Growth and development of plant occur under great influence of light, that quality and quantity changes are received by the specific photoreceptors. Various photoreceptors perceive the changing light condition and transform them into a molecular signal that results in the appropriate response. The photoreceptors of red/far-red light are phytochromes the dimeric proteins covalently linked with phytochromobilin that acts as a chromophore.
The phytohormone abscisic acid (ABA) coordinates plant responses to stressors such as drought, extreme temperature and high salinity, as well regulates non-stress responses including seed formation and maturation, seed and bud dormancy, root growth, leaf senescence, and transition between vegetative and reproductive growth. ABA, similarly like the others plant hormones, functions through a complex network of signaling pathway, where ABA signal perception by ABA receptors is the primary event that triggers downstream signaling cascades to induce the final physiological responses.
Polar auxin transport , which takes place with the carrier protein , is a unique way to distribute auxin in plant enabling the formation in particular cells or tissues phytohormone concentration gradient . The auxin transport protein involved belong to three families : media PIN (PIN -formed ) , the pump PGP / ABCb ( P-glycoprotein/ATP binding cassette ) and permease AUX1/LAX ( auxina RESISTANT1/LIKE-AUX1 ) . The results of recent studies have confirmed that five of the eight PIN proteins in A. thaliana , functioning as carriers transporting auxin out of the cell .
Abscisic acid (ABA ) regulates a number of different processes , including ripening and seed dormancy , root growth , leaf senescence , and the phase transition from vegetative to generative growth . ABA is the main hormone stress enabling the plant to adapt to environmental factors such as drought, cold or salinity , which mediates the regulation of stomatal thereby controlling water flow and affecting the expression of genes related to stress .
Polar auxin transport is essential for normal plant growth and development. Auxin moves between plant cells through a combination of membrane diffusion and carrier-mediated transport. Recent studies have identified several classes of membrane proteins involved in auxin transport, and have started to uncover a system that regulates auxin flux through plant tissues via the subcellular asymmetric locali- zation of these proteins.
In Arabidopsis thaliana more than 1300 genes (~5% of the proteome) encode components of the ubiquitin/26S proteasome pathway. Approximately 90% of these genes encode subunits of the E3 ubiquitin ligases, which confer substrate specificity to the ubiquitin/26S proteasome pathway. The plant E3 ubiquitin ligases comprise a large and diverse family of proteins or protein complexes containing a RING-finger, U-box domain or a HECT domain.
Short- portion of the solar spectrum , especially blue light (390500 nm) and near ultraviolet (320390 nm) have a significant impact on the growth and development of plants . Research in the field of genetics and molecular biology , carried out mainly on the model plant Arabidopsis thaliana , allowed to know the three classes of receptors of blue light and UV- A fototropin , cryptochromes and flavoproteins with family Zeitlupe .
Phytochromes are plant, cytoplasmic photoreceptors and far red light red, which in response to a given stimulus light to undergo photoconversion active form Pfr and migrate to the nucleus. Recent studies show that phytochromes can phosphorylate a number of proteins (PKS1, Aux / IAA, cryptochromes, NDPK2) or as a result of direct interaction with the relevant nuclear proteins (PIF3, HFR1/REP/RSF1, PIF4, ELF3, ARR4) are involved in the regulation of trankrypcji genes.
Some mono- and disaccharides act as signaling molecules that regulate gene expression. In budding yeast, the glucose sensor membrane Rgt2 Snf3 and activate signaling pathways regulating the expression of genes encoding glucose transporters . GPR1 membrane glucose receptor interacting with the G protein activates a signal transduction chain comprising the adenylate cyclase and protein kinase A. Results of many studies suggest that changes in intracellular levels of glucose by heksokinazę2 ( Hxk2 ) .
Previously known plant signal peptides (SCR CLAVATA3, fitosulfokina-a, systemin, ENOD40) are involved in the transmission of information between cells or organs. SCR polypeptide is recognized by the pollen ligand receptor complex epidermal nevus cells apophysary. The effect of pollen recognition response is the activation of the signaling pathway regulating the effector mechanism responsible for the hydration of pollen grains. CLAVATA3 is a small secreted polypeptide involved in the transfer of information between separate compartments phones shoot apical meristem.