title: Identification, duplication, evolution and expression analyses of caleosins in Brassica plants and Arabidopsis subspecies.
abstract: Caleosins are a class of Ca(2+) binding proteins that appear to be ubiquitous in plants. Some of the main proteins embedded in the lipid monolayer of lipid droplets, caleosins, play critical roles in the degradation of storage lipids during germination and in lipid trafficking. Some of them have been shown to have histidine-dependent peroxygenase activity, which is believed to participate in stress responses in Arabidopsis. In the model plant Arabidopsis thaliana, caleosins have been examined extensively. However, little is known on a genome-wide scale about these proteins in other members of the Brassicaceae. In this study, 51 caleosins in Brassica plants and Arabidopsis lyrata were investigated and analyzed in silico. Among them, 31 caleosins, including 7 in A. lyrata, 11 in Brassica oleracea and 13 in Brassica napus, are herein identified for the first time. Segmental duplication was the main form of gene expansion. Alignment, motif and phylogenetic analyses showed that Brassica caleosins belong to either the H-family or the L-family with different motif structures and physicochemical properties. Our findings strongly suggest that L-caleosins are evolved from H-caleosins. Predicted phosphorylation sites were differentially conserved in H-caleosin and L-caleosins, respectively. 'RY-repeat' elements and phytohormone-related cis-elements were identified in different caleosins, which suggest diverse physiological functions. Gene structure analysis indicated that most caleosins (38 out of 44) contained six exons and five introns and their intron phases were highly conserved. Structurally integrated caleosins, such as BrCLO3-3 and BrCLO4-2, showed high expression levels and may have important roles. Some caleosins, such as BrCLO2 and BoCLO8-2, lost motifs of the calcium binding domain, proline knot, potential phosphorylation sites and haem-binding sites. Combined with their low expression, it is suggested that these caleosins may have lost function.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.|College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Shen
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Liu
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
authors.forename: Zhuowei
authors.initials: Z
authors.lastname: Li
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: David C
authors.initials: DC
authors.lastname: Taylor
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China. lizhxi@nwsuaf.edu.cn.
authors.forename: Zhixi
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China. zhangm@nwsuaf.edu.cn.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics*; D001937:Brassica / Q000235:genetics*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D018525:Germination / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D002135:Calcium-Binding Proteins; D010940:Plant Proteins; C402836:caleosin protein, Sesamum indicum
keywords: Brassica; Caleosin; Characteristics; Evolution; Expression; Function