Characterization of a rice chlorophyll-deficient mutant using the T-DNA gene-trap system.
We have previously generated a large pool of T-DNA insertional lines in rice. In this study, we screened those T-DNA pools for rice mutants that had defective chlorophylls. Among the 1,995 lines examined in the T2 generation, 189 showed a chlorophyll-deficient phenotype that segregated as a single recessive locus. Among the mutants, 10 lines were beta-glucuronidase (GUS)-positive in the leaves. Line 9-07117 has a T-DNA insertion into the gene that is highly homologous to XANTHA-F in barley and CHLH in Arabidopsis: This OsCHLH gene encodes the largest subunit of the rice Mg-chelatase, a key enzyme in the chlorophyll branch of the tetrapyrrole biosynthetic pathway. In the T2 and T3 generations, the chlorina mutant phenotypes are co-segregated with the T-DNA. We have identified two additional chlorina mutants that have a Tos17 insertion in the OsCHLH gene. Those phenotypes were co-segregated with Tos17 in the progeny. GUS assays and RNA blot analysis showed that expression of the OsCHLH gene is light inducible, while TEM analysis revealed that the thylakoid membrane of the mutant chloroplasts is underdeveloped. The chlorophyll content was very low in the OschlH mutants. This is the first report that T-DNA insertional mutagenesis can be used for functional analysis of rice genes.
Jung
Ki-Hong
KH
National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 Republic of Korea.
Hur
Junghe
J
Ryu
Choong-Hwan
CH
Choi
Youngju
Y
Chung
Yong-Yoon
YY
Miyao
Akio
A
Hirochika
Hirohiko
H
An
Gynheung
G
D000483:Alleles; D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000096:biosynthesis*; D002736:Chloroplasts / Q000201:enzymology / Q000235:genetics / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000235:genetics; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D008027:Light; D008190:Lyases / Q000235:genetics* / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000201:enzymology / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000201:enzymology / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D004269:DNA, Bacterial; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C036483:T-DNA; D002734:Chlorophyll; D005966:Glucuronidase; D008190:Lyases; C086788:magnesium chelatase