Studies On Isolated Microspore Culture And Gene Expression Of SERK In Non-heading Chinese Cabbage

The isolated microspore culture technology could divert microsproe to the embryogenic stage,and obtain haploid or doubled haploid plants in 1-3 months,which could produce new varieties of excellent traits or are used as a parent to speed up the breeding process in 1-2 years.The study researched some factors which could affect the efficiency of isolated microspore culture in non-heading Chinese cabbage,obeserved the process of microspore development and regeneration of microspore-derived plants,which could be supplement with the optimization of microspore culture in non-head:ing Chinese cabbage.SERK1,which belongs to SERK gene family,had been identified relating to somatic embryogenesis.Some recent studies showed that SERK1 gene is involved in microspore embryogenesis.The study analyzed bio informatics of SERK gene family in non-heading Chinese cabbage and its tissue specific expression which could provide a preliminary understanding of function of SERK gene family in non-heading Chinese cabbage.The main results are as follows:1.In this experiment,20 genotypes of non-heading Chinese cabbage were used as materials,and we studied the relationship beteween the ratio of petal to anther(P/A)and the period of microspore development,the effects of genotype,low temperature stress treatment and cefotaxime on isolated microspore embryogenesis.We also observed the process of micro spore-derived embryo development.The main results were as follows:(i)When P/A is around 0.85-1.1,most of the microspore of non-heading Chinese cabbage were in the late uninucleate;(ii)There were 10 genotypes of non-heading Chinese cabbage becoming embryogenesis,the frequency of embryogenesis was 50%;the maximum was H20,which had 7.75 embryo ids every 10 buds;(iii)It was easy to form embryos when the buds were in the 4 ? stress treatment for 1 day,but the effect of low temperature stress treatment on embryogenesis was related to genotype;(iv)The effect of cefotaxime on the frequency of embryos was dependent on genotype.2.In this study,the process of microspore-derived plant regeneration in non-heading Chinese cabbage was observed and studied.And we identified the ploidy levels of the microspore-derived plants by flow cytometry.The results showed that from the embryoids to seedling stage,the frequency of embryo regeneration varied from different genotypes,it was 0-45.16%;23 plants were identified,21 of them were DH,while 2 of them were haploids,the natural doubling rate was 91.3%.The morphology of the obtained microspore-derived plants showed obvious diversity.3.Some recent studies showed that SERK1 gene is involved in microspore embryogenesis.In this experiment,we used bioinformatics methods for the identification and analysis of SERK gene family of non-heading Chinese cabbage.And the two varieties'wutacai' and 'sijiucaixin',which were different in embryogenesis,we took the seven part of them,root,stem,leaf,buds(<2 mm,2?3mm,>3 mm)and flower,to conduct a tissue specific expression analysis in BcSERK gene family.The results showed that,there were 8 members of SERK family in non-heading Chinese cabbage,we named them BcSERK01?BcSERK08.Through the construction of NJ tree of SERK family,we knew that BcSERK01 was 100%similarity with AtSERK1,and by MEME motif analysis,we found that the number and structure of motif between BcSERK01 and AtSERK1 was same.BcSERK01 may be the homologous structure of AtSERK1.BcSERK protein structure consisted of a SP-LZ-LRR(1-5)-SPP-TM-Kinase-C terminal region.The RT-qPCR data indicated that BcSERK gene family was involved in the whole development process of non-heading Chinese cabbage.The role of BcSERK01 on microspore embryogenesis in non-heading Chinese cabbage remained to be further studied.