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Local scours around the bridge pier are a common phenomenon in the mobile riverbed, leading to a substantial risk of bridge failures. In this study, the primary objective is to present a protective collar of pile foundations on the basis of flow structure and riverbed erosion. For this purpose, model experiment cooperating with numerical simulations under sandy water conditions was applied to investigate the changes in scour patterns around the rectangular pile cap, and the influence of flow velocity and riverbed height on the scour area and depth was analyzed under conditions without protective measures. On this basis, a horseshoe-shaped collar defined by the elliptical equation was proposed to mitigate the scour on the riverbed. The results show that the scour patterns calculated by computational fluid dynamics are similar to those with experimental methods, the maximum relative deviation of the scour area and depth are 9.16 and 23.94%, respectively. The simulation method can evaluate the rationality of anti-scouring collar designs. The comparison of topography indicates that scour around the foundation is effectively mitigated with a protective collar; the maximum scour area decreased by 64.85-85.52% for different conditions. The scour depth was significantly reduced, with a minimum reduction of 66.67%.

Key messageipa1 enhances rice drought tolerance mainly through activating the ABA pathway. It endows rice seedlings with a more developed root system, smaller leaf stomata aperture, and enhanced carbon metabolism.Drought is a major abiotic stress to crop production. IPA1 (IDEAL PLANT ARCHITECTURE 1)/OsSPL14 encodes a transcription factor and has been reported to function in both rice ideal plant architecture and biotic resistance. Here, with a pair of IPA1 and ipa1-NILs (Near Iso-genic Lines), we found that ipa1 could significantly improve rice drought tolerance at seedling stage. The ipa1 plants had a better-developed root system and smaller leaf stomatal aperture. Analysis of carbon–nitrogen metabolism-associated enzyme activity, gene expression, and metabolic profile indicated that ipa1 could tip the carbon–nitrogen metabolism balance towards an increased carbon metabolism pattern. In both the control and PEG-treated conditions, ABA content in the ipa1 seedlings was significantly higher than that in the IPA1 seedlings. Expression of the ABA biosynthesis genes was detected to be up-regulated, whereas the expression of ABA catabolism genes was down-regulated in the ipa1 seedlings. In addition, based on yeast one-hybrid assay and dual-luciferase assay, IPA1 was found to directly activate the promoter activity of OsHOX12, a transcription factor promoting ABA biosynthesis, and OsNAC52, a positive regulator of the ABA pathway. The expression of OsHOX12 and OsNAC52 was significantly up-regulated in the ipa1 plants. Combined with the previous studies, our results suggested that ipa1 could improve rice seedling drought tolerance mainly through activating the ABA pathway and that regulation of the ipa1-mediated ABA pathway will be an important strategy for improving drought resistance of rice.

Plant major resistance (R) genes are effective in detecting pathogen signal molecules and triggering robust defense responses. Investigating the natural variation in R genes will allow identification of the critical amino acid residues determining recognition specificity in R protein and the discovery of novel R alleles. The rice blast resistance gene Pike, comprising of two adjacent CC-NBS-LRR genes, namely, Pike-1 and Pike-2, confers broad-spectrum resistance to Magnaporthe oryzae. Here, we demonstrated that Pike-1 determined Pike-specific resistance through direct interaction with the pathogen signal molecule AvrPik. Analysis of natural variation in 79 Pike-1 variants in the Asian cultivated rice Oryza sativa and its wild relatives revealed that the CC and NBS regions, particularly the CC region of the Pike-1 protein were the most diversified. We also found that balancing selection had occurred in O. sativa and O. rufipogon to maintain the genetic diversity of the Pike-1 alleles. By analysis of amino acid sequences, we identified 40 Pike-1 variants in these rice germplasms. These variants were divided into three major groups that corresponded to their respective clades. A new Pike allele, designated Pikg, that differed from Pike by a single amino acid substitution (D229E) in the Pike-1 CC region of the Pike protein was identified from wild rice relatives. Pathogen assays of Pikg transgenic plants revealed a unique reaction pattern that was different from that of the previously identified Pike alleles, namely, Pik, Pikh, Pikm, Pikp, Piks and Pi1. These findings suggest that minor amino acid residues in Pike-1/Pikg-1 determine pathogen recognition specificity and plant resistance. As a new blast R gene derived from rice wild relatives, Pikg has potential applications in rice breeding.

Ground-penetrating radar (GPR) is a key non-destructive technique for subsurface reconstruction, widely valued for its ability to image buried structures without disruption. Among its various implementations, vehicle-mounted GPR has emerged as particularly suitable for highway tunnel assessment due to its rapid non-contact operation. However, current systems are often constrained by closely spaced antennas that generate strong direct coupling and consequently limit detection depth. To mitigate this issue, this paper proposes an antenna decoupling method based on coherent difference imaging. A differential decoupling model is first established to characterize the relationship between conventional transceiver signals and the derived differential signals, explicitly accounting for parameters such as antenna height and target depth. Furthermore, a coherent difference imaging algorithm is developed, employing a sliding-window coherence process to resolve dual-peak artifacts and restore focused target images. Simulations validate consistent performance across varying antenna heights, while experiments demonstrate over 37.2 dB isolation in the 1–3 GHz band and markedly improved imaging focus compared to conventional configurations, thereby enhancing buried target detection and supporting reliable data interpretation.

The root traits and response strategies of plants play crucial roles in mediating interactions between plant root systems. Current research on the role of root exudates as underground chemical signals mediating these interactions has focused mainly on crops, with less attention given to desert plants in arid regions. In this study, we focused on the typical desert plant Haloxylon ammodendron and conducted a pot experiment using three root isolation methods (plastic film separation, nylon mesh separation, and no separation). We found that (1) as the degree of isolation increased, plant biomass significantly increased (p < 0.05), while root organic carbon content exhibited the opposite trend; (2) soil electrical conductivity (EC), soil total nitrogen (STN), soil total phosphorus (STP), and soil organic carbon (SOC) were significantly greater in the plastic film and nylon mesh separation treatments than in the no separation treatment (p < 0.05), and the abundance of Proteobacteria and Actinobacteriota was significantly greater in the plastic film separation treatment than in the no separation treatment (p < 0.05); (3) both plastic film and nylon mesh separations increased the secretion of alkaloids derived from tryptophan and phenylalanine in the plant root system compared with that in the no separation treatment; and (4) Pseudomonas, Proteobacteria, sesquiterpenes, triterpenes, and coumarins showed positive correlations, while both pseudomonas and proteobacteria were significantly positively correlated with soil EC, STN, STP, and SOC (p < 0.05). Aurachin D was negatively correlated with Gemmatimonadota and Proteobacteria, and both were significantly correlated with soil pH, EC, STN, STP, and SOC. The present study revealed strong negative interactions between the root systems of H. ammodendron seedlings, in which sesquiterpenoids, triterpenoids, coumarins, and alkaloids released by the roots played an important role in the subterranean competitive relationship. This study provides a deeper understanding of intraspecific interactions in the desert plant H. ammodendron and offers some guidance for future cultivation of this species in the northwestern region of China.

Water and nitrogen sources have always been the primary limiting factors for vegetation growth in arid and semi-arid regions and play an important role in the physiological ecology of vegetation. In this work, we studied the effects of water deficit and nitrogen addition on the physiological traits and rhizosphere bacterial microbial community of Haloxylon ammodendron seedlings in sterilized and non-sterilized soil habitats. A pot experiment was conducted to control the water and nitrogen sources of H. ammodendron seedlings. The water deficit treatment was divided into two groups based on gradient: a normal water group (CK, 70% field water holding capacity) and water deficit group (D, 30% field water holding capacity). The nitrogen addition treatment was divided into a no addition group (CK, 2.8 mg·kg−1) and addition group (N, 22.4 mg·kg−1). At the end of the growing season, the biochemical indexes of H. ammodendron seedlings were measured, and the rhizosphere soil was subjected to 16S rDNA-high-throughput sequencing to determine the rhizosphere bacterial community composition of H. ammodendron seedlings under different treatments. The results showed that the root-to-crown ratio of H. ammodendron seedlings increased significantly (p < 0.05) under the water deficit treatment compared to the control and nitrogen addition treatments, indicating that H. ammodendron seedlings preferred to allocate biological carbon to the lower part of the ground. In contrast, plant height and root length were significantly lower (p < 0.05) under water deficit treatment compared to the control, and no significant change was observed under water deficit and nitrogen addition compared to the control, indicating that water deficit inhibited the growth of H. ammodendron seedlings and nitrogen addition mitigated the effect of water deficit on the growth of H. ammodendron seedlings. Under sterilized soil conditions, both water deficit and nitrogen addition significantly increased the abundance and diversity of bacterial communities in H. ammodendron seedlings (p < 0.05). Conversely, under non-sterilized conditions, both inhibited the diversity of microbial bacterial communities, and the microbial characteristic species under different controls were different. Therefore, in the short-term experiment, H. ammodendron seedlings were affected by water deficit and allocated greater quantities of biomass to the underground part, especially in the non-sterile microbial environment; different initial soil conditions resulted in divergent responses of rhizosphere bacterial communities to water deficit and nitrogen addition. Under different initial soil conditions, the same water deficit and nitrogen addition treatment will lead to the development of distinct differences in rhizosphere bacterial community composition.

Tiller number is one of the key factors that influences rice plant type and yield components. In this study, an EMS-induced rice tiller suppression mutant ts1 was characterized. Morphological and histological observations revealed that, in the ts1 plants, the tiller buds were abnormally formed and therefore cannot outgrow into tillers. With an F2 population derived from a cross between ts1 and an indica cultivar Wushansimiao, a major gene, tiller suppression 1 (ts1) was fine-mapped to a 108.5 kb genomic region between markers ID8378 and SSR6884 on the short arm of rice chromosome 2. Candidate gene analysis identified nineteen putative genes. Among them, ORF4 (LOC_Os02g01610) is a PPR gene which harbored a point mutation c.+733/C→T in ts1 mutant plants. A co-dominant SNP marker cd-733C/T was subsequently developed and the SNP assay demonstrated that the point mutation co-segregated with tiller suppression phenotype. Quantitative RT-PCR analysis showed that the expression level of ORF4 in ts1 plants was significantly lower than that in their wild plants, and the expression of rice tillering regulators MOC1 and HTD1 was also significantly decreased in ts1 plants. Our data indicated that ORF4 was a strong candidate gene for ts1 and ts1 might play a role in regulating rice tillering through MOC1 and HTD1 associated pathway. The results above provide a basis for further functional characterization of ts1 and will shed light on molecular mechanism of rice tillering. The informative SNP marker cd-733C/T will facilitate marker-assisted selection of ts1 in rice plant type breeding.

In the face of water pollution, constructing a photocatalyst with high redox ability to remove organic pollutants is necessary. A novel Z-scheme Bi 12 O 15 Cl 6 /Ag 2 CO 3 heterojunction was successfully designed. Under LED light, the best sample 8% Bi 12 O 15 Cl 6 /Ag 2 CO 3 can remove 99.8% RhB and 79.8% TC within 90 min. The morphology, structure, electrochemical and optical performance of Bi 12 O 15 Cl 6 /Ag 2 CO 3 were detected by a series of characterization. The charge separation and transition efficiency were verified by electrochemical impedance spectroscopy (EIS) and photocurrent. The photodegradation pathway, intermediate product and active substances were measured by mass spectrometry (MS). During photocatalytic reactions, ·OH, ·O 2 − and h + are active substances, among which h + played an extremely important role. A Z-type photocatalytic reaction mechanism was produced based on the capture test. This study provides a new idea for the synthesis of Z-type hybrid structure for the degradation of organic pollutants.

Key message OsCactin positively regulates drought tolerance in rice. OsCactin is regulated by OsTRAB1 and interacts with OsDi19 proteins to defend against drought stress. Drought stress significantly limits plant growth and production. Cactin, a CactinC_cactus domain-containing protein encoded by a highly conserved single-copy gene prevalent across the eukaryotic kingdom, is known to play diverse roles in fundamental biological processes. However, its function in rice drought tolerance remains poorly understood. In this study, with its overexpression and knockout rice lines in both a pot drought experiment and a PEG drought-simulation test, OsCactin was found to positively regulate rice drought tolerance during the rice seedling stage. The OsCactin -overexpressing lines presented high tolerance to drought stress, whereas the OsCactin -knockout plants were sensitive to drought stress. OsCactin was localized in the nucleus, and was predominantly expressed in the leaves and panicles at the seedling and booting stages, respectively. Furthermore, OsTRAB1, a drought-responsive TF of the bZIP family, binds to the promoter of OsCactin as a drought-responsive regulator. OsDi19 proteins, the Cys2/His2 (C2H2)-type zinc finger TFs from the drought-induced 19 family, interact with OsCactin both in vitro and in vivo. Our results provide new insights into the intricate mechanisms by which OsCactin regulates the rice drought stress response, which may contribute to the design of molecular breeding methods for rice.

Ideal Plant Architecture 1 (IPA1) encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of IPA1 in early seedling development, we developed a pair of IPA1/ipal-NILs and found that seed germination and early seedling growth were retarded in the ipa1-NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the α-amylase genes revealed that the starch metabolism was weakened in the ipa1-NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the IPA1-NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene OsGA20ox1 was downregulated, whereas the expression of GA inactivation-related genes was upregulated in ipa1-NIL seeds. In addition, the expression of OsWRKY51 and OsWRKY71 was significantly upregulated in ipa1-NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of OsWRKY51 and OsWRKY71, which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of α-amylase genes. In summary, our results suggest that IPA1 negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and WRKY pathways.