A J-Protein OsDjC46 Interacts with ZFP36 to Participate in ABA-Mediated Antioxidant Defense in Rice

Coexpression Regulation of New and Ancient Genes in the Dynamic Transcriptome Landscape of Stem and Rhizome Development in "Bainianzhe"-An Ancient Chinese Sugarcane Variety Ratooned for Nearly 300 Years

The sucrose yield in sugarcane largely depends on stem morphology, including length, diameter and sugar content, making sugarcane stem a key trait in breeding. The "Bainianzhe" variety from Songxi County, Fujian Province, possesses both aerial stems and rhizomes, providing a unique model for studying stem development. We performed a spatiotemporal transcriptomic analysis of the base, middle and apical sections of both aerial stems and rhizomes. The analysis categorized transcriptomes by developmental stage-base, middle and apical-rather than environmental differences. Apical segments were enriched with genes related to cell proliferation, while base segments were linked to senescence and fibrosis. Gene regulatory networks revealed key TFs involved in stem development. Orphan genes may be involved in rhizome development through coexpression networks. Plant hormones, especially genes involved in ABA and GAs synthesis, were highly expressed in rhizomes. Thiamine-related genes were also more prevalent in rhizomes. Furthermore, the apical segments of rhizomes enriched in photosynthesis-related genes suggest adaptations to light exposure. Low average temperatures in Songxi have led to unique cold acclimation in Bainianzhe, with rhizomes showing higher expression of genes linked to unsaturated fatty acid synthesis and cold-responsive calcium signalling. This indicates that rhizomes may have enhanced cold tolerance, aiding in the plant's overwintering success.

Physiological and Molecular Mechanisms of Rice Tolerance to Salt and Drought Stress: Advances and Future Directions

Rice, a globally important food crop, faces significant challenges due to salt and drought stress. These abiotic stresses severely impact rice growth and yield, manifesting as reduced plant height, decreased tillering, reduced biomass, and poor leaf development. Recent advances in molecular biology and genomics have uncovered key physiological and molecular mechanisms that rice employs to cope with these stresses, including osmotic regulation, ion balance, antioxidant responses, signal transduction, and gene expression regulation. Transcription factors such as DREB, NAC, and bZIP, as well as plant hormones like ABA and GA, have been identified as crucial regulators. Utilizing CRISPR/Cas9 technology for gene editing holds promise for significantly enhancing rice stress tolerance. Future research should integrate multi-omics approaches and smart agriculture technologies to develop rice varieties with enhanced stress resistance, ensuring food security and sustainable agriculture in the face of global environmental changes.

The transcription factor HBF1 directly activates expression of multiple flowering time repressors to delay rice flowering

Flowering time (or heading date) is an important agronomic trait that determines the environmental adaptability and yield of many crops, including rice (Oryza sativa L.). Hd3a BINDING REPRESSOR FACTOR 1 (HBF1), a basic leucine zipper transcription factor, delays flowering by decreasing the expression of Early heading date 1 (Ehd1), Heading date 3a (Hd3a), and RICE FLOWERING LOCUS T 1 (RFT1), but the underlying molecular mechanisms have not been fully elucidated. Here, we employed the hybrid transcriptional factor (HTF) strategy to enhance the transcriptional activity of HBF1 by fusing it to four copies of the activation domain from Herpes simplex virus VP16. We discovered that transgenic rice lines overexpressing HBF1-VP64 (HBF1V) show significant delays in time to flower, compared to lines overexpressing HBF1-MYC or wild-type plants, via the Ehd1-Hd3a/RFT1 pathway, under both long-day and short-day conditions. Transcriptome deep sequencing analysis indicated that 19 WRKY family genes are upregulated in the HBF1V overexpression line. We demonstrate that the previously unknown gene, OsWRKY64, is a direct downstream target of HBF1 and represses flowering in rice, whereas three known flowering repressor genes, Days to heading 7 (DTH7), CONSTANS 3 (OsCO3), and OsWRKY104, are also direct target genes of HBF1 in flowering regulation. Taking these results together, we propose detailed molecular mechanisms by which HBF1 regulates the time to flower in rice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42994-023-00107-7.