Developmental and light-dependent cues interact to establish steady-state levels of transcripts for photosynthesis-related genes (psbA, psbD, psaA and rbcL) in rice (Oryza sativa L.).
The steady-state transcript levels for psbA, psbD, psaA and rbcL are low in dark-grown rice seedlings as compared to those grown in light. Following seed germination, they accumulate in an age-dependent manner, in dark as well as light, reaching a maximal level on the 7th or 8th day, before a slow decline sets in. But transcripts for psbA and psbD continue to maintain relatively-high levels even after 10 days of growth in light. Exposure of 5-day-old dark-grown seedlings to light results in an approximately 25-60-fold increase in transcripts during a period of 72 h, followed by a decrease. An analysis of data from both lines of investigation reveals that the developmental programme increases the transcript levels for psbA, psbD, psaA and rbcL by about 10-, 2.3-, 7.0- and 8.0-fold, respectively, between 5-8 days after germination and it is independent of light. At the same time, exposure of the seedlings to light during this period further enhances transcript levels by 5-, 11.4-, 6.6- and 7.8-fold, respectively. Thus, both developmental and light-dependent cues contribute to establish steady-state levels of transcripts for the chloroplast genes investigated.
Kapoor
S
S
Department of Botany, University of Delhi, India.
Maheshwari
S C
SC
Tyagi
A K
AK
D002736:Chloroplasts / Q000378:metabolism; D003624:Darkness; D017343:Genes, Plant; D006706:Homeostasis / Q000235:genetics; D008027:Light; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010788:Photosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*
D012333:RNA, Messenger