Characterization of pullulanase (PUL)-deficient mutants of rice (Oryza sativa L.) and the function of PUL on starch biosynthesis in the developing rice endosperm
| Autor: | Hirohiko Hirochika, Naoko Fujita, Akiko Mori, Yoshiko Toyosawa, Yoshinori Utsumi, Hikaru Satoh, Isao Hanashiro, Rumiko Itoh, Sayuri Akuzawa, Mayumi Yoshida, Yasunori Nakamura, Akira Ikegami, Kotaro Inomata, Toshiyuki Higuchi, Akio Miyao |
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| Rok vydání: | 2009 |
| Předmět: |
Glycoside Hydrolases
Physiology Starch Amylopectin Mutant Plant Science Biology Polysaccharide Substrate Specificity Endosperm chemistry.chemical_compound Amylose Isoamylase mutant Biomass pullulanase chemistry.chemical_classification rice endosperm Calorimetry Differential Scanning Viscosity Phytoglycogen debranching enzyme food and beverages Oryza starch biosynthesis isoamylase Research Papers Elasticity Recombinant Proteins carbohydrates (lipids) Mutagenesis Insertional chemistry Biochemistry Mutation Seeds Chromatography Gel Carbohydrate Metabolism Crystallization |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/ern349 |
| Popis: | Rice (Oryza sativa) allelic sugary1 (sug1) mutants defective in isoamylase 1 (ISA1) accumulate varying levels of starch and phytoglycogen in their endosperm, and the activity of a pullulanase-type of a debranching enzyme (PUL) was found to correlate closely with the severity of the sug1 phenotype. Thus, three PUL-deficient mutants were generated to investigate the function of PUL in starch biosynthesis. The reduction of PUL activity had no pleiotropic effects on the other enzymes involved in starch biosynthesis. The short chains (DP < or = 13) of amylopectin in PUL mutants were increased compared with that of the wild type, but the extent of the changes was much smaller than that of sug1 mutants. The alpha-glucan composition [amylose, amylopectin, water-soluble polysaccharide (WSP)] and the structure of the starch components (amylose and amylopectin) of the PUL mutants were essentially the same, although the average chain length of the B(2-3) chains of amylopectin in the PUL mutant was approximately 3 residues longer than that of the wild type. The double mutants between the PUL-null and mild sug1 mutants still retained starch in the outer layer of endosperm tissue, while the amounts of WSP and short chains (DP < or = 7) of amylopectin were higher than those of the sug1 mutant; this indicates that the PUL function partially overlaps with that of ISA1 and its deficiency has a much smaller effect on the synthesis of amylopectin than ISA1 deficiency and the variation of the sug1 phenotype is not significantly dependent on the PUL activities. |
| Databáze: | OpenAIRE |
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