Correlation Analysis Of BvBTB Gene Expression And Brown Spot Resistance In Sugar Beet

Cercospora leaf spots(CLS)is a fungal disease of sugar beet caused by Cercospora beticola Sacc.(C.beticola),which seriously leads to yield cut on sugar beet.BTB proteins are the zinc finger proteins of poxvirus,which plays a critical role in the defense to plant pathogens.Researches on BTB genes in sugar beet were not reported so far.In the research,sugar beet leaves with CLS were obtained from the field,we isolated,purified and identified C.beticola,through molecular techniques,C.beticola of CLS was identified.According to the transcriptome datas of sugar beet disease resistant material F85621 and disease susceptible material KWS9147 infected by C.beticola,three BTB genes with the most significant expression were selected,the three genes are BvBTB1,BvBTB2,and BvBTB3,their full-length CDS sequences were acquired by RT-PCR.The phenotypes of sugar beet resistant and susceptible materials under different spore concentrations of C.beticola were analyzed.qRT-PCR was used for expression analysis,the expression levels of BvBTB1,BvBTB2,and BvBTB3 after high and low spore concentrations of C.beticola infection at different times in leaves and roots in sugar beet resistant material F85621 and susceptible material KWS9147,which provided a theoretical basis for further study on the resistance of BvBTB genes to CLS and laid a foundation for the research and development of new disease resistant varieties and transgenic resistant varieties of sugar beet.The results were as follows:(1)Isolation,purification,morphology and molecular identification of C.beticolaThe sugar beet diseased leaves with CLS were cultured in PDA medium until C.beticola was isolated and purified.Finally C.beticola was observed by morphology and identified by molecular biology.(2)Amplifying the target bandThe three genes screened are BvBTB1,BvBTB2,and BvBTB3,their full-length CDS sequences were acquired by RT-PCR,and their lengths were 1746,2097,and 1518 bp,respectively,primers according to the CDS sequences designed were for RT-PCR amplifying,the amplified bands were about 1000,2097,and 1518 bp,respectively.(3)Expression pattern of BvBTB genes under the stress of C.beticola infectionqRT-PCR results showed that the expression levels of BvBTB in roots and leaves of the resistant and susceptible materials were tissue-specific and expressed differently in various tissues.Under the stress of C.beticola,BvBTB1,BvBTB2,and BvBTB3 were overexpressed in the resistant and susceptible materials within five days after C.beticola infection: the peak appeared on the fifth day,the highest expression was 25 times of the control group,the lowest was 1.1 times of the control group,moreover,the expression in the resistant material was higher than in the susceptible material.Overall,these results showed that BvBTB genes were involved in the response in sugar beet to C.beticola infection.