Peanut, a major economic and oil crop known for the high protein and oil content, is extensively cultivated in China. Peanut plants have the ability to form nodules with rhizobia, where the nitrogenase converts atmospheric nitrogen into ammonia nitrogen that can be utilized by the plants. Analysis of nodule fixation is of positive significance for avoiding overapplication of chemical fertilizer and developing sustainable agriculture. In this study, AhNIGT1.2, a member of the NIGT family predominantly expressed in peanut nodules, was identified by bioinformatics analysis. Subsequent spatiotemporal expression analysis revealed that AhNIGT1.2 was highly expressed in nodules and showed significant responses to high nitrogen, low nitrogen, high phosphorus, low phosphorus, and rhizobia treatments. Histochemical staining indicated that the gene was primarily expressed in developing nodules and at the connection region between mature nodules and peanut roots. The fusion protein AhNIGT1.2-GFP was located in the nucleus of tobacco epidermal cells. The AhNIGT1.2-OE significantly increased the number of peanut nodules, while AhNIGT1.2-RNAi reduced the number of nodules, which suggested a positive regulatory role of AhNIGT1.2 in peanut nodulation. The AhNIGT1.2-OE in roots down-regulated the expression levels of NRT1.2, NRT2.4, NLP1, and NLP7, which indicated that AhNIGT1.2 influenced peanut nodulation by modulating nitrate transport and the expression of NLP genes. The transcriptome analysis of AhNIGT1.2-OE and control roots revealed that overexpressing AhNIGT1.2 significantly enriched the differentially expressed genes associated with nitrate response, nodulation factor pathway, enzymes for triterpene biosynthesis, and carotenoid biosynthesis. These findings suggest that AhNIGT1.2 play a key role in peanut nodulation by regulating nitrate transport and response and other related pathways. This study gives insights into the molecular mechanisms of nitrogen and phosphorus in regulating legume nodulation and nitrogen fixation, and sheds light on the development of legume crops that can efficiently fix nitrogen in high nitrogen environments.
Arachis/physiology* ; Nitrates/metabolism* ; Plant Proteins/physiology* ; Transcription Factors/metabolism* ; Plant Root Nodulation/physiology* ; Gene Expression Regulation, Plant ; Root Nodules, Plant/metabolism* ; Nitrogen Fixation

Soil cadmium pollution can adversely affect the cultivation of the ornamental plant, Coleus scutellarioides. Upon cadmium contamination of the soil, the growth of C. scutellarioides is impeded, and it may even succumb to the toxic accumulation of cadmium. In this study, we investigated the effects of arbuscular mycorrhizal fungi (AMF) on the adaptation of C. scutellarioides to cadmium stress, by measuring the physiological metabolism and the degree of root damage of C. scutellarioides, with Aspergillus oryzae as the test fungi. The results indicated that cadmium stress increased the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the content of malondialdehyde (MDA) and proline (Pro) within the cells of C. scutellarioides, but inhibited mycorrhizal infestation rate, root vigour and growth rate to a great degree. With the same cadmium concentration, the inoculation of AMF significantly improved the physiological indexes of C. scutellarioides. The maximum decrease of MDA content was 42.16%, and the content of secondary metabolites rosemarinic acid and anthocyanosides could be increased by up to 27.43% and 25.72%, respectively. Meanwhile, the increase of root vigour was as high as 35.35%, and the DNA damage of the root system was obviously repaired. In conclusion, the inoculation of AMF can promote the accumulation of secondary metabolites, alleviate root damage, and enhance the tolerance to cadmium stress in C. scutellarioides.
Cadmium/toxicity* ; Mycorrhizae/physiology* ; Plant Roots/drug effects* ; Soil Pollutants/toxicity* ; Stress, Physiological ; Superoxide Dismutase/metabolism*

The OsSPL10 gene has previously been reported to positively regulate trichome development and negatively regulate salt and drought stress tolerance in rice. However, it is not clear whether this gene can be used for gene editing to create new germplasm of glabrous leaf and salt-tolerant rice. In this study, we created six rice mutants by CRISPR/Cas9-mediated editing of OsSPL10 from 'Xinfeng 2', 'Xinkedao 31', and 'Xindao 25', the main rice cultivars along the Yellow River. Visual observation and scanning electron microscopy verified that the mutants lacked trichomes on the leaves and glumes, and the expression of glabrous marker genes OsHL6, OsGL6, and OsWOX3B in mutants was down-regulated compared with that in the wild type. The net photosynthetic rate, stomatal conductance, and transpiration rate of flag leaves in the mutants were significantly higher than those in the wild type. In addition, the survival rates of the mutants were much higher than that of the wild type after 7 days of treatment with 200 mmol/L NaCl. The results of quantitative real-time polymerase chain reaction (qRT-PCR) further verified that compared with the wild type, the mutants demonstrated down-regulated expression of the salt stress-related gene OsGASR1 and up-regulated expression of OsNHX2 and OsIDS1. Statistical analysis of agronomic traits showed that the mutants had increased plant height and no significant changes in yield-related traits compared with the wild type. The six spl10 mutants created in this study not only had glabrous leaves and glumes but also demonstrated enhanced tolerance to salt stress, serving as new germplasm resources for directional breeding of rice along the Yellow River.
Oryza/physiology* ; CRISPR-Cas Systems/genetics* ; Salt Tolerance/genetics* ; Gene Editing/methods* ; Plant Proteins/genetics* ; Rivers ; Plant Leaves/genetics* ; Mutation ; Plants, Genetically Modified/genetics* ; China

Lateral organ boundaries (LOB) domain (LBD) genes encode a family of transcription factors ubiquitous in higher plants, playing crucial roles in the growth, development, and stress responses. Hippophae rhamnoides, known for its drought, cold, and saline-alkali tolerance, offers significant economic benefits and ecological values. Utilizing the whole genome data and bioinformatics approaches, this study identified and analyzed the LBD gene family in H. rhamnoides. Additionally, we examined the expression pattern of HrLBD genes by integrating the transcriptome data from male and female flower buds in development. Eleven LBD genes were identified in H. rhamnoides, and these genes were distributed on five chromosomes. The HrLBD proteins showed the lengths ranging from 159 aa to 302 aa, the molecular weights between 18 249.91 Da and 33 202.01 Da, and the subcellular localization in the nucleus or chloroplasts. LBD protein domains and gene structures were highly conserved, featuring similar motifs. The phylogenetic analysis of HrLBD genes and the LBD genes in Arabidopsis thaliana and Hordeum vulgare revealed that HrLBD genes falled into two major categories: Class Ⅰ and Class Ⅱ. The transcriptome data and RT-qPCR showed that HrLBD genes were highly expressed in male flower buds, with up-regulated expression levels throughout bud development, indicating a role in the specific stage of male flower bud development. This study lays a theoretical foundation for exploring the roles of HrLBD genes in the growth, development, and sex differentiation of H. rhamnoides flower buds.
Flowers/genetics* ; Hippophae/metabolism* ; Phylogeny ; Gene Expression Regulation, Plant ; Plant Proteins/genetics* ; Transcription Factors/genetics* ; Multigene Family ; Genes, Plant

The regulation of rhizosphere bacterial community structure and metabolism by plants in municipal solid waste landfills is a key to enhancing the biodegradation of chlorobenzene (CB). In this study, we employed biodiversity and metabolomics methods to systematically analyze the mechanisms of different plant species in regulating the rhizosphere bacterial community structure and metabolic features and then improved the methane (CH₄) oxidation and CB degradation capacity. The results showed that the rhizosphere soil of Rumex acetosa exhibited the highest CH₄ oxidation and CB degradation capacity of 0.08 g/(kg·h) and 1.72×10^-6 g/(L·h), respectively, followed by the rhizosphere soil of Amaranthus spinosus L., with the rhizosphere soil of Broussonetia papyrifera showing the weakest activity. Rumex acetosa promoted the colonization of Methylocaldum in the rhizosphere, and the small-molecule organic amine, such as triethylamine and N-methyl-aniline, secreted from the roots of this plant enhanced the tricarboxylic acid cycle and nicotinamide metabolism, thereby increasing microbial activity and improving CH₄ and CB degradation efficiency. Conversely, cinnamic acid and its derivatives secreted by Broussonetia papyrifera acted as autotoxins, inhibiting microbial activity and exacerbating the negative effects of salt stress on key microbes such as methanotrophs. This study probed into the mechanisms of typical plants growing in landfill cover soil in regulating bacterial ecological functions, offering theoretical support and practical guidance for the plant-microbe joint control of landfill gas pollution.
Biodegradation, Environmental ; Rhizosphere ; Soil Microbiology ; Waste Disposal Facilities ; Chlorobenzenes/metabolism* ; Bacteria/metabolism* ; Soil Pollutants/metabolism* ; Methane/metabolism* ; Plant Roots/microbiology* ; Amaranthus/microbiology* ; Soil

Rice is the world's largest food crop, and its yield and quality are directly related to food security and human health. Grain size, as one of the important factors determining the rice yield, has been widely concerned by breeders and researchers for a long time. To decipher the regulatory mechanism of rice grain size, we obtained a multi-tiller, dwarf, and small-grain mutant htd1 by ethyl methanesulfonate (EMS) mutation from the Japonica rice cultivar 'Zhonghua 11' ('ZH11'). Genetic analysis indicated that the phenotype of htd1 was controlled by a single recessive gene. Using the mutation site map (Mutmap) method, we identified the candidate gene OsHTD1, which encoded a carotenoid cleavage dioxygenase involved in the biosynthesis of strigolactone (SL). The SL content in htd1 was significantly lower than that in 'ZH11'. Cytological analysis showed that the grain size of the mutant decreased due to the reductions in the length and width of glume cells. The function of htd1 was further verified by the CRISPR/cas9 gene editing technology. The plants with the gene knockout exhibited similar grain size to the mutant. In addition, gene expression analysis showed that the expression levels of multiple grain size-related genes in the mutant changed significantly, suggesting that HTD1 may interact with other genes regulating grain size. This study provides a new theoretical basis for research on the regulatory mechanism of rice grain size and potential genetic resources for breeding the rice cultivars with high yields.
Oryza/growth & development* ; Mutation ; Edible Grain/growth & development* ; Alleles ; Plant Proteins/genetics* ; Dioxygenases/genetics* ; Lactones/metabolism* ; Gene Expression Regulation, Plant ; Genes, Plant ; Gene Editing ; CRISPR-Cas Systems ; Phenotype

Flowering and bolting are important agronomic traits in cruciferous crops such as Brassica juncea. Timely flowering can ensure the crop organ yield and quality, as well as seed propagation. The WRKY family plays an important role in regulating plant bolting and flowering, while the function and mechanism of WRKY12 in B. juncea remain unknown. To explore its function and mechanism in bolting and flowering of B. juncea, we cloned and characterized the BjuWRKY12 gene in B. juncea and found that its expression levels were significantly higher in flowers and inflorescences than in leaves. BjuWRKY12 belonged to the Ⅱc subfamily of the WRKY family, and subcellular localization indicated that the protein was located in the nucleus. Ectopic overexpression of BjuWRKY12 in transgenic lines promoted bolting and flowering, leading to significant increases in the expression levels of flowering integrators SOC1 and FUL. Furthermore, yeast one-hybrid and dual luciferase reporter system assays confirmed that BjuWRKY12 directly bound to the promoters of BjuSOC1 and BjuFUL, undergoing protein-DNA interactions. This discovery gives new insights into the regulation network and molecular mechanisms of BjuWRKY12, laying a theoretical foundation for the breeding of high-yield and high-quality varieties of B. juncea.
Mustard Plant/metabolism* ; Flowers/growth & development* ; Plant Proteins/physiology* ; Promoter Regions, Genetic/genetics* ; Gene Expression Regulation, Plant ; Plants, Genetically Modified/genetics* ; Transcription Factors/metabolism* ; MADS Domain Proteins/metabolism*

Microalgae possess high photosynthetic efficiency, robust adaptability, and substantial biomass, serving as excellent biological resources for large-scale cultivation. Malic enzyme (ME), a ubiquitous metabolic enzyme in living organisms, catalyzes the decarboxylation of malate to produce pyruvate, CO₂, and NAD(P)H, playing a role in multiple metabolic pathways including energy metabolism, photosynthesis, respiration, and biosynthesis. In this study, we identified the Scenedesmus quadricauda malic enzyme gene (SqME) and its biological functions, aiming to provide excellent target genes for the genetic improvement of higher plants. Based on the RNA-seq data from S. quadricauda under the biofilm cultivation mode with high CO₂ and light energy transfer efficiency and small water use, a highly expressed gene (SqME) functionally annotated as ME was cloned. The physicochemical properties of the SqME-encoded protein were systematically analyzed by bioinformatics tools. The subcellular localization of SqME was determined via transient transformation in Nicotiana benthamiana leaves. The biological functions of SqME were identified via genetic transformation in Nicotiana tabacum, and the potential of SqME in the genetic improvement of higher plants was evaluated. The ORF of SqME was 1 770 bp, encoding 590 amino acid residues, and the encoded protein was located in chloroplasts. SqME was a NADP-ME, with the typical structural characteristics of ME. The ME activity in the transgenic N. tabacum plant was 1.8 folds of that in the wild-type control. Heterologous expression of SqME increased the content of chlorophyll a, chlorophyll b, and total chlorophyll by 20.9%, 26.9%, and 25.2%, respectively, compared with the control. The transgenic tobacco leaves showed an increase of 54.0% in the fluorescence parameter NPQ and a decrease of 30.1% in Fo compared with the control. Moreover, the biomass, total lipids, and soluble sugars in the transgenic tobacco leaves enhanced by 20.5%, 25.7%, and 9.5%, respectively. On the contrary, the starch and protein content in the transgenic tobacco leaves decreased by 22.4% and 12.2%, respectively. Collectively, the SqME-encoded protein exhibited a strong enzymatic activity. Heterologous expressing of SqME could significantly enhance photosynthetic protection, photosynthesis, and biomass accumulation in the host. Additionally, SqME can facilitate carbon metabolism remodeling in the host, driving more carbon flux towards lipid synthesis. Therefore, SqME can be applied in the genetic improvement of higher plants for enhancing photosynthetic carbon fixation and lipid accumulation. These findings provide scientific references for mining of functional genes from S. quadricauda and application of these genes in the genetic engineering of higher plants.
Nicotiana/genetics* ; Photosynthesis/physiology* ; Malate Dehydrogenase/biosynthesis* ; Plant Leaves/genetics* ; Scenedesmus/enzymology* ; Carbon Cycle/genetics* ; Lipid Metabolism/genetics* ; Plants, Genetically Modified/metabolism*

Rice (Oryza sativa L.) is an important food crop. The appearance of lesion mimics in rice leads to phytohormone disorders, which affects rice adaptation to environmental stresses and ultimately reduces the yield and quality. To explore whether the changes in the adaptability of rice lesion-mimic mutants to stressful environments are caused by the disorder of phytohormone metabolism in plants. In this study, we screened an ethyl methane sulfonate-treated population of the japonica cultivar 'Taipei 309' for a mutant with rust-like spots on leaves at the early tillering stage and brown-red spots at maturity and named it rsl1 (rust spotted leaf 1). Compared with the wild type, rsl1 showed decreases in plant height, panicle length, primary branch number, secondary branch number, filled grains per panicle, seed-setting rate, and 1 000-grain weight, and an increase in number of effective panicles. Genetic analysis indicated that rsl1 was controlled by a single recessive nuclear gene. RSL1 was localized between two molecular markers, B7-7 and B7-9, on rice chromosome 7 by map-based cloning. PCR sequencing of the annotated genes in this interval revealed a mutation of C1683A on the eighth exon of SPL5 (LOC_Os07g10390) in rsl1, which resulted in premature termination of protein translation. Exogenous phytohormone treatments showed that rsl1 was less sensitive to salicylic acid (SA), abscisic acid (ABA), and indo-3-acetic acid (IAA) and more sensitive to methyl jasmonate (MeJA) and gibberellin acid (GA) than the wild type. In addition, the survival rate of rsl1 was lower than that of the wild type under salt, alkali, drought, and high temperature stresses, and it was higher than that of the wild type under cold stress. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed that RSL1 was involved in the regulation of ABA, SA, MeJA, IAA, and GA-related genes under abiotic stresses. The present study showed that the RSL1 mutation led to the appearance of lesion mimics and affected the growth, development, and stress resistance of rsl1 under abiotic stresses. The study of the functional mechanism of this gene can provide theoretical guidance for the research on rice stress resistance.
Oryza/microbiology* ; Stress, Physiological/genetics* ; Plant Diseases/genetics* ; Cloning, Molecular ; Chromosome Mapping ; Plant Growth Regulators/metabolism* ; Plant Proteins/genetics* ; Mutation ; Cyclopentanes ; Genes, Plant ; Plant Leaves/genetics* ; Oxylipins

Perilla frutescens (L.) Britt. is a characteristic oil crop rich in polyunsaturated fatty acids, particularly α-linolenic acid, which has important development and utilization value. The Dof transcription factor is one of the plant-specific transcription factor families, which is widely involved in important biological processes such as plant growth, development, and metabolic regulation. In order to explore the key Dof transcription factors involved in the oil biosynthesis and systematically analyze their regulatory mechanisms of P. frutescens seeds, a total of 56 PfDof gene family members were identified from the genome and transcriptome data of P. frutescens and classified into four subfamilies according to sequence characteristics. All PfDofs contained highly conserved C₂-C₂ zinc finger domains, with gene duplication being the primary mechanism driving their evolution and expansion. Genes within the same subgroup exhibited similar gene structures and conserved motifs. The 56 PfDofs were predicted as unstable hydrophilic proteins, with α-helixes and random coils as their predominant structural components. The RNA-seq results revealed that 11 PfDofs exhibited differential expression during different developmental stages of P. frutescens seeds. RT-qPCR was performed to further validate the expression patterns of these 11 members across various tissue samples (root, stem, leaf, and flower) of P. frutescens and at different developmental stages of its seeds. The results showed that PfDof29 exhibited the highest expression level in seeds, which was consistent with the transcriptome data. Subcellular localization studies demonstrated that PfDof29 was localized to the nucleus and had a transcriptional activation activity. Overexpression of PfDof29 in Nicotiana tabacum resulted in a significant increase in total oil content of tobacco leaves, accompanied by reductions in starch and soluble sugar content, while the protein content remained unchanged. Additionally, the metabolic balance between saturated and unsaturated fatty acids in the transgenic tobacco leaves was altered, with a significant increase in α-linolenic acid content. The expression levels of the fatty acid desaturase genes NtFAD2, NtFAD3, and NtFAD8 were significantly upregulated. A yeast one-hybrid assay revealed that PfDof29 could directly bind to the promoter region of PfFAD8, thereby regulating its expression. This study provides an initial understanding of the regulatory mechanisms of PfDof transcription factors in the synthesis and accumulation of oil in P. frutescens. These findings offer new insights into the enhancement of oil content and quality of P. frutescens seeds.
Transcription Factors/physiology* ; Perilla frutescens/metabolism* ; Plant Proteins/metabolism* ; Gene Expression Regulation, Plant ; alpha-Linolenic Acid/biosynthesis* ; Lipids/biosynthesis* ; Seeds/genetics*