Abortin And Programmed Cell Death Of KTM3315A, A K-type Thermo-sensitive Cytoplasmic Male-sterile Wheat Linewith Aegilops Kotschyi Cytoplasm

Wheat(Triticum aestivum L.) is the most widely planted and important food crop throughout the world. Heterosis can be exploited to increase the crop yield and it has been utilized widely in cross-pollinating crops. Male sterility is an important tool in crop heterosis. Two-line breeding systems can facilitate crop breeding and provide an effective alternative to the cytoplasmic male-sterile(CMS) system for hybrid seed production. Recently, a thermo-sensitive cytoplasmic male-sterile(TCMS) line KTM3315 A was developped using a new breeding method based on tiller regeneration. According to our study, KTM3315 A, a K-type thermo-sensitive cytoplasmic male-sterile wheat line with Aegilops kotschyi cytoplasm, is completely male sterile at temperatures <18?C and it is capable of producing self-pollinated seeds when the temperature exceeds 20?C during this growth period. In this study, we investigated the fertility and cytology of temperature-treated plant anthers at various developmental stages by light microscopy, scanning and transmission electron microscopy, and nuclear staining. In order to distinguish T1 BL.1RS type and non T1 BL.1RS type of wheat, selected specific markers which located on 1RS of rye and 1BS of wheat for all tested materials were amplified by PCR electrophoresis analysis, at the same time, using the A-PAGE method to detect the Gliadin. The activities of protective enzymes(POD, SOD, and CAT) in anther of KTM3315 A were determined at different development stages(tetrad stage, early uninucleate stage, late uninucleate stage, binucleate stage, trinucleate stage).The results indicated the following.1. Molecular marker electrophoresis results showed that KTM3315 A could be amplified bands in the marker of wheat chromosome 1BS, but not amplified bands in the marker of chromosome 1RS in rye. KTM3315 A did not have the same bands in ω region as rye in A-PAGE electrophoresis. Therefore, KTM3315 A was non-1B/1R K type thermo-sensitive male sterile wheat line. Non-1B/1R K type thermo-sensitive male sterile wheat line is more valuable in practical production than T1 BL.1RS type. So, the development of TCMS wheat lines shows that there is great potential for producing hybrid wheat seed on a commercial scale.2. In this study, TCMS line KTM3315 A plants underwent premature tapetal programmed cell death(PCD), which was initiated at the early uninucleate stage of microspore development and continued until the tapetal cells were completely degraded. The microspore development process was then blocked and the pollen abortion type was stainable abortion. The research of cytology shows that the critical period of pollen abortion mainly occurred at late uninucleate stage. However, the molecular level regulation of tapetum PCD in plants remains poorly understood. In the present study, we obtained insights that may facilitate further investigations, which should explore the molecular mechanism that underlies anther degeneration.3. The activity of their protective enzymes was different in both sterile and fertile conditions. POD, SOD and CAT activity showed significant differences at late uninucleate stage, suggesting that male sterility was associated with activities of protective enzymes in active oxygen metabolism. KTM3315 A abortion mainly occurred at late uninucleate stage, the result of active oxygen metabolism is consistent with cytological studies.