Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Agriculture Botany

Chlamydomonas reinhardtii is a model organism for nutrient limitation studies and many other physiological studies. Particularly under nitrogen depleted conditions, microalgal lipid biosynthesis has been intensively studied where triacylglycerols (TAGs) rapidly accumulate, but much less is known under phosphorus depleted conditions. Moreover, knowledge about phosphate (Pi) uptake and polyphosphate (polyP) metabolism in microalgae remains limited. Phosphorus (P) limitation triggers the expression of many genes involved in P uptake and manipulation as well as implicates in lipid biosynthesis pattern alteration. Here, a knockout mutant of vacuolar transporter chaperone 1 (xvtc1) strain is physiologically characterized under P replete and deplete conditions comparing to its rescue strain. The growth rate of xvtc1 strain was faster than that of rescue strain under P repletion but much slower under P depletion. P starved xvtc1 cells showed higher death ratio. In xvtc1 strain grown under P deplete condition, the lower cell density, the lower self-shading, the lower chlorophyll (chl) b content, and the higher chl a/b ratio

Issued also as CD