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First published online August 26, 2005; 10.1104/pp.105.063420 Plant Physiology 139:296-305 (2005) © 2005 American Society of Plant Biologists
Loss of Function of OsDCL1 Affects MicroRNA Accumulation and Causes Developmental Defects in Rice1,[w]National Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China (B.L., P.L., C.L., S.C., C.C., X.C.); Graduate School of the Chinese Academy of Sciences, Beijing 100039, China (B.L., P.L.); and China Agricultural University, Beijing 100094, China (X.L.)
MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are two types of noncoding RNAs involved in developmental regulation, genome maintenance, and defense in eukaryotes. The activity of Dicer or Dicer-like (DCL) proteins is required for the maturation of miRNAs and siRNAs. In this study, we cloned and sequenced 66 candidate rice (Oryza sativa) miRNAs out of 1,650 small RNA sequences (19 to approximately 25 nt), and they could be further grouped into 21 families, 12 of which are newly identified and three of which, OsmiR528, OsmiR529, and OsmiR530, have been confirmed by northern blot. To study the function of rice DCL proteins (OsDCLs) in the biogenesis of miRNAs and siRNAs, we searched genome databases and identified four OsDCLs. An RNA interference approach was applied to knock down two OsDCLs, OsDCL1 and OsDCL4, respectively. Strong loss of function of OsDCL1IR transformants that expressed inverted repeats of OsDCL1 resulted in developmental arrest at the seedling stage, and weak loss of function of OsDCL1IR transformants caused pleiotropic developmental defects. Moreover, all miRNAs tested were greatly reduced in OsDCL1IR but not OsDCL4IR transformants, indicating that OsDCL1 plays a critical role in miRNA processing in rice. In contrast, the production of siRNA from transgenic inverted repeats and endogenous CentO regions were not affected in either OsDCL1IR or OsDCL4IR transformants, suggesting that the production of miRNAs and siRNAs is via distinct OsDCLs.
1 This work was supported by the National Natural Science Foundation of China (grant nos. 30430410 and 30325015 to X.C.) and the BaiRen and State High-Tech Program (grant to X.C.). 2 These authors contributed equally to the paper. [w] The online version of this article contains Web-only data. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.063420. * Corresponding author; e-mail xfcao{at}genetics.ac.cn; fax 861064873428. Received March 28, 2005; returned for revision June 8, 2005; accepted June 21, 2005. This article has been cited by other articles:
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