Abstract
Desirable morphological traits in rice plants, such as shorter stalks and erect leaves, are being pursued in breeding programs. Rice brassinosteroid (BR)-deficient mutants display the phenotype of reduced heights and erect lamina. Therefore, biotechnology can be used for controlled deactivation of bioactive BRs in specific tissues. Here, we isolated a gene encoding for a BR-deactivating enzyme. Based on its sequence identity with a known enzyme, Arabidopsis Cytochrome P450 734A1, we identified a rice homolog named OsCYP734A6 (LOC_Os01g29150). A search of the rice T-DNA mutant population for insertional mutants of this gene revealed two alleles. These T-DNA loss-of-function mutants displayed a strongly bending lamina phenotype similar to the morphology of rice plants treated with BRs. These two mutants were named bending lamina (bla)2-1 and bla2-2. In Arabidopsis, the transcript level of a putative BR biosynthetic gene, OsDWARF4, is feed-back down-regulated in response to exogenous application of BRs. Similarly, a steady-state level of OsDWARF4 transcripts was significantly down-regulated here in the bla2 mutant background. Based on their sequence similarity, the bending-lamina phenotype in the bla2 mutant, and down-regulation of the BR biosynthetic gene OsDWARF4, we therefore propose that OsCYP734A6 (BLA2) is likely to be involved in BR deactivation.
Original language | English |
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Pages (from-to) | 469-476 |
Number of pages | 8 |
Journal | Journal of Plant Biology |
Volume | 49 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2006 Dec 31 |
Bibliographical note
Funding Information:This work was supported in part by grants from the BioGreen 21 Program, Rural Development Administration, Korea; and from the Plant Metabolism Research Center at Kyung Hee University, Korea (Science Research Center Program from the Korea Science and Engineering Foundation).
All Science Journal Classification (ASJC) codes
- Plant Science