Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice. In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice. The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase. Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type (WT) in response to natural storage or artificial aging treatments. The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species (ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination. Hydrogen peroxide (H₂O₂) treatments promoted the vigor of aged seeds in various rice varieties. Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.

The jasmonate ZIM-domain (JAZ) family of proteins serves as co-receptors and transcriptional repressors of jasmonic acid (JA) in plants. Their functional diversity and multiple roles make them important components of the regulatory network of JA and other hormonal signaling pathways. In this review, we provide an overview of the latest findings on JAZ family proteins and emphasize their roles in plant growth and development, and response to biotic and abiotic stress, along with their underlying mechanisms. Moreover, existing challenges and future applications are outlined with the aim of offering a reference for further research on JAZ proteins in the context of plant physiology.

Seed germination is a complex trait regulated by multiple genes in rice. However, the regulators of rice seed germination have yet to be sufficiently determined. Here, a quantitative trait locus (QTL) for rice seed germination was identified in a genome-wide association study. The candidate gene JASMONATE ZIM-DOMAIN 5 (OsJAZ5) of the QTL was verified that positively regulates seed germination. OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway. Overexpression of OsJAZ5 facilitated seed germination. The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding.

Poor seedling emergence is a challenge for direct seeding of rice under deep-sowing field conditions. Here we reveal that UDP-glucosyltransferase OsUGT75A promotes rice seedling emergence under deep-sowing conditions by increasing shoot length. Expression of OsUGT75A was higher in the middle regions of the shoot and in shoots under deep-sowing conditions. Levels of free abscisic acid (ABA) and jasmonates (JA) were higher in shoots of OsUGT75A mutants than in those of wild-type plants, and OsUGT75A mutants were more sensitive to ABA and JA treatments. Reduced shoot length was attributed to higher ABA INSENSITIVE 3 (OsABI3) expression and lower JASMONATE-ZIM domain protein (OsJAZ) expression in shoots. Shoot extension by OsUGT75A is achieved mainly by promotion of cell elongation. An elite haplotype of OsUGT75A associated with increased shoot length was identified among indica rice accessions. OsUGT75A acts to increase seedling emergence under deep-sowing conditions.