Plant Cell Reports最新文献

Key message: This study first demonstrates that PsGSH2 enhances cadmium tolerance not only by boosting antioxidant defense but also by modulating metal transporter genes to reduce Cd accumulation in plants. Cadmium (Cd) stress poses a significant environmental issue. Potentilla sericea, characterized by strong resistance, is an excellent groundcover for pollution remediation. Glutathione synthetase is one of the key enzymes that promote the synthesis of the antioxidant glutathione (GSH). We cloned PsGSH2, which was up-regulated under Cd stress, and introduced it into Arabidopsis thaliana to validate the response of transgenic lines to Cd. The results showed that the expression level of PsGSH2 was significantly up-regulated (15.45-fold) in the roots of P. sericea under cadmium stress. Overexpression (OE) of PsGSH2 in A. thaliana significantly enhanced Cd tolerance. Compared to wild-type (WT) plants, OE lines exhibited a more than sevenfold increase in seed germination rate under Cd stress, with a significantly reduced biomass loss (< 40%). The transgenic lines showed enhanced photosynthetic performance, a reinforced antioxidant system (up to 1.9- and 2.2-fold higher than WT), and reduced oxidative damage (50-75% of WT). Crucially, they exhibited a 59.05% reduction in shoot Cd accumulation, supported by significantly lower bioconcentration factor and transport factor values (46.12% and 69.17%, respectively). Molecular analysis revealed upregulation (1.84- to 5.44-fold) of key genes related to Cd detoxification (AtGSH1, AtGSH2, AtIRT1, AtPCR1, AtPCR2, AtMT3). Therefore, this study provides valuable insights for developing Cd-tolerant plants through genetic engineering approaches, laying the foundation for further research on Cd resistance in P. sericea.

Key message: We identify 30 plant genera supporting GFP expression via syringe agroinfiltration, demonstrating a versatile system for non-model plant research.

Drought is a major abiotic constraint that limits plant growth and productivity worldwide. To cope with water scarcity, plants employ complex adaptive strategies, with stomatal regulation serving as a central mechanism for balancing water conservation and photosynthetic efficiency. Phytohormones are crucial signaling mediators in this process, coordinating the molecular, physiological, and biochemical responses that govern stomatal dynamics during drought. Abscisic acid (ABA) is the principal regulator of drought-induced stomatal closure; however, other hormones, including salicylic acid, methyl jasmonates, ethylene, gibberellins, cytokinins, and auxins, modulate stomatal function through synergistic or antagonistic interactions. Such hormonal crosstalk shapes guard cell sensitivity to ABA, regulates ion channel activity, influences transcriptional networks, and ultimately determines water-use efficiency. While earlier reviews have addressed the broader roles of phytohormones in drought adaptation, they often overlook the nuanced regulation of stomatal behavior. This review uniquely synthesizes recent advances in phytohormone signaling networks, with particular emphasis on their synergistic and antagonistic crosstalk and downstream signaling cascades that govern stomatal regulation under drought stress. It further integrates current insights into hormone-mediated adaptive responses coordinated with stomatal dynamics, establishing a mechanistic framework that links molecular signaling with physiological regulation and drought tolerance. We also highlight emerging strategies to harness hormonal regulation to enhance drought resilience and outline key research priorities for translating these insights into crop improvement.

Key message: Maize roots respond to iron stress through cell type specificity and enhanced radial transport of Fe-DMA in root cells. Iron (Fe) deficiency, resulting from low Fe solubility in aerated soils, represents a major constraint for crop productivity. Maize (Zea mays), a Strategy II plant, acquires Fe through phytosiderophore (PS)-mediated chelation of rhizospheric Fe (III) and subsequent uptake of Fe (III)-PS complexes. However, cell-type-specific responses governing this process under Fe deficiency remain uncharacterized. Leveraging single-cell RNA sequencing (scRNA-seq), we constructed a root tip atlas using 15,306 high-quality cells from V3 stage primary roots under Fe-sufficient and Fe-deficient conditions, resolving seven distinct cell types. Under iron deficiency stress, significant changes were observed in the cell populations of cortex, epidermis, stele, and xylem. The cortex undergoes functional reprogramming following iron deficiency, with heme-binding and glutathione metabolism-related genes playing crucial roles in the iron deficiency response. Expression analysis of iron homeostasis genes revealed that iron-deficient root tips are associated with the biosynthesis of nicotianamine (NA) and 2'-deoxymugineic acid (DMA) and facilitated radial Fe-chelator transport. Notably, both scRNA-seq and bulk RNA-seq data revealed the downregulation of a FER-like iron deficiency-induced transcription factor (FIT) gene homologous to Arabidopsis AtFIT. This contrasts with the well-established role of AtFIT in Arabidopsis, where it acts as a positive regulator under iron-deficient conditions. Phylogenetic analysis suggests that AtFIT, OsFIT, and ZmFIT may share conserved functions, while their divergent expression patterns could be associated with differences between monocots and dicots. Through weighted gene co-expression network analysis (WGCNA), we identified cell-type-specific co-expression modules for the cortex, stele, epidermis, and xylem. The stele-specific module was significantly enriched with transcription factors, suggesting its role as a transcriptional regulatory hub for the iron deficiency response. Protein-protein interaction (PPI) network analysis revealed that core regulatory transcription factors (ZmWRKY76, ZmbHLH49, ZmMKK9) were distributed across various cell types including epidermis, xylem, phloem, and lateral root cap, indicating that the iron deficiency response is coordinated by a distributed regulatory network where the stele integrates signals and different cell types execute specific functions. In this study, we constructed a transcription map of iron-deficient maize root tips at single-cell resolution, uncovering fundamental adaptation strategies and potential targets for enhancing crop Fe efficiency.

Key message: The receptor-like kinase SlLRR-RLK94 enhances tomato resistance to Phytophthora infestans by effecting pathogenesis-related (PR) gene expression, reactive oxygen species (ROS) homeostasis, and the phenylpropanoid biosynthesis pathway. Late blight, caused by Phytophthora infestans (P. infestans), is one of the most devastating diseases affecting tomato yield and quality. Receptor-like kinases (RLKs) are essential for plants to sense various signaling molecules and to trigger early immune responses. However, most Leucine-rich repeat receptor-like kinases (LRR-RLKs), the largest RLK subfamily, have unknown functions in tomato resistance to P. infestans. Here, we identified 209 LRR-RLK family members in tomato, and clustered them into 14 subfamilies based on phylogenetic analysis. Transcriptome analysis revealed that SlLRR-RLK94 (belonging to the XI subfamily) showed the strongest response to P. infestans infection. Using virus-induced gene silencing and overexpression in tomato, we demonstrated that SlLRR-RLK94 positively regulates tomato resistance to P. infestans. In addition, SlLRR-RLK94 also regulates the expression of PR genes, ROS-scavenging genes, and antioxidant enzyme activity. Integrated transcriptomic and metabolomic analyses suggested that SlLRR-RLK94 mediates tomato resistance to P. infestans, possibly by effecting the phenylpropanoid biosynthesis pathway. These findings establish SlLRR-RLK94 as a key factor facilitating tomato defense signaling and offer a valuable genetic basis for its potential application in crop breeding.

Key message: Replacing wheat chromosome 1D with its relative Leymus mollis chromosome 1Ns facilitates the incorporation of storage protein subunits, thereby improving the grain quality of wheat. Wild relatives of wheat serve as valuable gene pools for enhancing genetic diversity of wheat. Leymus mollis Trin. (L. mollis, 2n = 4x = 28, NsNsXmXm) exhibits multiple advantageous traits including disease resistance, stress tolerance, and high grain quality, rendering it a promising genetic resource for wheat improvement via distant hybridization. In this study, 82 wheat-L. mollis derivatives were assessed for grain quality. The superior line WM24 was further analyzed using biochemical, molecular, and cytogenetic methods. Seed storage protein electrophoresis revealed that improved quality of WM24 stems from introducing high-molecular-weight glutenin subunits and gliadins from L. mollis. Genomic in situ hybridization (GISH) confirmed that the chromosomal composition of WM24 was 2n = 42 = 21 II, including a pair of homologous chromosomes from Ns genome of L. mollis. The combination of molecular markers and sequential FISH-GISH indicated that WM24 carries two 1Ns chromosomes substituting for wheat chromosome 1D. SNP array analysis showed predominantly deletion (NA) genotypes of SNPs at 1D loci, corroborating the substitution event. These findings demonstrate that the introducing of L. mollis chromatin positively influences wheat grain quality. WM24 is a wheat-L. mollis 1Ns (1D) substitution line with higher protein content and sedimentation value due to altered storage protein profiles, resulting in enhanced quality traits. The development of these derivatives provides valuable germplasms for wheat quality breeding and exploration of novel exogenous quality-related genes.

Key message: NDR1 and AHA5 coordinate drought stress and immune responses via stomatal regulation, uncovering a molecular link between abiotic and biotic stress adaptation in Arabidopsis. Plant stress responses have overlapping molecular and physiological signatures. Not surprisingly, many of these are also shared with numerous other processes, including growth and development, as well as abiotic and biotic signaling. NON-RACE-SPECIFIC DISEASE RESISTANCE1 (NDR1) is a key component of plant immune signaling, required for defense against the bacterial pathogen Pseudomonas syringae. In this study, we have identified that NDR1 contributes to stomatal-based processes following exposure to biotic (flg22 (flagellin peptide) and elf26 (EF-Tu-related elicitor)) and abiotic (ABA, drought, etc.) elicitors. Interestingly, we found that NDR1 is part of a signaling cascade that confers tolerance to water loss-a required component of drought stress responses in plants, a role that couples stress signaling in an abscisic acid-dependent manner. As a definition of its broader connectivity to this response, we identified that NDR1 physically associates with the PM-localized H⁺-ATPases AHA1, AHA2, and AHA5, an association that is required for proper regulation of H⁺-ATPase activity and stomatal guard cell dynamics. Using a comprehensive whole-transcriptome analysis, we further show that NDR1 is required for multiple, genetically overlapping physiological processes, including response to water withholding. In total, we demonstrate that NDR1 functions in signaling processes associated with both biotic and abiotic stress response pathways, a function we hypothesize illustrates NDR1's role in the maintenance of cellular homeostasis during stress response activation.

Key message: CsnsLTP6 may participate in balancing ROS signaling and scavenging by enhancing ROS content and antioxidant enzyme activity, thereby mediating the defense response of cucumber. Target leaf spot, caused by Corynespora cassiicola, poses a significant threat to economically important crops such as cucumber (Cucumis sativus). To combat this stress, plants have evolved a range of defense mechanisms that ultimately enhance their resistance. CsnsLTP6, a non-specific lipid transfer protein, has previously been shown to be highly associated with the cucumber's response to attack by C. cassiicola. Here, we investigated the precise role of CsnsLTP6 in the defense of cucumber against C. cassiicola infection. Comprehensive sequence alignment revealed that CsnsLTP6 harbors a highly conserved nsLTP1 domain. Subcellular localization and tissue-specific expression profiling revealed that CsnsLTP6 is localized to the cell wall and functions primarily in cucumber leaves. Functional assays demonstrated that transient silencing of CsnsLTP6 significantly compromised resistance against C. cassiicola, whereas its overexpression markedly enhanced resistance to this pathogen. Investigation of ROS metabolism in transient transgenic plants indicated that CsnsLTP6 participates in ROS homeostasis via a dual mechanism: it first promotes transient ROS accumulation to activate downstream signaling pathways, then rapidly up-regulates the activities of key antioxidant enzymes and the contents of non-enzymatic antioxidants to scavenge the excess ROS. This coordinated action sustains cellular redox balance and ultimately enhances stress tolerance. Our findings not only identify a promising gene target for breeding stress-resilient cucumber cultivars but also provide new insights into ROS-centered strategies for controlling plant diseases.

Key message: Two melon OFP proteins, CmFSI8 and CmOVATE can interact directly with each other, and overexpression of CmOVATE alters the plant architecture and negatively influences organ size in Arabidopsis and melon.