The presented project focuses on research of alternative development of the male gametophyte observed in wild sorghum (Sorghum purpureosericeum) and will be carried out in close connection with COST Action CA22157 (Reproductive Enhancement of CROP resilience to extreme climate).
In general, plants respond to stress with reduced fertility, often through the production of non-viable pollen. In S. purpureosericeum, however, the presence of the so-called B chromosome in the genome (found only in some individuals) provides an advantage in this respect. Individuals carrying the B chromosome show a change in the developmental programme of the male gametophyte and produce pollen grains that contain a higher than normal number of cells. The resulting four- or more-cellular pollen is viable, capable of pollination and has been observed to have an earlier onset of pollen tube germination, which represents a definite advantage in the fertilization process. The mechanism of the extra division of pollen nuclei is surprising and unique in natural conditions in angiosperms. The existence of this mechanism fundamentally alters pollen grain anatomy and points to the flexibility of biological systems.