Upland rice varieties exhibit significant genetic diversity and broad environmental adaptability, making them ideal candidates for identifying consistently expressed stress-responsive genes. F-box proteins typically function as part of the SKP1-CUL1-F-box protein (SCF) ubiquitin ligase complexes to precisely regulate gene expression and protein level, playing essential roles in the modulation of abiotic stress responses. Therefore, utilizing upland rice varieties for screening stress-responsive F-box genes is a highly advantageous approach. Through mRNA-seq analysis in the Brazilian upland rice (cv. IAPAR9), the research identified 29 drought-responsive F-box genes. Gene distribution and duplication analysis revealed these genes are distributed on 11 of the 12 chromosomes and 10 collinear gene pairs were identified on different chromosomes. 13 cis-elements or binding sites were identified in the promoters of the 29 drought-responsive F-box genes by analysis. Protein domain, stability and subcellular localization analysis results suggest that these F-box proteins possess F-box domain and several other domains, and they are mostly unstable proteins with subcellular localization in cytoplasm, nucleus, chloroplasts, mitochondria and endoplasmic reticulum. Most of drought-responsive F-box genes exhibited expression in various tissues such as root, stem, leaf, leaf sheath and panicle except for OsFBO10 and OsFBX283. These genes exhibited various responses to abiotic stresses such as osmotic, cold, heat, and salt stresses, along with ABA treatment. Importantly, a frame-shift mutation in OsFBX148 was created in the ZH11 variety, leading to altered ABA signal transduction and ROS accumulation. The study further elucidated the interaction of OsFBX148 with SKP1 family proteins OSK4/7/17 to form the SCF complex, dependent on the F-box domain. The research identified and analyzed 29 drought-responsive F-box genes in upland rice and provides valuable insights into the role of OsFBX148 in ABA and ROS responses. It establishes a basis for future exploration of F-box genes in improving resistance to abiotic stresses, especially drought.

Background: ATP sulfurylase (ATPS) is a crucial enzyme for the selenate assimilation pathway in plants. Results: In this study, genome-wide and comparative analyses of ATPS in Cardamine hupingshanensis, including sequence and structural analyses, were performed. The expression of ChATPS gene family members in C. hupingshanensis under selenium (Se) stress was also investigated, and our results suggest that ChATPS1-2 play key roles in the response to Se stress. Nine ATPS genes were found from C. hupingshanensis, which share highly conserved sequences with ATPS from Arabidopsis thaliana. In addition, we performed molecular docking of ATP sulfurylase in complex with compounds ATP, selenate, selenite, sulfate, and sulfite. ChAPS3-1 was found to have stronger binding energies with all compounds tested. Among these complexes, amino acid residues Arg, Gly, Ser, Glu, and Asn were commonly present. Conclusion: Our study reveals the molecular mechanism of C. hupingshanensis ATP sulfurylase interacting with selenate, which is essential for understanding selenium assimilation. This information will guide further studies on the function of the ChATPS gene family in the selenium stress response and lay the foundation for the selenium metabolic pathway in higher plants.

Drought stress presents a significant challenge to rice production, affecting global food security. The protein degradation pathway is vital for regulating plant drought stress responses. Subtilisins, a family of serine proteases, are known to be involved in various stress responses in plants, yet their specific roles in drought tolerance are still not well understood in rice. In this study, we identified 13 out of 63 subtilisin genes in upland rice that respond to drought stress. Phylogenetic analysis classified these 13 genes and their homologs into nine distinct groups. Collinearity analysis indicated that subtilisin-encoding genes have undergone evolutionary gene duplication events, with a greater number of collinear gene pairs observed between rice and wheat compared to Arabidopsis and maize. Cis-element analysis revealed stress-related regulatory motifs in the promoters of these 13 genes. Furthermore, qRT-PCR results demonstrated their responsiveness to multiple abiotic stresses, with OsSub14 exhibiting pronounced upregulation under various stress conditions. To investigate its function, we generated rice mutant plants with an OsSub14 frameshift mutation. Phenotypic characterization revealed increased sensitivity of Ossub14 mutant to ABA and elevated ROS accumulation under external stimuli, suggesting its crucial role in regulating ABA signaling and ROS content. The study identified and characterized 13 subtilisin genes in upland rice that respond to drought, offering important insights into the role of OsSub14 in the regulation of ABA response and ROS accumulation. The findings lay a foundation for further investigation into the molecular mechanisms of subtilisin-mediated stress responses in rice.

Cardamine hupingshanensis is a novel selenium (Se) hyperaccumulator within the Brassicaceae family, yet the genomic basis of its stress adaptation remains

Background: The Calcineurin B-like (CBL) and CBL-interacting protein kinase (CIPK) system constitute critical signaling modules mediating plant responses to abiotic stress. Although these families have been studied across various species, their evolutionary dynamics across grasses and the functional plasticity of specific isoforms remain elusive. Methods: A genome-wide analysis of CBL and CIPK families was conducted across five major Poaceae species (Oryza sativa, Triticum aestivum, Zea mays, Sorghum bicolor, and Saccharum spontaneum). Phylogenetic and synteny analyses were analyzed to family expansion and evolution. Cis-regulatory elements analysis in gene promoter regions were examined to predict potential stress-responsive features. Expression profiles of OsCBL and OsCIPK gene families were examined by qRT-PCR under conditions involving PEG-induced osmotic stress, pathogen strain P6 inoculation, and exogenous application of the phytohormones abscisic acid (ABA) and methyl jasmonate (MeJA). Protein–protein interactions between selected CBL (OsCBL4) and CIPK pairs were assessed via Yeast Two-Hybrid (Y2H) and Luciferase Complementation Imaging assays (LCI). Results: Phylogenetic and synteny analyses indicated that segmental duplications have contributed substantially to the expansion of these gene families. Promoter analysis revealed that the majority of CBL and CIPK family members, exemplified by OsCBL4, traditionally characterized as a salt sensor, possesses a cis-element architecture (rich in ABREs and MBS) heavily biased towards dehydration responsiveness. Expression profiling showed that OsCBL4 is significantly hyper-induced by direct osmotic stress (PEG) but exhibits almost no response to exogenous ABA. A subset of kinases genes (e.g., OsCIPK2, 9, 18) displayed PEG-induced expression patterns resembling those of OsCBL4, whereas OsCIPK30 remained transcriptionally unresponsive under the same conditions. Protein interaction assays demonstrated that OsCBL4 physically interacts exclusively with PEG-responsive transcriptionally activated kinases such as OsCIPK9, but failed to interact with the non-responsive OsCIPK30. Conclusions: Our study provides a genomic characterization of CBL and CIPK families across five major Poaceae species. The combined expression and interaction data reveal that OsCBL4-assembles with specific CIPKs into signaling modules during osmotic stress responses in rice, pointing to roles that go beyond salt stress responses. The findings establish a foundation for further functional dissection of CBL-CIPK pathway diversification in abiotic stress adaptation.

Multi-walled carbon nanotubes (MWCNTs) can modulate plant growth and development, but the signaling mechanisms underlying their effects on organogenesis remain unclear. Here, we found that MWCNTs promote adventitious root (AR) formation and that RBOH-dependent hydrogen peroxide (H₂O₂) production plays a key role in this process in cucumber (Cucumis sativus L.) and Arabidopsis thaliana. MWCNTs treatment promoted AR formation in cucumber hypocotyls. Concomitantly, endogenous H₂O₂ levels increased rapidly, along with enhanced CsRBOHD expression and NADPH oxidase activity, suggesting activation of an RBOH-dependent H₂O₂ response. Consistent with this, scavenging H₂O₂ or inhibiting NADPH oxidase markedly reduced MWCNTs-induced rooting, whereas exogenous H₂O₂ partially restored AR formation under NADPH oxidase inhibition. Genetic evidence further supported this relationship, as Atrbohd and Atrbohf mutants showed reduced responses to MWCNTs but remained responsive to exogenous H₂O₂, suggesting that RBOH-mediated H₂O₂ generation is a critical step in MWCNTs-induced adventitious rooting. In parallel, MWCNTs and H₂O₂ treatments enhanced the expression of genes associated with adventitious root development. Together, these findings support a model in which MWCNTs promote adventitious rooting through RBOH-dependent H₂O₂ signaling, providing new insight into nanomaterial-mediated regulation of plant development.