Genetic Study Of Double Flower Trait And Expression Of Genes Related With Flower Development In Brassica Napus L

Rapeseed is a cruciferous plant with 4 petals in its flowers, and the reports on double flower materials are rare. A double flower line,375 and a normal line B409 were used in this research, and segregation populations were constructed for studying the genetic behavior of the double flower trait. Morphological and cytological differences between the two materials in the process of flower development were compared, and the expression pattern of several genes related to petal development were studied. The main results were as follows,1. Morphological and cytological characteristics of the experimental materials were studied by stered microscope, scanning electron microscopy (SEM) and semi-thin sectioning technology. The petal number of 375 was about 8-15, compared with B409, the observed differences were in petal shape and number while no obvious differences were observed in other flowers organs. The increased petal number of 375 did not affect pollen fertility and seed setting.2. The genetic analysis showed that double flower is a recessive trait, and the number of petals is a quantitative trait controlled by multiple nuclear genes probably.3. The expression pattern of six genes (AP1、AP2、AP3、PI、AG、SEP) related to flower development were analysed by the method of RT-PCR in 375 and B409. The result showed great difference was found in the expression pattern of AP2 and AP3 between 375 and B409, and other genes did not reveal the difference.4. AP3 gene was cloned by the homologous sequence method in 375 and B409(Brassica napus L), and two copies of AP3 genes were found in both of them. The length of the AP3 genes sequence were 1708bp and 1714bp in 375, respectively, and that of B409 are the same length 1710bp. Those nucleotide sequence cloned were aligned with the sequence of AP3 genes published by Brassica napus Genome Browser, revealing 96.7% in similarity. Compared the sequence of AP3 gene of 375 with that of B409, it was 94% in similarity, and multiple SNPS locis were discovered. Less conservatism of sequence were found between 63bp-100bp.