ABSTRACT
It is proven that retrograde tetrapyrrole-induced plastid signals, light signals, and signals induced by hormones and carbohydrates influence expression of nuclear genes of plastid stress proteins ELIP in Arabidopsis thaliana L. Plastid signals differently regulated expression of genes from multigene family of photosynthesis proteins (ELIP and Lhcb2) and were modulated by light. The influence of a regulator of plant growth--abscisic acid--led to activation of expression of ELIP genes in the light. Carbohydrates suppressed transcription of ELIP genes. Thus, signals of exogenous (light) and endogenous (retrograde signals, hormones, carbohydrates) origin influence the expression of ELIP genes. These types of signals probably interact with each other and favor the increase of resistance of plants to the action of stress factors of the environment.
Subject(s)
Abscisic Acid/pharmacology , Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Carbohydrate Metabolism , Gene Expression Regulation, Plant , Light , Plant Growth Regulators/pharmacology , Plastids/metabolism , Signal Transduction , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Carbohydrate Metabolism/drug effects , Carbohydrate Metabolism/physiology , Carbohydrate Metabolism/radiation effects , Carbohydrates/genetics , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/physiology , Gene Expression Regulation, Plant/radiation effects , Plastids/genetics , Signal Transduction/drug effects , Signal Transduction/physiology , Signal Transduction/radiation effectsABSTRACT
The effect of melafen, a plant growth regulator of a new generation, on the growth, pigment composition, and expression of nuclear genes Elip1 and Elip2 encoding chloroplast light-stress proteins in barley (Hordeum vulgare L) seedlings was studied. It is shown that the height of seedlings treated with melafen at concentrations of 0.5 x 10(-10) and 0.5 x 10(-8) M increased by approximately 10 and 20%, respectively, as compared to the control. At high concentrations (10(-5) and 10(-3) M), melafen had no effect on the growth of seedlings. The content of chlorophylls and carotenoids in chloroplasts barely differed from the control at all melafen concentrations tested. Reverse transcription-polymerase chain reaction (RT-PCR) showed that melafen did not influence the expression of the nuclear gene encoding the low-molecular-weight plastid stress protein ELIP1. At the same time, the expression of the nuclear gene encoding the high-molecular-weight light-inducible stress protein ELIP2 in the plants treated with melafen at a concentration of 0.5 x 10(-8) M, increased by approximately 70 %. At higher concentrations, melafen suppressed the Elip2 gene expression. Thus, melafen affects the expression of the Elip2 gene, which is involved in the regulation of chlorophyll synthesis and chloroplast biogenesis, which, in turn, may lead to changes in the resistance of plants to light-induced stress.
