Abstract Heat stress poses a major threat to global crop productivity, with the male gametophyte being the most thermosensitive stage. While peptide hormones are known orchestrators of plant vegetative adaptation, their roles in reproductive thermotolerance remain largely undefined. Here, we show that phytosulfokine (PSK) signaling determines tomato pollen thermotolerance, as heat-induced anther PSK precursor expression correlates with pollen germination, and exogenous PSK application mitigates heat-induced pollen abortion. Loss of the PSK receptor PSKR1 or the NADPH oxidase Respiratory burst oxidase homolog B (RBOHB) compromises reactive oxygen species (ROS) homeostasis and pollen thermotolerance, causing severe yield losses under both controlled and natural field heat-stress conditions. Mechanistically, genetic rescue experiments establish that RBOHB-dependent ROS signaling functions downstream of PSK perception driven by PSKR1-mediated phosphorylation of RBOHB at Threonine-266 and Serine-340 in pollen grains, which triggers protective ROS bursts to activate the downstream heat shock transcription factors/heat shock proteins (HSF/HSP) pathway. Genetic complementation with phospho-mimic variants confirms that phosphorylation at these residues is sufficient to enhance pollen thermotolerance. Our findings define a PSK peptide-ROS signaling axis that safeguards male thermotolerance, providing both genetic targets and peptide-based strategies for sustaining crop yields in a warming climate.

Plants are increasingly subjected to concurrent heat stress and elevated CO2; however, how they perceive and integrate these combined stresses remains poorly understood. Here, we identify the β-carbonic anhydrase βCA2 as a central signaling hub in tomato that decodes these combined cues. We demonstrate that βCA2 physically interacts with the receptor kinase PSKR1 at the plasma membrane and that PSKR1-mediated phosphorylation of βCA2 is significantly enhanced under simultaneous elevated CO2 and heat stress. We further identify Ser231 as the crucial phosphorylation site on βCA2. Phosphorylation at Ser231 activates βCA2 and is essential for the accumulation of phosphatidic acid, a lipid signaling molecule that protects plants from heat damage. These findings provide new insight into the complex integration of environmental stress signals through βCA2 and underscore the critical role of CO2-heat interactions in plant stress responses. Our work not only deepens understanding of plant adaptation to climate change but also provides potential targets for developing climate-resilient crops.

Theanine, a tea-enriched nonprotein amino acid, plays key roles in plant metabolism and stress adaptation. To test whether theanine biosynthesis can be reconstructed in a nontea crop and whether this metabolic network contributes to stress tolerance, we heterologously expressed the tea alanine decarboxylase gene CsAlaDC in tomato (Solanum lycopersicum cv. Micro-Tom). The resulting OE-CsAlaDC lines accumulated ethylamine and synthesized theanine without introducing a tea theanine synthase gene, demonstrating that endogenous tomato glutamine synthetase supports theanine formation. Transgenic plants exhibited distinct morphological changes, including dwarfism and dark-green leaves, while their fruits showed accelerated development, elevated levels of theanine and GABA, and improved quality-related traits such as enhanced lycopene accumulation. Under heat stress, OE-CsAlaDC plants maintained higher PSII efficiency, reduced membrane damage and reactive oxygen species accumulation, and stronger antioxidant enzyme activities than wild-type plants. Exogenous theanine further enhanced thermotolerance, promoted SlGAD1/2 expression, and increased GABA accumulation, whereas silencing SlGAD1 and SlGAD2 markedly diminished the protective effect of theanine. Exogenous ethylamine also conferred partial heat protection, but theanine showed a stronger association with GAD-dependent GABA biosynthesis. Collectively, these findings demonstrate that heterologous expression of CsAlaDC establishes a functional ethylamine-theanine metabolic branch in tomato and enhances thermotolerance through coordination with the GABA metabolic network, offering a promising strategy to improve both stress resilience and nutritional quality in crops.

Photorespiration is vital for C3 plant carbon (C) and nitrogen (N) metabolism, yet most engineering ignores N-related constraints. Here, we engineered a chloroplast-targeted bypass in tomato (GCMG), comprising glycolate oxidase 1 (SlGLO1), catalase 2 (SlCAT2), malate synthase A (SlMSA), and glutamine synthetase 2 (SlGS2). This bypass integrates carbon concentration with enhanced ammonium reassimilation via the GS2/ferredoxin-dependent glutamate synthase (Fd-GOGAT) cycle. GCMG plants showed synergistic improvements in photosynthesis, biomass, and fruit quality; while total yield significantly increased over wild-type (WT), GCMG maintained a favorable trend beyond C-focused GCM lines. Mechanistically, GCMG partitions glycolate flux into parallel routes, maintaining N assimilation while enhancing chloroplastic CO2 enrichment. 15N-labeling confirmed this metabolic synergy, revealing a 146% higher N turnover rate (fnew). GCMG also sustained robust N assimilation under elevated CO2 and conferred resilience to N-deficiency, high oxygen, and heat stress. Coordinating C/N metabolism boosts productivity and resilience, offering a blueprint for crop improvement.

Acylsugars are defensive glycolipids in Solanaceae glandular trichomes, and their biosynthesis offers an exemplary system for understanding the evolutionary mechanisms of plant chemical defense, yet their transcriptional regulation is poorly understood. Here, we identified and characterized WRINKLED3 (WRI3), which is critical for acylsugar biosynthesis in tomato. SlWRI3 is specifically expressed in trichome tip cells, and its knockout reduces acylsugar accumulation. Using transcriptomics, DNA-protein interaction assays, and metabolomics, we demonstrate that SlWRI3 acts via a dual regulatory mechanism: directly activating the acyltransferase gene SlASAT1 for the initial acylation of sucrose core and upregulating multiple acetyl-CoA carboxylase (ACCase) subunits to provide acyl chain precursors. Silencing these ACCase genes similarly decreased acylsugar levels. Phylogenetic analysis indicates that the function of WRI3 in acylsugar biosynthesis is evolutionarily conserved in Solanaceae. These findings elucidate how a primary metabolism-associated regulator was repurposed to coordinate precursor supply and specialized metabolite production, deepening our understanding of plant metabolic evolution, providing a target for engineering pest-resistance in Solanaceae crops.

Global agriculture faces critical challenges due to the overreliance on chemical pesticides, driving an urgent need for eco-friendly biopesticides and biostimulants (BioP&S). Plant-derived peptides, evolved as natural regulators of growth, development, and stress adaptation, offer immense potential as biodegradable and biocompatible alternatives. However, their commercialization remains constrained by limited exploration of the diversity and activity, high production costs, incomplete ecological risk evaluations, and undefined application scenarios. This Perspective overviews emerging discoveries and proposes integrated frameworks for plant peptide identification, molecular design, biomanufacturing, and ecological impact assessments integrated with germplasm development and field application systems. To overcome existing bottlenecks, we discuss the integrative potential of emerging technologies that synergistically combine artificial intelligence for high-throughput peptide discovery and de novo structural refinement, nanotechnology for enhancing environmental resilience and targeted delivery, and synthetic biology for developing industrial biomanufacturing platforms. We emphasize the need to align phytopeptide BioP&S with compatible germplasm resources, stage-specific crop requirements, and complementary chemical pesticides to maximize their efficacy, cost-effectiveness, and trait-specific agronomic performance by integrating with precision agriculture systems. Future advancements will rely on interdisciplinary innovations and policy support to unlock their full potential in enhancing crop resilience, productivity, and quality while ensuring ecological sustainability.

Prolonged exposure to low temperatures during agricultural production often leads to fruit malformation in crops, significantly reducing market value. However, the underlying molecular mechanisms remain poorly understood. In this study, we identify sugar transport protein 2 (STP2) as a critical regulator of tomato fruit locule development under cold conditions. Low temperatures impair long-distance sucrose transport from leaves to shoot apices, resulting in reduced accumulation of glucose and arabinose. In response, STP2 expression is strongly upregulated in shoot apices, promoting glucose and arabinose transport. We found that the CLAVAT3-WUSCHEL (CLV3-WUS) regulatory module, which governs locule formation, relies on STP2-mediated sugar transport for CLV3 arabinosylation. Overexpression of STP2 promotes glucose and arabinose accumulation in shoot apices, enhances CLV3 arabinosylation and the WUS suppression, mitigating the multi-locular malformations induced by low temperatures. Conversely, disruption of STP2 function exacerbates locule number increases under low temperatures, which could not be rescued by exogenous sugar supplementation. Our findings reveal a key mechanism by which STP2-mediated sugar transport supports CLV3 arabinosylation to maintain fruit locule development under low temperatures, offering potential strategies to alleviate fruit malformations in winter crop cultivation.

Heterotrimeric G protein serves as a central hub in plant signal transduction, playing a pivotal role in integrating endogenous developmental signals and external environmental cues. While significant advances have been made in understanding G protein signaling mechanisms in model plants such as Arabidopsis and major crops like rice and maize, the precise regulatory roles in growth, development, and adaptation in horticultural crops are still poorly understood. In this review, we systematically summarize recent advances in uncovering both conserved and species-specific regulatory mechanisms of G protein signaling across diverse plant species. We also highlight key discoveries on the crosstalk between G protein-mediated pathways and other signaling cascades, such as hormone signaling, transcriptional regulation, and stress response networks. Finally, we discuss the potential applications of G protein signaling research in future crop improvement, offering new perspectives for advancing sustainable horticultural production.

The shoot apex is a critical determinant of plant growth, development, morphology, and yield. The G protein β subunit (Gβ) is an essential regulator of apical meristem dynamics, yet its precise mechanism of action remains unclear, with notable interspecific variation. This study reveals that in the dicot tomato (Solanum lycopersicum), Gβ subunit mutants (Slgb1) display abnormal shoot morphogenesis and, in severe cases, shoot apex death. Such a phenotype has also been observed in monocot species like maize (Zea mays) and rice (Oryza sativa), but not in the model dicot Arabidopsis (Arabidopsis thaliana). Using integrated multi-omics and liquid chromatography-mass spectrometry, we identified a significant upregulation in tyramine-derived phenolamides in Slgb1 mutants, particularly N-p-trans-coumaroyltyramine (N-P-CT) and N-trans-feruloyltyramine (N-FT). Biochemical and genetic assays pinpointed tyramine hydroxycinnamoyl transferases (THTs) as the enzymes catalyzing N-P-CT and N-FT biosynthesis, with THT8 overexpression inducing shoot apex death. Comparative genomic analysis revealed the presence of a THT-mediated tyramine-derived phenolamide metabolic pathway in species exhibiting gb1 mutant-associated apex death, which is notably absent in Arabidopsis. Protein interaction assays showed that SlGB1 interacts with bHLH79 at the cell membrane and cytoplasm, thereby attenuating the bHLH79-MYB10 interaction within the nucleus, leading to altered THT expression and phenolamide biosynthesis. This study unravels the molecular mechanisms by which SlGB1 governs tomato shoot apex growth and development, highlighting interspecific differences critical for developing breeding strategies aimed at optimizing shoot apex architecture.

Maintaining robust plant vigor is essential for sustaining crop productivity, yet the precise roles and molecular underpinnings of G protein γ subunits in this process remain elusive. This study reveals that GGC1 is under selection during tomato domestication, and its mutants exhibit enhanced plant vigor, characterized by superior growth, increased yield, and improved fruit quality. In contrast, triple mutants gga1/ggb1/ggb2 display severely compromised vigor resembling slgb1 mutants lacking the Gβ subunit. Protein assays reveal that GGC1 suppresses the interaction between the three Gγ subunits (GGA1, GGB1, and GGB2) and SlGB1. Further, GGC1 inhibits calcium-dependent protein kinase 28 (CPK28)-mediated phosphorylation of aquaporin plasma membrane intrinsic protein 1;2 (PIP1;2) at the T172 site. Downstream of GGC1, both CPK28 and PIP1;2 positively regulate plant vigor by enhancing photosynthesis. These findings illuminate the functional divergence among G proteins in controlling crop vigor, offering potential strategies to engineer high-yield germplasm with enhanced CO2 assimilation and photosynthetic efficiency.

Phytosulfokine (PSK) is a secreted peptide that plays a pivotal role in regulating plant growth, development, and environmental adaptability. PSK biosynthesis begins with a pre-proprotein precursor that undergoes sulfation by tyrosylprotein sulfotransferase in the cis-Golgi apparatus, followed by proteolytic cleavage by subtilases in the apoplast to yield the mature PSK. This mature peptide is recognized by membrane-bound leucine-rich repeat receptor kinases, known as PSK receptors (PSKRs), which subsequently activate diverse signaling cascades, including cGMP-dependent signaling, phosphorylation events, Ca2+ signaling, mitogen-activated protein kinase pathways, and transcriptional regulation. This review consolidates recent advances in PSK biosynthesis, biological functions, signaling mechanisms, and crosstalk with other plant hormones. By summarizing these insights, we aim to provide a theoretical framework for developing PSK-based strategies to enhance crop resilience and productivity in response to environmental challenges.

Spartina anglica (SA), a plant rich in dietary fiber, has demonstrated considerable potential for enhancing gut health and antioxidant capacity in animals. This study investigates the integration of SA as a novel dietary ingredient for Zhedong white geese, with a specific focus on evaluating its effects on growth performance, nutrient digestibility, antioxidant capacity, intestinal health, and cecal microbiota composition. A total of 360 1-day-old Zhedong white geese with an average weight of 114.94 ± 0.81 g were randomly allocated to 4 dietary treatments, with 6 replicates per treatment and 15 geese per pen. The 4 dietary treatments included different SA supplement levels: a control group receiving a basal diet (CON), and three experimental groups supplemented with 3% SA (SA3), 6% SA (SA6), and 12% SA (SA12). Supplementation with 6% SA significantly enhanced the final body weight, average daily gain, and feed conversion ratio (FCR) compared to the CON group (p < 0.05). In contrast, the SA12 group exhibited reduced digestibility of crude protein and ether extract, relative to the SA3 and SA6 groups (p < 0.05). The highest antioxidant capacity was observed in the SA6 and SA12 groups, while the lowest was recorded in the CON group. SA supplementation did not significantly influence serum biochemical parameters or organ indices but increased cecum length (p < 0.05). Notably, SA supplementation markedly improved intestinal morphology, although excessive levels appeared to compromise these benefits. Additionally, SA supplementation significantly enhanced the richness and diversity of cecal microbiota and increased short-chain fatty acid concentrations. In conclusion, SA at an optimal supplementation level of 6% may be effectively utilized in Zhedong white geese diets to improve growth performance, gut health, and antioxidant capacity.

Plants have evolved sophisticated defense systems to protect against herbivory, including the systemic induction of jasmonic acid (JA) synthesis. However, the molecular mechanisms underlying this process remain poorly understood. Here, we report that root-knot nematode (RKN) attack induced a phyB-dependent accumulation of ELONGATED HYPOCOTYL 5 (HY5) in the leaves, which activates the expression of JA biosynthesis genes and HY5 itself in tomato. In addition, the systemic transmission of GLUTAMATE RECEPTOR-LIKE 3.5 (GLR3.5)-dependent electrical signals induced by RKN triggers the physical interaction between CALMODULIN 2 (CaM2) and HY5 to amplify the transcriptional regulation of HY5 and JA synthesis. HY5 functions as a systemic signal that moves from leaves to roots to maintain the electrical signaling from roots to leaves by activating GLR3.5 expression. Together, these results reveal a HY5-dependent systemic signaling cascade that integrates light and electrical signals to activate JA-mediated defense against nematodes in tomato.

Global climate change challenges agricultural production, as extreme temperature fluctuations negatively affect crop growth and yield. Low temperature (LT) stress impedes photosynthesis, disrupts metabolic processes, and compromises the integrity of cell membranes, ultimately resulting in diminished yield and quality. Notably, many tropical or subtropical horticultural plants are particularly susceptible to LT stress. To address these challenges, it is imperative to understand the mechanisms underlying cold tolerance in horticultural crops. This review summarizes recent advances in the physiological and molecular mechanisms that enable horticultural crops to withstand LT stress, emphasizing discrepancies between horticultural crops and model systems. These mechanisms include C-repeat binding factor-dependent transcriptional regulation, post-translational modifications, epigenetic control, and metabolic regulation. Reactive oxygen species, plant hormones, and light signaling pathways are integrated into the cold response network. Furthermore, technical advances for improving cold tolerance are highlighted, including genetic improvement, the application of light-emitting diodes, the utility of novel plant growth regulators, and grafting. Finally, prospective directions for fundamental research and practical applications to boost cold tolerance are discussed.

Elevated atmospheric CO2 concentrations increase the productivity of plants by enhancing the photosynthesis/photorespiration balance. It has long been recognized that CO2 acts as a signal, for example, in the regulation of stomatal closure, as well as the substrate of photosynthesis. Early concepts of CO2 signalling in plants focused on a mode of action based on alterations in primary metabolism, particularly sugar availability and signalling. However, stomatal guard cells employ a CO2 sensing and signalling mechanism that is independent of sugars. We discuss the possibility that a similar pathway exists in all cells, where it drives calcium-mediated waves of reactive oxygen species (ROS), facilitating cell-to-cell communication of biotic and abiotic threats. The plasma membrane H2O2 receptor HPCA1 is required for both stomatal closure and the systemic transmission of stress signals. Moreover, increased oxidation of the apoplast activates G protein functions and alters sugar processing and signalling in the apoplast. We discuss the concept elevated CO2 constitutes an environmental stress that has a positive effect on plant innate immunity but a negative impact on crop nutritional quality.This article is part of the theme issue 'Crops under stress: can we mitigate the impacts of climate change on agriculture and launch the 'Resilience Revolution'?'.

Nitrate serves as an essential nutrient for plant growth and functions as a signaling molecule that modulates plant growth and development. Shoot branching is known to be responsive to nitrogen levels and associated with the nitrogen use efficiency (NUE), yet the underlying mechanisms remain unclear. Through RNA-seq, we identified NAM3, which encodes a NAC transcription factor, as a gene responsive to low nitrate levels in tomato (Solanum lycopersicum). NAM3 inhibits lateral bud growth by directly promoting the transcription of BRC1. Meanwhile, NAM3 enhances nitrate accumulation through promoting the expression of the nitrate transporter gene NRT1.7. Further genetic analysis showed that NAM3's regulation of shoot branching is independent of the expression of NRT1.7. The Ca2+ influx and transcription of CIPK1 are induced in response to the low nitrate level. The CBL3-CIPK1 complex phosphorylates NAM3 at Ser-183, thereby enhancing its protein stability and strengthening the transcriptional activity of NAM3 on BRC1 and NRT1.7. Our findings provide evidence that the CIPK1-regulated NAM3 modulates shoot branching and nitrate accumulation by activating the transcription of BRC1 and NRT1.7 in response to low nitrate levels. The coordination of shoot branching and nitrate accumulation by NAM3 implies that it is a promising genetic modification target for improving NUE.

Phytosulfokine (PSK) is a tyrosine-sulfated pentapeptide found throughout the plant kingdom, playing key roles in plant growth, development, and responses to biotic and abiotic stresses. However, there is still a lack of a comprehensive analysis of the CsPSK gene family in Camellia sinensis. In this study, we conducted a genome-wide identification and characterized 14 CsPSK genes in tea plants, which are unevenly distributed across seven chromosomes. CsPSK genes encode proteins ranging from 75 to 124 amino acids in length, all belonging to the PSK-α type and containing conserved PSK domains. A synteny analysis revealed that the expansion of the CsPSK gene family is primarily attributed to whole-genome duplication, with homology to Arabidopsis thaliana PSK genes. A promoter region analysis identified cis-regulatory elements related to hormone and stress responses. An expression profile analysis showed that CsPSK genes are highly expressed in roots, stems, flowers, and leaves, and are induced by both biotic and abiotic stresses. Furthermore, an RT-qPCR assay demonstrated that the expression levels of CsPSK8, CsPSK9, and CsPSK10 are significantly upregulated following Discula theae-sinensis infection. These findings establish a basis for further research into the role of the CsPSK gene family in tea plant disease resistance and underlying molecular mechanisms, offering valuable perspectives for developing novel antimicrobial peptides.

Light is one of the most important environmental factors for plant growth and development. In relay cropping systems, crop layouts influence light distribution, affecting light use efficiency (LUE). However, the response of light interception, light conversion, and LUE for relay maize and relay soybean to different crop layouts remains unclear. We aimed to quantify the effect of crop layout on intraspecific and interspecific competition, light interception, light conversion, LUE, and land productivity between relay maize and relay soybean. We conducted a field experiment for four consecutive years from 2017 to 2020 in Sichuan province, China, comparing different crop layouts (bandwidth 2.0 m, row ratio 2:2; bandwidth 2.4 m, row ratio 2:3; bandwidth 2.8 m, row ratio 2:4), with sole maize and sole soybean as controls. The results showed that relay maize in the 2.0 m bandwidth layout had the largest leaf area index and plant biomass, the lowest intraspecific competitive intensity and the highest aggressiveness. Compared to a bandwidth of 2.0 m, a bandwidth of 2.8 m significantly decreased relay maize leaf area index by 11% and plant biomass by 24%, while a 2.4 m bandwidth caused roughly half these reductions. The 2.0 m bandwidth layout also significantly improved crop light interception and LUE compared to sole maize. The light interception, light interception rate, light conversion rate and LUE in relay maize all decreased significantly with increasing bandwidth, but they increased in relay soybean. The increased light transmittance to the lower and middle canopy with increasing bandwidth did not compensate for the loss of relay maize yield caused by increased intraspecific competition. However, it enhanced the yield of relay soybeans. Increasing the bandwidth by 80 cm increased the relay maize intraspecific competition by 580%, and reduced maize yield by 33%, light interception by 12%, and LUE by 18%. In contrast, the relay soybean intraspecific competition was reduced by 64%, and the soybean yield was increased by 26%, light interception by 32% and LUE by 46%. Relay cropping systems with a 2.0 m bandwidth optimize the trade-off between light transmittance and intraspecific competition of relay crops. These systems achieve the highest LUE, group yield and economic benefits, making them a recommended crop layout for the southwest regions of China. Our study offers valuable insights for developing strip relay cropping systems that maximize light utilization and contributes to the theoretical understanding of efficient sunlight use in relay cropping practices.