Project description:Flag (FL) and second leaves (SL) in rice show differential aging patterns during monocarpic senescence. Coordination of aging programs in the top leaves is important for effective grain-filling. However, molecular bases for differential aging programs in the top leaves have not been systematically explored in rice. Here, we performed mRNA-sequencing of FL and SL at six time points during the grain-filling period. mRNA expression data revealed 6,365 genes showing aging-dependent expression changes in FL and/or SL. Of them, while 3047 genes showed shared aging-dependent expression patterns between FL and SL, 3058 genes showed differential expression patterns, which were classified into 5 major groups (G1-5) based on their differential expression patterns. Of the groups, G3 representing amino acid (AA) transport showed consistent differential age-dependent expression patterns in independent samples, whereas the other groups showed inconsistent differential expression patterns. Moreover, of AA transporters (AATs) in G3, long-distance AATs showed invariant differential age-dependent expression patterns after panicle removal, consistent to panicle removal-invariant differential nitrogen contents between FL and SL, known to be associated with protein concentration in grains. Our results suggest that long-distance AA transport is an invariant core transcriptional program of differential aging in rice top leaves for nitrogen remobilization during grain-filling.
Project description:Enhancing grain production of rice (Oryza sativa L.) is a top priority in ensuring food security for human being. One approach to increase yield is to delay leaf senescence and to extend the available time for photosynthesis. microRNAs (miRNAs) are key regulators for aging and cellular senescence in eukayotes. However, miRNAs and their roles in rice leaf senescence remain unexplored. Here, we report identification of miRNAs and their putative target genes by deep sequencing of six small RNA libraries, six RNA-seq libraries and two degradome libraries from the leaves of two super hybrid rice, Nei-2-You 6 (N2Y6, age-resistant rice) and Liang-You-Pei 9 (LYP9, age-sensitive rice). Totally 372 known miRNAs and 162 miRNA candidates were identified, and 1145 targets were identified. Compared with the expression of miRNAs in the leaves of LYP9, the numbers of miRNAs up-regulated and down-regulated in the leaves of N2Y6 were 47 and 30 at early stage of grain-filling, 21 and 17 at the middle stage, and 11 and 37 at the late stage, respectively. Six miRNA families, osa-miR159, osa-miR160 osa-miR164, osa-miR167, osa-miR172 and osa-miR1848, targeting the genes encoding APETALA2 (AP2), zinc finger proteins, salicylic acid-induced protein 19 (SIP19), Auxin response factors (ARF) and NAC transcription factors, respectively, were found to be involved in leaf senescence through phytohormone signaling pathways. These results provided valuable information for understanding the miRNA-mediated leaf senescence of rice, and offered an important foundation for rice breeding. [miRNA] sample 1:The flag leaves at early stage of grain-filling of N2Y6 rice; sample 2: The flag leaves at middle stage of grain-filling of N2Y6 rice;sample 3:The flag leaves at late stage of grain-filling of N2Y6 rice; sample 4:The flag leaves at early stage of grain-filling of LYP9 rice; sample 5: The flag leaves at middle stage of grain-filling of LYP9 rice;sample 6:The flag leaves at late stage of grain-filling of LYP9 rice. [DGE]: samples 7-12 [degradome (targets)]: samples 13:The flag leaves at mixed stages of grain-filling of N2Y6 rice; sample 14:The flag leaves at mixed stages of grain-filling of LYP9 rice
Project description:The biological functions of differently expressed proteins between superior and inferior spikelet grains were investigated based on the isobaric tags for relative and absolute quantification to further clarify the mechanism of rice grain filling at the proteomic level, as well as the response of inferior spikelets to drought dress (-20 kPa or -40 kPa). Compared with superior spikelets, inferior ones had lower sink strength due to the lower sink activities (lower expressions of ADP-glucose pyrophosphorylase, granule-bound starch synthase, starch branching enzyme and pullulanase) and smaller sink sizes (lower abundances of structural proteins). The slower and later grain filling resulted from the weaker decomposition and conversion of photoassimilate and the slower cell division. Moderate drought stress (-20 kPa) promoted the grain filling of inferior spikelets through regulating the proteins associated with photoassimilate supply and conversion. These proteins may be important targets for rice breeding programs that raise the rice yield under drought condition. The findings offer new insights into rice grain-filling and provide theoretical evidences for better quality control and scientific improvement of super rice in practice.
Project description:A heat and drought tolerant rice cultivar (N22) was grown in the field under control and drought conditions during the dry season in 2013. Drought was applied during early grain filling and resulted in simultaneous heat stress, leading to reduced grain yield and quality. Total RNA was extracted from developing seeds under stress and control (fully flooded) conditions and RNA-seq analysis was performed. These samples are a part of a bigger experiment analysing the responses of three contrasting rice cultivars (N22, Dular, Anjali) to combined heat and drought stress including different organs (developing seeds, flag leaves, flowering spikelets) and developmental stages (early grain filling, flowering) at the transcriptomic level.
Project description:High temperature during the grain-filling stage causes deleterious effects on storage material accumulation and grain quality. But it is still unclear how high temperature affects storage materials accumulation. In this study, we systemically analyzed the expression pattern of rice genes under high temperture during the grain-filling stage.
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:Enhancing grain production of rice (Oryza sativa L.) is a top priority in ensuring food security for human being. One approach to increase yield is to delay leaf senescence and to extend the available time for photosynthesis. microRNAs (miRNAs) are key regulators for aging and cellular senescence in eukayotes. However, miRNAs and their roles in rice leaf senescence remain unexplored. Here, we report identification of miRNAs and their putative target genes by deep sequencing of six small RNA libraries, six RNA-seq libraries and two degradome libraries from the leaves of two super hybrid rice, Nei-2-You 6 (N2Y6, age-resistant rice) and Liang-You-Pei 9 (LYP9, age-sensitive rice). Totally 372 known miRNAs and 162 miRNA candidates were identified, and 1145 targets were identified. Compared with the expression of miRNAs in the leaves of LYP9, the numbers of miRNAs up-regulated and down-regulated in the leaves of N2Y6 were 47 and 30 at early stage of grain-filling, 21 and 17 at the middle stage, and 11 and 37 at the late stage, respectively. Six miRNA families, osa-miR159, osa-miR160 osa-miR164, osa-miR167, osa-miR172 and osa-miR1848, targeting the genes encoding APETALA2 (AP2), zinc finger proteins, salicylic acid-induced protein 19 (SIP19), Auxin response factors (ARF) and NAC transcription factors, respectively, were found to be involved in leaf senescence through phytohormone signaling pathways. These results provided valuable information for understanding the miRNA-mediated leaf senescence of rice, and offered an important foundation for rice breeding.