The Role of Light Acclimation and Retrograde Signalling in Regulation of Cell Death and Immune Defences in Higher Plants.

Regulation and optimization of photosynthesis, transpiration, light acclimation and innate immunity is essential for agriculture and forestry plants’ productivity. Our results suggest that changes in photosystem II (PS II) maximum efficiency, water use efficiency, hormonal and reactive oxygen species cellular homeostasis, cell death and seed yield can be defined by the exponential function and simple equation with natural logarithm (y = y_0*e^-Kx), that depends on molecular regulators: LESION SIMULATING DISEASE 1 (LSD1), ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) and PHYTOALEXIN DEFICIENT 4 (PAD4). The LSD1 recessive null mutant (lsd1) regardless of permissive laboratory or non-permissive laboratory and field conditions demonstrates constant seed yield, but significant variation in PSII maximum and water use efficiencies, and in foliar transcriptomes that depend on EDS1 and PAD4. Obtained results suggest that LSD1/EDS1/PAD4 constitute at least tree component molecular machinery of chloroplast retrograde signalling regulating plant productivity in the field. Biotechnologically proven potential of these and other cell death regulators in regulation of  crops’ stress tolerance (drought, UV, pathogen attack, root hypoxia and excess light), biomass quality (cell wall composition and its energy potential) and quantity (trees growth in the field) and seed yield will be presented and discussed. In our recent studies, we have identified a novel transcriptional regulators of the chloroplast retrograde signalling and are assessing the modulation of the redox homeostasis as a new strategy to improve plant performance in stress conditions.