomes by modifying microbial gene expression or indirectly by influencing root morphology, exudate release, and immune responses, thus affecting microbial community structure and composition. Leveraging the bidirectional signaling facilitated by SPPs and SPMs between plants and their rhizosphere microbes offers a novel strategy in holobiont engineering, and the potential of exploring transgenic microbes to synthesize small peptides on a large scale merits further investigations. The crucial role of rhizosphere microbes in plant growth and their resilience to environmental stresses underscores the intricate communication between microbes and plants. Plants are equipped with a diverse set of signaling molecules that facilitate communication across different biological kingdoms, although our comprehension of these mechanisms is still evolving. Small peptides produced by plants (SPPs) and microbes (SPMs) play a pivotal role in intracellular signaling and are essential in orchestrating various plant development stages. In this review, we posit that SPPs and SPMs serve as crucial signaling agents for the bidirectional cross-kingdom communication between plants and rhizosphere microbes. We explore several potential mechanistic pathways through which this communication occurs. Additionally, we propose that leveraging small peptides, inspired by plant–rhizosphere microbe interactions, represents an innovative approach in the field of holobiont engineering. [ABSTRACT FROM AUTHOR]

Aluminum (Al) toxicity limited root growth by reducing nutrient translocation and promoting reactive oxygen species (ROS) accumulation, particularly in soybean. The endophyte of root could be modified by plant metabolites, which could potentially alter the tolerance to environmental toxicity of plants in acidic-Al soils. To explore how they help soybean mitigate Al toxicity by altering root endophytes, zinc oxide nanoparticles (ZnO NPs) at doses of 0, 30, 60, 90 mg/kg and 2% biochar (BC) were selected as bio modifiers, and Al 2 (SO 4) 3 at 19 mg/kg was used to simulate Al toxicity. We analyzed root endophytes and metabolites by high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS). We found that ZnO NPs with BC could bolster soybean resilience against Al toxicity by enriching soil nutrients, activating enzymes, and bolstering antioxidant mechanisms. We also observed that it enriched root endophytic microbial diversity, notably increasing populations of Nakamurella , Aureimonas , Luteimonas , and Sphingomonas. These changes in the endophytes contributed to the improved adaptability of plants to adversity under Al toxicity. This study highlighted the potential of using ZnO NPs and BC as a sustainable approach to combat Al toxicity, emphasizing the intricate interplay between plant physiology and rhizosphere microbial dynamics in mitigating the effects of environmental toxicity. • Both ZnO NPs and BC enhance soybean's defense against Al toxicity. • The addition of ZnO NPs and BC facilitates the recruitment of endophytes. • The application of ZnO NPs with BC markedly intensifies the resistance to toxicity. [ABSTRACT FROM AUTHOR]

Quantifying residue carbon (C) incorporation into soil organic C (SOC) fractions, and underpinning microbial community in the decomposition process of crop residues are essential for improving SOC management in agricultural systems. However, the fate of residue-C and associated responses of microbial communities remain unclear in Mollisols in north-eastern China, where SOC varies geographically. A 150-day incubation experiment was conducted with 13 C-labelled soybean residue (4%) amended into two Mollisols differing in SOC (SOC-poor and SOC-rich soils). The 13 C abundances in SOC fractions and the CO 2 –C efflux from soil were determined, and bacterial community composition was analyzed with MiSeq sequencing. The amounts of residue-C incorporated into the coarse particulate organic C (POC), fine POC and mineral-associated C (MOC) fractions were 4.5-, 4.3- and 2.4-fold higher in the SOC-rich soil than in the SOC-poor soil, respectively. Residue amendment led to negative SOC priming before Day 50 but positive priming thereafter. The primed CO 2 per unit of native SOC was greater in the SOC-poor soil than in the SOC-rich soil. This indicates that the contributions of residue-C to the POC and MOC fractions were greater in the SOC-rich soil while residue amendment had stronger priming effect in the SOC-poor soil, stimulating the C exchange rate between fresh and native SOC. A principal coordinates analysis (PCoA) showed that the shift of bacterial community structure in response to residue amendment varied between the two soils. Genera Verrucosispora , Xanthomonadales and Steroidobacter were mainly enriched in the residue-amended SOC-poor soil while Anaerolineaceae_uncultured was dominant in the SOC-rich soil. The canonical correspondence analysis (CCA) revealed that the relative abundance of the bacterial operational taxonomic unit (OTU) among residue treatments was significantly associated with soil characteristics, especially C content in coarse POC and MOC fractions ( p < 0.01), implying that the shift of bacterial community composition in response to residue amendment contributes to the sequestration of residue-C in SOC fractions. [ABSTRACT FROM AUTHOR]

Waterlogging stress is an increasing threat to cotton production worldwide. The use of cultivation measures to combat waterlogging stress is a promising approach. As a traditional cultural practice, ridge intertillage is usually conducted before flowering to form a ridge along a row and a furrow between two rows in order to reduce lodging and control weeds in cotton fields. However, it is unclear whether ridge intertillage can alleviate waterlogging stress in field-grown cotton. Flat and ridge intertillage were conducted at 10 days after squaring of cotton to establish flat and ridge–furrow configurations, respectively, with or without 10-d waterlogging. To determine effects of intertillage pattern on mitigating waterlogging stress, changes in rhizosphere bacterial communities and plant physiological parameters were examined in waterlogged cotton. Compared with flat tillage, ridge intertillage significantly decreased hydrogen peroxide production, malonaldehyde content, and alcohol dehydrogenase and pyruvate decarboxylase activities in both roots and leaves of waterlogged cotton but significantly increased nitrogen, phosphorus, and potassium concentrations, leaf area, and plant biomass. Compared with flat intertillage under waterlogging (FIW), ridge intertillage under waterlogging (RIW) changed the abundance and composition of rhizosphere bacterial communities. In addition, several taxa of bacteria with beneficial functions were enriched in the rhizosphere under ridge intertillage. Pearson correlations indicated that changes in rhizosphere bacteria and plant physiological parameters in waterlogged cotton were significantly correlated (P < 0.05), suggesting that adjustments in rhizosphere bacterial communities were involved in the physiological response to waterlogging stress. Moreover, compared with FIW, RIW increased canopy photosynthesis and lint yield of waterlogged cotton by 51.5% and 18.3%, respectively, and decreased lint yield loss by 61.3%. Compared with flat intertillage, ridge intertillage induced adjustments in rhizosphere bacterial communities, reduced oxidative membrane damage, improved nutrient uptake and canopy photosynthesis, and ultimately reduced the stress damage and yield loss of waterlogged cotton. Ridge intertillage before flowering is a promising agronomic measure to combat waterlogging stress in cotton and possibly other major field crops. • Ridge intertillage produced ridge-furrow configuration by piling up the topsoil to cotton plants base before flowering. • Effects of flat and ridge intertillage on waterlogged cotton were compared. • Ridge intertillage adjusted rhizosphere microbe and nutrient uptake of waterlogged cotton. • The adjustments induced a set of physiological changes and reduced the yield loss of waterlogged cotton. [ABSTRACT FROM AUTHOR]