Ph.D student University of Tsukuba Tsukuba, Ibaraki, Japan
Body of Abstract: Cytoplasmic male sterility (CMS) is a plant phenotype that is unable to produce fertile pollen caused by a mitochondrial abnormal gene (called CMS gene). Although a mitochondrial gene called orf137 was identified as a tomato CMS gene, male sterile mechanism has been unknow. In this research, we aimed to characterize tomato CMS pollen in detail to reveal the male sterile mechanism.
Our analysis revealed that CMS tomato had normal development in vegetative tissues and pollen as same as fertile tomato. Abnormal phenotype was observed only in pollen germination. Although fertile pollen germinated at only one aperture (i.e. germination pore), CMS pollen showed triple-protrusions on the pollen surface.
To investigate more detail phenotypes during pollen germination, we observed Ca2+ localization which has been known to be important factor for pollen germination by using Lat52::GCaMP5 vector. Ca2+ localized at only one aperture in fertile pollen, but that localized at two or three apertures in CMS pollen. Furthermore, vesicles that include some essential components for pollen tube formation also localized in at only one aperture in fertile pollen, observed by transmission electron microscope. However, in CMS pollen, vesicles localized in multiple apertures. These results suggested that CMS pollen try to germinate at multiple apertures, which is completely different germination system from fertile pollen.
Supported by the Bio-oriented Technology Research Advancement Institution (Research Program on Development of Innovative Technology, Grant numbers: JPJ007097), JSPS KAKENHI Grant Number JP21J20479 and JSPS Core-to-Core Program (Formation of the international hub for plant organelle research)