Oryza sativa dicer-like4 reveals a key role for small interfering RNA silencing in plant development.
MicroRNAs and small interfering RNAs (siRNAs) are two classes of small regulatory RNAs derived from different types of precursors and processed by distinct Dicer or Dicer-like (DCL) proteins. During evolution, four Arabidopsis thaliana DCLs and six rice (Oryza sativa) DCLs (Os DCLs) appear to have acquired specialized functions. The Arabidopsis DCLs are well characterized, but those in rice remain largely unstudied. Here, we show that both knockdown and loss of function of rice DCL4, the homolog of Arabidopsis DCL4, lead to vegetative growth abnormalities and severe developmental defects in spikelet identity. These phenotypic alterations appear to be distinct from those observed in Arabidopsis dcl4 mutants, which exhibit accelerated vegetative phase change. The difference in phenotype between rice and Arabidopsis dcl4 mutants suggests that siRNA processing by DCL4 has a broader role in rice development than in Arabidopsis. Biochemical and genetic analyses indicate that Os DCL4 is the major Dicer responsible for the 21-nucleotide siRNAs associated with inverted repeat transgenes and for trans-acting siRNA (ta-siRNA) from the endogenous TRANS-ACTING siRNA3 (TAS3) gene. We show that the biogenesis mechanism of TAS3 ta-siRNA is conserved but that putative direct targets of Os DCL4 appear to be differentially regulated between monocots and dicots. Our results reveal a critical role of Os DCL4-mediated ta-siRNA biogenesis in rice development.
Liu
Bin
B
State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Chen
Zhiyu
Z
Song
Xianwei
X
Liu
Chunyan
C
Cui
Xia
X
Zhao
Xianfeng
X
Fang
Jun
J
Xu
Wenying
W
Zhang
Huiyong
H
Wang
Xiujie
X
Chu
Chengcai
C
Deng
Xingwang
X
Xue
Yongbiao
Y
Cao
Xiaofeng
X
D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D005808:Genes, Recessive; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009711:Nucleotides / Q000378:metabolism; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D043244:Ribonuclease III / Q000378:metabolism*; D019076:Transgenes
D009711:Nucleotides; D010940:Plant Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D043244:Ribonuclease III