Cloning One CIPK Gene from a Thermo-Sensitive Genic Self-Incompatible Line in Maize Expressing Under Different Temperatures

A calcineurin B-like protein-interacting protein kinases (CIPK) gene was cloned (EU 424058) from a thermo-sensitive genic self-incompatibility (TSGI) line, HE97, in maize, which was selected for suppression subtractive hybridization (SSH) library of the self-incompatible and self-compatible silks of the TSGI line under different temperatures. The full-length cDNA of the candidate CIPK-like gene consisted of 1 918 nucleotides and contained a 1332-bp open reading frame in maize. Real-time PCR indicated that the candidate CIPK-like gene was highly expressed in the self-incompatible pollen of the TGSI line, and promoted elevated levels of calcium (Ca2+). High Ca2+ concentrations in the pollen strongly inhibit pollen tube formation in silk of the same plant, thus inducing self-incompatibility (SI) under high temperature. These results implied that the CIPKs-like gene would play an important role in the regulation of HE97 characteristics under different temperatures, perhaps acting as a secondary messenger in the expression of SI in the TGSI line in maize.