ArchiveInflorescence architecture strongly influences reproductive success in angiosperms by affecting pollination efficiency, seed production, and other agronomic traits. The diversity of inflorescence forms reflects long-term evolutionary adaptation to ecological conditions, pollination strategies, and resource allocation. Developmental studies indicate that inflorescence formation is governed by hierarchical changes in meristem identity through coordinated maintenance, proliferation, and termination of stem cell populations. Although major regulatory pathways have been identified, an integrated framework linking stem cell dynamics, branching architecture, environmental responsiveness, and evolutionary diversification remains lacking.
Recent studies have substantially improved understanding of the molecular networks controlling inflorescence development. Conserved stem cell regulatory systems, particularly the WUSCHEL–CLAVATA feedback loop and KNOX-mediated pathways, are central to maintaining meristem activity and branching potential. Meristem identity genes, including TFL1, LFY, and AP1, regulate the balance between indeterminacy and floral commitment. Hormonal signaling, especially interactions between auxin and cytokinin, provides positional information for branch initiation and organ differentiation. Comparative studies have identified lineage-specific regulatory modules, revealing both the conservation and diversification of developmental mechanisms.
Current knowledge remains constrained by an overreliance on a limited number of model species, restricting broader evolutionary interpretation. In addition, regulatory pathways are often investigated independently despite extensive interactions among stem cell regulation, hormone signaling, and environmental responses. These limitations underscore the need for more integrative approaches linking developmental genetics, comparative morphology, and evolutionary biology.
Future research integrating comparative evo-devo approaches with emerging technologies is expected to clarify how evolutionary changes in developmental regulatory networks shape inflorescence diversity across angiosperms, while providing a theoretical foundation for crop architectural improvement.
The specialized plant leaf epidermal cells develop into pavement cells with complex interdigitated jigsaw puzzle-like structures through polarized growth. Their morphogenesis is primarily orchestrated by Rho-related GTPases of plants (ROP) signaling, which integrates signaling mechanism networks such as hormones, cytoskeletal reorganization, and mechanical stress responses. This review systematically elucidates the mechanisms by which brassinosteroids (BRs) and auxin synergizing with PHGAPs-ROP signaling to regulate the morphogenesis of pavement cells. In particular, it characterizes the molecular mechanism through which BR signaling negatively regulates ROP2 activity via PHGAPs. Through identifying PHGAPs as a pivotal node, this review refines the multi-signaling pathway coordinated regulatory model of pavement cells morphogenesis and provides a comprehensive theoretical framework for deciphering crosstalk mechanism between PHGAPs-ROP and various signaling pathways, as well as mechanical signal sensing mechanism.
Plants have evolved a sophisticated internal timing system—the circadian clock—to adapt to the diurnal and seasonal changes of light and temperature. This system enables plants to maintain a dynamic balance between growth and defense responses. Pseudo-Response Regulators (PRRs) are central components of the core oscillator in plant circadian clock, and play vital roles in regulating circadian rhythms, photoperiod-induced flowering, and abiotic stress responses. Systematic characterization of the PRR gene family will deepen our understanding of the molecular mechanisms underlying circadian clock regulation in plants and provide theoretical insights for improving crop agronomic traits such as stress tolerance and yield.
PRR proteins typically contain a relatively conserved N-terminal PR domain and a C-terminal CCT domain. Based on phylogenetic analyses, PRR family members are classified into three subclades: TOC1/PRR1, PRR7/3 and PRR9/5. Although PRRs have been identified in rice, wheat, barley, sorghum, and soybean, researches on the molecular mechanisms of PRRs in regulating plant circadian clock have been conducted primarily in Arabidopsis. The core circadian clock oscillator is composed of interconnected morning, central and evening feedback loops, with PRRs serving as key regulators. Studies have demonstrated that PRRs play crucial roles in regulating plant developmental processes spanning from seed germination, hypocotyl elongation to flowering time. In addition, PRRs also modulate plant responses to various abiotic stresses such as drought, cold, and salinity. Recent studies in wheat, rice and soybean have provided crucial theoretical foundations for crop genetic improvement. For example, TaPRR95 in wheat functions as a negative regulator of flowering and thus represents a promising genetic target for enhancing wheat yield. Similarly, GmPRR3b from soybean negatively regulates drought response, offering a novel candidate gene for breeding stress-tolerant crops.
Although progress has been made in PRRs research, several questions remain elusive. First, the functional conservation and diversification of PRRs in plant species beyond Arabidopsis requires systematic investigation. Second, the biological functions, regulatory networks, and potential applications of PRRs in plant biotic stress responses remain unclear. Third, the upstream regulators and downstream components of PRR-regulated pathways have not been fully characterized.
Future research should focus on three directions: Elucidating the functional conservation and species-specific roles of PRRs across diverse plant species; utilizing gene editing technologies to precisely manipulate PRR expression and evaluate their potential applications for breeding stress-resistant crops; characterizing the core functions and regulatory mechanisms of PRRs in plant biotic stress responses to expand our understanding of PRRs functions.
Natural disasters such as sea level rise and drought caused by climate warming and extreme weather have posed severe challenges to woody plants under the combined stress of water and salt. Although many breakthroughs have been made in the study of plants' responses to single adverse stress, research on combined stress caused by the superposition of multiple stresses, especially on woody plants, remains relatively scarce. This article focuses on comprehensively analyzing the response mechanisms and adaptation strategies of woody plants under salt-flooding and salt-drought combined stress from the perspectives of growth, physiology, and molecular biology. Studies have revealed that woody plants mainly exhibit a synergy effect when exposed to combined stress. Among them, mangroves, as a community of wetland woody plants distributed in the intertidal zone, show unique tolerance to salt and flooding stress, while the response of woody plants to drought and salt stress is mostly concentrated on the research of two single stresses. In addition, we also discuss the similarities and differences in the responses of woody plants to combined stress, research deficiencies and future research directions, which is expected to provide a theoretical basis for ecological restoration and molecular breeding of stress-resistant trees.
The mechanical strength of rice culms plays a critical role in plant growth and development and is directly associated with lodging resistance. Brittle culm mutants serve as valuable genetic resources for dissecting the molecular mechanisms underlying culm strength regulation. In this study, a brittle culm mutant, named ebc (extreme brittle culm), was isolated from a T-DNA insertion population of the indica variety ‘Guangluai 4’ (GLA4). The causal gene was mapped using TAIL-PCR and MutMap+ approaches, and its identity and expression pattern were further characterized by RNA-seq and qRT-PCR. The results showed that, compared with the wild type, ebc was characterized by brittleness in all examined organs, accompanied by abnormal secondary cell wall structure and composition; meanwhile, no significant differences were observed in key agronomic traits including plant height, per-plant grain yield, seed setting rate, and grain shape between ebc and wild-type GLA4. Genetic analysis indicated that the brittle phenotype is controlled by a single recessive nuclear gene. TAIL-PCR analysis confirmed that the T-DNA insertion was located in an intergenic region, with no causal relationship to the brittle phenotype. MutMap+ mapping identified a candidate causal mutation in BRITTLE CULM 1 (BC1): a single guanine (G) deletion at codon 427 of its third exon (CGG→CG). This mutation triggers a frameshift mutation and disrupts the C-terminal functional domain including the conserved GPI modification site. qRT-PCR showed that the expression level of BC1 in the culms and leaves of ebc was significantly decreased. Complementation of the mutant with the BC1 whole genomic region restored the wild-type phenotype, confirming that ebc is a novel allelic mutant of BC1. Transcriptome analysis revealed that differentially expressed genes (DEGs) were primarily involved in biological processes such as transmembrane transport and carbohydrate metabolism, were significantly associated with cellular components including the plasma membrane, and were enriched in pathways related to secondary metabolite biosynthesis and phenylpropanoid biosynthesis. qRT-PCR validation showed that the expression levels of multiple key enzyme-encoding genes involved in lignin biosynthesis within the phenylpropanoid pathway were significantly altered in ebc, consistent with the trends observed in the transcriptome data. In conclusion, the brittle culm gene ebc is a novel allele of BC1. BC1 may participate in the coordinated assembly of cell wall components through feedback regulation of the phenylpropanoid pathway, providing a new basis for further elucidating its molecular mechanism.
The Camellia sinensis cultivar ‘Naibaicha’ is a natural albino mutant with young shoots that are creamy white in spring and yellow-green or green in summer. The mechanisms underlying this leaf color transformation remain poorly understood. This study aims to investigate the changes in key metabolites and proteomic profiles during the color transition to elucidate the molecular basis of leaf color variation and flavor component formation in ‘Naibaicha’.
One bud and one leaf of ‘Naibaicha’ were collected at the albino, color-turning and green stages. Chlorophyll content, catechin composition, and free amino acid components were measured. In addition, proteomic sequencing and bioinformatic analysis were performed to identify differentially expressed proteins (DEPs) and enriched functional pathways.
During the transition from albino to green leaves, chlorophyll a, chlorophyll b and total chlorophyll content increased significantly, whereas total free amino acids and theanine showed a decreasing trend. In contrast, total catechins, galloylated catechins and non-galloylated catechins accumulated continuously, reaching the highest levels at the green stage. Proteomic analysis identified 594 DEPs, including 30 common DEPs. GO enrichment showed that the top three functional categories were cellular process, metabolic process and cellular anatomical entity. KEGG enrichment revealed that the most significantly enriched pathways were photosynthesis, photosynthesis-antenna proteins and carbon metabolism. Two key proteins were identified through bioinformatic screening: the LHC protein (a transmembrane protein involved in plastocyanin-mediated electron transfer) and the PsaF subunit (a key component of thylakoid structure and photosynthesis). Their expression patterns revealed that the photosynthetic system of ‘Naibaicha’ exhibits defects in light capture, electron transfer, and thylakoid assembly during the albino stage.
This study demonstrates that leaf color greening in ‘Naibaicha’ is accompanied by marked increases in chlorophyll and catechin accumulation but a decline in amino acids. The restored expression of these two proteins is crucial for the reconstruction of photosynthetic function and the transition from albino to green leaves. These findings provide a theoretical basis for understanding the mechanisms underlying leaf color transition and flavor substance formation in ‘Naibaicha’.
OsSCYL2 gene, a member of the SCY1-LIKE gene family in rice, encodes a protein that interacts with clathrin heavy chain 1 (CHC1) and localizes to the clathrin-coated vesicles. In this study, the drought tolerance of OsSCYL2 mutants, scyl2-1 and scyl2-2, was analyzed. The results showed that compared with the wild-type ‘Xiushui 134’, the mutant plants had a higher degree of stomatal closure on leaf surfaces, lower water loss rate in detached leaves, and higher water content under drought stress conditions. The drought tolerance of the scyl2 mutants was significantly enhanced as compared with the wild-type. The response to ABA treatment in the scyl2 mutants was not significantly different from the wild-type, and the endogenous ABA content in the mutants was significantly decreased compared with the wild-type, indicating that the enhanced drought tolerance in the mutants is not dependent on ABA signaling. The H2O2 content in the leaves of scyl2 increased, especially in the guard cells of stomata. The expression levels of multiple Osrboh genes encoding NADPH oxidases increased, indicating that the OsSCYL2 gene-mediated signaling pathway regulates rice drought stress response by negatively regulating the expression of Osrboh genes. These findings provide new insights into the molecular regulatory mechanisms of rice in response to drought stress.
Cinnamic acid 4-hydroxylase (C4H) is a key rate-limiting enzyme in the plant phenylpropanoid metabolic pathway, which regulates the biosynthesis of flavonoids, lignins and phenolic acids, and plays essential roles in plant growth, development and stress adaptation. Euphorbia maculata is a traditional medicinal plant abundant in bioactive secondary metabolites. To date, the molecular features and catalytic function of C4H genes in E. maculata remain poorly characterized, limiting the understanding of its secondary metabolic regulatory mechanism. Therefore, this study was performed to clone the EmC4H2 gene and its promoter sequence, analyze its structural characteristics and spatiotemporal expression profiles, and validate its in vitro catalytic activity, aiming to clarify the biological function of EmC4H2 in phenylpropanoid metabolism of E. maculata.
Based on transcriptome and genomic data, the ORF and promoter sequences of EmC4H2 were cloned and identified. Bioinformatic tools were applied to analyze the protein's physicochemical features, conserved domains and phylogenetic relationships, and further conducted three-dimensional structure modeling and molecular docking against the substrate. The spatiotemporal expression pattern of EmC4H2 in different tissues and developmental stages of E. maculata was detected via RT-qPCR. Recombinant expression of EmC4H2 protein was induced by Escherichia coli, and the enzyme activity was detected in vitro.
The ORF and promoter sequences of EmC4H2 were 1 518 bp and 1 696 bp in length, respectively. The EmC4H2 protein contains 505 amino acids and is subcellular localized in the cytoplasm. It contains a conserved domain of the cytochrome P450 (CYP450) family and shares the highest similarity with the C4H protein from Euphorbia lathyris, with a similarity of 91.29%. The molecular docking of EmC4H2 with the substrate trans-cinnamic acid shows high affinity, with a binding energy (ΔG) of −5.98 kcal·mol−1. The expression of EmC4H2 had spatiotemporal specificity, and the expressed recombinant protein has a molecular weight of about 75 kDa. It has the activity of catalyzing the generation of 4-coumaric acid from trans-cinnamic acid in vitro, with an enzyme activity of 327 U·g−1.
This work systematically clarifies the sequence traits, phylogenetic topology, tissue expression patterns and catalytic properties of EmC4H2. Combined data confirm that EmC4H2 acts as an active catalytic enzyme involved in the phenylpropanoid metabolism of E. maculata. The study constructs a robust theoretical basis for exploring the molecular regulatory network of secondary metabolite synthesis and supplies excellent genetic resources for quality breeding of medicinal E. maculata.
Foxtail millet (Setaria italica) is a typical short-day plant, and its photoperiod sensitivity severely restricts regional adaptation. This study aims to identify core genes involved in the photoperiod response, elucidate the underlying molecular mechanism and provide a theoretical basis for breeding widely adaptable varieties.
Foxtail millet cultivar ‘Jingu 21’ was grown under long-day (LD, 16 h light/8 h dark) or short-day (SD, 10 h light/14 h dark) conditions. The second leaf from the top was sampled at 21 and 45 days after emergence. Total RNA was extracted using a plant RNA kit. RNA-seq libraries were prepared and sequenced on an Illumina NovaSeqTM X Plus platform. Differentially expressed genes (DEGs) were identified with |log2(Fold Change)|≥1 and adjusted P≤0.05. RT-qPCR was performed to validate the RNA-seq data using the reference gene SiH3.3. Gene expression was calculated using the 2−ΔΔCt method. Functional annotation of DEGs was performed using the ‘Xiaomi’ reference genome, followed by gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.
A total of 3 771 and 4 514 DEGs were identified in the SD21/LD21 and SD45/LD45 comparisons, respectively, with 1 291 common DEGs shared between the two stages. KEGG and GO analyses revealed that the DEGs were significantly enriched in pathways such as photoperiod response, porphyrin metabolism, and secondary metabolite biosynthesis. Under SD conditions, florigen genes SiFTa and SiFTL9 and flowering-promoting factor SiEhd1 were up-regulated, while under LD conditions, flowering repressor SiGhd7, circadian clock gene SiPRR37, and multiple SiCOL genes were significantly up-regulated.
Notably, eight key heading-date regulatory genes—SiMADS14, SiFTa, SiGhd7, SiPCL1, SiFTL9, SiCOL9, SiHd1, and SiFPFL4—were differentially expressed at both stages, suggesting that they may constitute core regulatory components of the photoperiod response. This study provides a theoretical basis for clarifying the molecular mechanism of photoperiod regulation in foxtail millet and for breeding widely adaptable varieties.
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