Maintaining a low sodium (Na+) concentration in shoots is a key determinant of salt tolerance in cereal crops. This process is largely mediated by Na+ transporters such as HKT1;5, which controls long-distance Na+ transport; however, the molecular mechanisms governing the transcriptional regulation of HKT1;5 under salt stress remain poorly understood. Here, we identify the rice transcription factor OsNAC10 and characterize its role as a transcriptional repressor of the high-affinity K+ transporter gene OsHKT1;5 under salt stress. OsNAC10 expression is predominantly root-localized and is rapidly downregulated in response to salt treatment. OsNAC10 knockout mutants exhibit enhanced salt tolerance, reduced shoot Na+ accumulation, and decreased root-to-shoot Na+ transport, whereas overexpression lines show increased Na+ accumulation and pronounced salt sensitivity. Subcellular localization and molecular interaction analyses reveal that OsNAC10 is a nuclear-localized transcription factor that directly and competitively binds to an ACGTA-core cis element within the OsHKT1;5 promoter. Consequently, OsHKT1;5 expression is markedly upregulated in nac10 mutants under salt stress. Genetic analysis further demonstrates that the enhanced salt tolerance of the nac10 mutant depends on OsHKT1;5, as the nac10 hkt1;5 double mutant exhibits a salt-sensitive phenotype comparable to that of the hkt1;5 single mutant. Importantly, under saline soil conditions, OsNAC10 knockout lines maintain significantly higher grain yield than wild-type plants. Together, these findings uncover a novel transcriptional regulatory mechanism in which OsNAC10 negatively modulates rice salt tolerance by competitively inhibiting OsHKT1;5 expression, highlighting OsNAC10 as a promising target for breeding salt-tolerant crops.
The decreasing abundance of insect species is a common phenomenon of the present era. To detect the change in species abundance, it is essential to have a sufficiently long time series over which the change can be detected. We examined the time series of the abundance of 110 moth species using annual captures in a light trap operated nightly from April to November of 1967-1995. For each species, the time series was fitted by a state-space model allowing for a time-varying slope (ie for a locally linear trend with the slope allowed to change over time). We then determined the position in time and the length of the period when the estimate of the slope became significant. No significant change in abundance was detected for 65 species. Significant negative trends were established in 29 species; at first after 17 yr from the beginning of the study, significant positive trends were established in 16 species, with the earliest trend being detected after 15 yr. The trends were either transient or remained significant for the duration of the study (and possibly longer), demonstrating that the state-space modelling approach is suitable for detecting long-term changes in species abundance. The time series needed to be long (≥15 yr) to detect significant trends in abundance.
The heading date is an important trait that affects crop adaptability and significantly affects crop yield. The discovery and functional understanding of genes related to heading are crucial for wheat breeding in various environments. Aegilops tauschii, the D-genome donor of wheat, serves as an important model for exploring genetic regulatory mechanisms in common wheat. In this study, extremely early heading mutants were identified after treatment with 0.4% ethyl methanesulfonate (EMS) and compared with the wild type. Genetic analysis revealed that a single recessive gene was responsible for early heading, and gene mapping revealed a mutation in a 10.3-Mb region on the short arm of chromosome 6D. Bulked segregant exon capture sequencing revealed a missense mutation within the highly conserved nucleotide-binding domain of AET6Gv20469900, which encodes a protein phosphatase 2C (PP2C). This gene was in the mapping interval and associated with early heading. Transcriptomic profiling and quantitative validation analyses suggest that PP2C likely modulates vernalization pathways, thereby affecting heading date. This work provides a novel genetic resource for breeding early heading wheat cultivars.
Brassinosteroids (BRs) are essential steroid hormones that coordinate plant growth, development and adaptation to changing environments. Although BR signaling has long been viewed primarily as a phosphorylation-dependent pathway, increasing evidence shows that ubiquitination provides an additional regulatory layer that shapes the abundance, activity, subcellular distribution and turnover of key signaling components. Ubiquitin-mediated regulation operates at multiple points in the BR pathway, including receptor homeostasis at the plasma membrane, turnover of GSK3-like kinases, and stability control of the transcription factors BES1/BZR1. These processes determine not only the strength and duration of BR signaling but also its coordination with other hormonal and stress-response pathways. In this review, we discuss recent advances in ubiquitin-mediated regulation of BR signaling, focusing on receptor-level control, proteolytic regulation of core signaling components, and modulation of transcriptional outputs. We also highlight emerging links between ubiquitination, selective autophagy, deubiquitination and BR-associated stress responses and outline key questions concerning ubiquitin chain specificity, substrate recognition and conservation of these regulatory modules in crops. Defining how ubiquitination fine-tunes BR signaling will deepen our understanding of plant steroid hormone regulation and may provide new strategies for optimizing crop architecture, productivity, and stress resilience.
As global temperatures rise, soil warming is emerging as a critical factor influencing maize productivity. However, the impacts on root function and nitrogen utilization remain insufficiently understood. To investigate these effects, a pot experiment was conducted in an environment-controlled greenhouse during the late vegetative stage under three soil temperature regimes: 28 °C, 33 °C, and 38 °C. 15N-labeled urea was applied to trace nitrogen dynamics. Results showed that elevated soil temperature markedly altered root morphology and microstructure. Root length and surface area decreased, while cortical lacunae proportion increased significantly, particularly at 38 °C. These structural changes were accompanied by lower root activity, reduced stomatal conductance and transpiration, and a 46.97-60.44% decrease in 15N uptake rate. The decline in nitrogen uptake rate reduced total nitrogen content in vegetative organs, whereas nitrogen content in grain remained relatively stable, indicating enhanced internal nitrogen remobilization. However, under 38 °C, this compensatory effect was not sufficient to prevent accelerated leaf senescence, which caused a 3.96% reduction in kernel weight, and a 34.52% decline in grain yield. Overall, these results showed that soil warming disrupted nitrogen uptake, allocation, and utilization in maize, and that 38 °C soil warming exceeded the capacity of the plant to maintain coordinated nitrogen supply during grain filling. These findings provide a physiological basis for developing management strategies to mitigate the adverse effects of soil warming on maize productivity.
