Canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) is a severe bacterial infection threatening global kiwifruit production. Psa causes lignin degradation, cell wall rupture, leaf wilting, and canker formation on branches and trunks, often leading to plant death. The plant cell wall serves as a structural barrier against pathogens, with its thickness, composition, and cell density influencing disease resistance. Comparative studies between resistant germplasms Actinidia eriantha "Maohuaxiong" (A. eriantha 'MHX') and Actinidia latifolia "Kuoye" (A. latifolia 'KY') and susceptible cultivars Actinidia chinensis "Hongyang" (A. chinensis 'HY') and "Donghong" (DH) indicate that the resistant lines developed smaller lesions and slower disease progression after Psa infection, compared with susceptible cultivars. Histological and biochemical analyses revealed that "MHX" and "KY" had denser mesophyll cells and higher lignin deposition. Transcriptomic analysis and transient overexpression screening identified AcLFYL1 as a positive regulator of Psa resistance. AcLFYL1 overexpression increased cell density, lignin content, and disease resistance, while RNAi silencing produced the opposite phenotypes. Yeast one-hybrid, dual-luciferase reporter, and ChIP-qPCR assays confirmed that AcLFYL1 directly activates AcCSE, a key gene in lignin biosynthesis. Consistent with this, overexpression of AcCSE similarly increased cell density and lignin content and improved Psa resistance, whereas knockdown of AcCSE in both wild-type (WT) and AcLFYL1 overexpression lines significantly reduced lignin accumulation and compromised disease resistance. These findings demonstrate that AcLFYL1 enhances resistance by promoting lignin biosynthesis and increasing mesophyll cell density through direct regulation of AcCSE, offering valuable genetic targets for breeding Psa-resistant kiwifruit varieties.

Salicylic acid (SA) is essential for plant immunity, but excessive SA accumulation accelerates leaf senescence, necessitating tight control of its biosynthesis. Although AVRPPHB SUSCEPTIBLE3 (PBS3) is a key enzyme in SA biosynthesis, how PBS3 abundance is regulated to coordinate immunity and longevity remains unclear. Using genetic, biochemical, and physiological analyses, we show that PBS3 functions as a quantitative regulator of the immunity-longevity balance. Loss of PBS3 compromises disease resistance but delays senescence, whereas graded increases in PBS3 abundance progressively enhance pathogen-induced SA accumulation, systemic acquired resistance (SAR), and senescence severity. We further identify the E3 ubiquitin ligase PLANT U-BOX PROTEIN 13 (PUB13) as a direct regulator of PBS3. PUB13 physically associates with PBS3 and promotes its polyubiquitination and degradation through the 26S proteasome pathway. Disruption of PUB13 stabilizes PBS3, resulting in elevated SA accumulation, enhanced SAR, and accelerated leaf senescence. Time-course analyses revealed that pathogen-induced PBS3 accumulation and SA biosynthesis are transient in wild-type plants but remain elevated in pub13 mutants, indicating that PUB13 promotes the attenuation of immune-associated SA production after defense activation. Together, our findings establish the PUB13-PBS3 module as a post-translational mechanism that fine-tunes SA biosynthesis, enabling effective immunity while preventing prolonged SA accumulation and its detrimental effects on plant longevity.

The import of nuclear-encoded preproteins into chloroplasts ensures normal organismal function. This process is recognized by the translocon at the outer membrane of chloroplast Toc GTPase dependency receptors. We identified seven Toc GTPase genes in tomato genome through bioinformatics methods, they can be divided into two subclasses (Toc34 and Toc159). The results showed that the Toc GTPase family members possessed a typical G-conserved domain and contained 0-6 introns. Expression profile analysis showed that the Toc GTPases were expressed in multiple tissues, some responsive to hormones. The yeast two-hybrid results demonstrated that nine photosynthetic proteins and 21 non-photosynthetic proteins could interact with the SlToc34-1 protein in the tomato cDNA yeast library. We found that SlToc34-1 had a higher expression level than other six Toc GTPases in tomato fruit. Transient silence expression of SIToc34-1 gene in tomato fruits resulted the fruit in a slightly lighter green color and a decreased in chlorophyll content. qRT-PCR analysis showed that silencing SIToc34-1 inhibited the expression of chloroplast synthesis genes (SlTKN2 and SlAPRR2) and photosynthetic genes (SlCBC-1, SlRCA and SlPSBR). This observation indicated that SlToc34-1 was involved in early chloroplast development and chlorophyll reduction in tomato fruit. This work lays a foundation for further in-depth study of a complex plastid protein transport network.

Salicylic acid (SA) is a key defense hormone shaped by temperature. High temperatures suppress, while low temperatures enhance, SA biosynthesis and signaling, thereby influencing plant immunity and temperature resilience. This review synthesizes current understanding of how temperature modulates SA pathways and their cross-talk with other hormones to balance growth and defense. We also propose a conceptual model positioning SA as a central integrator of temperature perception, immune regulation, and hormonal signaling. However, key questions remain: How do plants sense temperature shifts to regulate SA dynamics? How do temperature-induced epigenetic changes in SA pathways contribute to long-term adaptation? And how can these insights inform crop improvement? Addressing these gaps is essential for developing climate-resilient crops.

Calcium ion (Ca2+) serves as a versatile and conserved second messenger in orchestrating immune responses. In plants, plasma membrane-localized Ca2+-permeable channels can be activated to induce Ca2+ influx from extracellular space to cytosol upon pathogen infection. Notably, different immune elicitors can induce dynamic Ca2+ signatures in the cytosol. During pattern-triggered immunity, there is a rapid and transient increase in cytosolic Ca2+, whereas in effector-triggered immunity, the elevation of cytosolic Ca(2+ )is strong and sustained. Numerous Ca2+ sensors are localized in the cytosol or different intracellular organelles, which are responsible for detecting and converting Ca2+ signals. In fact, Ca2+ signaling coordinated by cytosol and subcellular compartments plays a crucial role in activating plant immune responses. However, the complete Ca2+ signaling network in plant cells is still largely ambiguous. This review offers a comprehensive insight into the collaborative role of intracellularCa(2+) stores in shaping the Ca2+ signaling network during plant immunity, and several intriguing questions for future research are highlighted.

The flavor profile of tea is influenced not only by different tea varieties but also by the surrounding soil environment. Recent studies have indicated the regulatory role of soil microbes residing in plant roots in nutrient uptake and metabolism. However, the impact of this regulatory mechanism on tea quality remains unclear. In this study, we showed that a consortium of microbes isolated from tea roots enhanced ammonia uptake and facilitated the synthesis of theanine, a key determinant of tea taste. Variations were observed in the composition of microbial populations colonizing tea roots and the rhizosphere across different seasons and tea varieties. By comparing the root microorganisms of the high-theanine tea variety Rougui with the low-theanine variety Maoxie, we identified a specific group of microbes that potentially modulate nitrogen metabolism, subsequently influencing the theanine levels in tea. Furthermore, we constructed a synthetic microbial community (SynCom) mirroring the microbe population composition found in Rougui roots. Remarkably, applying SynCom resulted in a significant increase in the theanine content of tea plants and imparted greater tolerance to nitrogen deficiency in Arabidopsis. Our study provides compelling evidence supporting the use of root microorganisms as functional microbial fertilizers to enhance tea quality.

Calcium ions (Ca2+) serve as key messengers in plant immune reactions. A typical Ca2+ signaling involves three steps: encoding specific Ca2+ signatures by Ca2+-permeable channels, decoding Ca2+ signals by Ca2+ sensors, and downstream responses. This review focuses on plasma membrane-localized Ca2+-permeable channels and cytosolic Ca2+ sensors, unraveling their roles in cytosolic Ca2+ influx and immune signaling during pattern-triggered immunity, effector-triggered immunity, and autoimmunity. Several unresolved questions were highlighted, including the regulation of Ca2+-permeable channel activity for immune induction and the mechanism behind Ca2+ influx-triggered hypersensitive response cell death. This concise overview provides insights into the complex interplay of Ca2+ signaling in plant immunity, paving the way for future investigations on molecular plant-microbe interactions.

The toxic metalloid arsenic is prevalent in the environment and poses a threat to nearly all organisms. However, the mechanism by which phytohormones modulate arsenic resistance is not well-understood. Therefore, we analyzed multiple phytohormones based on the results of transcriptome sequencing, content changes, and related mutant growth under arsenic stress. We found that ethylene was the key phytohormone in Arabidopsis thaliana response to arsenic. Further investigation showed the ethylene-overproducing mutant eto1–1 generated less malondialdehyde (MDA), H2O2, and O2•- under arsenic stress compared to wild-type, while the ethylene-insensitive mutant ein2–5 displayed opposite patterns. Compared to wild-type, eto1–1 accumulated a smaller amount of arsenic and a larger amount of non-protein thiols. Additionally, the immediate ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), enhanced resistance to arsenic in wide-type, but not in mutants with impaired detoxification capability (i.e., cad1–3, pad2–1, abcc1abcc2), which confirmed that ethylene regulated arsenic detoxification by enhancing arsenic chelation. ACC also upregulated the expression of gene(s) involved in arsenic detoxification, among which ABCC2 was directly transcriptionally activated by the ethylene master transcription factor ethylene-insensitive 3 (EIN3). Overall, our study shows that ethylene is the key phytohormone to enhance arsenic resistance by reducing arsenic accumulation and promoting arsenic detoxification at both physiological and molecular levels.

Autophagy is a highly conserved method of recycling cytoplasm components in eukaryotes. It plays an important role in plant growth and development, as well as in response to biotic and abiotic stresses. Although autophagy-related genes (ATGs) have been identified in several crop species, their particular role in potato (Solanum tuberosum L.) remains unclear. Several transcription factors and signaling genes in the transgenic lines of the model plant Arabidopsis thaliana, such as AtTSPO, AtBES1, AtPIP2;7, AtCOST1 as well as AtATI1/2, ATG8f, GFP-ATG8F-HA, AtDSK2, AtNBR1, AtHKT1 play crucial functions under drought and salt stresses, respectively. In this study, a total of 29 putative StATGs from 15 different ATG subfamilies in the potato genome were identified. Their physicochemical properties, evolutionary connections, chromosomal distribution, gene duplication, protein-protein interaction network, conserved motifs, gene structure, interspecific collinearity relationship, and cis-regulatory elements were analyzed. The results of qRT-PCR detection of StATG expression showed that 29 StATGs were differentially expressed in potato's leaves, flowers, petiole, stem, stolon, tuber, and root. StATGs were dynamically modulated by salt and drought stresses and up-regulated under salt and drought conditions. Our results showed that the StATG8a localized in the cytoplasm and the nucleus. Potato cultivar "Atlantic" overexpressing or downregulating StATG8a were constructed. Based on physiological, biochemical, and photosynthesis parameters, potato lines overexpressing StATG8a exhibited 9 times higher drought and salt tolerance compared to non-transgenic plants. In contrast, the potato plants with knockdown expression showed a downtrend in drought and salt tolerance compared to non-transgenic potato lines. These results could provide new insights into the function of StATG8a in salt and drought response and its possible mechanisms.

White tea stored for various times have different flavors. However, the mechanism of flavor conversion remains elusive. Flavonoids and amino acids are two typical flavor components in tea. Herein, the contents of 46 flavonoids and 40 amino acids were measured in white tea (Shoumei) stored for 1, 3, 5 and 7 years, respectively. L-tryptophan, L-ornithine and L-theanine contribute to the refreshing taste of Shoumei 1 and 3. Quercetin, rutin and hesperidin contribute to aging charm and grain aroma of Shoumei 5 and 7. 306 bacterial OTUs and 268 fungal OTUs core microbiota existed in all samples. Interestingly, white teas contained higher richness of fungi than bacteria. The correlation analysis showed that the cooperation with bacteria and fungi may result in the flavonoids and amino acids composition changes in white teas during storage. Overall, this study provides new insights into flavor conversion of white tea during storage.

AVRPPHB SUSCEPTIBLE 3 (PBS3) belongs to the GH3 family of acyl acid amido synthetases, which conjugates amino acids to diverse acyl acid substrates. Recent studies demonstrate that PBS3 in Arabidopsis plays a key role in the biosynthesis of plant defense hormone salicylic acid (SA) by catalyzing the conjugation of glutamate to isochorismate to form isochorismate-9-glutamate, which is then used to produce SA through spontaneous decay or ENHANCED PSEUDOMONAS SUSCEPTIBILITY (EPS1) catalysis. Consistent with its function as an essential enzyme for SA biosynthesis, PBS3 is well known to be a positive regulator of plant immunity in Arabidopsis. Additionally, PBS3 is also involved in the trade-off between abiotic and biotic stress responses in Arabidopsis by suppressing the inhibitory effect of abscisic acid on SA-mediated plant immunity. Besides stress responses, PBS3 also plays a role in plant development. Under long-day conditions, PBS3 influences Arabidopsis flowering time by regulating the expression of flowering regulators FLOWERING LOCUS C and FLOWERING LOCUS T. Taken together, PBS3 functions in the signaling network of plant development and responses to biotic and/or abiotic stresses, but the molecular mechanisms underlying its diverse roles remain obscure.

Shoot architecture in maize is critical since it determines resource use, impacts wind and rain damage tolerance, and affects yield stability. Quantifying the diversity among inbred lines in heterosis breeding is essential, especially when describing germplasm resources. However, traditional geometric description methods oversimplify shoot architecture and ignore the plant’s overall architecture, making it difficult to reflect and illustrate diversity. This study presents a new method to describe maize shoot architecture and quantifies its diversity by combining computer vision algorithms and persistent homology. Our results reveal that persistent homology can capture key characteristics of shoot architecture in maize and other details often overlooked by traditional geometric analysis. Based on this method, the morphological diversity of shoot architecture can be mined (quantified), and the main shoot architecture types can be obtained. Consequently, this method can easily describe the diversity of shoot architecture in many maize materials.

This paper aims to find a fertilization method that better matches the growth characteristics of vegetables and reduces the soil and environmental problems caused by unreasonable fertilization methods, in view of the strong buffering of the clayey black soil in the north and the mismatch between the amount of chemical fertilizer applied and the growth characteristics of vegetables during cultivation. In this experiment, Lactuca sativa L. (Lactuca sativa) was studied in a randomized complete block design in greenhouse and five different fertilizer application methods were arranged: exponential fertilization (EF), linear fertilization (LF), average fertilization (AF), one-time fertilization (OF), and no fertilization as a control group (CG). The effects of different fertilization methods on soil nutrients, agronomic traits of Lactuca sativa growth, and related quality were investigated, and the pattern of effects of different fertilization methods on growth and soil nutrients was obtained. The results of the experiment showed that the exponential fertilization method gradually took advantage as the growth time extended. The plant height (PLH), leaf length (LL), leaf width (LW), yield, soluble protein (SP), soluble sugar (SS), vitamin C (VC), and elemental nitrogen (EN) and potassium (EK) of Lactuca sativa were significantly improved under the exponential fertilization method compared with other fertilization methods, by 29.9 cm, 51.5 cm, 5.96 cm, 22, 2.32 kg/m(2), 0.23%, 0.44%, 3.93%, 94.66 mg/kg, 1.58 g/kg, and 1.94 g/kg, respectively. The alkali-hydrolyzed nitrogen (SAN), available phosphorus (SAP), and available potassium (SAK) in the soil after fertilization were 139.69 mg/kg, 50.23 mg/kg, and 180.30 mg/kg, respectively. The above results showed that the exponential fertilization method not only improved the quality of Lactuca sativa and thus the quality of the crop growth traits, but also changed the soil nutrients favorably after fertilization, which is of some importance for the protection of black soils.

Extracellular perception of auxin, an essential phytohormone in plants, has been debated for decades. Auxin-binding protein 1 (ABP1) physically interacts with quintessential transmembrane kinases (TMKs) and was proposed to act as an extracellular auxin receptor, but its role was disputed because abp1 knockout mutants lack obvious morphological phenotypes. Here, we identified two new auxin-binding proteins, ABL1 and ABL2, that are localized to the apoplast and directly interact with the extracellular domain of TMKs in an auxin-dependent manner. Furthermore, functionally redundant ABL1 and ABL2 genetically interact with TMKs and exhibit functions that overlap with those of ABP1 as well as being independent of ABP1. Importantly, the extracellular domain of TMK1 itself binds auxin and synergizes with either ABP1 or ABL1 in auxin binding. Thus, our findings discovered auxin receptors ABL1 and ABL2 having functions overlapping with but distinct from ABP1 and acting together with TMKs as co-receptors for extracellular auxin.

Anthocyanins are a subgroup of plant flavonoids with antioxidant activities and are often induced by various biotic and abiotic stresses in plants, probably to efficiently scavenge free radicals and reactive oxygen species. However, the regulatory mechanisms of salt stress-induced anthocyanin biosynthesis remain unclear. Using molecular and genetic techniques we demonstrated key roles of ECAP in differential salt-responsive anthocyanin biosynthesis pathways in Arabidopsis thaliana. ECAP, JAZ6/8 and TPR2 are known to form a transcriptional repressor complex, and negatively regulate jasmonate (JA)-responsive anthocyanin accumulation. In this study, we demonstrated that under moderate salt stress, the accumulation of anthocyanins is partially dependent on JA signaling, which degrades JAZ proteins but not ECAP. More interestingly, we found that high salinity rather than moderate salinity induces the degradation of ECAP through the 26S proteasome pathway, and this process is independent of JA signaling. Further analysis revealed that ECAP interacts with MYB75 (a transcription factor activating anthocyanin biosynthetic genes) and represses its transcriptional activity in the absence of high salinity. Our results indicated that plants adopt different strategies for fine-tuning anthocyanin accumulation under different levels of salt stress, and further elucidated the complex regulation of anthocyanin biosynthesis during plant development and responses to environmental stresses.

Lipoprotein deficient serum has been shown to enhance lipid synthesis in cultured normal human skin fibroblasts incubated in the presence of oleate-albumin. The factor responsible is nondialyzable and trypsin sensitive. The stimulation is proportional to the concentration of lipoprotein deficient serum in the media and is present at all oleate concentrations and incubation times assayed. The protein has been partially purified by column chromatography to yield a Peak II fraction which stimulates triglyceride synthesis in both fibroblasts and isolated human adipocytes. The stimulation is dependent on the concentration of protein fraction and increases to an apparent saturation level of 200% in fibroblasts. Triglyceride synthesis, however, increases to a much greater extent in adipocytes and did not demonstrate saturation at the maximum Peak II protein concentration assayed. These results suggest that human serum contains a protein which stimulates fatty acid uptake and esterification by adipose tissue.

A MYB family transcription factor ZmMYB69 is a transcriptional activator at the upper level of ZmMYB31 and ZmMYB42 in the hierarchical network that controls lignin biosynthesis in maize.

In plants, reactive oxygen species (ROS) produced following the expression of the respiratory burst oxidase homolog (Rboh) gene are important regulators of stress responses. However, little is known about how plants acclimate to salt stress through the Rboh-derived ROS signaling pathway. Here, we showed that a 400-bp fragment of the tobacco (Nicotiana tabacum) NtRbohE promoter played a critical role in the salt response. Using yeast one-hybrid (Y1H) screens, NtbHLH123, a bHLH transcription factor, was identified as an upstream partner of the NtRbohE promoter. These interactions were confirmed by Y1H, electrophoretic mobility assay, and chromatin immunoprecipitation assays. Overexpression of NtbHLH123 resulted in greater resistance to salt stress, while NtbHLH123-silenced plants had reduced resistance to salt stress. We also found that NtbHLH123 positively regulates the expression of NtRbohE and ROS production soon after salt stress treatment. Moreover, knockout of NtRbohE in the 35S::NtbHLH123 background resulted in reduced expression of ROS-scavenging and salt stress-related genes and salt tolerance, suggesting that NtbHLH123-regulated salt tolerance is dependent on the NtbHLH123-NtRbohE signaling pathway. Our data show that NtbHLH123 is a positive regulator and acts as a molecular switch to control a Rboh-dependent mechanism in response to salt stress in plants.