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Overlapping expression of cytosolic glutamine synthetase and phenylalanine ammonia‐lyase in immature leaf blades of rice
Author(s) -
Sakurai Nozomu,
Katayama Yoshihiro,
Yamaya Tomoyuki
Publication year - 2001
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2001.1130314.x
Subject(s) - xylem , vascular bundle , phenylalanine ammonia lyase , parenchyma , cytosol , oryza sativa , phenylalanine , biochemistry , lignin , secondary cell wall , cell wall , lyase , biology , glutamine synthetase , phloem , enzyme , glutamine , microbiology and biotechnology , botany , gene , amino acid
In order to estimate whether cytosolic glutamine synthetase (GS1; EC 6.3.1.2) is partly coupled to the reaction of phenylalanine ammonia‐lyase (PAL; EC 4.3.1.5) in developing organs of rice ( Oryza sativa L.), we compared the expression pattern of transcripts and proteins for GS1 and PAL in the tissue sections from leaf blades at various stages of development. In immature vascular bundles of unexpanded leaf blades, GS1 mRNA was mainly detected in xylem parenchyma cells, mestome‐sheath cells, and sclerenchyma cells. PAL transcripts were also accumulated in these cell types. Vascular bundles in midribs of immature leaf blades contained mRNAs and proteins for both GS1 and PAL abundantly in sclerenchyma cells, although distribution of these two proteins was not completely overlapped. In immature vascular bundles in midribs, lignin deposition was observed in cell walls of xylem parenchyma cells, mestome‐sheath cells and sclerenchyma cells. These results implied that a part of GS1 in unexpanded leaf blades is possibly involved in reassimilation of ammonia released from PAL reaction during the lignin production.