Developmental- and Tissue-Specific Expression of NbCMT3-2 Encoding a Chromomethylase in Nicotiana benthamiana.
The chromomethylase (CMT) protein family is unique to plants and controls non-CpG methylation. Here, we investigated the developmental expression of CMT3-2 in Nicotiana benthamiana (NbCMT3-2) and its significance by analyzing plants with silenced NbCMT3-2 and leaf tissues transiently expressing the N-terminal polypeptide. Alignment of the NbCMT3-2 amino acid sequence with that of other plant CMT3s showed a specific N-terminal extension required for nuclear localization. Transient expression of the N-terminal polypeptide in N. benthamiana resulted in chlorotic lesions. NbCMT3-2 was expressed mainly in proliferating tissues such as the shoot apex and developing leaves. We generated transgenic N. benthamiana harboring a fusion reporter construct linking the NbCMT3-2 promoter region and the β-glucuronidase (GUS) reporter (pNbCMT3-2::GUS) to analyze the tissue-specific expression of NbCMT3-2. NbCMT3-2 was expressed in the shoot and root apical meristem and leaf primordia in young seedlings and highly expressed in developing leaves and ovary as well as lateral buds in mature plants. Virus-induced gene silencing used to knock down the expression of NbCMT3 or NbCMT3-2 or both led to partial loss of genomic DNA methylation. Plants with suppressed NbCMT3 expression grew and developed normally, whereas leaves with NbCMT3-2 knockdown showed mild curling as compared with controls. Silencing NbCMT3/3-2 severely interfered with leaf development and directly or indirectly affected the expression of genes involved in jasmonate homeostasis. The differential roles of NbCMT3 and NbCMT3-2 were investigated and compared. We reveal the expression patterns of NbCMT3-2 in proliferating tissues. NbCMT3-2 may play an essential role in leaf development by modulating jasmonate pathways.
Department of Biology, National Changhua University of Education, No. 1, Jin-De Road, Changhua, 500, Taiwan.
Yu-Ting
YT
Lin
Department of Biology, National Changhua University of Education, No. 1, Jin-De Road, Changhua, 500, Taiwan.
Huei-Mei
HM
Wei
Department of Biology, National Changhua University of Education, No. 1, Jin-De Road, Changhua, 500, Taiwan.
Hsueh-Yu
HY
Lu
Botany Department, National Museum of Natural Science, No. 1, Guancian Road, Taichung 404, Taiwan.
Yung-I
YI
Lee
Department of Biology, National Changhua University of Education, No. 1, Jin-De Road, Changhua, 500, Taiwan sffuplant@cc.ncue.edu.tw.
Shih-Feng
SF
Fu
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant; D005966:Glucuronidase / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics*; D038081:Organogenesis / Q000235:genetics; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics; D018520:Plant Shoots / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
D018076:DNA, Complementary; D010940:Plant Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases; C112810:chromomethylase; D005966:Glucuronidase
Chromomethylase; DNA methylation; Meristem; Virus-induced gene silencing