Construction And Utilization Of Brassica Napus Lines With Multicolor And Aromatic Flowers

The Chinese woad(Isatis indigotica,2n=14,II)which belongs to the Isatideae tribe of Brassicaceae family is widely culticated as medicinal plants in our country,and it produces the fragrant flowers.In the previous study,the somatic hybrid of Brassica napus L.(2n=38,AACC)and I.indigotica(2n=52,AACCII)was continuously backcrossed and with Huashuang 3 to construct seven groups of monosomic alien addition lines(MAALs,2n=39,AACC+1Ia-g).Mc with the addition of chromosome of I.indigotica also produces the same aromatic flowers as the woad does.In this study,to produce B.napus lines with multicolor and aromatic flowers,Mc was crossed with the B.napus line with multicolor flowers,and the selfed progenies were identified by molecular markers and cytological analysis,and the comparative transcriptomic analyses between Mc and two parental species were made.The main results are as follows:1.Molecular and cytological screening of B.napus lines with multicolor and aromatic flowersThe selfed progeny plants from Mc × multicolor flower B.napus line were selected by olfactory senses,molecular markers specific for woad chromosome and cytological observation,three types of plants with floral aromas were identified,including the additions with 2n=39 or 40,those with 2n=38 with alien chromosome fragments amplified or not.Totally,81 multi-flower color progeny plants with aromatic trait were obtained.Lagging chromosome or chromosomal bridges occurred in pollen mother cells at anaphase Ⅰ of the additional aromatic progenies.The pollen fertility of B.napus lines with multicolor and aromatic flowers was 71.42%-81.71%,significantly lower than 92.33%of Huashuang 3.2.Agronomic characters of B.napus lines with multicolor and aromatic flowersAmong the selfed progeny plants from Mc × multicolor flower B.napus line,the fragrant plants presented eight different petal colors,yellow,yellow-brown,pink,pink-brown,pink-white,orange-red,purple and white.These plants showed some differences in flower buds,anthers,petals,agronomic traits and fatty acid composition of seeds.3.Transcriptomic analysis of Mc,B.napus and I.indigoticaA total of 4967 differentially expressed genes(DEGs)were obtained between Mc and Huashuang3.Some genes were enriched in GO pathways such as defense response,response to biological stimulus,circadian rhythm and KEGG pathway of plant-pathogen interaction,which might be related to the synthesis of floral aroma substances.A total of13746 DEGs were obtained between Mc and I.indigotica(Ii).Through GO analysis,these genes were associated with the formation of cytoplasmic fragments and ribonucleoprotein complexes,and may be associated with influenza virus resistance.In summary,the novel lines with multicolor and aromatic flowers were produced from the cross of the fragrant B.napus-I.indigotica addition and red flowered B.napus line,which provided the new germplasm for multi-function exploitation of rapeseed.