Project description:Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investigated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Habataki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substitution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and decreased in Habataki. Interestingly, the levels of some phytohormones (jasmonic acid, jasmonoyl-L-isoleucine, and abscisic acid) known to be involved in attenuation of ozone-induced leaf injury tended to decrease in Sasanishiki but to increase in Habataki upon ozone exposure. These data indicate that ozone-induced grain yield loss in Habataki is caused by a reduction in the APO1 transcript level through an increase in the levels of phytohormones that reduce leaf damage.
Project description:Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investigated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Habataki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substitution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and decreased in Habataki. Interestingly, the levels of some phytohormones (jasmonic acid, jasmonoyl-L-isoleucine, and abscisic acid) known to be involved in attenuation of ozone-induced leaf injury tended to decrease in Sasanishiki but to increase in Habataki upon ozone exposure. These data indicate that ozone-induced grain yield loss in Habataki is caused by a reduction in the APO1 transcript level through an increase in the levels of phytohormones that reduce leaf damage. Ozone induced gene expression in rice inflorescence meristem was measured at 6 month after exposure to dose of 43.7 nL L-1 (ambient air) and 85.7 nL L-1 (2-fold concentration compared to ambient air) (12 hours mean). The two culticars, Sasanishiki and Habataki, were used for each experiment.
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: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:In the current study, we characterized an miRNA, OsmiR397, which was found to be associated with increased grain size, more rice panicle branching and higher grain productivity. We also elucidated the molecular mechanisms by which OsmiR397 increased grain yield. This miRNA downregulated the expression of its target gene, OsLAC, which then affected the sensitivity of plants to brassinosteroids. These results should be useful for breeding high-yield crops through genetic engineering. We performed RNA-seq on the young panicles of the wild-type, OXmiR397b and OXLAC plants and found that lots of brassinosteroid-related genes were differentially expressed between the three samples
Project description:A biological phenomenon in which hybrids exhibit superior phenotypes from its parental inbred lines known as heterosis, has been widely exploited in plant breeding and extensively used in crop improvement. Hybrid rice has immense potential to increase yield over other rice varieties and hence is crucial in meeting increasing demand of rice globally. Moreover, the molecular basis of heterosis is still not fully understood and hence it becomes imperative to unravel its genetic and molecular basis. In this context, RNA sequencing technology (RNA-Seq) was employed to sequence transcriptomes of two rice hybrids, Ajay and Rajalaxmi, their parental lines, CRMS31A (sterile line, based on WA-CMS) and CRMS32A (sterile line based on Kalinga-CMS) respectively along with the common restorer line of both hybrids, IR-42266-29-3R at two critical rice developmental stages viz., panicle initiation (PI) and grain filling (GF). Identification of differentially expressed genes (DEGs) at PI and GF stages will further pave the way for understanding heterosis. In addition, such kind of study would help in better understanding of heterosis mechanism and genes up-regulated and down-regulated during the critical stages of rice development for higher yield.
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:The ‘O3-responsive transcriptome’ behavior in the panicles and grains of rice plant was studied individually through high-throughput oligo-DNA microarray technique. Obtained results showed that O3 differentially regulated 620 and 130 genes in the panicles and grains separately, by at least two-fold changes. However, only five genes were found to be common in both the tissues, suggesting towards the tissue specific O3-sensitivity in rice plants. Among the O3-responsive genes, 176 and 444 genes were up- and down-regulated in rice panicle; whereas, 24 and 106 genes in rice grain, respectively. Further mapping onto various regulatory events revealed that, the majority of differentially expressed genes were mainly involved in signaling, hormonal, cell wall, transcription, proteolysis, and defense events. Many previously unknown O3-responsive novel genes were identified, including the brassinosteroid insensitive-1 receptor kinase, wall-associated kinase like receptor, calcium-dependent protein kinases, phosphatidylinositol kinases, G-protein components, ethylene insensitive-3, cellulose synthases, pectatelyase, etc. Inventory of 745 O3-responsive genes and their mapping will surely expand our knowledge on novel regulatory processes in both panicles and grains of rice; and, serve as a resource towards the designing of rice crops for future high-O3 world. Comparison between healthy rice plant panicles and ozone treated plant panicles (for 8 h) and seed (grain) of healthy rice plants and of rice plants grown under ozone for their lifeftime was performed. Three biological replicates (panicle or seed; pooled) were used, and dye-swaped.
Project description:Two types of small (18-24 nt) non-coding RNAs (ncRNAs), microRNAs (miRNAs) and small interfering RNAs (siRNAs) have been found to exist widely in higher plants. OsDCL3b has just been reported to process the 24-nt phased small RNAs in rice, which are preferentially expressed in panicle. In this study, we find that down-regulated expression of OsDCL3b leads to lower pollen sterility and seed setting rate, which results in decreased grain yield per plant in rice. Next, small RNA and mRNA sequencing were performed to study the decrease of pollen fertility and seed setting rate. 942 differentially expressed genes were identified, and some of them have already been known to be involved in rice panicle development. Our results indicate that there is a close correlation between small RNA and rice yield.
Project description:To investigate how OsGATA6 regulates heading date, grain number per panicle, and grain phenotypes, we collected panicle primordia of ZH11 and OsGATA6-AM lines at the In2 and In3 stages. We analyzed gene expression using a rice expression profiling chip. Compared with ZH11, OsGATA6-AM lines had 818 up-regulated genes and 284 down-regulated genes