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[学术文献 ] Overexpression of OsLCT2, a Low-Affinity Cation Transporter Gene, Reduces Cadmium Accumulation in Shoots and Grains of Rice 进入全文
RICE
Cadmium (Cd)-contaminated rice is a serious issue affecting food safety. Understanding the molecular regula-tory mechanisms of Cd accumulation in rice grains is crucial to minimizing Cd concentrations in grains. We identi-fied a member of the low-affinity cation transporter family, OsLCT2 in rice. It was a membrane protein. OsLCT2 was expressed in all tissues of the elongation and maturation zones in roots, with the strongest expression in pericycle and stele cells adjacent to the xylem. When grown in Cd-contaminated paddy soils, rice plants overexpressing OsLCT2significantly reduced Cd concentrations in the straw and grains. Hydroponic experiment demonstrated its overexpres-sion decreased the rate of Cd translocation from roots to shoots, and reduced Cd concentrations in xylem sap and in shoots of rice. Moreover, its overexpression increased Zn concentrations in roots by up-regulating the expression of OsZIP9, a gene responsible for Zn uptake. Overexpression of OsLCT2 reduces Cd accumulation in rice shoots and grains by limiting the amounts of Cd loaded into the xylem and restricting Cd translocation from roots to shoots of rice. Thus, OsLCT2 is a promising genetic resource to be engineered to reduce Cd accumulation in rice grains.
[学术文献 ] Application of the Nitrogen Nutrition Index to Estimate the Yield of Indica Hybrid Rice Grown from Machine-Transplanted Bowl Seedlings 进入全文
AGRONOMY-BASEL
The purpose was to comprehensively compare the prediction accuracy of different nitrogen nutrition indexes (NNILAI and NNIDM) derived from critical nitrogen concentration (N-c) models established by the leaf area index (LAI) and dry matter (DM) in estimating the grain yield of indica hybrid rice grown from machine-transplanted bowl seedlings. Therefore, field experiments were conducted with two high-yielding indica hybrid rice varieties and five nitrogen application rates in 2018 and 2019. The results show that NNIDM peaked in the stem elongation stage, while NNILAI had its maximal value in the mid-tillering stage during the growth stages. The NNILAI had the highest correlation with the relative effective panicle number in the tillering stage when compared with the NNIDM, and the threshold points of the NNI were 0.971 (active tillering stage) and 1.106 (mid-tillering stage). Moreover, the NNILAI had the highest correlation with the relative seed setting rate in the stem elongation-panicle initiation stage compared with the NNIDM, and its threshold points were 1.116 (stem elongation stage) and 1.053 (panicle initiation stage). In contrast, the NNIDM had the highest correlation with the relative seed setting rate in the heading stage compared with the NNLAI, and its threshold point was 1.050 (heading stage). Therefore, the NNILAI in the tillering-panicle initiation stage and NNIDM in the heading stage should be merged to effectively improve the nitrogen nutrition status and its evaluation in addition to the prediction accuracy of the yield of indica hybrid rice grown from machine-transplanted bowl seedlings. This study provides a theoretical basis for improved understanding of the nitrogen status and yield prediction of indica hybrid rice grown from machine-transplanted bowl seedlings.
[学术文献 ] IPA1 Negatively Regulates Early Rice Seedling Development by Interfering with Starch Metabolism via the GA and WRKY Pathways 进入全文
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Ideal Plant Architecture 1 (IPA1) encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of IPA1 in early seedling development, we developed a pair of IPA1/ipal-NILs and found that seed germination and early seedling growth were retarded in the ipa1-NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the alpha-amylase genes revealed that the starch metabolism was weakened in the ipa1-NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the IPA1-NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene OsGA20ox1 was downregulated, whereas the expression of GA inactivation-related genes was upregulated in ipa1-NIL seeds. In addition, the expression of OsWRKY51 and OsWRKY71 was significantly upregulated in ipa1-NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of OsWRKY51 and OsWRKY71, which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of alpha-amylase genes. In summary, our results suggest that IPA1 negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and WRKY pathways.
[学术文献 ] Analysis of parental genetic diversity and its impact on grain yield and quality of japonica hybrid rice in northern China 进入全文
web of Science
The relationship between parental genetic differences and the quality and yield of japonica hybrid rice strongly influences japonica hybrid rice breeding. In this study, 137 parental lines of japonica hybrid rice were genotyped using 8K rice SNP-Chips to characterize their genetic diversity, population structure, and indica -genotype proportion. The genetic diversity of total parental lines averaged 0.264, with values of 0.287 for restorer lines and 0.148 for the sterile lines. The introduction of indica lineage increased the genetic diversity of restorer lines relative to that of sterile lines. By model-based population structure analysis, the 137 lines were divided into 14 groups. According to the grouping results, eight restorer lines and five sterile lines were selected from different groups for cross breeding, yielding 40 japonica hybrid rice combinations (F1). Investigation of the yield and quality of these combinations showed that high -yield combinations could be obtained by increasing parental genetic distance to 0.8-0.9, a result accom-plished largely by the introduction of indica genomic components of restorer lines. To further improve grain quality, the genetic distance between parents should be reduced to 0.4-0.5, suggesting an indica -genotype proportion of 30%-40% for restorer lines. This study may provide a reference for breeding of japonica hybrid rice.(c) 2022 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
[学术文献 ] Transcriptome profiling of two super hybrid rice provides insights into the genetic basis of heterosis 进入全文
Web of Science
Background: Heterosis is a phenomenon that hybrids show superior performance over their parents. The successful utilization of heterosis has greatly improved rice productivity, but the molecular basis of heterosis remains largely unclear.Results: Here, the transcriptomes of young panicles and leaves of the two widely grown two-line super hybrid rice varieties (Jing-Liang-You-Hua-Zhan (JLYHZ) and Long-Liang-You-Hua-Zhan (LLYHZ)) and their parents were analyzed by RNA-seq. Transcriptome profiling of the hybrids revealed 1,778 similar to 9,404 differentially expressed genes (DEGs) in two tissues, which were identified by comparing with their parents. GO, and KEGG enrichment analysis showed that the pathways significantly enriched in both tissues of two hybrids were all related to yield and resistance, like circadian rhythm (GO:0,007,623), response to water deprivation (GO:0,009,414), and photosynthetic genes (osa00196). Allele-specific expression genes (ASEGs) were also identified in hybrids. The ASEGs were most significantly enriched in ionotropic glutamate receptor signaling pathway, which was hypothesized to be potential amino acid sensors in plants. Moreover, the ASEGs were also differentially expressed between parents. The number of variations in ASEGs is higher than expected, especially for large effect variations. The DEGs and ASEGs are the potential reasons for the formation of heterosis in the two elite super hybrid rice.Conclusions: Our results provide a comprehensive understanding of the heterosis of two-line super hybrid rice and facilitate the exploitation of heterosis in hybrid rice breeding with high yield heterosis.
[学术文献 ] The Next Generation of Rice: Inter-Subspecific Indica-Japonica Hybrid Rice 进入全文
web of science
Rice (Oryza sativa) is an important food crop and has two subspecies, indica and japonica. Since the last century, four generations of rice varieties have been applied to rice production. Semi-dwarf rice, intra-subspecific hybrid rice, and inter-subspecific introgression rice were developed successively by genetic modification based on the first generation of tall rice. Each generation of rice has greater yield potential than the previous generation. Due to the stronger heterosis of indica-japonica hybrids, utilization of the inter-subspecific heterosis has long been of interest. However, indica-japonica hybrid sterility hinders the utilization of heterosis. In the past decades, indica-japonica hybrid sterility has been well understood. It is found that indica-japonica hybrid sterility is mainly controlled by six loci, S5, Sa, Sb, Sc, Sd, and Se. The indica-japonica hybrid sterility can be overcome by developing indica-compatible japonica lines (ICJLs) or wide-compatible indica lines (WCILs) using genes at the loci. With the understanding of the genetic and molecular basis of indica-japonica hybrid sterility and the development of molecular breeding technology, the development of indica-japonica hybrid rice has become possible. Recently, great progress has been made in breeding indica-japonica hybrid rice. Therefore, the indica-japonica hybrid rice will be the next generation of rice. It is expected that the indica-japonica hybrid rice will be widely applied in rice production in the near future.
