摘要:
This invention relates to an O-methyltransferase gene cloned from sorghum, the sorghum O-methyltransferase-3 gene, SbOMT3. Quantitative real-time RT-PCR and recombinant enzyme studies with putative O-methyltransferase sequences obtained from an EST data set from sorghum have led to the identification of the novel root hair-specific O-methyltransferase designated SbOMT3. Transgenic plants which express SbOMT3 can convert resveratrol into pterostilbene in planta. SbOMT3 is also involved in the biosynthesis of sorgoleone.
摘要:
Sorghum is considered an allelopathic crop species and sorgoleone likely accounts for much of its allelopathic properties. Prior investigations into the biosynthesis of sorgoleone suggested the participation of one or more alkylresorcinol synthases (ARS), which are type III polyketide synthases (PKS) that produce 5-alkylresorcinols using medium to long-chain fatty acyl-CoA starter units via iterative condensations with malonyl-CoA. Quantitative real-time RT-PCR analysis of PKS-like sequences mined from isolated root hairs revealed that two sequences, designated ARS1 and ARS2, were preferentially expressed. Recombinant enzyme studies demonstrated that both sequences encode ARS enzymes capable of accepting a variety of fatty acyl-CoA starter units. RNA interference (RNAi) experiments directed against ARS1 and ARS2 resulted in the generation of multiple independent transformant events exhibiting dramatically reduced sorgoleone levels. Thus, both ARS1 and ARS2 participate in the biosynthesis of sorgoleone in planta. ARS1 and ARS2 sequences were used to identify rice genes encoding alkylresorcinol synthases.
摘要:
Sorghum is considered to be an allelopathic crop species, producing phytotoxins such as the lipid benzoquinone sorgoleone (2-hydroxy-5-methoxy-3-[(Z,Z)-8′,11′,14′-pentadecatriene]-p-benzoquinone) which likely accounts for much of its allelopathic properties. Prior investigations into the biosynthesis of sorgoleone have suggested the participation of one or more alkylresorcinol synthases (ARS), which are type III polyketide synthases (PKS) that produce 5-alkylresorcinols using medium to long-chain fatty acyl-CoA starter units via iterative condensations with malonyl-CoA. Current evidence suggests that sorgoleone biosynthesis occurs exclusively in root hair cells, involving the synthesis of a 5-pentadecatrienyl resorcinol intermediate derived from an unusual 16:3 fatty acyl-CoA starter unit. To characterize the enzymes responsible for the biosynthesis of this alkylresorcinol intermediate, a previously-described expressed sequence tag (EST) database prepared from isolated root hairs was first mined for all PKS-like sequences. Quantitative real-time RT-PCR analyses revealed that two of these sequences were preferentially expressed in root hairs, and recombinant enzyme studies demonstrated that both sequences (designated ARS1 and ARS2) encode ARS enzymes capable of accepting a variety of fatty acyl-CoA starter units. Furthermore, RNA interference (RNAi) experiments directed against ARS1 and ARS2 resulted in the generation of multiple independent transformant events exhibiting dramatically reduced sorgoleone levels. Thus, both ARS1 and ARS2 are likely to participate in the biosynthesis of sorgoleone in planta. The sequences of ARS1 and ARS2 were also used to identify several rice genes encoding ARSs, which are likely involved in the production of defense-related alkylresorcinols.
摘要:
This invention relates to the fatty acid desaturase genes, designated SbDES2 and SbDES3, cloned from an expressed sequence tag (EST) database prepared from isolated root hairs from sorghum. Heterologous expression of the cDNAs in S. cerevisiae revealed that recombinant SbDES2 converted palmitoleic acid (16:1Δ9) to hexadecadienoic acid (16:2Δ9, 12), and that recombinant SbDES3 was capable of converting hexadecadienoic acid into hexadecatrienoic acid (16:3Δ9, 12, 15). Desaturase enzymes capable of performing desaturation reactions producing a terminal double bond have not previously been characterized in a plant system.
摘要:
The present invention relates to polynucleotide molecules for regulating gene expression in plants. In particular, the invention relates to DNA sequences of the rice (Oryza sativa cv Nipponbare) triosephosphate isomerase (OsTPI) gene promoter that are useful for regulating gene expression of heterologous polynucleotide molecules in plants. The invention also relates to expression constructs and transgenic plants containing the heterologous polynucleotide molecules operably linked to and regulated by OsTPI DNA sequences.
摘要:
The methods and materials disclosed herein are directed to glyphosate herbicide tolerance in plants. In particular, the isolation of a glyphosate resistant EPSP synthase coding sequence from Eleusine indica. The coding sequence is useful to genetically engineer plants for tolerance to glyphosate herbicide.
摘要:
Methods and materials are disclosed for the inhibition and control of gibberellic acid levels. In particular, nucleic acid sequences of copalyl diphosphate synthase, 3-&bgr; hydroxylase, and 2-oxidase and additional nucleic acid sequences are disclosed. Gibberellic acid levels may be inhibited or controlled by preparation of a chimeric expression construct capable of expressing antisense RNA which suppresses the gibberellin biosynthetic pathway sequence. The antisense sequence is the complement of a copalyl diphosphate synthase sequence, a 3&bgr;-hydroxylase sequence, or a C20-oxidase sequence. Administration of a complementing agent, preferably a gibberellin or gibberellin precursor or intermediate restores bioactivity.
摘要:
Methods and materials are disclosed for the inhibition and control of gibberellic acid levels. In particular, nucleic acid sequences of copalyl diphosphate synthase. 3-β hydroxylase, and 2-oxidase and additional nucleic acid sequences are disclosed. Gibberellic acid levels may be inhibited or controlled by preparation of a chimeric expression construct capable of expressing a RNA or protein product which suppresses the gibberellin biosynthetic pathway sequence, diverts substrates from the pathway or degrades pathway substrates or products. The sequence is preferably a copalyl diphosphate synthase sequence, a 3β-hydroxylase sequence, a 2-oxidase sequence, a phytoene synthase sequence, a C20-oxidase sequence, and a 2β,3β-hydroxylase sequence. Administration of a complementing agent, preferably a gibberellin or gibberellin precursor or intermediate restores bioactivity.