Rice Science最新文献

Rice cooking and eating qualities (CEQ) are mainly determined by cooked rice textural parameters and starch physicochemical properties. However, the genetic bases of grain texture and starch properties in rice have not been fully understood. We conducted a genome-wide association study for apparent amylose content (AAC), starch pasting viscosities, and cooked rice textural parameters using 279 indica rice accessions from the 3 000 Rice Genome Project. We identified 26 QTLs in the whole population and detected single nucleotide polymorphisms (SNPs) with the lowest P-value at the Waxy (Wx) locus for all traits except pasting temperature and cohesiveness. Additionally, we detected significant SNPs at the SUBSTANDARD STARCH GRAIN6 (SSG6) locus for AAC, setback (SB), hardness, adhesiveness, chewiness (CHEW), gumminess (GUM), and resilience. We subsequently divided the population using a SNP adjacent to the Waxy locus, and identified 23 QTLs and 12 QTLs in two sub-panels, Wx^T and Wx^A, respectively. In these sub-panels, SSG6 was also identified to be associated with pasting parameters, including peak viscosity, hot paste viscosity, cold paste viscosity, and consistency viscosity. Furthermore, a candidate gene encoding monosaccharide transporter 5 (OsMST5) was identified to be associated with AAC, breakdown, SB, CHEW, and GUM. In total, 39 QTLs were co-localized with known genes or previously reported QTLs. These identified genes and QTLs provide valuable information for genetic manipulation to improve rice CEQ.

Glutinous rice (Oryza sativa var. glutinosa) stands out as one of the most popular rice varieties globally, amidst thousands of rice cultivars. Its increasing popularity is attributed to its rich nutritional compositions and health benefits. This review aims to summarize the nutritional compositions, volatile compounds, and health benefits of glutinous rice. Further, in-depth studies are necessary to explore the utilization of glutinous rice in enhancing processing technologies and developing new food products. Glutinous rice has been shown to possess numerous health benefits, including antioxidant activity, bioactive compounds, anti-cancer properties, anti-inflammatory effects, anti-diabetic potential, and cholesterol-lowering effects. Besides its nutritional compositions, the major volatile compounds identified in glutinous rice could serve as a functional food for human consumption. Emerging processing technologies related to glutinous rice are elaborated to improve the latest developments for incorporating them into various food products.

This study aims to investigate grain quality and nutritional values of rice (Pokkali, a salt-tolerant cultivar; RD73, a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali, and KDML105, a moderately salt-susceptible cultivar) grown under non-saline (0.04–0.87 dS/m) and slightly saline (1.08–4.83 dS/m) field conditions. The results revealed that salinity caused significant reduction in grain size but significant increments in reducing sugar and total protein contents in the grains. Nevertheless, the amounts of starch in the grains of KDML105 and Pokkali rice genotypes were unaffected by the stress. The starch granule size distribution was also unaffected by salinity. Interestingly, only starch from Pokkali was significantly diminished in amylose content, from 19.18% to 16.99%. Accordingly, parameters relating to starch gelatinization, retrogradation, and pasting properties of KDML105 and RD73 were unaffected by salinity; only Pokkali showed a significant increase in percentage of retrogradation along with a significant reduction in gelatinization enthalpy. In the saline field, total phenolic content and antioxidant capacity in the grains of all rice cultivars tended to increase, particularly in Pokkali. On average, essential element contents in grains from the saline-treated plants showed a 33%, 32%, 32%, 22%, 20%, 11%, and 10% increase in total P, N, K, Mg, Zn, Fe, and Ca content, respectively. Interestingly, total Fe content exhibited the greatest percentage of increments in KDML105 (187%). Taken together, cultivation of rice in the slightly saline field did not alter its eating and cooking qualities, while enhanced some nutritional properties such as proteins, minerals, and secondary metabolites like phenolic compounds.

The basic region/leucine zipper (bZIP) transcription factors play important roles in plant development and responses to abiotic and biotic stresses. OsbZIP53 regulates resistance to Magnaporthe oryzae in rice by analyzing APIP5-RNAi transgenic plants. To further investigate the biological functions of OsbZIP53, we generated osbzip53 mutants using CRISPR/Cas9 editing and also constructed OsbZIP53 over-expression transgenic plants. Comprehensive analysis of phenotypical, physiological, and transcriptional data showed that knocking-out OsbZIP53 not only improved disease resistance by inducing a hypersensitivity response in plants, but also regulated the immune response through the salicylic acid pathway. Specifically, disrupting OsbZIP53 increased H₂O₂ accumulation by promoting reactive oxygen species generation through up-regulation of several respiratory burst oxidase homologs (Osrboh genes) and weakened H₂O₂ degradation by directly targeting OsMYBS1. In addition, the growth of osbzip53 mutants was seriously impaired, while OsbZIP53 over-expression lines displayed a similar phenotype to the wild type, suggesting that OsbZIP53 has a balancing effect on rice immune response and growth.

Rice (Oryza sativa L.) stands as the most significantly influential food crop in the developing world, with its total production and yield stability affected by environmental stress. Drought stress impacts about 45% of the world’s rice area, affecting plants at molecular, biochemical, physiological, and phenotypic levels. The conventional breeding method, predominantly employing single pedigree selection, has been widely utilized in breeding numerous drought-tolerant rice varieties since the Green Revolution. With rapid progress in plant molecular biology, hundreds of drought-tolerant QTLs/genes have been identified and tested in rice crops under both indoor and field conditions. Several genes have been introgressed into elite germplasm to develop commercially accepted drought-tolerant varieties, resulting in the development of several drought-tolerant rice varieties through marker-assisted selection and genetically engineered approaches. This review provides up-to-date information on proof-of-concept genes and breeding methods in the molecular breeding era, offering guidance for rice breeders to develop drought-tolerant rice varieties.

The rice false smut disease, caused by Ustilaginoidea virens, has emerged as a significant global threat to rice production. The mechanism of carbon catabolite repression plays a crucial role in the efficient utilization of carbon nutrients and enzyme regulation in the presence of complex nutritional conditions. Although significant progress has been made in understanding carbon catabolite repression in fungi such as Aspergillus nidulans and Magnaporthe oryzae, its role in U. virens remains unclear. To address this knowledge gap, we identified UvCreA, a pivotal component of carbon catabolite repression, in U. virens. Our investigation revealed that UvCreA localized to the nucleus. Deletion of UvCreA resulted in decreased growth and pathogenicity in U. virens. Through RNA-seq analysis, it was found that the knockout of UvCreA led to the up-regulation of 514 genes and down-regulation of 640 genes. Moreover, UvCreA was found to be involved in the transcriptional regulation of pathogenic genes and genes associated with carbon metabolism in U. virens. In summary, our findings indicated that UvCreA is important in fungal development, virulence, and the utilization of carbon sources through transcriptional regulation, thus making it a critical element of carbon catabolite repression.

Cadmium (Cd) contamination in rice has been a serious threat to human health. To investigate the effects of arbuscular mycorrhizal fungi (AMF) on the Cd translocation in rice, a controlled pot experiment was conducted. The results indicated that AMF significantly increased rice biomass, with an increase of up to 40.0%, particularly in root biomass by up to 68.4%. Notably, the number of prominent rice individuals also increased, and their plasticity was enhanced following AMF inoculation. AMF led to an increase in the net photosynthetic rate and antioxidant enzyme activity of rice. In the AMF treatment group, the Cd concentration in the rice roots was significantly higher (19.1%‒68.0%) compared with that in the control group. Conversely, the Cd concentration in the rice seeds was lower in the AMF treatment group, indicating that AMF facilitated the sequestration of Cd in rice roots and reduced Cd accumulation in the seeds. Path coefficients varied across different treatments, suggesting that AMF inoculation reduced the direct impact of soil Cd concentration on the total Cd accumulation in seeds. The translocation of Cd was consistently associated with simultaneous growth dilution and compensatory accumulation as a result of mycorrhizal effects. Our study quantitatively analyzed this process through path analysis and clarified the causal relationship between rice growth and Cd transfer under the influence of AMF.