A Step in the Biosynthesis of Gibberellins that Is Controlled by the Mutation in the Semi-Dwarf Rice Cultivar Tan-Ginbozu

Ogawa, Sachiko; Toyomasu, Tomonobu; Yamane, Hisakazu; Murofushi, Noboru; Ikeda, Ryoichi; Morimoto, Yasuyuki; Nishimura, Yasuhiko; Omori, Toshio

doi:10.1093/oxfordjournals.pcp.a028954

Cited by 30 publications

(23 citation statements)

References 17 publications

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“…These observations are fully consistent with the established role of ent-kaurene oxidases in GA biosynthesis and with the established role of GAs in plant growth and development. It is significant to note that the phenotypes of RDV-infected plants are strikingly similar to those exhibited by the ent-kaurene oxidase mutant rice plant d35 Tan-Ginbozu , which also showed GA deficiency (Kobayashi et al, 1989;Ogawa et al, 1996;Itoh et al, 2004). Taking all data together, we propose that in an RDV-infected plant, the RDV P2 interacts with entkaurene oxidases.…”

Section: Discussionsupporting

confidence: 54%

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms

et al. 2005

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The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with entkaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA 1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA 3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development.

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Section: Discussionsupporting

confidence: 54%

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms

et al. 2005

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“…4A), or 5.0 g fresh weight each of UV-irradiated and control rice leaves (Fig. 4B) were extracted with methanol, and the methanol extracts were purified as described previously [17]. OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor As already reported [12], we exhibited that at least two diterpene cyclase genes tentatively named OsDTC1 and OsDTC2 were expressed in the elicited rice (O. sativa L. cv.…”

Section: Gc-mssupporting

confidence: 62%

Stemar‐13‐ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice

et al. 2004

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In suspension-cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli as a fusion protein with glutathione S-transferase, and the recombinant OsDTC2 was indicated to function as stemar-13-ene synthase that converted syn-copalyl diphosphate to stemar-13-ene, a putative diterpene hydrocarbon precursor of the phytoalexin oryzalexin S. The level of OsDTC2 mRNA in suspension-cultured rice cells began to increase 3 h after addition of the elicitor and reached the maximum after 8 h. The expression of OsDTC2 was also induced in UV-irradiated rice leaves. In addition, we indicated that stemar-13-ene accumulated in the chitin-elicited suspension-cultured rice cells and the UVirradiated rice leaves.

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“…5). In rice, mutants dx and d18 are defective in ent-kaurene oxidase and GA 3-oxidase activity, respectively, representing early and late steps in the GA biosynthetic pathway (6,7). These dwarf plants have a low content of GA 1 (a major growth active GA in rice) and can be rescued by application of active GAs such as GA 3 .…”

mentioning

confidence: 99%

Semidwarf ( sd-1 ), “green revolution” rice, contains a defective gibberellin 20-oxidase gene

Spielmeyer

Ellis

Chandler

2002

Proc. Natl. Acad. Sci. U.S.A.

786

587

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The introduction of semidwarf rice (Oryza sativa L.) led to record yield increases throughout Asia in the 1960s. The major semidwarfing allele, sd-1, is still extensively used in modern rice cultivars. The phenotype of sd-1 is consistent with dwarfism that results from a deficiency in gibberellin (GA) plant growth hormones. We propose that the semidwarf (sd-1) phenotype is the result of a deficiency of active GAs in the elongating stem arising from a defective 20-oxidase GA biosynthetic enzyme. Sequence data from the rice genome was combined with previous mapping studies to locate a putative GA 20-oxidase gene (Os20ox2) at the predicted map location of sd-1 on chromosome 1. Two independent sd-1 alleles contained alterations within Os20ox2: a deletion of 280 bp within the coding region of Os20ox2 was predicted to encode a nonfunctional protein in an indica type semidwarf (Doongara), whereas a substitution in an amino acid residue (Leu-266) that is highly conserved among dioxygenases could explain loss of function of Os20ox2 in a japonica semidwarf (Calrose76). The quantification of GAs in elongating stems by GC-MS showed that the initial substrate of GA 20-oxidase activity (GA53) accumulated, whereas the content of the major product (GA20) and of bioactive GA1 was lower in semidwarf compared with tall lines. We propose that the Os20ox2 gene corresponds to the sd-1 locus.

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A Step in the Biosynthesis of Gibberellins that Is Controlled by the Mutation in the Semi-Dwarf Rice Cultivar Tan-Ginbozu

Cited by 30 publications

References 17 publications

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms

Stemar‐13‐ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice

Semidwarf ( sd-1 ), “green revolution” rice, contains a defective gibberellin 20-oxidase gene

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