Whole-Genome Identification and Expression Pattern of the Vicinal Oxygen Chelate Family in Rapeseed (Brassica napus L.)

Abstract

Vicinal oxygen chelate proteins (VOC) are members of the metalloenzyme superfamily, which plays roles in many biological reactions. Some members of the VOC superfamily have been systematically characterized but not in Brassica napus. In this study, 38 VOC genes were identified based on their conserved domains. The present results revealed that most of the BnaVOC genes have few introns, and all contained the typical VOC structure of βαβββ modules. The BnaVOC genes are distributed unevenly across 15 chromosomes in B. napus and occur as gene clusters on chromosomes C5 and A6. The synteny and phylogenetic analyses revealed that the VOC gene family is a consequence of mesopolyploidy events that occurred in Brassica evolution, and whole-genome duplication and segmental duplication played a major role in the expansion of the BnaVOC gene family. The expression profile analysis indicated that the expression of most BnaVOCs was increased in the leaves and late stage seeds. Further results indicated that seeds of B. napus with a high oil content show higher expression levels under drought stress conditions, suggesting that BnaVOCs not only respond to abiotic stress but may also affect lipid metabolism in drought stress. This present study provides a comprehensive overview of the VOC gene family and provides new insights into their biological function in B. napus evolution.

Genome-wide identification and characterization of the Hsp70 gene family in allopolyploid rapeseed (Brassica napus L.) compared with its diploid progenitors

“…Altogether, whole genome triplication followed by main segmental duplication, played a major role in the expansion of BnHsp70 gene family (Cheng, Wu & Wang, 2014; Chalhoub et al, 2014; Liu et al, 2014). Similar genome duplication patterns have been observed in late embryogenesis abundant ( LEA ) genes and Vicinal Oxygen Chelate ( VOC ) genes of Brassica species (Liang et al, 2016; Liang et al, 2017).…”

“…While polyploidy is a vital mechanism of gene family expansion, tandem duplication and infrequently segmental duplication are thought to commonly evaluated mechanisms for gene family copy numbers evolution and expansion (Liang et al, 2017). Therefore, it was assessed that roles of gene duplication events and Darwin’s positive selection in the divergence of genes for understanding Hsp70 gene family expansion (Cannon et al, 2004).…”

Genome-Wide Identification and Structural Analysis of bZIP Transcription Factor Genes in Brassica napus

“…Some other gene superfamilies in the allotetraploid species B . napus have been described, including the SnRK2 , ERF , VOC , ACBP , and MAPKKK superfamilies [ 52 , 53 , 54 , 55 , 56 ]. In the current study, we found that the copy number of bZIP genes varied from two to eight, which is consistent with the finding that two or more copies of homologous genes have been detected in B .…”

Drought‐responsive genes, late embryogenesis abundant group3 (LEA3) and vicinal oxygen chelate, function in lipid accumulation in Brassica napus and Arabidopsis mainly via enhancing photosynthetic efficiency and reducing ROS

“…, , , , , , , ), respectively. These copies were selected because their expression levels were relatively stable and higher in seeds and leaves during drought, based on our previous studies (Liang et al ., , ). In addition, they were located in four different A or C subgenomes of B. napus .…”

“…In our previous study, it was revealed that the LEA and VOC proteins were highly expressed in B. napus plants that had high oil content (Gan et al ., ). We also found that most of the BnLEA and BnVOC genes had higher expression levels under drought stress in B. napus with high oil content (Liang et al ., , ). These results suggested that drought‐stress‐responsive genes might have a relationship with lipid metabolism.…”