Journal of Integrative Plant Biology最新文献

Ongoing climate warming has altered precipitation patterns and increased the frequency and intensity of climate extremes such as droughts, heatwaves, floods, and frosts. These changes have significantly influenced tree growth and development processes, including canopy phenology, intra-annual wood formation dynamics, and annual stem growth. However, these processes are affected by various climatic factors, and their responses are highly species-specific and vary across temporal and spatial scales. Beyond these rapid growth responses, trees may also undergo long-term genetic adaptation to climate change. This review synthesizes how canopy phenology, intra-annual wood formation dynamics, and annual stem growth respond to climate change and climate extremes. We summarize the response and adaptation of these growth processes to various climatic drivers and highlight the interactions among them in determining tree growth. Concepts and mechanisms of rapid response and heritable genetic adaptation in trees under climate change are also reviewed. We identify the key knowledge gaps in tree growth response and adaptation, such as integrative multiple organ and growth process monitoring and genetic-level studies, which are critical to further improve our understanding of tree growth to support sustainable forest management and enhance forest carbon storage under ongoing climate warming.

Plant metabolism is increasingly being demonstrated to be partially controlled by dynamically assembled metabolons-multienzyme complexes that enable substrate channeling, insulate reactive intermediates, and permit rapid, low-energy flux control. Rigorous criteria are defined to distinguish true metabolons from generic assemblies, and evidence is synthesized across cyanogenic glucoside, phenylpropanoid/flavonoid, alkaloid, terpenoid, polyamine, sporopollenin, and auxin pathways. A practical workflow is presented in which AP-MS (Affinity purification mass spectrometry)/Co-IP (Co-immunoprecipitation), proximity labeling, BiFC (Bimolecular fluorescence complementation)/FRET (Förster resonance energy transfer)/Split-luciferase, and isotope-dilution metabolomics are integrated to resolve composition, dynamics, and direct channeling in vivo. In enzyme-based substrate channeling engineering, design rules are distilled for membrane anchoring, modular scaffolds, compartment targeting, and inducible/optogenetic control, and limitations such as metabolic burden, stoichiometry, and leakiness are noted. An AI-assisted loop is outlined in which structure-aware generative models produce binders/interfaces that are coupled to spatial optimization of enzyme order, orientation, and distance. Together, these advances reposition metabolons as a deployable technology for programmable flux in plants, enabling safer handling of labile intermediates and higher titers of valuable natural products.

In exo-recretohalophytes, specialized structures known as salt glands secrete excess salt ions from plant tissues, thereby maintaining intracellular ion homeostasis and sustaining normal metabolism under salt stress. Based on their cellular composition, salt glands can be unicellular, bicellular, or multicellular, and they originate from undifferentiated precursor cells known as multipotent epidermal stem cells. A complex regulatory network drives the division and differentiation of these cells into functional salt-secreting structures. Three hypotheses have been proposed to explain the physiological mechanisms underlying salt secretion by salt glands, each supported by experimental evidence: The osmotic mechanism, the reverse pinocytosis mechanism, and the animal-like fluid transport mechanism. This review summarizes the structural characteristics, developmental processes, salt secretion mechanisms, and potential applications of salt glands in exo-recretohalophytes, providing a foundation for future studies on salt gland biology and their utilization in developing salt-tolerant crops.

Saline-alkali stress is one of the major abiotic factors limiting crop production and affecting the ecological environment. The plasma membrane (PM) H⁺-ATPases are involved in modulating the membrane potential in response to alkaline stress. The central loop (cytoplasmic domain) of the PM H⁺-ATPase AHA2, in contrast to its well-studied C-terminal regulatory domain, remains poorly understood in terms of its regulatory function. In this study, we found that CARK1 and CARK3 (cytosolic ABA receptor kinase 1 and 3) positively modulate saline-alkali stress tolerance in Arabidopsis. Using molecular biology and biochemistry approaches, we reveal that CARK1 and CARK3 interact with and phosphorylate AHA2 at Thr469 in the central loop domain. Molecular mechanism indicates that CARK1/3-mediated phosphorylation elevates AHA2 activity through two key actions: First, by increasing Thr947 phosphorylation and promoting binding to 14-3-3 protein, and second, by releasing autoinhibitory interaction between the C-terminus and the central loop of AHA2. Functional and genetic analyses reveal that the phosphorylation-mimicking mutation AHA2^T469D dramatically rescues hypersensitivity to alkali tolerance, H⁺ efflux, and cytosolic ROS accumulation in aha2 and cark1/3aha2 triple mutants. Collectively, our work reveals the central regulatory loop of AHA2 in response to alkali stress and reports that its activity is enhanced through Thr469 phosphorylation by CARK1/3.

Modern maize stems possess a well-developed vascular bundle system, which is critical for providing mechanical support and lodging resistance. However, characterization of the microanatomical features of vascular bundles and their functional implications in stem mechanics remains challenging, primarily due to technical limitations in high-throughput microanatomical analysis of stem tissues. We thus constructed data sets consisting of over 500,000 maize stem CT images from a maize diversity panel of 383 inbred lines. We evaluated 32 microanatomical phenotypes of maize basal internodes across two environments in different years. By incorporating engineering mechanics parameters, we calculated novel characteristics of the vascular bundles, including the moment of area (MOA) and the polar moment of inertia (PMOI). Through the high-density phenotypic data set, we identified multiple stem microanatomical phenotypes strongly associated with lodging resistance, particularly of vascular bundle mechanical traits. By integrating population genetic profiling, we discovered and confirmed that ZmLSM2 (U6 small nuclear ribonucleoprotein specific Sm-like 2) serves as a key regulator of stem mechanical strength, might function in RNA processing and maturation within vascular stem cells, identifying novel genetic targets for improving maize lodging resistance. This approach demonstrates the value of combining advanced phenotyping with multi-omics analyses for crop improvement. These discoveries will deepen the understanding of plant stem biomechanical principles and provide novel targets for enhancing lodging resistance in crop breeding programs.

Transposable elements (TEs) are abundant and evolutionarily important components of plant genomes, yet the population-scale landscape of TE insertion polymorphisms (TIPs) and their regulatory roles in gene expression and trait variation remain insufficiently understood. In this study, genomic resequencing, RNA-seq, and agronomic trait data from a panel of 381 Brassica napus accessions were integrated to characterize population-level TIP dynamics and assess their impacts on gene regulation, ecotype differentiation, and phenotypic innovation. Using a developed computational pipeline, a robust pan-TE library was constructed based on 28 diverse reference genomes, and 77,603 TIP loci were profiled by mapping resequencing data from 381 accessions. Most TE insertions were found to be dispensable and weakly linked to neighboring SNPs, suggesting that they represent recent or ecotype-specific variants that serve as independent sources of regulatory and adaptive diversity in B. napus. The regulatory roles of TEs were examined through two complementary strategies (direct-effect analyses and TIP-based eQTL mapping), which together revealed that TEs modulate gene expression via both cis- and long-range trans-effects. Notably, TE-mediated trans-regulation, rarely investigated in previous studies, was found to be widespread, with trans-effects predominating and displaying strong tissue specificity, emphasizing the extensive regulatory influence of TEs on the plant transcriptome. Furthermore, selective sweep analyses identified ecotype-specific TIPs associated with adaptive divergence, particularly those contributing to semi-winter type diversification. TIP-based genome-wide association studies (GWAS) revealed 1,102 candidate insertions significantly associated with key agronomic traits, including flowering time, fatty acid composition, and glucosinolate content, some of which were not detected by SNP-based analyses. This study provides the population-scale atlas of TE insertions in B. napus, uncovers their extensive regulatory roles, and demonstrates their contribution to adaptation and trait variation, offering valuable resources for breeding and functional genomics.

Gastrodia elata is an important edible and medicinal plant, and its yield is a significant factor limiting the industry's development. The number of branches produced by vegetative propagation corms (VPCs) is a limiting factor for the yield of G. elata. Hormonal signals, along with sucrose and starch biosynthesis, are key factors potentially influencing VPC formation. However, the mechanisms underlying VPC formation in G. elata remain poorly understood. In this study, we identified a member of the SWEET family, GeSWEET14, through single-stem/multi-stem (SS/MS) transcriptome screening. GeSWEET14 has the potential to increase both VPC formation and the yield of G. elata by promoting sucrose and starch biosynthesis while simultaneously reducing gastrodin biosynthesis. Further results demonstrated that the auxin increases the VPC formation by activating GeARF5-GeSWEET14 expression. In contrast, the auxin signaling inhibitor GeIAA33 was found to be upregulated in the OE-GeSWEET14 transgenic lines. GeIAA33 interacts with GeARF5 both in vivo and in vitro, attenuating its transcriptional activation of GeSWEET14 and thus establishing a feedback regulatory mechanism. Moreover, GeARF5 promotes the accumulation of sucrose and starch by binding to the promoters of GeISA3 and GeglgB1. Additionally, GeARF5 enhances gastrodin biosynthesis by binding to the promoters of GePAL1 and GeGT3-1. Collectively, these findings elucidate the role of the GeARF5/GeIAA33-GeSWEET14 module in VPC formation and secondary metabolite accumulation, providing a foundation for the genetic improvement of G. elata germplasm resources.

Sphingolipids, including ceramides, are structural membrane lipids that function in membrane trafficking and cell polarity. Very-long-chain (VLC) ceramide synthases are essential for plant growth and development, but how VLC ceramide synthases affect developmental programs and their exact roles in plant growth remain unclear. Here, we report that two VLC ceramide synthases, LONGEVITY ASSURANCE GENE ONE HOMOLOG 1 (LOH1) and LOH3, link sphingolipid metabolism and thermomorphogenesis, that is, plant morphogenesis in response to higher temperatures. We found that high ambient temperature (28°C) induced an increase in plant VLC ceramide contents, and defects in LOH1 or LOH3 function inhibited hypocotyl elongation at this temperature. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) potentiates the thermal sensitivity of hypocotyl morphogenesis in a LOH1- and LOH3-dependent manner, directly binding to the LOH1 and LOH3 promoters to enhance their expression. Strikingly, LOH1 and LOH3 also enhance PIF4-dependent transcriptional activation of downstream genes, including PIF4 itself, LOH1, and LOH3. Our study reveals a regulatory mechanism in which PIF4 activates the transcription of LOH1 and LOH3; in turn, LOH1 and LOH3 enhance PIF4 signaling by supporting PIF4-mediated transcriptional responses, thereby controlling plant growth in response to temperature.

Numerous members of the Nepeta genus (family Lamiaceae, subfamily Nepetoideae) are medicinal herbs and sources of important bioactive compounds. Most Nepeta species produce iridoids, which are monoterpenoids that deter herbivores and pathogens and are potential biopesticides. In Nepeta, some species produce iridoid aglycones and glycosylated iridoids (referred to as chemotype A), some produce only glycosylated iridoids (chemotype B), and some produce neither iridoid aglycones nor glycosylated iridoids (chemotype C). Here, we show that the observed diversity in iridoids is, at least partially, attributed to evolutionary gains and losses of key biosynthetic genes. Based on reconstructed phylogenetic relationships, we propose a scenario in which partial or complete loss of the ability to synthesize iridoids with specific stereochemistries in the taxa with chemotypes B and C resulted from independent evolutionary events. These observations improve our understanding of metabolic diversity in the Nepeta genus and may inform efforts to produce specific iridoids in plants.