Figure 6.

PIRL6 knockdown disrupts male gametogenesis. Microspores and pollen produced by plants hemizygous for the PIRL6-KD construct, which segregate at 50% for PIRL6 knockdown, were stained with DAPI and viewed by confocal fluorescence or DIC microscopy. A, Microspores and pollen from anthers at the indicated developmental stages, viewed by confocal fluorescence (top row) or DIC (middle row). Arrows indicate pollen segregating for developmental defects of varying severity, including arrested microspores (broad arrows), enlargement with absence of germinal nucleus (hollow triangle), arrest after PM1 (short arrow), or abnormal male germ unit configuration (long arrows). The bottom row shows wild-type control samples at corresponding developmental stages. Bars = 10 µm. B, Tetrads from tricellular stage anthers, showing meiotic segregation of developmentally arrested PIRL6-KD pollen in the qrt1 background. Bars = 10 µm. C, Simplified diagram of the major stages of wild-type Arabidopsis pollen development, provided for reference. PM, Pollen mitoses. White ovals represent idealized nuclear configurations observable with DAPI staining: large ovals, vegetative cell nuclei; small ovals, generative nucleus (bicellular stage) and sperm nuclei (tricellular stage). The tricellular stage nuclei illustrate the triangular configuration of the male germ unit characteristic of mature Arabidopsis pollen.