Figure 2. Expression of marker genes implicated in photosynthesis and light stress.

(a) Plant photosynthetic pathway. (b) Six photosynthetic marker genes, photosystem II reaction center protein A, psbA (ATCG00020.1), photosystem I P700 chlorophyll A apoprotein A1, psaA (ATCG00350.1), photosynthetic electron transfer A, petA (ATCG00540.1), ferredoxin 2, ATFD2 (AT1G60950.1), chlorophyll A/B binding protein 1.1, LHCB1.1 (AT1G29920.1) and beta carbonic anhydrase 3, ATBCA3 (AT1G23730.1), each representing the main components of the photosynthetic pathway, are selected for expression study using semi-quantitative PCR. (c) Expression levels of two genes implicated in light stress, L-ascorbate peroxidase 1, APX1 (AT1G07890.3) and glutathione S-transferase phi8, GST6 (AT2G47730.1). 21-days old Arabidopsis plantlets grown under 90–100 μmol m⁻² s⁻¹ of cool-white fluorescent (W) light for 16/8-hour photoperiod at 22 °C with a relative humidity of 50–60% were illuminated with a continuous regime of red and blue (RB) laser light for seven days. Rosette leaves from three different biological replicates were harvested at 0, 1, 2, 4, 8, 16, 32, and 168 hours, after which the RNA were isolated and cDNA synthesized for the gene expression studies. All data were normalized against the protein phosphatase 2A subunit A3, PP2AA3 (AT1G13320) gene. Error bars represent standard error of the mean calculated from three independent biological replicates.