title: 1-MCP treatment enhanced expression of genes controlling endosperm cell division and starch biosynthesis for improvement of grain filling in a dense-panicle rice cultivar.
abstract: High ethylene production in dense-panicle rice cultivars impacts grain filling. 1-MCP (ethylene action inhibitor) treatment increased assimilates partitioning, cell number and size and expression of starch synthesizing enzyme genes of developing caryopses mostly in the basal spikelets of panicle at early post-anthesis stage. The gain in cell number was less compared to the increase of size. High ethylene production in spikelets matched with greater expression of ethylene receptor and signal transducer genes. Genes encoding cell cycle regulators CDK, CYC and CKI expressed poorly on 9 DAA. 1-MCP treatment enhanced their expression; the increase of expression was higher for CDKs and lower for CKIs in basal compared to apical spikelets. Greater expression of CDKB2:1 might have lifted cytokinesis of nascent peripheral cells of endosperm, while promotion of CDKAs, CYCD2:2 and inhibition of CYCB2:2 expression contributed to endoreduplication of central cells increasing cell size and DNA ploidy level. It is concluded that the process of endoreduplication, which begins at mid-grain filling stage, is crucially linked with the final caryopsis size of rice grain. The enhanced endosperm growth brought about by repressed ethylene action during the first few days after anthesis seems to be associated with the overall increased cell cycle activity and sink strength.
authors.affiliation: Environmental Biotechnology Laboratory, Institute of Life Sciences, Bhubaneswar 751023, India.
authors.forename: B B
authors.initials: BB
authors.lastname: Panda
authors.affiliation: Environmental Biotechnology Laboratory, Institute of Life Sciences, Bhubaneswar 751023, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Badoghar
authors.affiliation: Environmental Biotechnology Laboratory, Institute of Life Sciences, Bhubaneswar 751023, India.
authors.forename: S
authors.initials: S
authors.lastname: Sekhar
authors.affiliation: Environmental Biotechnology Laboratory, Institute of Life Sciences, Bhubaneswar 751023, India.
authors.forename: B P
authors.initials: BP
authors.lastname: Shaw
authors.affiliation: School of Life Science, Sambalpur University, Jyoti Vihar, Sambalpur 768019, India. Electronic address: pravat1948@rediffmail.com.
authors.forename: P K
authors.initials: PK
authors.lastname: Mohapatra
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000187:drug effects / Q000235:genetics; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects* / Q000235:genetics; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003521:Cyclopropanes / Q000494:pharmacology*; D062951:Endoreduplication / Q000187:drug effects; D056625:Endosperm / Q000166:cytology* / Q000187:drug effects / Q000235:genetics*; D005030:Ethylenes / Q000378:metabolism; D005434:Flow Cytometry; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D007527:Isoenzymes / Q000378:metabolism; D008190:Lyases / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D012275:Oryza / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D012995:Solubility; D013213:Starch / Q000096:biosynthesis*; D013997:Time Factors
chemical_list: D003521:Cyclopropanes; D005030:Ethylenes; D007527:Isoenzymes; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D013213:Starch; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; C412563:1-methylcyclopropene
keywords: Cell cycle; Endoreduplication; Ethylene signal; Rice; Spikelet; Starch synthesis