Cell-wall invertases from rice are differentially expressed in Caryopsis during the grain filling stage.
Cell-wall invertase plays an important role in sucrose partitioning between source and sink organs in higher plants. To investigate the role of cell-wall invertases for seed development in rice (Oryza sativa L.), cDNAs of three putative cell-wall invertase genes OsCIN1, OsCIN2 and OsCIN3 were isolated. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed different expression patterns of the three genes in various rice tissues/organs. In developing caryopses, they exhibited similar temporal expression patterns, expressed highly at the early and middle grain filling stages and gradually declined to low levels afterward. However, the spatial expression patterns of them were very different, with OsCIN1 primarily expressed in the caryopsis coat, OsCIN2 in embryo and endosperm, and OsCIN3 in embryo. Further RNA in situ hybridization analysis revealed that a strong signal of OsCIN2 mRNA was detected in the vascular parenchyma surrounding the xylem of the chalazal vein and the aleurone layer, whereas OsCIN3 transcript was strongly detected in the vascular parenchyma surrounding the phloem of the chalazal vein, cross-cells, the aleurone layer and the nucellar tissue. These data indicate that the three cell-wall invertase genes play complementary/synergetic roles in assimilate unloading during the grain filling stage. In addition, the cell type-specific expression patterns of OsCIN3 in source leaf blades and anthers were also investigated, and its corresponding physiological roles were discussed.
Wang
Yong-Qin
YQ
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China.
Wei
Xiao-Li
XL
Xu
Hong-Lin
HL
Chai
Cheng-Lin
CL
Meng
Kun
K
Zhai
Hong-Li
HL
Sun
Ai-Jun
AJ
Peng
Yong-Gang
YG
Wu
Bin
B
Xiao
Gui-Fang
GF
Zhu
Zhen
Z
D000595:Amino Acid Sequence; D002473:Cell Wall / Q000201:enzymology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D035264:Flowers / Q000201:enzymology* / Q000235:genetics*; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012275:Oryza / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D043324:beta-Fructofuranosidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D018076:DNA, Complementary; D010940:Plant Proteins; D012333:RNA, Messenger; D043324:beta-Fructofuranosidase