Genome-wide analysis of LBD genes in Sapindus mukorossi identifies SmuLBD26, whose overexpression causes anther malformation and male sterility, offering insights for non-model tree breeding. The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene family is a plant-specific family of transcription factors which regulate various physiological processes in plants, including the development of lateral organs, cell fate determination, regeneration processes, stress responses, and reproductive organ development. However, the biological functions of LBD genes in Sapindus mukorossi (soapberry), a tree species with significant economic and ecological value, remain unknown. Understanding male sterility in soapberry is important for facilitating hybrid breeding and improving fruit yield. This study aimed to systematically identify LBD family members in soapberry and explore their potential roles in regulating male sterility. A genome-wide analysis of LBD genes was conducted in soapberry and 29 SmuLBD genes distributed across 12 chromosomes were identified. Gene structure and phylogenetic analyses reveal that all genes contain the LOB (LATERAL ORGAN BOUNDARIES) conserved motif and indicate LBD genes are conserved in both sequence and function during evolution. Subsequent co-expression network analysis and expression analyses identified SmuLBD26 as a key candidate gene with potential role in the regulation of male sterility. Overexpression of SmuLBD26 in Arabidopsis thaliana (Arabidopsis) was found to deform another development, cause pollen abortion, and reduce the rate of seed setting. These findings elucidate the structural and expression features of the LBD gene family in soapberry, and identify SmuLBD26 as a key regulator underlying male sterility. This work not only extends our understanding of LBD gene function in non-model woody species, but also provides a reliable candidate gene for molecular breeding of male-sterile lines in soapberry.

Increased auxin transport toward and within young organs may promote greater root branching when plants are grown with ammonium as a nitrogen source. Accessibility to different forms of nitrogen is a critical condition for shaping plant root morphology. Nitrate promotes and ammonium impedes primary root growth, but they show a converse effect on root branching. In this study, we demonstrated how using ammonium as the sole nitrogen source modifies auxin distribution in Arabidopsis thaliana to adjust root system development to this nutritional stress. Local changes in PIN-FORMED protein abundance and auxin levels were detected using GFP and DR5 reporter lines. Higher PIN1 abundance correlated with auxin enrichment in the primary root apex, whereas increased abundance of PIN1, PIN2, and PIN3 correlated with auxin accumulation in root primordia under ammonium nutrition. These findings suggest that the ammonium-induced pattern of the auxin transporters may facilitate auxin buildup in these tissues. Consequently, lateral root density increased in higher-order lateral roots of ammonium-grown plants, resulting in a branched root phenotype in mature Arabidopsis thaliana.

High-altitude environments impose a multifactorial stress matrix, including cold, intense UV-B radiation, hypoxia, and drought, which demand integrated adaptive responses. The genus Artemisia exhibits coordinated phenotypic, physiological, and metabolic adaptations to altitude, collectively termed the Altitudinal Stress Syndrome. While recent work has established that this syndrome emerges from integration across genomic, physiological, metabolic, and architectural levels, the regulatory mechanisms coordinating this multi-level integration remain undefined. This review synthesizes molecular evidence from Artemisia to construct a testable framework for the regulatory architecture underlying altitude adaptation. We organize the known components into three functionally distinct levels: signal transducers (reactive oxygen species, calcium, hormones) that convert physical stress into biochemical information; signal integrators (hormonal crosstalk nodes, photoreceptor pathways) where convergent inputs combine; and transcriptional regulators (bHLH, MYB, WRKY families) that execute genome-wide reprogramming. The artemisinin biosynthetic pathway provides a well-mapped case study, revealing how cold signals propagate through AabHLH112 and AaERF1 to biosynthetic genes, how UV-B signals are transduced via AaHY5 and AaGSW1, and how AabHLH113 integrates jasmonate and abscisic acid signals. Competitive dimerization among bHLH factors creates tunable regulatory nodes, whereas epigenetic modifications at AaPAL1 may stabilize adaptive states. We critically evaluate evidence for each connection, distinguishing direct biochemical validation, genetic evidence, and correlational observations. This framework generates specific hypotheses about network architecture testable via genetic, biochemical, and systems-level approaches. By building upon the systems-level foundation of Altitudinal Stress Syndrome, this review advances our understanding from descriptive cataloging to a mechanistic and predictive model of plant adaptation to extreme environments.

Symbiotic nitrogen fixation (SNF) by legumes is essential for sustainable agriculture, providing plant-available nitrogen while reducing reliance on synthetic fertilizers. The establishment of legume-rhizobium symbiosis requires tightly regulated host signaling to coordinate rhizobia infection, nodule development, and nitrogen fixation, while preventing excessive colonization or immune activation. Accumulating evidence indicates that ubiquitination, mediated by E1, E2, E3 ubiquitin ligases and deubiquitinating enzymes, plays a central role in controlling multiple stages of this process. In this review, we summarize current knowledge on ubiquitination-mediated regulation of symbiotic nitrogen fixation, with a focus on early symbiotic signaling and nodule development. We highlight key E3 ligases that modulate Nod factor receptor homeostasis, receptor-associated kinases, transcription factors, and infection thread growth, and discuss how ubiquitination interfaces with nutrient and stress signaling pathways. Finally, we outline key knowledge gaps and discuss the potential of manipulating ubiquitination pathways to improve nodulation efficiency and nitrogen use efficiency in crops.

SlSNAT1-dependent melatonin synthesis enhances tomato cold tolerance by promoting SlNCED1-mediated ABA accumulation, thereby strengthening antioxidant capacity, maintaining photosynthesis, and reducing ROS-induced membrane damage under cold stress. Cold stress limits greenhouse tomato growth by suppressing photosynthesis, promoting reactive oxygen species (ROS) accumulation, and disrupting membrane integrity, which ultimately reduces yield. Melatonin (MT) enhances plant stress tolerance, but its role in regulating cold adaptation in tomato remains unclear. Here, we used CRISPR/Cas9-generated SlSNAT1 mutants and VIGS-mediated SlNCED1-silenced plants to test how MT influences abscisic acid (ABA) biosynthesis and cold tolerance. The SlSNAT1 mutation markedly reduced endogenous MT, decreased the expression of ABA biosynthetic genes (SlNCED1/2), and increased the expression of ABA catabolic genes (SlCYP707A1/2), thereby weakening cold-induced ABA accumulation. Accordingly, the mutants showed higher membrane permeability and ROS levels, together with lower photosynthetic efficiency and reduced antioxidant enzyme activity under cold stress. SlNCED1 silencing further reduced ABA accumulation and antioxidant capacity. By contrast, exogenous MT partly restored ABA content, antioxidant enzyme activity, and photosynthetic performance, thereby alleviating cold injury. Correlation analysis showed that ABA content was positively associated with antioxidant activity, photosynthetic traits, and osmotic regulators, but negatively associated with ROS levels and membrane damage. MT synthesis mediated by SlSNAT1 promotes ABA accumulation, at least in part, by enhancing SlNCED1 expression. These findings clarify a mechanism underlying MT-ABA cross talk during cold stress and suggest a potential strategy to enhance cold tolerance in greenhouse tomato.

A conserved germanicol synthase (GNS) lineage exists in Panax; a single methionine-to-asparagine switch at residue 728 controls triterpene scaffold divergence from β-amyrin to germanicol. Triterpenoid scaffold diversification in Panax is governed by oxidosqualene cyclases (OSCs); however, it remains unclear whether this genus has the ability to produce noncanonical pentacyclic skeletons. In this study, we functionally characterized a previously unrecognized germanicol synthase (PvOSC9) alongside its paralog, β-amyrin synthase (βAS), known as PvOSC8, from Panax vietnamensis var. fuscidiscus. Structural comparisons reveal a single residue 728 (Asn ↔ Met) that alters carbocation folding trajectories, thereby establishing a minimal molecular switch for scaffold identity. Notably, PvOSC9 is enriched in flowers and responds to jasmonate, suggesting a possible context-dependent role of PvOSC9 in floral tissues. Collectively, these findings broaden the triterpene scaffold repertoire in Panax and offer a mechanistically grounded framework for programmable triterpenoid biosynthesis.

PMTR1 is essential for melatonin-improved plant broad-spectrum disease resistance to bacterial pathogens and viruses. Melatonin plays vital roles in various plant stress responses, and the identification of phytomelatonin receptor 1 (PMTR1) in recent decades further extends the phytomelatonin signaling pathway. However, whether and how PMTR1 participates in plant broad-spectrum disease resistance has remained unclear. Here, we confirmed that exogenous melatonin enhanced disease resistance to bacterial blight and mosaic disease, indicating the crucial role of melatonin in cassava broad-spectrum disease resistance. In addition, the transcription of MePMTR1 was induced by Xanthomonas axonopodis pv. manihotis (Xam), common mosaic virus (CMV) and exogenous melatonin, suggesting that MePMTR1 may be involved in cassava immunity. Further investigation illustrated that MePMTR1 was a positive regulator in disease resistance to Xam and CMV, and it was necessary for melatonin-improved broad-spectrum disease resistance to the bacterial pathogen and the virus. Moreover, RNA-sequencing identified many differentially expressed genes (DEGs) in melatonin-improved disease resistance through MePMTR1, including calmodulin-like proteins (CMLs), calmodulin-binding proteins (CaMBPs), transcription factors WRKYs and MYBs, respiratory burst oxidase homolog protein C (RBOHC), heat shock protein 20, pathogenesis-related protein (PR10), etc. In total, this study provides new light on the theoretical foundation of melatonin in modulating broad-spectrum disease resistance in cassava, extending the understanding of the melatonin signaling pathway in plant immunity.

VvGA2ox8-Like confers drought tolerance in grape by interacting with VvGRX-S7 for inhibited GA biosynthesis and upregulating antioxidant enzyme activities, proline accumulation, and stress-responsive genes. Drought stress severely limits grape productivity. Gibberellin (GA) metabolism is involved in drought responses, yet the role of specific GA catabolic genes remains unclear. In the present study, VvGA2ox8-Like, a member of the grape GA 2-β-dioxygenase (VvGA2ox) gene family, was identified to confer drought tolerance in Vitis vinifera cv. 'Pinot Noir'. As a GA catabolic enzyme, VvGA2ox8-Like expression is significantly induced by drought stress. Transient transformation of 'Pinot Noir' grape leaves showed that VvGA2ox8-Like overexpression decreased H2O2 and MDA contents, while increasing proline content, antioxidant enzyme activities, and drought-responsive gene expressions; in contrast, virus-induced gene silencing of VvGA2ox8-Like exhibited opposite results. Furthermore, VvGA2ox8-Like overexpression in 'Pinot Noir' grape calli further confirmed its positive regulatory role in drought tolerance, whereas CRISPR/Cas9-edited VvGA2ox8-Like calli showed opposite phenotypes. A drought-responsive protein VvGRX-S7 was identified as an interacting partner of VvGA2ox8-Like via yeast two-hybrid assay. RNA sequencing analysis revealed that VvGA2ox8-Like overexpression significantly affected the biosynthesis of secondary metabolites, phenylpropanoids, and flavonoids. In conclusion, VvGA2ox8-Like plays a key role in grape drought tolerance, providing theoretical support for elucidating the molecular mechanism of grape drought resistance.

AcMYB10 promotes anthocyanin accumulation in kiwifruit flesh. Among these genes, the downstream AcF3GT1 and AcGST1 are the key genes that restrict anthocyanin synthesis. The specific accumulation of anthocyanin in organs and tissues is a phenomenon seen in various fruit species, which can drive consumer preferences and product novelty. Certain cultivated kiwifruit develop red flesh, typically localized to the inner pericarp. To elucidate the mechanisms underlying this specific accumulation, we identified and analyzed the genes encoding the enzymes of the anthocyanin biosynthesis pathway, focusing on specificity to the inner pericarp. Our findings revealed that six anthocyanin-related genes and transcription factors, which included the anthocyanin-related AcMYB10, were highly expressed in the inner pericarp. Dual-luciferase assays showed that AcMYB10 can regulate the promoters of these genes-AcCHI1, AcF3H2, AcF3'H3, AcANS4, AcF3GT1, and AcGST1-to activate their expression. Over-expression of AcMYB10 in kiwifruit callus promotes anthocyanin accumulation while significantly inducing the expression of these six anthocyanin-biosynthesis-related genes. However, RNA-seq results indicated that AcCHI1, AcF3H2, AcF3'H3, and AcANS4 had elevated basal expression both in green fruit outer pericarp and non-transgenic callus. In contrast, in non-pigmented tissues, expression of AcF3GT1 and AcGST1 remained extremely low. It, therefore, appears that expression levels of AcF3GT1 and AcGST1 are critical in limiting anthocyanin accumulation within kiwifruit tissues. Our study elucidates how the AcMYB10-AcF3GT1/AcGST1 module regulates tissue-specific anthocyanin accumulation in kiwifruit.

The vernalization-responsive intronless gene in faba bean, VfERF017, functions as a flowering repressor, and its KASP marker enables early flowering selection with 83.15% accuracy. In this study, the genomic characteristics of intronless genes in faba bean (Vicia faba L.) and their changes in expression during vernalization-regulated flowering were systematically analyzed by bioinformatics analysis and transcriptome sequencing. A comparative analysis between the vernalization-sensitive cultivar Yundou 1183 and the insensitive cultivar Haiqing No. 1 revealed 888 intronless differentially expressed genes (DEGs), of which 58 were common to both varieties. Two key genes, VfERF017 and VfH2B, were screened from these 58 common genes, and both were significantly downregulated by vernalization treatment, which was confirmed by quantitative real-time PCR (qRT-PCR). VfERF017 belongs to the Apetala2/ethylene responsive factor (AP2/ERF) transcription factor family; its overexpression in Arabidopsis thaliana resulted in increased rosette leaf number and delayed flowering, demonstrating its function as a flowering repressor. A dual-luciferase complementation assay confirmed the direct interaction between VfERF017 and VfCBF4, coupling vernalization signaling with flowering regulation. A kompetitive allele-specific PCR (KASP) marker based on VfERF017 achieved 83.15% accuracy across 89 accessions, with the CC genotype flowering significantly earlier than the TT genotype. These findings reveal the roles of intronless genes in the vernalization response and provide a molecular tool for breeding early flowering varieties.