cytgen

Abstract An important model system for studying the role of genetic diversity and hybridization in plant invasions is the species complex of the genus Reynoutria Houtt. Within the secondary distribution range, two species of this genus are widespread, R. japonica Houtt. and R. sachalinensis (F. Schmidt) Nakai, as well as their derivatives, the hexaploid R. × bohemica Chrtek & Chrtková and the tetraploid R. × moravica (Hodálová and Mereďa) Olshanskyi and Antonenko, which are recognized as separate species. The genetic diversity of the species of the genus Reynoutria in Ukraine is still almost unexplored by molecular methods. In this work, we determined chloroplast haplotypes for samples of R. japonica, R. sachalinensis and R. × bohemica from Ukraine and other European countries and compared them with haplotypes of Reynoutria from the primary distribution range in China and Korea. The genetic diversity of R. japonica from the primary distribution range was significantly higher compared to European samples, which are mainly represented by the haplotype J1.1. At the same time, we identified haplotypes J1.2 and J1.3 specific to the Eastern European area, which probably arose as a consequence of the divergence of the chloroplast genome within the secondary distribution range. Of the five samples morphologically identified as R. × bohemica, three carry the haplotype J1.1, which is consistent with the idea that R. japonica var. japonica was involved as a maternal form in the formation of R. × bohemica. However, a chloroplast haplotype identical to R. sachalinensis was detected in two samples from the Alpine region of Europe. These samples likely represent another hybrid species of R. × moravica. Therefore, the use of chloroplast DNA markers is crucial for identifying the donor of maternal subgenomes in hybrid forms of the genus Reynoutria.

Abstract In this research the involvement of autophagy in the development of microsporogenesis in shepherd’s purse (Capsella bursa-pastoris) as a representative of dicotyledons and in Siebold’s plantain lily (Hosta sieboldiana) and Virginia spiderwort (Tradescantia virginiana) as representatives of monocotyledons was investigated. It was shown that microsporogenesis in the studied species is accompanied by the activation of autophagy, which is associated with both the onset and completion of meiosis and corresponds to the accumulation and degradation of regulators involved in meiotic division and tapetogenesis. The presence of cytomixis in meiosis prophase may serve as additional confirmation of the regulatory role of autophagy in meiosis. It was confirmed that autophagy is involved in the functioning and degradation of the tapetum. The activation of autophagy may accompany the formation of tetrads of microspores (C. bursa-pastoris), the functioning and degradation of the tapetum (H. sieboldiana), as well as the formation of tetrads and the final degradation of the tapetum (T. virginiana). This may be because the studied species differ in the type of tapetum (secretory and plasmodial). This difference between tapetum types is not clearly diagnosed, and varieties are differentiated in terms of reorganization, intensity of autophagy, and time of degradation of the tapetum tissue within the secretory type. The obtained results allow for the conclusion that, in general, the functioning and degradation of the tapetum in the studied monocots are accompanied by more intense autophagy than in the representative of dicot.