InterPro domain: IPR006969

This representative of this family is the STIG1 cysteine rich protein. The tobacco stigma-specific gene, STIG1 is developmentally regulated and expressed specifically in the stigmatic secretory zone. Pistils of transgenic STIG1-barnase tobacco plants undergo normal development, but lack the stigmatic secretory zone and are female sterile. Pollen grains are unable to penetrate the surface of the ablated pistils. Application of stigmatic exudate from wild-type pistils to the ablated surface increases the efficiency of pollen tube germination and growth and restores the capacity of pollen tubes to penetrate the style [ 1 ]. The function of STIG1 is unknown.

1. Female sterile tobacco plants are produced by stigma-specific cell ablation. EMBO J. 13, 2976-84