Fig. 2: efd is defective in sporopollenin synthesis and endothecium lignification.
From: An epigenetically mediated double negative cascade from EFD to HB21 regulates anther development
a the pollen mother cell, tapetum and endothecium are three diploid sporophytic cells in the anther that provide the materials for both pollen development and anther dehiscence. At stage 6, callose and primexine material are provided by the pollen mother cell (2n) on its surface. At stage 7, in the tapetum (2n), sporopollenin precursors are synthesised and secreted into tetrads which are the fundamental material for the sexine of the pollen wall. At stage 11, the endothecium cells (2n) start to lignify, which is an essential process for anther dehiscence. b Tinopal/DiOC2 staining of the pollen walls of the wild-type (n = 15) and efd plants (n = 20). Bars = 100 μm. c BF staining of the endothecium cells of the wild type (n = 10) and efd (n = 20). Arrow, the red fluorescent signal indicates the lignified area. En, endothecium cell layer. Bar = 20 μm. d gene rescue analysis and pollen staining of pNPU:RPG1, pAMS:CYP703A2 and pEFD:NST2 transgenic plants showed that pAMS:CYP703A2 can rescue the male sterility of efd.
