Genome Wide Identification And Expression Analysis Of RING Gene Family In Brassica Rapa

The RING-type E3 ligases are characterized by the existence of a RING domain is one the most important class involved in 26S proteasome system.More and more RING finger genes were found to be implicated in various important bio-logical processes.In the present study,a total of 731 RING domains in 715 pro-teins were identified in Brassica rapa genome(AA,2n=20),which were further divided into eight types:RING-H2(371),RING-HCa(215),RING-HCb(47),RING-v(44),RING-C2(38),RING-D(10),RING-S/T(5)and RING-G(1).The 715 RING finger proteins were further classified into 51 groups according to the presence of additional domains.700 RING finger protein genes were mapped to the 10 chromosomes of B.rapa with a range of 47 to 111 genes for each chromo-some.Analysis of syntenic relationships between RING finger genes of B.rapa and A.thaliana showed that,only in 50 cases,the triplicated copies were well re-tained on all the three sub genomes(LF,MF1 and MF2)of B.rapa,while in 146 cases,only two of the three triplicated copies were retained,and 294 cases,only one of the three triplicated copies was retained in B.rapa genome.51 B.rapa as well as 58 A.thaliana RING finger genes were involved in tandem repeat.667 RING finger protein genes were expressed in at least one of the six tissues exam-ined,indicating their involvement in various physiological and developmental pro-cesses in B.rapa.Hierarchical clustering analysis of RNA-seq data divided them into seven major groups,one of which includes 231 members preferentially ex-pressed in leaf,and constitutes then a panel of gene candidates for studying the ge-netic and molecular mechanisms of leafy head traits in Brassica crops.The expres-sion patterns of 29 representatives RING finger genes were further examined by semi-quantitative RT-PCR.Additionally 17 different RING types genes was ana-lyzed by qPCR under salt and drought stress,and 14 and 13 genes were detected to be induced by salt and drought respectively.Our results lay the foundation for further studies on the classification,evolution and putative functions of RING fin-ger protein genes in Brassica species.