Differential expression of TLP, ERF1, and R2R3MYB in annual Medicago species under salinity conditions.

The present study was conducted to evaluate the responses of three annual Medicago species (M. truncatula, M. laciniata, and M. polymorpha) to salinity. We analyzed publicly available microarray data in NCBI pertaining to salinity-response genes in M. truncatula. Our data search identified Tubby C2 (TLP) and ethylene responsive transcription factor 1 (ERF1) as genes that potentially respond to salinity. We evaluated morpho-physiological traits and the expression of the genes in three Medicago species that had been maintained under control and saline conditions. The analysis of morpho-physiological traits showed that M. polymorpha and M. laciniata were more tolerant to salinity than M. truncatula, as they had lower reductions in biomass and dry root weight and lower increases in anthocyanin concentration. The saline conditions caused a significant increase (P < 0.01) in the expression of TLP in all Medicago species, but caused a significant decrease in the expression of ERF1. Considerable variation in anthocyanin concentrations was found among the three Medicago species. To investigate the cause of this variation, we examined the expression of R2R3MYB, a gene involved in the biosynthesis of anthocyanins. Our analysis showed that saline conditions induced high over-expression of R2R3MYB in all three Medicago spp. The high efficiency of the primer pairs used in qRT-PCR enabled us to compare the expression levels of each gene in the three species. We concluded that the more salt tolerant species showed higher expression of TLP and R2R3MYB under both control and salinity conditions.

[Experimental models for creation of transgenic plants resistant to stress factors].

Experimental models of the potato primary transgenic plants which express the hybrid gene cry3aM-licBM2 have been created. Modecular analysis and the biotests of the experimental models allow proposing a new system of cry genes expression in plants. The system is based on the expression of hybrid genes possessing the sequence of reporter lichenase gene and the use as a regulator element of a light-induced promoter providing preferential expression of the controled genes only in green plant tissues (leaves)--the target tissues for pests. The lichanase presence in hybrid proteins facilitates selection and analysis of the expression level of the hybris proteins in transgenic organisms. Basing on the lichenase properties in hybrid proteins it seems possible to use this reporter system for transgene monitoring in agrocoenosis as this system is rather simple and precise and does not need large material and time expenses.