Effect of photooxidative destruction of chloroplasts on the expression of nuclear genes for C4 photosynthesis and for chloroplast biogenesis in maize.
Norflurazon, an inhibitor of carotenoid synthesis, is known to cause photooxidative destruction of chloroplasts. Expression of many nuclear genes for chloroplast-destined proteins is suppressed in the photobleached seedings due to impairment of signaling from chloroplasts to nuclei. Here the effect of norflurazon-treatment on the expression of genes for C4 photosynthesis was investigated. Unlike the genes of Cab and RbcS, the levels of mRNA for pyruvate Pi dikinase and NADP-malic enzyme were not markedly reduced. However, their protein levels were more significantly reduced suggesting a control by chloroplast exerted at the translational step. From their molecular sizes these proteins seemed to have been correctly processed and hence localized in the rudimental chloroplasts. In support of this, 9 kinds of proteins for chloroplast biogenesis such as Toc family and Hsp 70 proteins were not suppressed, suggesting that protein import machinery and processing are still functional in the cells harboring rudimental chloroplasts. Diurnal changes of the levels of transcripts for photosynthetic genes persisted in the norflurazon-treated seedlings indicating non-involvement of chloroplast in this light control.
Tamada
Yosuke
Y
Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Imanari
Eiji
E
Kurotani
Ken-ichi
K
Nakai
Masato
M
Andreo
Carlos S
CS
Izui
Katsura
K
D002338:Carotenoids / Q000096:biosynthesis; D002352:Carrier Proteins / Q000235:genetics; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D002940:Circadian Rhythm; D015870:Gene Expression / Q000187:drug effects / Q000528:radiation effects; D017343:Genes, Plant; D006540:Herbicides / Q000494:pharmacology; D045342:Light-Harvesting Protein Complexes; D008291:Malate Dehydrogenase / Q000235:genetics; D018462:Photobiology; D038761:Photobleaching; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000235:genetics; D011724:Pyridazines / Q000494:pharmacology; D011772:Pyruvate, Orthophosphate Dikinase / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects*
D002352:Carrier Proteins; D006540:Herbicides; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D011724:Pyridazines; D012333:RNA, Messenger; D018749:RNA, Plant; C085170:chlorophyll a-b-binding protein type II, Zea mays; D002338:Carotenoids; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+); D011772:Pyruvate, Orthophosphate Dikinase; D012273:Ribulose-Bisphosphate Carboxylase; C008677:norflurazone