Phosphorus remobilization from rice flag leaves during grain filling: an RNA‐seq study |
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Authors: | Kwanho Jeong Abdul Baten Daniel L E Waters Omar Pantoja Cecile C Julia Matthias Wissuwa Sigrid Heuer Tobias Kretzschmar Terry J Rose |
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Institution: | 1. Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia;2. Southern Cross GeoScience, Southern Cross University, Lismore, NSW, Australia;3. Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico;4. Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki, Japan;5. University of Adelaide, School of Agriculture Food and Wine / Australian Centre for Plant Functional Genomics (ACPFG), Adelaide, SA, Australia;6. Genotyping Services Laboratory, International Rice Research Institute (IRRI), Metro Manila, Philippines |
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Abstract: | The physiology and molecular regulation of phosphorus (P) remobilization from vegetative tissues to grains during grain filling is poorly understood, despite the pivotal role it plays in the global P cycle. To test the hypothesis that a subset of genes involved in the P starvation response are involved in remobilization of P from flag leaves to developing grains, we conducted an RNA‐seq analysis of rice flag leaves during the preremobilization phase (6 DAA) and when the leaves were acting as a P source (15 DAA). Several genes that respond to phosphate starvation, including three purple acid phosphatases (OsPAP3, OsPAP9b and OsPAP10a), were significantly up‐regulated at 15 DAA, consistent with a role in remobilization of P from flag leaves during grain filling. A number of genes that have not been implicated in the phosphate starvation response, OsPAP26, SPX‐MFS1 (a putative P transporter) and SPX‐MFS2, also showed expression profiles consistent with involvement in P remobilization from senescing flag leaves. Metabolic pathway analysis using the KEGG system suggested plastid membrane lipid synthesis is a critical process during the P remobilization phase. In particular, the up‐regulation of OsPLDz2 and OsSQD2 at 15 DAA suggested phospholipids were being degraded and replaced by other lipids to enable continued cellular function while liberating P for export to developing grains. Three genes associated with RNA degradation that have not previously been implicated in the P starvation response also showed expression profiles consistent with a role in P mobilization from senescing flag leaves. |
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Keywords: | Illumina sequencing
Oryza sativa
differential gene expression phosphorus translocation senescence |
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