[Analysis of the Gamete-Fusion Genes in the Haploid-inducing ZMS-P Maize Line].

This article is devoted to the study of the double fertilization mechanism in plants, in particular of the maize gamete membrane fusion genes. We detected and analyzed for the first time gamete-fusion genes in the maize genome. Using the BLAST program, we searched for the hap2 gene (generative cell specific 1 (gcs1)) homologs from Arabidopsis in the maize genome. The ZM_BFb0162K03 maize transcript was found, which had 67% identity to the Athap2 gene and contained a conserved region similar to the Athap2 gene fragment. In mRNA samples from the haploid-inducing and control maize lines, an PCR was conducted by using primers specific to the ZM_BFb0162K03 sequence fragment. Sequences of the PCR products from a fragment (1467 bp) of the Zm_hap2 gene of the haploid-inducing and the control maize lines were identical and also were identical to the maize sequences from the GenBank (ZM_BFb0162K03). PCR products (656 bp region of Zm_hap2) for the ZM_BFb0162K03 (1925 bp) maize sequence were observed for the cDNA of pollen grains, ovary, leaves, and roots of the haploid-inducing and control maize lines. Using the Blastx program, we found significant homology of the maize translated proteins to the GEX2, TET11, and TET12 proteins, involved in Arabidopsis gamete-fusion contacts.

Supramolecular complexes of the Agrobacterium tumefaciens virulence protein VirE2.

Virulence protein VirE2 from Agrobacterium tumefaciens is involved in plant infection by transferring a fragment of agrobacterial Ti plasmid ssT-DNA in complex with VirE2-VirD2 proteins into the plant cell nucleus. The VirE2 protein interactions with ssDNA and formation of VirE2 protein complexes in vitro and in silico have been studied. Using dynamic light scattering we found that purified recombinant protein VirE2 exists in buffer solution in the form of complexes of 2-4 protein molecules of 12-18 nm size. We used computer methods to design models of complexes consisting of two and four individual VirE2 proteins, and their dimensions were estimated. Dimensions of VirE2 complexes with ssDNA (550 and 700 nucleotide residues) were determined using transmission electron microscopy and dynamic light scattering. We found that in vitro, upon interaction with ssDNA recombinant protein, VirE2 is able to alter conformation of the latter by shortening the initial length of the ssDNA.