Project description:Purpose:The purpose of this study is to explore the transcriptome analysis of the heterosis of the grain type and grain weight of the super rice WFYT025 hybrid combination at the grain filling stage.
Project description:Yield and quality are the two most important traits in crop breeding. Exploring the regulatory mechanisms that affect both yield and quality traits is of great significance for understanding the molecular genetic networks controlling these key crop attributes. Expansins are cell wall loosening proteins that play important roles in regulating rice grain size. We investigated the effect of OsEXPA7, encoding an expansin, on rice grain size and quality. OsEXPA7 overexpression resulted in increased plant height, panicle length, grain length, and thousand-grain weight in rice. OsEXPA7 overexpression also affected gel consistency and amylose content in rice grains, thus affecting rice quality. Subcellular localization and tissue expression analyses showed that OsEXPA7 is localized on the cell wall and is highly expressed in the panicle. Hormone treatment experiments revealed that OsEXPA7 expression mainly responds to methyl jasmonate, brassinolide, and gibberellin. Transcriptome analysis and RT-qPCR experiments showed that overexpression of OsEXPA7 affects the expression of OsJAZs in the jasmonic acid pathway and BZR1 and GE in the brassinosteroid pathway. In addition, OsEXPA7 regulates the expression of key quantitative trait loci related to yield traits, as well as regulates the expression levels of BIP1 and bZIP50 involved in the seed storage protein biosynthesis pathway. These results reveal that OsEXPA7 positively regulates rice yield traits and negatively regulates grain quality traits by involving plant hormone pathways and other trait-related pathway genes. These findings increase our understanding of the potential mechanism of expansins in regulating rice yield and quality traits and will be useful for breeding high-yielding and high-quality rice cultivars.
Project description:We aimed to identify differential expression of microRNAs between superior and inferior spikelets by using a deep sequencing approach developed by Solexa (Illumina). Two small RNA libraries were constructed from superior and inferior spikelets at 18 days after fertilization, and more than nine million small RNA sequence reads were generated for each library. Totals of 351 and 312 known miRNAs were obtained from the superior and inferior spikelets, respectively. Analysis of the expression profiles of these miRNAs showed that 189 miRNAs were differentially expressed between superior spikelets and inferior spikelets. In addition, 43 novel miRNAs were identified mostly by the accumulations of miRNA*s were also expressed differentially. Further analysis shows that these miRNAs may individually participate in regulating hormone metabolism, carbohydrate metabolic pathways, and cell division during rice grain development. These results indicate that slow grain filling and low grain weight of rice inferior spikelets probably relation to the expression and function differences between superior and inferior spikelet miRNAs.
Project description:In rice (Oryza sativa L.), the number of panicles, spikelets per panicle and grain weight are important components of grain yield. These characteristics are controlled by quantitative trait loci (QTLs) and are derived from variation inherent in crops.The identification of different yield related QTLs facilitates an understanding of the mechanisms involved in cereal crop yield, and may have utility in improving grain yield in cereal crops. an understanding of the mechanisms involved in cereal crop yield, and may have utility in improving grain yield in cereal crops. In the present study, We cloned and characterized a large-panicle QTL, and confirmed that the newly identified gene OsEBS (enhancing biomass and spikelet number) increased plant height, leaf size and spikelet number per panicle, leading to an average of 37.62% increase in total grain yield per plant. trait loci (QTLs) and are derived from variation inherent in crops. OsEBS-transgenic rice B10201 and B10301 and control Guichao2
Project description:Tiller angle is a key factor determining rice plant architecture, planting density, light interception, photosynthetic efficiency, disease resistance, and grain yield. The distribution of auxin and shoot gravitropism play important roles in regulating tiller angles of rice. Several tiller angle-associated genes have been cloned. However, the mechanisms underlying tiller angle control are far from clear. In this study, we isolate bta1-1, a mutant with an enlarged tiller angle throughout its life cycle. A detailed analysis reveals that BTA1 has multiple functions because several major agronomic traits, including tiller and panicle number, biomass production, secondary branch number per panicle, panicle weight, grain size, and grain weight, are increased in bta1-1 plants. Moreover, BTA1 is a positive regulator of shoot gravitropism in rice. Shoot responses to gravistimulation are disrupted in bta1-1 under both light and dark conditions. Gene cloning reveals that bta1-1 is a novel mutant allele of LA1. LA1 is able to rescue the tiller angle and shoot gravitropism defects observed in bta1-1. BTA1/LA1 is required to regulate the expression of auxin transporters and signaling factors that control shoot gravitropism and tiller angle. High-throughput mRNA sequencing is performed to elucidate the molecular and cellular functions of BTA1/LA1. The results show that BTA1/LA1 may have multiple functions in regulating nucleosome and chromatin assembly, and protein and DNA interactions. Our results provide new insight into the mechanisms whereby BTA1/LA1 controls shoot gravitropism and tiller angle in rice.
Project description:Genetic imprinting is an epigenetic phenomenon that describes unequal expression of paternal and maternal alleles of a gene in sexually reproducing organisms including mammals and flowering plants. The function of imprinted genes was rarely reported. We report genome-wide analysis of gene expression, DNA methylation, and small RNAs in the rice endosperm and functional tests of five imprinted genes in seed development using CRISPR/Cas9 editing technology. We identified 162 maternally expressed genes(MEGs) and 95 paternally expressed genes (PEGs) in the rice endosperm, which were associated with miniature inverted-repeat transposable elements, imprinted differentially methylated loci, and some 21-22-siRNAs and lncRNAs. Remarkably, one-third of MEGs and nearly half of PEGs were associated with grain-yield quantitative trait loci and enriched in the endosperm-expressed genes. Disrupting two MEGs increased the amount of small starch granules and reduced grain size, weight, and embryo size, while mutating three PEGs reduced starch content and seed fertility. Our data support both MEGs and PEGs in rice are required for starch and nutrient accumulation, mediating offspring fitness and optimal seed size. This imprinting strategy provides potential means for improving grain yield of rice and other cereal crops.
Project description:In rice (Oryza sativa L.), the number of panicles, spikelets per panicle and grain weight are important components of grain yield. These characteristics are controlled by quantitative trait loci (QTLs) and are derived from variation inherent in crops.The identification of different yield related QTLs facilitates an understanding of the mechanisms involved in cereal crop yield, and may have utility in improving grain yield in cereal crops. an understanding of the mechanisms involved in cereal crop yield, and may have utility in improving grain yield in cereal crops. In the present study, We cloned and characterized a large-panicle QTL, and confirmed that the newly identified gene OsEBS (enhancing biomass and spikelet number) increased plant height, leaf size and spikelet number per panicle, leading to an average of 37.62% increase in total grain yield per plant. trait loci (QTLs) and are derived from variation inherent in crops.
Project description:Gene expression profoling of developping endosperm at 3 and 6 days after flowering (DAH): Nipponbare vs NIL(TGW6) We used two rice varieties, NIL(TGW6) and Nipponbare.NIL(TGW6) is a nearly isogenic line containing the thousand grain weight qTGW6. For samples used three stages: 3 and 6 DAH endosperm in both Nipponbare and NIL(TGW6). Two dye swapped experiments were performed.
Project description:Plant height and grain size are important agronomic traits affecting rice yield. Various plant hormones participate in the regulation of plant height and grain size in rice. However, how these hormones cooperate to regulate plant height and grain size is poorly understood. In this study, we identified a brassinosteroid-related gene, hfr131, from an introgression line constructed using Oryza longistaminata, that caused brassinosteroid insensitivity and reduced plant height and grain length in rice. Further study showed that hfr131 is a new allele of OsBRI1 with a single-nucleotide polymorphism (G to A) in the coding region, leading to a T988I conversion at a conserved site of the kinase domain. An auxin response factor, OsARF17, could bind to the promoter region of HFR131 and positively regulated HFR131 expression, thereby regulating the plant height and grain length, and influencing brassinosteroid sensitivity. Haplotype analysis showed that the consociation of OsAFR17Hap1/HFR131Hap6 conferred an increase in grain length. Overall, this study identified hfr131 as a new allele of OsBRI1 that regulates plant height and grain length in rice, revealed that brassinosteroid and auxin might coordinate through OsARF17–HFR131 interaction, and provided a potential breeding target for improvement of rice yield.
Project description:Popular rice mega varieties lack sufficient key micronutrients (e.g., Fe, Zn), vitamins and a balanced amino acid composition that are essential for a healthy diet. The major bottleneck for improving the nutritional quality of popular rice varieties through conventional breeding or gene technology is our lack of an integrated understanding of the biochemical and molecular processes that occur during rice grain filling (and their determining genes or loci). In this project, we will perform molecular expression profiling on specific tissue layers of the rice grain. To perform this experiment, the material will be developing rice seeds from plants grown hydroponically under controlled greenhouse conditions. Then, the laser microdissection approach will be applied to dissect different parts of the grain (i.e, vascular trace, aleurone, nucellar epidermis, etc). Total RNA will be extracted from these dissected parts and RNA sequencing will be performed. In this project, we will learn how the synthesis and deposition of grain nutrients is regulated, particularly, during grain filling.