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| | + | The rice gene '''Os08g0191433''' was reported as ''''' SSIIIa''''' in 2010<ref name="ref1" /> by researchers from China. |
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| | ==Annotated Information== | | ==Annotated Information== |
| − | [[File:BC12_1.jpg|right|thumb|320px|'''Figure 1.''' '' '''BC12''' Mutant VS. WT(from reference) <ref name="ref2" />.'']]
| + | ===Gene Symbol=== |
| | + | *'''Os08g0191433''' <=> '''SSIIIa''' |
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| | ===Function=== | | ===Function=== |
| − | '''''OsSSIIIa''''' plays an important role in starch granule structures, amylose ratios and metabolite changes of starch grains in the monocot plant rice<ref name="ref4" />. This gene OsIIIa is are major enzymes involved in starch biosynthesis in developing rice (Oryza sativaL.) endosperm.If ''OsSSIIIa'' gene encoding deletion or mutation , this will lead to changes in the grain starch -related traits.<ref name="ref1" />. It is also likely to be a good subject for exploring the link between cell growth and cell wall formation in rice<ref name="ref1" />.<br><br> | + | *SSIIa and '''SSIIIa''' play distinctive, but partially overlapping, roles during rice grain starch synthesis. |
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| | ===Mutation=== | | ===Mutation=== |
| − | * Figure 1 shows the gross morphology of the wild type and mutant plants. The mutant was shorter than the wild type at the three-leaf and heading stages (Figures 1A and 1B). Also, mutant spikes and grains were slightly shorter than those of the wild type (Figure 1C). Nearly every internode of the mutant was shorter than that in the wild type<ref name="ref2" />.<br><br> | + | *Transgenic RNA interference (RNAi) repressed lines for seven of the eight members of the rice SS gene family and studied their effects on starch synthesis and grain formation. Consistent with their expression domains, RNAi repression of genes that encode isozymes SSI, '''SSIIa,''' and '''SSIIIa''' had strong effects on grain development, whereas no obvious phenotypic changes were observed in transgenic plants with the other SS genes being RNAi repressed, indicating functional redundancies among the genes. |
| − | *The breaking force of '''''bc12''''' mutation culms and leaves was reduced to approximately 25% of that in the wild-type. The cellulose content was not significantly altered, but the lignin content was increased by approximately 50% in mutation. The higher lignin content resulted from a general increase in all three monomers.<ref name="ref1" />.
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| − | [[File:BC12_4.jpg|right|thumb|320px|'''Figure 2.''' ''Classification of the genes up- or downregulated fourfold or more in Mutation by whole-genome DNA microarray analysis<ref name="ref2" />'']]
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| − | ===Expression===
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| − | * '''Expression pattern of ''BC12'' '''<br> Quantitative PCR revealed that '''''BC12''''' is universally expressed in all organs examined, with higher expression in panicles and culms<ref name="ref1" /><ref name="ref2" />. The RT-PCR analyses also shows greater expression of '''''BC12''''' in the tissues enriched in dividing cells than in those enriched in non-dividing cells<ref name="ref1" />.<br><br>
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| − | * '''Expression Analysis in Mutant'''<br> Affymetrix whole-genomemicroarray chip analyses by ''Juan Li et al.'' shows that 116 downregulated and 125 upregulated genes in the mutant compared with the wild type (more than four fold expression change; Figure 2). Of note, the genes involved in cell wall expansion were significantly altered in expression in the mutant. <br>Those encoding xylanase inhibitor protein and cellulose synthase (CESA6) were greatly upregulated. By contrast, the gene for lignin forming anionic peroxidase was downregulated. That imply '''''BC12''''' might be involved in the regulation of genes associated with cell wall assembly.Of note, the expression of the rice KO gene KO2, a key enzyme in early GA synthesis, was greatly decreased in mutation compared with the wild type<ref name="ref2" />.
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| − | [[File:BC12_5.jpg|right|thumb|320px|'''Figure 3.''' ''Phylogenetic tree of '''BC12''' and representative homologs from Arabidopsis and animals.(from reference) <ref name="ref1" />.'']]
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| − | ===Localization=== | + | ===Expression === |
| − | The production of '''''OsSSIIIa''''' was located at both the nucleus and cytoplasm and associated with microtubule arrays during cell division<ref name="ref1" /><ref name="ref2" /><ref name="ref3" /><ref name="ref4" />. An NLS with 17 amino acid sequence was found in this gene<ref name="ref1" />.
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| − | ===Evolution===
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| − | Phylogenetic analysis by ''Mu Zhang et al.'' revealed that '''''BC12''''' and motor proteins selected from various kinesin subfamilies are divided into separated clades(Figure 3). Kinesin-4 proteins from several representative species were clustered together but formed different subclades. Among the kinesin-4 proteins, those from rice and Arabidopsis were found to belong to a monophyletic clade with 100% bootstrap support. '''''BC12''''' showed the closest homology to FRA1, which has been reported to be involved in cellulose microfibril deposition<ref name="ref1" />.
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| − | ===Knowledge Extension===
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| − | * [http://en.wikipedia.org/wiki/Gibberellins Gibberellins (GAs)] are one of the most important endogenous growth regulators in plants<ref name="ref2" /><ref name="ref3" /><ref name="ref4" /><ref name="ref5" />. They are not only required for stem elongation but indeed participate in most stages of plant development<ref name="ref3" />. GAs mediate between certain environmental signals (e.g. light quality and photoperiod) and the inducedphysiological responses <ref name="ref3" />(e.g. stem extension and flowering). GA-deficient mutants are usually much shorter than the wild type, which indicates the corresponding genes such as '''''sd1''''' ('''''[[Os01g0883800]]''''')<ref name="ref6" /> in rice may have a relationship with [http://en.wikipedia.org/wiki/The_Green_Revolution The Green revolution].
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| − | * The biosynthesis of GA in higher plants can be divided into three stages: (1) biosynthesis of ''ent''-kaurene in proplastids;(2) conversion of ''ent''-kaurene to GA12 via microsomal cytochrome P450 monooxygenases;(3) formation of C20- and C19-GAs in the cytoplasm<ref name="ref4" /><ref name="ref2" />. GA biosynthesis is catalyzed by three classes of enzymes: terpene cyclases catalyze the synthesis of ''ent''-kaurene from geranylgeranyl diphosphate; cytochrome P450 monooxygenases catalyze the steps of the pathway from ''ent''-kaurene to GA12; and soluble dioxygenases catalyze the final steps of the pathway<ref name="ref5" />.
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| | + | ==Labs working on this gene== |
| | + | *Institute of Crop Science and the National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China. |
| | + | *National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095,China. |
| | + | * Institubr of Crop Science and the National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China; |
| | + | *National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. |
| | + | <br> |
| | ==References== | | ==References== |
| | <references> | | <references> |
| | * <ref name="ref1"> | | * <ref name="ref1"> |
| − | Zhang M, Zhang B, Qian Q, et al. Brittle Culm 12, a dual‐targeting kinesin‐4 protein, controls cell‐cycle progression and wall properties in rice[J]. The Plant Journal, 2010, 63(2): 312-328.
| + | Double repression of soluble starch synthase genes SSIIa and SSIIIa in rice (Oryza sativa L.) uncovers interactive effects on the physicochemical properties of starch |
| − | </ref>
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| − | * <ref name="ref2">
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| − | Miyako Kusano;Atsushi Fukushima;Naoko Fujita;Yozo Okazaki;Makoto Kobayashi;Naoko Fujita Oitome;Kaworu Ebana;Kazuki Saito. Deciphering Starch Quality of Rice Kernels Using Metabolite Profiling and Pedigree Network Analysis. Molecular Plant, 2011, 5(2): 442-451.
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| − | </ref>
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| − | * <ref name="ref3">
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| − | Nayeon Ryoo;Chul Yu;Cheon-Seok Park;Moo-Yeol Baik;In Myoung Park;Man-Ho Cho;Seong Hee Bhoo;Gynheung An;Tae-Ryong Hahn;Jong-Seong Jeon. Knockout of a starch synthase gene OsSSIIIa / Flo5 causes white-core floury endosperm in rice ( Oryza sativa L.). Plant Cell Reports, 2007, 26(7): 1083-1095.
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| − | </ref>
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| − | * <ref name="ref4">
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| − | Naoko Fujita;Mayumi Yoshida;Tomonori Kondo;Kaori Saito;Yoshinori Utsumi;Takashi Tokunaga;Aiko Nishi;Hikaru Satoh;Jin-Hee Park;Jay-Lin Jane;Akio Miyao;Hirohiko Hirochika and Yasunori Nakamura. Characterization of SSIIIa-Deficient Mutants of Rice: The Function of SSIIIa and Pleiotropic Effects by SSIIIa Deficiency in the Rice Endosperm. Plant Physiology, 2007, 144(4): 2009-2023.
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| | </ref> | | </ref> |
| | </references> | | </references> |
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| | + | ==Structured Information== |
| | + | [[Category:Genes]][[Category:Oryza Sativa Japonica Group]][[Category:Japonica Chromosome 08]] |
