Mapping Of The Yellow-seeded Gene And White Petal Gene In Rapeseed

Compared with brown-seeded rapeseed, the yellow-seeded variety has a higher oilcontent, which has an important practical value. Previous research has studied the inheritanceand mapped the yellow-seeded gene in Brassica juncea L. of Northern Shaanxi, andconstructed a high-resolution map around the brown seed locus. A white flower character is auseful marker trait in Brassica napus L.. The Brassica napus L. flower color is usuallyyellow, but the flowers can also be white, milky white, golden yellow and orange. Theseflower color traits are easily identified with the naked eye and can be used to identify true andfalse hybrids and seed purity. In this report,1, An F₂population derived from the local B.juncea L. varieties, Wuqi yellow mustard, which is grown in the Loess Plateau in NorthernShaanxi （light-yellow seeds）, and Wugong mustard （brown seeds）, were analyzed forassociations with seed color. IP （Intron Polymorphism） makers, PCR-walking, amplifiedfragment length polymorphism （AFLP） and simple sequence repeats （SSR） techniques wereused to identify markers linked to the brown seed locus in an F₂population.2, White flowerrapeseed and their segregation populations were used as the experimental materials, and theywere used to study the inheritance of white flower traits. AFLP and SSR technologies wereemployed to identify the markers linked to the white flower gene. The main results were asfollows:（1） We submitted15markers sequences （from CB10373to P15MG15） on the genetic maparound the brown seed locus to the NCBI website for a BLAST search.7markerssequences were found to have highly conserved homologs in the Arabidopsis genome,spanning a large region from At3g14120to At3g59670on Arabidopsis chromosome3.The two either marker showed that the homolog of the gene was between At3g14120andAt3g29615.（2） We designed4IP primers accroding to the sequence between At3g14120and At3g29615of Arabidopsis chromosome3. As a result, the marker3g23030Y was linked to theyellow-seeded gene.（3） We extended the flanking sequence of EA02MC08by PCR-walking, which was one ofthe closest markers linked to the yellow-seeded gene in Brassica juncea L. of Northern Shaanxi. Afterwards, we found it was on the BAC clone （KBrH105I15） of chromosomeA1of Brassica rapa L. by BLAST analysis. Then we designed10primers according tothe BAC clones of chromosome A1of Brassica rapa L.. Finally,2IP markers （Y3、Y7）were found to be linked to the yellow-seeded gene.（4） We use AFLP and SSR markers （CB10022、CB10373、EA03MC₁3、EA06MC₁1） on eitherside of the gene to screen the exchange plants in F₂population （1500individuals）. Finally,we found12exchange plants.6exchange plants were yellow seed and6exchange plantswere brown seed.（5） The inheritance of flower color was analyzed using two F₁, two F₂and two BC₁populations. The white flower character was controlled by one pair of incompletedominant gene in Brassica napus L. Of the two F₁populations, all of the individuals weremilky white, which revealed that the white flower gene was incompletely dominant overthe yellow flower gene.（6） After screening256AFLP primer combinations and456pairs of SSR primers, three AFLPmarkers and two SSR markers tightly linked to the white flower gene were identified.EA06MG08and EA11MG12, the two closest markers, were located on either side of thewhite flower gene at a distance of3.2and3.0cM, respectively.（7） We submitted the three AFLP marker sequences to the NCBI website for a BLAST search.A BLAST analysis indicated that the sequences of the three AFLP markers showed goodcolinearity with those of Arabidopsis chromosome5and that the homolog of the whiteflower locus might exist between At5g49780and At5g58230.