Rice (Oryza sativa L.), as one of the most significant food crops worldwide, holds paramount importance for global food security. Throughout its extensive evolutionary journey, rice has evolved a diverse array of defense mechanisms to fend off pest and disease infestations. Notably, labdane-related diterpenoid phytoalexins play a crucial role in aiding rice in its response to both biotic and abiotic stresses. This article provides a comprehensive review of the research advancements pertaining to the chemical structures, biological activities, and biosynthetic pathways, as well as the molecular regulatory mechanisms, underlying labdane-related diterpenoid phytoalexins discovered in rice. This insight into the molecular regulation of labdane-related diterpenoid phytoalexin biosynthesis offers valuable perspectives for future research aimed at improving crop resilience and productivity.

Heat stress has emerged as a significant abiotic constraint affecting rice yield and grain quality. In recent years, substantial advancements have been achieved in elucidating molecular regulatory mechanisms and breeding applications pertinent to rice heat tolerance. This review offers a comprehensive examination of the fundamental regulatory pathways involved in rice responses to heat stress, encompassing membrane lipid homeostasis, heat signal transduction, transcriptional regulation, RNA stability and translation, epigenetic modifications, hormone signaling, antioxidant defense, and the protection of reproductive organs. Particular emphasis is placed on the functional mechanisms and breeding potential of pivotal thermotolerance-associated genes and quantitative trait loci (QTLs), such as TT1, TT3, and QT12. Additionally, we summarize recent applications of cutting-edge technologies in the enhancement of heat-tolerant rice varieties, including multi-omics integration, CRISPR/Cas9 genome editing, marker-assisted selection (MAS), and rational design breeding. Finally, we address current challenges, including integrating regulatory mechanisms, developing realistic heat simulation systems, validating the functionality of candidate genes, and managing trait trade-offs. This review provides a theoretical foundation for developing heat-tolerant rice cultivars and offers valuable insights to accelerate the breeding of climate-resilient rice varieties for sustainable production.

Black rice (Oryza sativa L.), valued for its nutritional benefits, was investigated to elucidate metabolite profiles and antioxidant capacity differences between waxy and non-waxy varieties. Eight black rice varieties sourced from diverse Chinese provinces were categorized based on amylose content. Non-waxy varieties demonstrated significantly superior antioxidant capacity, evidenced by elevated levels of DPPH and ABTS radical-scavenging activities, FRAP values, total polyphenol content, and α-glucosidase inhibitory activity. Utilizing UPLC-MS/MS, a total of 1130 secondary metabolites were identified, with flavonoids and phenolic acids constituting prominent classes. Multivariate analysis revealed distinct metabolite profile differences between the waxy and non-waxy groups, particularly in associated metabolic and genetic pathways. The enhanced antioxidant capacity and α-glucosidase inhibitory activity were strongly associated with differential metabolites, notably flavonoids. These findings underscore the potential of non-waxy black rice bran components, particularly flavonoid-rich fractions, for development in functional food applications. .

Successfully breeding high-yield, lodging-resistant hybrid rice varieties is critical for ensuring food security. Two-line hybrid rice system plays an essential role in rice breeding, and 1892S, an important two-line sterile line, has contributed significantly to the development of over 100 hybrid rice varieties with superior agronomic traits, including lodging resistance. Despite its importance, a comprehensive understanding of the genomic basis underlying these traits in 1892S has been lacking due to the limitations of short-read sequencing technologies. To address this gap, we utilized advanced telomere-to-telomere (T2T) genome assembly techniques to generate a high-quality, gap-free genome of 1892S—the final genome comprises 12 complete chromosomes with 40,560 protein-coding genes. Comparative genomic analysis identified multiple known lodging resistance genes, including SD1, Sdt97, SBI, OsFBA2, APO1, and OsTB1, with unique allelic variations that may enhance resistance. The pan-genome analysis identified 2347 strain-specific genes in 1892S, further supporting its unique genetic advantages. This study represents the complete T2T genome assembly of a two-line sterile line and provides novel insights into the genetic foundation of lodging resistance in hybrid rice. This study highlights the genetic potential of 1892S in hybrid rice breeding and provides a model for the genomic analysis of other two-line sterile lines, offering valuable insights for improving in hybrid rice, including traits lodging resistance, yield stability, and adaptability, which are crucial for global food security.

Hybrid rice has revolutionized food security by leveraging heterosis, a phenomenon where offspring outperform their parents. Sterile lines, crucial for controlled cross-pollination in hybrid breeding, have played a central role in this success. This study delves into the superior alleles of 1892S, a two-line sterile rice line widely used as a female parent in central China. By integrating extensive hybridization data, high-throughput genome sequencing, and bioinformatic analysis (RiceNavi), we elucidate the genetic underpinnings of 1892S’s exceptional adaptability. The results reveal its remarkable compatibility as a female parent in over 114 hybrid varieties, potentially due to the influence of Japonica characteristics contributing to strong hybrid vigor. Furthermore, some favorable alleles were identified that were associated with lodging resistance, high yield potential, and improved nitrogen use efficiency etc. The comprehensive characterization of 1892S provides valuable insights for future hybrid rice breeding programs, ultimately facilitating the development of superior rice varieties.