AUTHOR=Chen Bing , Liu Yu , Xiang Chunfang , Zhang Dandan , Liu Zhuoyu , Liu Yihua , Chen Jingjing 

TITLE=Identification and in vitro enzymatic activity analysis of the AOP2 gene family associated with glucosinolate biosynthesis in Tumorous stem mustard (Brassica juncea var. tumida)

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1111418

DOI=10.3389/fpls.2023.1111418

ISSN=1664-462X

ABSTRACT=<p>The major enzyme encoded by the glucosinolate biosynthetic gene <italic>AOP2</italic> is involved in catalyzing the conversion of glucoiberin (GIB) into sinigrin (SIN) in Brassicaceae crops. The <italic>AOP2</italic> proteins have previously been identified in several Brassicaceae species, but not in Tumorous stem mustard. As per this research, the five identified members of the <italic>AOP2</italic> family from the whole genome of <italic>Brassica juncea</italic> named <italic>BjuAOP2.1</italic>-<italic>BjuAOP2.5</italic> were found to be evenly distributed on five chromosomes. The subcellular localization results implied that BjuAOP2 proteins were mainly concentrated in the cytoplasm. Phylogenetic analysis of the AOP2 proteins from the sequenced <italic>Brassicaceae</italic> species in BRAD showed that <italic>BjuAOP2</italic> genes were more closely linked to <italic>Brassica carinata</italic> and <italic>Brassica rapa</italic> than <italic>Arabidopsis</italic>. In comparison with other <italic>Brassicaceae</italic> plants, the <italic>BjuAOP2</italic> members were conserved in terms of gene structures, protein sequences, and motifs. The light response and hormone response elements were included in the <italic>BjuAOP2</italic> genes’ cis-regulatory elements. The expression pattern of <italic>BjuAOP2</italic> genes was influenced by the different stages of development and the type of tissue being examined. The BjuAOP2 proteins were used to perform the heterologous expression experiment. The results showed that all the five BjuAOP2 proteins can catalyze the conversion of GIB to SIN with different catalytic activity. These results provide the basis for further investigation of the functional study of <italic>BjuAOP2</italic> in Tumorous stem mustard glucosinolate biosynthesis.</p>