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A virescent gene V 1 determines the expression timing of plastid genes for transcription/translation apparatus during early leaf development in rice
Author(s) -
Kusumi Kensuke,
Mizutani Akiko,
Nishimura Mitsuo,
Iba Koh
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.12061241.x
Subject(s) - biology , plastid , gene , nuclear gene , mutant , chloroplast , transcription (linguistics) , genetics , gene expression , microbiology and biotechnology , botany , genome , linguistics , philosophy
Differentiation of proplastids into functionally active chloroplasts is one of the most significant changes in cellular organization associated with leaf development in higher plants. This process involves activation of a large number of nuclear and chloroplast genes. A central question, therefore, concerns the nature and origin of the signals that initiate and control this process. The rice nuclear mutant, virescent‐1 ( v 1 ), is temperature‐conditional and develops chlorotic leaves when grown at restrictive temperatures. We report here the effects of v 1 mutation on the expressions of plastid and nuclear genes during leaf development. In the wild‐type rice seedlings, the transcripts of the plastid RNA polymerase gene ( rpoB ) and ribosomal protein genes ( rps7, rps15 ) accumulated during a strictly limited period of early leaf development, prior to the accumulation of the transcripts of photosynthetic genes ( rbcL, RbcS, psbA, Lhc ). This period coincides very closely with the leaf developmental stage (late P4) at which the V 1 gene gives the signal that determines the virescent phenotype. On the contrary, in the v 1 seedlings grown at a restrictive temperature (20°C), this stage‐specific accumulation of the rpo and rps transcripts was missing. Instead, the accumulation of these transcripts occurred during a later stage of leaf maturation. In such mutant seedlings, the expression of other plastid genes ( psbA, rbcL , 16S rDNA ) was strongly suppressed and the normal chloroplast development was disturbed. These data indicate that the V 1 gene controls the timing of expression of the key plastid genes for the transcription/ translation apparatus that are essential for the subsequent activation of other plastid genes.