[Effect of ectopic expression of NtEXPA5 gene on cell size and growth of organs of transgenic tobacco plants].

We obtained transgenic tobacco plants demonstrating overexpression of NtEXPA5 gene that encodes alpha-expansin of Nicotiana tabacum. The transgenic plants were characterized by increased size of leaves and stems. However, size of flowers remained almost unchanged. The increase of organ sizes was induced by cell stretching only. Moreover, the number of cell divisions was even decreased. The obtained data suggest tight interaction between cell stretching regulation and cell division, which together provide the basic mechanism aimed at the controlling of plant organ sizes.