Rice Science最新文献

Biological nitrification inhibitors (BNIs) are released from plant roots and inhibit the nitrification activity of microorganisms in soils, reducing NO₃^‒ leaching and N₂O emissions, and increasing nitrogen- use efficiency (NUE). Several recent studies have focused on the identification of new BNIs, yet little is known about the genetic loci that govern their biosynthesis and secretion. We applied a combined transcriptomic and metabolomic analysis to investigate possible biosynthetic pathways and transporters involved in the biosynthesis and release of BNI 1,9-decanediol (1,9-D), which was previously identified in rice root exudates. Our results linked four fatty acids, icosapentaenoic acid, linoleate, norlinolenic acid, and polyhydroxy-α,ω-divarboxylic acid, with 1,9-D biosynthesis and three transporter families, namely the ATP-binding cassette protein family, the multidrug and toxic compound extrusion family, and the major facilitator superfamily, with 1,9-D release from roots into the soil medium. Our finding provided candidates for further work on the genes implicated in the biosynthesis and secretion of 1,9-D and pinpoint genetic loci for crop breeding to improve NUE by enhancing 1,9-D secretion, with the potential to reduce NO₃^‒ leaching and N₂O emissions from agricultural soils.

As the ‘Green Revolution’ gene, SD1 (encoding GA20ox2), has been widely applied to improve yield in rice breeding. However, research on its transcriptional regulation is limited. Here, we identified a transcription factor OsbZIP01, which can suppress the expression of SD1 and regulate gibberellin (GA) biosynthesis in rice. Knockout mutants of OsbZIP01 exhibited increased plant height, while the over- expression lines showed a semi-dwarf phenotype and diminished germination rate. Furthermore, the semi-dwarf phenotype of OE-bZIP01, was caused by the reduced internode length, which was accompanied by a thin stem width. The predominant expression of OsbZIP01 was observed in leaves and sheaths. OsbZIP01 protein was localized in the nucleus and showed transcriptional repression activity. In addition, OsbZIP01 could directly bind to the promoter of the OsSD1 gene, and inhibit its transcription. The semi-dwarf phenotype of OE-bZIP01 could be rescued by exogenous GA₃. Meanwhile, the bzip01 sd1 double mutant showed a shorter shoot length compared with the wild type, indicating that OsbZIP01 regulated plant growth mainly through the GA biosynthesis pathway. Collectively, OsbZIP01 negatively regulates GA biosynthesis by restraining SD1 transcription, thereby affecting plant growth and development.

Clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)-mediated genome editing has greatly accelerated progress in plant genetic research and agricultural breeding by enabling targeted genomic modifications. Moreover, the prime editing system, derived from the CRISPR/Cas system, has opened the door for even more precise genome editing. Prime editing has the capability to facilitate all 12 types of base-to-base conversions, as well as desired insertions or deletions of fragments, without inducing double-strand breaks and requiring donor DNA templet. In a short time, prime editing has been rapidly verified as functional in various plants, and can be used in plant genome functional analysis as well as precision breeding of crops. In this review, we summarize the emergence and development of prime editing, highlight recent advances in improving its efficiency in plants, introduce the current applications of prime editing in plants, and look forward to future prospects for utilizing prime editing in genetic improvement and precision molecular breeding.

Global warming poses a threat to rice production. Breeding heat-tolerant rice is an effective and economical approach to address this challenge. African rice is a valuable genetic resource for developing heat-tolerant crops due to its intricate mechanism for adapting to high temperatures. Oryza longistaminata, a widely distributed wild rice species in Africa, may harbor an even richer gene pool for heat tolerance, which remains untapped. In this study, we identified three heat tolerance QTLs from O. longistaminata at the seedling stage, including novel heat tolerance loci qTT4 and qTT5. Our findings demonstrated that the O. longistaminata alleles for these two QTLs can enhance the heat tolerance of rice seedlings. Remarkably, qTT5 was mapped to a region spanning approximately 287.2 kb, which contains 46 expressing genes. Through the analysis of Gene Ontology and expression differences under heat induction, we identified four candidate genes. Our results lay the foundation for discovering heat tolerance genes underlying O. longistaminata and developing new genetic resources for heat-tolerant rice breeding.

Phosphorus (P) deficiency limits the growth, development, and productivity of rice. To better understand the underlying mechanisms in P-deficiency tolerance and the role of Pup1 QTL in enhancing P use efficiency (PUE) for the development of P-efficient rice cultivars, a pair of contrasting rice genotypes (Pusa-44 and NIL-23) was applied to investigate the morpho-physio-biochemical and proteomic variation under P-starvation stress. The rice genotypes were grown hydroponically in a PusaRich medium with adequate P (16 mg/kg, +P) or without P (0 mg/kg, -P) for 30 d. P-starvation manifested a significant reductions in root and shoot biomass, shoot length, leaf area, total chlorophyll, and P, nitrogen and starch contents, as well as protein kinase activity. The stress increased root-to-shoot biomass ratio, root length, sucrose content, and acid phosphatase activity, particularly in the P-tolerant genotype (NIL-23). Comparative proteome analysis revealed several P metabolism-associated proteins (including OsCDPKs, OsMAPKs, OsCPKs, OsLecRK2, and OsSAPks) to be expressed in the shoot of NIL-23, indicating that multiple protein kinases were involved in P-starvation/deficiency tolerance. Moreover, the up-regulated expression of OsrbcL, OsABCG32, OsSUS5, OsPolI-like B, and ClpC2 proteins in the shoot, and OsACA9, OsACA8, OsSPS2F, OsPP2C15, and OsBiP3 in the root of NIL-23, indicated their role in P-starvation stress control through the Pup1 QTL. Thus, our findings indicated that -P stress-responsive proteins, in conjunction with morpho-physio-biochemical modulations, improved PUE and made NIL-23 a P-deficiency tolerant genotype due to the introgression of the Pup1 QTL in the Pusa-44 background.

Germplasm resource innovation is a crucial factor for cultivar development, particularly within the context of hybrid rice breeding based on the three-line system. Quan 9311A, a cytoplasmic male sterile (CMS) line, has been successfully cultivated using rice restoration materials and extensively employed as a female parent in hybrid breeding program in China. This line was developed by crossing the CMS line Zhong 9A with a two-line restorer line 93-11, with the intention of eliminating the restoring ability of 93-11 while retaining the sterility gene WA352c from Zhong 9A. Quan 9311A effectively amalgamates the most favorable agronomic traits from both parental lines. In this study, the relationship between phenotypic characteristics and the known functional genes of Quan 9311A were analyzed using the rice genome navigation technology based on whole-genome sequencing. The findings revealed that Quan 9311A harbors multiple superior alleles from both 93-11 and Zhong 9A, providing exceptional agronomic traits that are unavailable in earlier CMS lines. Despite the removal of the fertility restorer gene Rf3 from 93-11, numerous chromosomal segments from 93-11 persist in the Quan 9311A genome. Furthermore, the hybrid rice Quanyousimiao (QYSM) and the restorer line Wushansimiao (WSSM) were used as examples to illustrate the important role of Quan 9311A as the female parent in heterosis. It was found that QYSM carries a great number of superior alleles, which accounts for its high grain yield and wide adaptability. These insights not only advanced the utilization of hybrid rice pairing groups but also provided guidance for future breeding endeavors. The study introduced innovative concepts to further integrate genomics with traditional breeding techniques. Ultimately, Quan 9311A signified a significant milestone in rice breeding technology, opening up novel avenues for hybrid rice development.

Apolipoprotein A-I_Milano (ApoA-I_M) has been shown to significantly reduce coronary atherosclerotic plaques. However, the preparation of cost-effective pharmaceutical formulations of ApoA-I_M is limited by the high cost and difficulty of purifying the protein and producing the highly effective dimeric form. The aim of this study was to create an expression cassette that specifically drives the expression of dimeric ApoA-I_M in the protein bodies of rice seeds. The ApoA-I_M protein under control of the 13 kDa prolamin promoter is expressed exclusively in its dimeric form within the seeds, and immunocytochemical and immunogold analyses confirmed its expression in different caryopsis tissue such as seed coat, aleurone cell and endosperm, particularly in amyloplast and storage vacuoles. A plant-based ApoA-I_M production system offered numerous advantages over current production systems, including the direct production of the most therapeutically effective dimeric ApoA-I_M forms, long-term protein storage in seeds, and ease of protein production by simply growing plants. Therefore, seeds had the potential to serve as a cost-effective source of therapeutic ApoA-I_M.

The present study aimed to investigate the hypolipidemic, antioxidant and cardiac risk-suppressing effects of Chakhao poireiton (CP), a GI-tagged pigmented black rice from India. In vitro and ex vivo studies confirmed that whole rice extracts of CP have potent antioxidant, 3-hydroxy-3- methylglutaryl-CoA reductase, cholesterol esterase inhibitory, and antilipase effects. An in vivo study was conducted to evaluate the effects of the ethanol extracts of CP on high-fat high-sugar induced hyperlipidemic rats. The ethanol extract significantly ameliorated lipid parameters and liver enzymes to normal. Levels of lactate dehydrogenase, creatine kinase-N-acetyl cysteine, C-reactive protein, and lipoprotein a were significantly lower in the extract-treated groups than those in the disease control group. A marked reduction of ApoB/ApoA1 and other atherogenic indices were observed in extract-treated groups. Twelve phenolic compounds, i.e. rosamarinic acid, gallic acid, protocatechuic acid etc., were quantified in CP. This study provided the first evidence of the antihyperlipidemic and cardiac risk inhibitory effects of CP, which would be beneficial in preventing and managing hyperlipidemia, associated oxidative stress, and cardiac complications.