Fig. 4.

Phenotypes of roco4-null cells. (A) Development of roco4-null. Wild-type AX2 and roco4-null cells were plated on nutrient-free agar and allowed to develop. Photographs were taken at various time points. At the end of the mound phase, roco4-null cells transform into circular structures that take hours to form slugs. These slugs finally form spores and aberrant stalks, resulting in spore heads that are located at the surface instead of in the air. (B) Close-up pictures of stalk and spore cells, respectively, from wild-type and roco4-null cells. (C) Rescue of aberrant roco4-null fruiting body morphology by reexpression of Roco4. Cells were allowed to develop for 48 h (plates lid up), and pieces of agar were excised and photographed from the side. (D) roco4-null stalks produce little cellulose. Wild-type and roco4-null cells were allowed to develop on nutrient-free agar upside down (plates lid down). After fruiting body formation, plates were turned, causing roco4-null fruiting bodies to spontaneously fall over on the agar; wild-type fruiting bodies were allowed to fall over by gentle tapping of the plate. Fruiting bodies were stained with 0.01% calcofluor to visualize cellulose production. Fluorescent and bright-light pictures were taken simultaneously and assembled afterwards using assembly software. (E) Fruiting body formation of wild-type and roco4-null chimeras. AX2 and roco4-null cells were mixed in various compositions and allowed to develop on nutrient-free agar. Photographs are shown of final structures of these chimeras at 48 h after the start of starvation. The number of fruiting bodies with wild-type-like morphology gradually diminishes at higher percentages of roco4-null cells, suggesting that the developmental defect in these cells is cell autonomous.