BcMF27, A Pectin Methylesterase Gene, Regulates Pollen Development and Pollen Tube Growth in Brassica Campestris

Abstract

Functional pollen grains are an essential ingredient of successful reproduction in flowering plants and are protected by outer walls. Pectin methylesterases (PMEs) modify pectin, a structural component of pollen intine. However, there are few studies on PMEs. Artificial microRNA (amiRNA) and overexpression technology was performed to investigate the function of pollen-specific PME gene, BcMF27, in pollen development. Knockdown of BcMF27 led to pollen wall collapse, 20% of which unknown material adhered to. Wall-collapsed pollen had abnormally thick intine outside of the germinal furrows. A portion of the cytoplasm was degraded in the remaining pollen with unknown material on the wall, in addition to a thick intine. Overexpression of BcMF27 resulted in 66.67% pollen wall disruption, causing an abnormally thick intine. In addition, functional interruption of BcMF27 gave rise to pollen tubes twisted in vitro. Taken together, BcMF27 contributes to the intine morphogenesis during pollen development and stabilizes pollen tube elongation. This research can promote knowledge of PMEs function and the molecular mechanism in pollen wall construction.