Soil salinity is a major abiotic stress that threatens global crop productivity. Calcium (Ca2+) is a pivotal second messenger in plant stress signalling, but how Ca2+ sensors such as calmodulin (CaM) transcriptionally control ion homeostasis and salt tolerance remains largely understood in crops. Here, we identified a novel calmodulin-binding protein HvCBP60b, which is a negative regulator of salt resilience in salt-tolerant barley. We showed that HvCBP60b interacts with Ca2+ sensor HvCaM1 via its C-terminal domain in a Ca2+-dependent manner. Loss of either HvCBP60b or HvCaM1 promoted the uptake of K+, increased the K+/Na+ ratio, and markedly enhanced both growth performance and grain yield under salinity stress. Furthermore, HvCBP60b binds to the promoter of R2R3-type MYB transcription factor HvMYB77 through its N-terminal domain. HvMYB77 then transcriptionally reduces the expression of HvHAK5, a high-affinity K+ transporter essential for maintaining K+ homeostasis under salinity. Mutations in HvMYB77 or HvHAK5 compromise salt tolerance, whereas the salt-sensitive phenotype of hvhak5 is rescued in hvcbp60b-hvhak5 double mutants. Therefore, we uncover a novel Ca2+-responsive regulatory module CaM1-CBP60b-MYB77-HAK5 essential for K+ homeostasis and salt tolerance in barley, highlighting new targets of Ca2+ signalling for improving salt resilience in cereal crops.

Phytobacteria release type 3 effectors (T3Es) abundant in intrinsically disordered regions (IDRs) to undermine plant defenses. How flexible IDRs contribute to T3Es' function in subverting plant immunity remains unclear. Here, we identify a plant plasma membrane (PM)-associated macromolecular condensation mechanism that governs the sophisticated interplay between T3E XopR and the plant's Resistance to Pseudomonas syringae pv. maculicola 1 (RPM1)-interacting protein 4 (RIN4) immune complex. Upon deployment into plants, XopR undergoes PM association, percolation clustering, and spanning networking on the PM, ranging from subnanomolar to tens of nanomolar. This spatiotemporal building of the XopR network enables an efficient manipulation of plant surface immune regulators, including a coiled-coil nucleotide-binding leucine-rich repeat receptor (CNL)-guardee complex with highly disordered RIN4. When XopR hijacks and fluidizes the RIN4-RPM1 condensates, Arabidopsis shows reduced RIN4 phosphorylation and diminished RPM1-activated defense in vivo, consistent with XopR-impaired RIN4 phosphorylation by RPM1-interacting protein kinase (RIPK). Our research illuminates the mechanism underlying the dynamic interplay between bacterial T3Es and plant receptor complex condensates during infection.

Low-phosphorus (LP) tolerance varies among plant species and genotypes within a species, and the molecular mechanisms underlying phosphorus (P) signaling in barley (Hordeum vulgare L.) remain unclear. Here, we report the function of HvSPX4, a member of the SPX (SYG1/Pho81/XPR1) subfamily, in maintaining P homeostasis and regulating LP responses in barley. HvSPX4 exhibited lower expression in the LP-tolerant genotype Zaoaibai than the LP-sensitive Salooni2. Knocking out HvSPX4 resulted in growth inhibition due to over-accumulation of P under normal P conditions. Overexpression of HvSPX4 resulted in reduced biomass under both normal and LP conditions and less P uptake, especially in shoots under normal P conditions. HvSPX4 directly interacted with transcription factors Phosphate Starvation Response 1/2/4 (HvPHR1/2/4) to inactivate PSI genes such as Phosphate Transporter 1;6 (HvPHT1;6). An expression genome-wide association studies analysis of HvSPX4 expression revealed that a 50-bp insertion in the promoter region of HvSPX4 enhances its expression, probably due to the presence of 2 CAAT boxes in this insertion. Moreover, the absence of the insertion was associated with improved plant growth in a natural population of barley under LP conditions. These findings suggest that fine-tuning the expression of HvSPX4 could be a promising strategy to improve plant adaptation to LP stress.

Most arable lands in the world are quite low in available phosphorus (P), becoming an important factor restricting crop yield. However, the genotypic difference of low-P tolerance in barley is rarely understood at molecular level. In this study, low-P responses of three barley genotypes were explored by physiological, transcriptomic and metabolomic analysis. The results showed that low-P-tolerant genotypes Zaoaibai (cultivar) and X130 (Tibetan wild accession) showed less growth inhibition compared to low-P-sensitive Salooni2 under low-P stress. Omics analysis showed that many genes involved in Pi acquisition and transport were more upregulated in Zaoaibai, which had relatively higher concentrations of shoot P and glucose-6-phosphate, indicating that enhancement of P acquisition, P translocation and P availability contributed to low-P tolerance in Zaoaibai. On the other hand, the genes and metabolites involved in biosynthesis of Pi-free lipids were highly expressed and more abundant in X130, suggesting that remodeling of membrane lipids by replacing phospholipids with Pi-free lipids is an important strategy for X130 in its adaptation to low-P stress. The divergent evolution of low-P tolerance in Zaoaibai and X130 could be driven by diverse ecological factors in Eastern China (low soil P) and Tibet Plateau (high soil P and low temperature), respectively.

Colored crops are increasingly used in agricultural landscapes to attract tourists to rural areas. In plants, the pigments responsible for vibrant colors are primarily anthocyanins. However, the molecular mechanisms underlying anthocyanin biosynthesis remain elusive. In this study, we investigated the molecular mechanisms behind the purple pigmentation in the stalks and husks of barley genotype Zipi. Using UPLC-Q-TOF-MS analysis, we identified cyanidin 3-O-glucoside as the primary anthocyanin, with significant accumulation in Zipi compared to yellow variety Golden Promise. Transcriptomic analysis revealed that structural and transport genes involved in anthocyanin biosynthesis, such as HvCHS, HvCHI, HvANS, and HvGST, as well as their upstream regulators HvANT1 and HvANT2, exhibited higher expression in Zipi. A weighted gene co-expression network analysis (WGCNA) identified HvMYB112 as a key upstream regulator of anthocyanin biosynthesis, activating the transcription of HvANT1, which was proved using dual-luciferase reporter assay. These findings provide crucial insights into the genetic regulation of anthocyanin accumulation in barley, offering a potential pathway for breeding ornamental barley varieties with enhanced pigmentation.

We introduce MolPhase ( http://molphase.sbs.ntu.edu.sg/ ), an advanced protein phase separation (PS) prediction algorithm that improves accuracy and reliability by utilizing diverse physicochemical features and extensive experimental datasets. MolPhase applies a user-friendly interface to compare distinct biophysical features side-by-side along protein sequences. By additional comparison with structural predictions, MolPhase enables efficient predictions of new phase-separating proteins and guides hypothesis generation and experimental design. Key contributing factors underlying MolPhase include pi-pi interaction, disorder, and prion-like domain. As an example, MolPhase finds that phytobacterial type III effectors (T3Es) are highly prone to homotypic PS, which was experimentally validated in vitro biochemically and in vivo in plants, mimicking their injection and accumulation in the host during microbial infection. In addition, the phase-separation of T3Es were evolved both in vivo and in vitro , suggesting their determinative scaffolding function, though there is a difference in material properties, implying a difference in homotypic and heterotypic macromolecular condensation. Robust integration of MolPhase’s effective prediction and experimental validation exhibit the potential to evaluate and explore how biomolecule PS functions in biological systems.

Malt production is one of the important uses of barley, and its quality differs greatly depending on the barley varieties used. In this study, ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry technology was used to investigate the temporal changes of metabolites during malting in two barley varieties: Franklin (malt barley) and Yerong (non-malt barley). Also, differences in metabolite profiles were compared in the kilned malt between two other malt barley varieties (Copeland and Planet) and two non-malt varieties (ZD10 and Hua30). Results showed that degradation of trisaccharide and accumulation of UDP-glucose and mannose-1-phosphate are the key metabolic events during steeping, with Franklin showing earlier and greater changes. Earlier increase of sugars and amino acids in Franklin is associated with its faster germination rate. Comparative metabolome analysis of kilned malt from the different barley varieties indicated that malt barley accumulated more sugars, hordatine-glucoside, and oxoproline, and non-malt barley accumulated more polyphenols and monogalactosylmonoacylglycerol. These results improved the understanding of the genotypic difference in the formation of malt quality at the metabolomic level.

A novel heterotrophic nitrification and aerobic denitrification (HNAD) bacteria, identified as Bacillus thuringiensis strain WXN-23, was isolated from husk feed filtrate of a pig farm. It was the first report of Bacillus thuringiensis with the capability for HNAD and could adapt to the condition of low Carbon/Nitrogen (C/N) ratio. Nitrogen could be efficiently removed by the strain WXN-23 in simulated wastewater, be it in single or mixed form nitrogen sources. The nitrogen balance revealed that 63.5% of the initial nitrogen (5.32 mg) was lost in the form of N-2. The conditions for maximum total nitrogen (TN) removal efficiency (95.996%) were shaking speed of 126.89 r/min, a carbon C/N ratio of 5.91, the temperature of 32.81. C, and a pH value of 8.17. The nitrification-denitrification metabolic pathway (NH4+-N -> NH2OH -> NO2--N -> NO3--N -> NO2--N.NO -> N2O -> N-2) under aerobic conditions was determined on the basic of characteristic of N removal, N balance analysis, enzyme assay and functional genes amplification results. Strain WXN-23 was effective at wastewater treatment, with TN, NH4+-N, NO3--N and NO2--N removal efficiencies of 82.12%, 86.74%, 90.74% and 100%, respectively.

随着工农业的快速发展,导致不同来源的铅不断释放进入土壤,土壤铅污染已成为了土壤污染中亟待解决的问题之一,污染来源的示踪以及污染物的定量源解析是土壤污染防治的重要一环.近年来,国内外研究表明,铅同位素特征值法是土壤铅污染定量源解析的重要方法之一,并已在土壤铅污染定量源解析中得到了较广泛的应用.概述了铅同位素定量解析的方法原理以及国内外研究现状与进展,并通过文献调研构建了国内部分省市铅同位素特征值指纹库,以期为研究者在探究所在区域主要铅污染源及其贡献率时提供一定的参考,最后针对铅同位素特征值法在土壤铅污染定量源解析应用中的局限性提出了展望.

为了揭示红壤地区铅锌冶炼厂冶炼渣中的铅淋溶释放后在堆放场地土壤中的垂直迁移特征,以湖南株洲某铅锌冶炼厂冶炼渣堆放场地土壤为研究对象,采用等温吸附及土柱淋溶模拟试验探究了冶炼渣淋溶释放的铅在冶炼渣堆放场地土壤中的吸附与垂直迁移特征.结果表明:堆放场地土壤对冶炼渣淋溶释放的铅有较强的吸附能力,吸附由低能位和高能位共同控制,其中高能位对铅的最大吸附量为7392.771 mg/kg,低能位对铅的最大吸附量为13518.278 mg/kg,说明铅在堆放场地土壤中不易迁移.10 cm厚冶炼渣淋溶模拟释放的铅在堆放场地土壤中缓慢向下迁移,较长时间内(3 a)冶炼渣淋溶释放的铅主要富集在30 cm以内的土层中,30 cm处淋出液中的铅在0.006 mg/L内浮动;可采用多物理场仿真软件COMSOL对铅的垂直淋溶迁移过程进行定量描述和预测,预测结果与淋溶试验实测值基本相符,3 a内淋出液中的铅实测值均匀分布于模拟值曲线两侧,COMSOL预测结果进一步表明冶炼渣淋溶9 a释放的铅仍主要富集在30 cm以内的土层中,但呈现缓慢下移趋势.

This study was conducted to reveal the effects of silicon (Si) application on nutrient utilization efficiency by rice and on soil nutrient availability and soil microorganisms in a hybrid rice double-cropping planting system. A series of field experiments were conducted during 2017 and 2018. The results showed that Si nutrient supply improved grain yield and the utilization rates of nitrogen (N) and phosphorus (P) to an appropriate level for both early and late plantings, reaching a maximum at 23.4 kg/ha Si. The same trends were found for the ratios of available N (AN) to total N (TN) and available P (AP) to total P (TP), the soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP), and the ratios of MBN to TN and MBP to TP, at different levels of Si. Statistical analysis further revealed that Si application enhanced rice growth and increased the utilization rate of fertilizer due to an ecological mechanism, i.e., Si supply significantly increased the total amount of soil microorganisms in paddy soil compared to the control. This promoted the mineralization of soil nutrients and improved the availability and reserves of easily mineralized organic nutrients.