Steady state transcript levels of psbA, rbcL, atpB, and psbN genes accumulated differentially in mature leaves of a field-grown tree Populus deltoides during natural diurnal cycle and in dark adaptation followed by irradiation. The rbcL transcript accumulated independent of irradiation under diurnal conditions, which demonstrated a correlation with the phenomenon of midday depression in photosynthesis. The psbA and atpB transcripts accumulated more in dark whereas psbN accumulated more in light. Diurnal rhythm of gene expression in mature chloroplasts was independent of development related changes. and S. Srivastava, P. K. Trivedi, P. Nath.
Prosopis juliflora is a hardy plant tolerant to drought, salinity, extremes of soil pH, and heavy metal stress. We isolated and characterized a photosystem 2 (PS2) gene PsbR (Pj PsbR) and its promoter. Northern analysis for Pj PsbR in P. juliflora leaves under 25 % polyethylene glycol stress showed steady decrease in transcript level at 12, 24, and 48 h after stress application. Under 90 mM H2O2 stress, transcript level dropped drastically at 12 h, but increased again compared to the control at 24 h. A 1.7 kb fragment upstream the 5' UTR of this gene (putative promoter) was isolated and analyzed in silico. Several putative cis-acting DNA elements were identified in this sequence. and G. Suja, A. Parida.