OsUCL8 regulates pollen intine and interacts with OsPKIWI protein. (a) Pollen germination rate of WT and mutants in different germination mediums,values are the means ± s.d. (n = 480 pollens from 3 plants). (b) Pollen germination of WT, ucl8 and OXUCL8 pollens in GM1 with 0 or 30 mg/L VB1. Scale bars, 100 μm. (c) Pollen germination rate of WT, ucl8 and OXUCL8 pollens in GM1 with 0, 3 and 30 mg/L VB1, values are the means ± s.d. (n = 480 pollens from 3 plants). (d) Observation of the ultrastructure of pollen wall for WT, OXUCL8, ucl8 and OXmiR408 by TEM. The parts surrounded by red lines are intine, Scale bars, 2 μm. (e) The statistical results of intine thinkness, values are the means ± s.d. (n ≧ 77 pollens). (f) Detection of OsUCL8-OsPKIWI interaction with a yeast two-hybrid assay. The combinations of AD/BD-OsUCL8 and AD-OsPKIWI/BD were used as negative controls. (g) Verification of the interaction between OsUCL8 and OsPKIWI by BiFC assay in rice protoplasts. Empty YC and YN were used as negative controls. Scale bars, 10 μm. Asterisks (***) indicate P value < 0.0001 (t tests), Asterisks (**) indicate P value < 0.01 (t tests)