Cytological Observation And Expression Of Fertility-related Genes In Recessive Digenic Male Sterilite A/B Line In Brassica Napus L.

Rapeseed is one of the major oil crops in China. It contributes to appropriately 50% of the vegetable oil consumption. Improving the yield of rapeseed varieties has always been one of the most important goals for the canola breeders. To achieve this, heterosis utilization is proved to be a very effective way. So far, genic male sterility (GMS) is becoming a practicable approach to improve yield performance in Brassica napus. Much attention has been paid to research on the plant breeding and application of male sterility. However, mechanism of male sterility is very complex, which involved a set of structural and regulative genes in microspore development. The analysis of those genes associated with microspore development should contribute to elucidate the mechanism of male sterility.We studied a digenic recessive genic male sterility 479A/B lines of Brassica napus about their spatial and temporal expression characters at morphological, physiological and molecular levels. The results were as follows:1. Meiosis and microspore development of the sterile and fertile plants of a digenic recessive genic male sterile (DRGMS) lines 479AB Brassica napus were investigated by the methods of cytological squashing and crossing section. Abnormality was observed at the stages of microspore mother cell (MMC), tetrads and uninucleate microspore, such as chromosomal bridge, chromosomal fragments and paraspores with unequal size microspores. Asynchrony of meiosis also took place within one anther in sterile plants i.e. microspore mother cells at the pachytene I stage, metaphase and at the telophase II were all observed simultaneously in a single anther, whereas in fertile plants meiotic cells were at the same meiotic stage. In addition, microspores released from callose did not form the exine and their cytoplasm degraded gradually. Consequently, only debris was left in the distorted and shrank locules.2. Several kinds of gene expression models between male sterile and fertile plants were detected. With two-group primers including 36 primer pairs, averagely 50 clear bands were generated per primer pair. The polymorphic bands between the male sterile and fertile plants could be divided into classes as following:(1)Differential expression was showed in floral buds, pistil, stamen, some only derived from sterility; some only from ferility. However, no difference in leaves was found. (2) The transcript-derived fragments (TDFs) acquired from feritile floral buds of three group and fertile stamen, while no bands in fertile and sterile pistil and leaves. Maybe it is stamen-specific and need to be studied further.3.According to the expression pattern of cDNA-AFLP, we did cluster analysis with 12...