Comparative Analysis And Functional Study Of PP2C Genes In Brassica Rapa,Brassica Oleracea And Arabidopsis Thaliana

Abscisic Acid(ABA)is an important plant hormone which participates in response to stress and modulation of plant growth and development.It is very important to regulate seed germination,seed dormancy,root development and stomatal closure.A number of significant progresses in dissecting the molecular basis of ABA metabolism and ABA signal transduction have been acquired during past decades.In terms of the core signal transduction regulatory network of ABA signalling,PP2C(Type-2C Protein Phosphatases)is a key adaptor between ABA receptors and downstream kinases.Recently,genome-wide annotation of Brassica rapa,rice and maize have been carried out,but there are few studies in Brassica oleracea.In the current study,comparative analysis and functional study of PP2C-likegenes in Brassica rapa and Brassica oleracea were performed.We obtainedfollowing results:(1)The genome of Brassica rapa encodes 121 putative PP2 Cs gene,the genome of Brassica oleracea encodes 128 putative PP2 Cs gene.The PP2 Cs in Brassica rapa(BrPP2Cs)and Brassica oleracea(BoPP2Cs)are also classified into 10 subfamilies.Phylogenetic relationship analysis reveals that subfamily A consists of 14 BrPP2 Cs and 14 BoPP2 Cs respectively;(2)Chromosome localization reveal that BrPP2 Cs were distributed in chromosomes of A01-A10,and BoPP2 Cs were also found on the 9 chromosomes of Brassica oleracea(C01-C09).(3)Most of gene structure of BrPP2 Cs,BoPP2Cs and AtPP2 Cs are highly conserved The BoHAB2 b gene contains no intron.(4)protein structure analysis found that the motif composition and arrangement of A subfamily BrPP2 Cs,BoPP2Cs and AtPP2 Csis highly conserved;(5)Based on transcriptome sequencing data,it was found that BrPP2 Cs of subfamily A were expressed in callus,flower,leaf,root,siliique and stem.BoPP2 Cs of subfamily A were expressed in seven tissues which conclude Bud,callus,flower,leaf,root,silique and stem;(6)We found that the BoABI1 c sequence was separated by 28 bp and spliced byBol006485 and Bol006484 after entensive sequence alignment,gene location mapping and protein structure analysis.(7)The CRISPR-Cas9 vector intending to knonk-out ABI1,HAB1 and PP2 CA homologous genes in Brassica oleracea and Brassica rapa was constructed,and the regenerated seedlings of Brassica napus were obtained successfully.In summary,we found that the BrPP2 Cs,BoPP2Cs and AtPP2 Cs especially subfamily A PP2 Cs are highly conserved in the gene and protein structurelevel..Furthermore,the ABI1,HAB1 and PP2 CA homolog genes in Brassica oleracea and Brassica rapa may also have key roles in the regulation of ABA or drought responses..