Frontiers in Plant Science最新文献

Introduction: The "novel weapon hypothesis" posits that invasive plants suppress native species by releasing allelochemicals, which is a crucial factor for their successful invasion. While most studies focus on interspecific allelopathy, with insufficient attention paid to intraspecific allelopathy.

Methods: This study employed an in pot experiment with different litter concentrations (0, 5, 10, 20 g/kg) to cultivate Solanum rostratum Dunal seedlings in both sterilized and unsterilized soils. The plant growth parameters, soil physicochemical properties, soil metabolites, and soil microbial communities were measured, and their interrelationships were also analyzed.

Results: The results indicated that the litter from Solanum rostratum Dunal significantly inhibited the growth of its seedlings, and the inhibitory effect is even stronger in sterile soil. Additionally, the addition of litter decreased the soil pH value, while increasing the soil electrical conductivity, total carbon, total nitrogen and total phosphorus contents. Metabolomic analysis identified the phenolic compound 4-Ethyl-2-methylphenol and the ester compound Carvyl propionate as main secondary metabolites in soil, whose concentrations showed significant negative correlations with seedling growth. In unsterilized soil, the abundance of Sphingomonas and Dongia-bacteria with degradation potential-increased, exhibiting negative correlations with allelopathic metabolite levels and positive correlations with seedling growth indicators.

Discussion: In summary, the self toxic effect of Solanum rostratum Dunal litter on seedling growth increased with the increasing of litter content, and soil microorganisms mitigate the allelopathic effects by degrading or transforming allelopathic compounds in litter, thereby playing a crucial role in regulating its invasion process.

Water salinity and scarcity constitute major limitations to crop production in arid and semi-arid regions. Introduction of nutritious and stress-tolerant underutilized crops is a promising approach for dietary enrichment, cropping system diversification, remediation of marginal and degraded lands, and building climate resilience. The primary objectives of this study were to investigate the effect of water salinity and managed water-deficit stress on grain and fodder yield, identify multi-trait ideotypes, and validate the stability and genetic gain in finger millet ideotypes over a 2-year period. A total of 80 finger millet accessions were evaluated under fresh water (0 dS/m) and two saline irrigation water (6 and 10 dS/m) in Dubai during the 2020/2021 cropping season. Validation of a selected elite subset was conducted under a combination of optimum, salinity, and drought-stress regimes (0 dS/m, 6 dS/m, 10 dS/m, and 50% irrigation) during the 2021/2022 cropping season. Initial analysis showed a grain yield (GYLD) reduction of 87% under 10 dS/m saline irrigation water compared with the control, and the genotype-by-treatment (G × T) interaction revealed highly significant effects for GYLD. Using multi-trait genotype-ideotype distance index (MGIDI), 20 elite accessions were identified, demonstrating a remarkable increase in mean GYLD under high saline irrigation water, corresponding to a genetic gain of 167% over the reference population mean. Validation trials confirmed the success of the selection by showing a non-significant G × T for GYLD and dry fodder yield (DFYLD) across the four validation treatments, alongside a significant increase in heritability (H² ) for GYLD from 0.60 to 0.78. Comparative analysis revealed that managed water-deficit stress was the most limiting factor for GYLD in the elite subset, causing an average loss of 42.7% compared to 20.4% under high saline water irrigation. However, DFYLD displayed exceptional stability across both saline water and water-deficit stress types. The comparative analysis presented in Venn diagrams ultimately identified a core group of stable, broadly adapted accessions, including IE 4028 and IE 4570, which are recommended as high- impact parental lines for combined stress tolerance. These findings establish a reliable selection framework for enhancing the climate-resilience of underutilized crops in marginal environments.

Introduction: Soil salinization threatens global land use and food security, and halophytes combined with peat amendments are promising for saline-alkali soil remediation.

Methods: Here, we integrated transcriptomic and physiological analyses to investigate the adaptive responses of Suaeda glauca and S. salsa grown in saline-alkaline soils amended with peat at 0, 6, or 18 g/kg.

Results and discussion: Our results showed that a high peat concentration (18 g/kg) significantly improved salt tolerance and biomass accumulation in both species through distinct species-specific strategies. S. glauca upregulated growth-related pathways (e.g., nitrogen metabolism, and tricarboxylic acid cycle) mediated by bHLH and bZIP transcription factors (TFs), whereas S. salsa activated stress-mitigating secondary metabolism (e.g., flavonoids, phenylpropanoids, anthocyanins) regulated by MYB and NAC TFs. A conserved response across both species was the downregulation of genes involved in amino acid degradation, which helps conserve nitrogen for osmoprotection. RT-qPCR analysis confirmed the reliability of the RNA-seq data. This study identified 18 g/kg as the optimal peat concentration, uncovers species-specific adaptive mechanisms in halophytes, and lays a foundation for the precisely selection of halophyte-peat combinations in saline-alkaline soil remediation.

Temperature-induced lipocalins (TILs) are a class of thermoregulated lipid-transporting proteins crucial for plant stress responses. However, systematic research on the TIL gene family remains relatively limited. In the present study, we conducted a comparative analysis of the TIL gene family in five Brassicaceae species (Arabidopsis thaliana, Brassica rapa L., Brassica rapa subsp. pekinensis, Brassica juncea L., and Brassica napus L.), identifying a total of 23 TIL genes. Analyses of their gene structures, evolutionary relationships, conserved motifs, and cis-acting elements showed extensive collinearity, close homology, and functional conservation, implying they may possess similar biological functions across different Brassicaceae species. The Brassica rapa TIL1 (BrTIL1) gene was significantly upregulated under low-temperature stress. Functional validation showed that Arabidopsis thaliana plants overexpressing BrTIL1 exhibited higher survival rates, soluble protein levels, and peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) activities under low-temperature conditions, confirming that BrTIL1 positively regulates cold tolerance. The BrTIL1 protein was localized to the cell membrane. A yeast two-hybrid screen identified six proteins interacting with BrTIL1. The genes encoding these interacting proteins exhibited differential expression under low-temperature stress, suggesting they may affect the functional activity of BrTIL1. In summary, this study provides a systematic analysis of the TIL gene family in five Brassicaceae species, elucidates the role of BrTIL1 in cold tolerance, and establishes a foundation for deciphering the molecular mechanisms of the cold stress response in Brassicaceae species.

Introduction: Putrescine, a polyamine involved in plant growth and stress responses, has shown potential in mitigating abiotic stress effects. However, little is known about the effects of exogenous addition of putrescine regarding salt tolerance in trees.

Methods: This study was conducted to investigate whether exogenous putrescine application via foliar spray enhances growth in a hybrid poplar (Populus nigra x maximowiczii, clone NM6) under a short duration of salt stress. Salt stress was induced by irrigating roots with 100 mM and 200 mM NaCl, followed by foliar spraying of putrescine on several days. Measurement of growth including plant height and stem diameter for each plant were recorded in the greenhouse every 15 days throughout the experiment. Gas exchange, total chlorophyll, carotenoids, soluble sugars and proteins, amino acids, polyamines, and relative water content were analyzed in foliage collected 3, 6, 7, 13, 20, 35 days after treatment.

Results: Foliar putrescine application significantly promoted growth, increasing stem height by ~20% and stem diameter by ~15% under 100 mM NaCl compared to untreated plants. Foliar spray significantly enhanced fructose accumulation, with ~37% higher levels at day 6 under 100 mM NaCl compared to unsprayed plants and increased sucrose by ~28% at day 13. Based on metabolic responses, plants treated with 100 mM NaCl fared better when sprayed with putrescine than those treated with 200 mM NaCl.

Discussion: Exogenous application of putrescine alleviated salt-induced growth inhibition, likely through its role in maintaining osmotic balance and energy metabolism. These findings highlight the potential of exogenous putrescine treatment as a practical strategy to enhance salt tolerance in young poplar trees, with implications for forestry and land reclamation in saline environments.

Introduction: Polygonatum cyrtonema Hua is an important economic crop with dual use as food and medicine. Its market demand has been increasing steadily. However, in the current market, widespread cultivar confusion coupled with the lack of efficient and accurate cultivar identification methods has severely hindered the genetic improvement and standardized development of its industry. In this study, we aimed to address the issues of germplasm resource confusion and difficulty in cultivar discrimination of P. cyrtonema while providing a novel technical tool for investigating the genetic diversity of Polygonatum plants.

Methods: We successfully developed a high-throughput identification system based on multiple nucleotide polymorphism (MNP) markers for P. cyrtonema cultivar identification. Via genome sequencing of 30 representative accessions, we screened 505 core MNP loci with high polymorphism and further optimized and established stable protocols for multiplex polymerase chain reaction amplification and high-throughput sequencing.

Results: Validation results revealed that this marker panel had excellent amplification efficiency and polymorphism across all 80 tested accessions. For the MNP markers, the average number of allelic genotypes reached 28.95 ± 15.11. The polymorphism information content was 0.73 ± 0.16. Both metrics were substantially superior to those of traditional identification methods. Both phylogenetic analysis and principal component analysis distinguished all the tested accessions, with an identification accuracy rate of 99.90%. A unique molecular ID code was assigned to each cultivar.

Discussion: The MNP marker system developed in this study combines the advantages of high throughput, high accuracy, and favorable reproducibility. It provides the technical means and solutions for the authenticity identification of P. cyrtonema cultivars, purity detection of seeds and seedlings, conservation of germplasm resources, as well as the conduct of distinctness, uniformity, and stability testing for new plant varieties and the application for new variety protection rights. These findings are expected to be applied for the source authentication of medicinal plants and population genetics research.

The glycerol-3-phosphate acyltransferase (GPAT) gene family plays a critical role in the biosynthesis of lipids in plants. However, the GPAT gene family has not yet been systematically analyzed in wheat, and in particular, the relationship between the GPAT genes and male fertility in wheat (Triticum aestivum L.) remains unclear. In this study, a total of 64 TaGPAT genes were identified at the whole-genome level and classified into three clades. The genes within each clade exhibited conserved motif distributions and gene structures, whereas clear differences were observed among the different clades. A synteny analysis indicated that segmental duplication was the major driving force for the expansion of the TaGPAT gene family. An analysis of the expression pattern showed that the TaGPAT genes showed distinct expression patterns among different tissues and reproductive stages, with some genes preferentially expressed in roots, grains, or spikes, and specific TaGPAT genes reaching peak expression at key meiotic stages. In the temperature-sensitive male-sterile wheat line YS3038, TaGPAT58 was specifically highly expressed at the trinucleate pollen stage under fertile conditions, and the encoded protein was localized to the endoplasmic reticulum. Virus-induced gene silencing targeted to TaGPAT58 resulted in a reduction in the number of pollen, abnormal pollen morphology, and a significant decrease in the seed-setting rate. Collectively, this study provides a comprehensive characterization of the TaGPAT gene family in wheat and evidence that TaGPAT58 and its two homoeologous genes are involved in male reproductive development, thereby offering important insights into the molecular mechanisms of male sterility and the exploitation of heterosis in wheat.

Crossbreeding is the primary approach for sweet potato improvement, however, frequent cross-incompatibility during intraspecific hybridization remains a major bottleneck in breeding programs. EXO70 proteins, which regulate vesicle secretion during pollen germination, have been reported to play important roles in self-incompatibility in Brassicaceae. To investigate the potential involvement of EXO70 genes in intraspecific cross-incompatibility in sweet potato, members of the EXO70 gene family were systematically identified from the sweet potato genome and analyzed for their molecular characteristics as well as expression patterns across different tissues. A total of 35 EXO70 genes (IbEXO70) were identified in sweet potato (Ipomoea batatas). Phylogenetic analysis classified these genes into three branches and nine subgroups, showing similar gene number and subgroup distributions to those in the diploid wild relatives of Ipomoea trifida and Ipomoea triloba, although differences were observed in chromosomal distribution and conserved protein motif composition. Gene structure analysis revealed that members of the IbEXO70A subgroup contained a higher number of exons and introns. Tissue specific expression profiling indicated that nine IbEXO70 genes were significantly upregulated in compatibly pollinated stigmas compared with incompatible or unpollinated stigmas. Among these, IbEXO70-26, belonging to the EXO70H subgroup, was identified as a strong candidate regulator of cross-incompatibility due to its highest and stigmas and pollen specific expression, particularly under compatible pollination conditions. These results were further supported by transcriptomic comparisons between compatible and incompatible samples, and subcellular localization analysis showed that IbEXO70-26 protein was localized to the nucleus. This study provides a comprehensive characterization of the EXO70 gene family in sweet potato and lays a solid foundation for future functional studies of compatibility factors involved in pollen-stigma interactions.

The outbreak of poplar canker caused by Botryosphaeria dothidea poses a severe threat to poplar growth. Its resistance mechanisms are closely linked to the regulation of plant secondary metabolism and transcription factor-mediated defense pathways. However, as a plant-specific regulatory factor family, the functional mechanisms of the WRKY transcription factor (TF) family in poplar resistance to B. dothidea remain unclear. This study systematically elucidated the evolutionary characteristics of the WRKY gene family in Populus trichocarpa and their roles in disease resistance regulation in P. davidiana × P. alba var. Pyramidalis (Pdpap) through integrated genome-wide identification and molecular functional validation. Using BLASTp and Hidden Markov Model screening, 102 PtrWRKYs were identified. Phylogenetic analysis classified them into seven subfamilies based on Arabidopsis thaliana classification criteria. Functional diversification of this family was driven by plasticity in motif combinations, segmental duplication events, and subfamily-specific cis-regulatory elements. PdpapWRKY11, selected via RNA-seq and gene family analysis, significantly enhanced resistance to B. dothidea in transgenic Pdpap lines. Using the Pdpap-B. dothidea interaction system as a model, we further propose that PdpapWRKY11 may activate key phenylpropanoid pathway genes (PdpapPAL and PdpapCAD), promoting lignin accumulation and thereby enhancing pathogen resistance. This research provides foundational insights into WRKY TF functions in poplar and establishes a theoretical basis for improving disease resistance for controlling canker disease.

Stomata are core channels for plant gas exchange and water transpiration, and precise regulation of their development directly impacts photosynthetic efficiency, water use, and stress resistance. Plant receptor kinases, particularly leucine-rich repeat receptor-like kinases (LRR-RLKs), function as key signal sensors: they perceive endogenous and exogenous signals, trigger downstream cascades, and finely regulate stomatal initiation, differentiation, and patterning. Deciphering these mechanisms is therefore critical for improving crop stomatal traits, stress tolerance, and yield. Among receptors regulating stomatal development, LRR-RLKs and leucine-rich repeat receptor-like proteins (LRR-RLPs) are the best studied. Too Many Mouths (TMM), the first identified stomatal receptor (LRR-RLP), forms a multiprotein complex with ERECTA family (ERf) and SERK family LRR-RLKs. This complex recognizes Epidermal Patterning Factors (EPFs)/EPF-like factors (EPFLs) peptides., activates the YODA (YDA)-MAPK cascade, and inhibits the key stomatal lineage transcription factor SPEECHLESS (SPCH), thereby precisely regulating stomatal patterning and differentiation in Arabidopsis. Beyond this core complex, other LRR-RLKs (e.g., HSL1, CLV1, MUS) also regulate Arabidopsis stomatal development or morphogenesis. HSL1 recruits SERK co-receptors and perceives CLE9/10 ligands, but the ligands for CLV1 and MUS in stomatal development remain unknown. Notably, maize PAN1 and PAN2 are essential for asymmetric division of subsidiary mother cells (SMCs) and subsidiary cell (SC) formation, with their cognate ligands also uncharacterized. This review summarizes key advances in stomatal receptor (especially LRR-RLK) mediated stomatal development in Arabidopsis and grasses and highlights core issues such as ligand recognition.