NgRDR1, an RNA-dependent RNA polymerase isolated from Nicotiana glutinosa, was involved in biotic and abiotic stresses.
The RNA-dependent RNA polymerases (RDRs) play a key role in RNA silencing, heterochromatin formation and natural gene regulation. Here, a novel RDR gene was isolated from Nicotiana glutinosa, designated as NgRDR1. The full-length cDNA of NgRDR1 encodes a 1117-amino acid protein which harbors the five conserved regions in plant RDRs, including the most remarkable motif DbDGD (b is a bulky residue). Amino acid sequence alignment revealed that NgRDR1 exhibited a high degree of identity with other higher plant RDR genes. Five exons were detected in the genomic DNA sequence, and the fourth exon is 151bp, the location and the length of which are conserved among different plant species. From the phylogenetic tree constructed with different kinds of plant RDRs, it is determined that NgRDR1 falls into group I, and is closely associated with the dicotyledons RDRs. The analysis of the 5'-flanking region of NgRDR1 revealed a group of putative cis-acting elements. The results of expression analysis showed that the transcripts of NgRDR1 can be induced by biotic stresses, such as exogenous signaling molecules including salicylic acid (SA), SA analogues, hydrogen peroxide (H(2)O(2)), and methyl jasmonate (MeJA). Furthermore, NgRDR1 expression can be up-regulated by potato virus Y (PVY), tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV), but not by potato virus X (PVX). Besides, different kinds of fungi can also induce NgRDR1 expression. These results indicate that NgRDR1 may play an important role in response to biotic and abiotic stresses.
Liu
Yan
Y
Shandong Agricultural University, Taian, PR China.
Gao
Qiuqiang
Q
Wu
Bin
B
Ai
Taobo
T
Guo
Xingqi
X
D024506:5' Flanking Region / Q000235:genetics; D000085:Acetates / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017799:Cucumovirus / Q000502:physiology; D003517:Cyclopentanes / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics*; D017800:Potyvirus / Q000502:physiology; D012324:RNA-Dependent RNA Polymerase / Q000145:classification / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020156:Salicylic Acid / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000502:physiology
D000085:Acetates; D003517:Cyclopentanes; D018076:DNA, Complementary; D018744:DNA, Plant; D016877:Oxidants; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; D012324:RNA-Dependent RNA Polymerase; D020156:Salicylic Acid