A calcium-dependent protein kinase, ZmCPK32, specifically expressed in maize pollen to regulate pollen tube growth
Fig 6
Transient expression of ZmCPK32 suppresses tobacco pollen tube growth.
(A) Schematic diagram showing the structures of fusion proteins used for pollen transient expression. Wild-type, constitutively active (CA), kinase domain-deficient (KD), and N-terminal-deleted (ΔN) variants of ZmCPK32 were generated as GFP fusion proteins and introduced into tobacco pollen grains via microparticle bombardment. The red line in ZmCPK32KD indicates the mutation (Asp230 to Asn230) in the kinase domain. (B) Representative pollen tubes transformed with the indicated plasmid. Images were taken 4 h after germination. The scale bars represent 50 μm. (C) Quantitative analysis of pollen tube growth phenotypes. The germination rate and pollen tube length were measured from more than 50 transformed pollen grains after culturing in vitro for 4 h. Different lowercase letters represent significant differences (P < 0.05) according to Tukey’s test. The error bars indicate standard deviations.