Overexpression of pectate lyase gene FvPLB leads to pollen abortion in Fragaria vesca

The pectate lyase gene FvPLB has been implicated in the regulation of fruit softening in previous studies. We have now also found that abortions occurred in FvPLB overexpression lines. After overexpression of FvPLB, the cellulose content in the pollen grain and pollen tube wall was not affected, but the esterified and de-esterified pectin content in the pollen grain and pollen tube wall was significantly reduced, resulting in looser cell walls and deeper pollen grain deformation. This also led to a reduction in the pollen germination rate, and thus deformation of the growth of the germinated pollen tubes. Due to the low expression of FvPLB in the stamen, the fruits in the silenced FvPLB line developed normally and without abortions. The pollen germination rate was significantly increased and the length of the pollen tubes became longer. The morphology and structure of the pollen grains remained intact and the cell walls of the pollen grains and pollen tubes showed no major changes with de-esterified pectin and cellulose. However, the esterified pectin of the pollen grains decreased and the esterified pectin of the pollen tubes did not change significantly.