bus, a Bushy Arabidopsis CYP79F1 Knockout Mutant with Abolished Synthesis of Short-Chain Aliphatic Glucosinolates

Abstract

A new mutant of Arabidopsis designated bus1-1 (for bushy ), which exhibited a bushy phenotype with crinkled leaves and retarded vascularization, was characterized. The phenotype was caused by an En-1 insertion in the gene CYP79F1 . The deduced protein belongs to the cytochrome P450 superfamily. Because members of the CYP79 subfamily are believed to catalyze the oxidation of amino acids to aldoximes, the initial step in glucosinolate biosynthesis, we analyzed the level of glucosinolates in a CYP79F1 null mutant ( bus1-1f ) and in an overexpressing plant. Short-chain glucosinolates derived from methionine were completely lacking in the null mutant and showed increased levels in the overexpressing plant, indicating that CYP79F1 uses short-chain methionine derivatives as substrates. In addition, the concentrations of indole-3-ylmethyl-glucosinolate and the content of the auxin indole-3-acetic acid and its precursor indole-3-acetonitrile were increased in the bus1-1f mutant. Our results demonstrate for the first time that the formation of glucosinolates derived from methionine is mediated by CYP79F1 and that knocking out this cytochrome P450 has profound effects on plant growth and development.

Arabidopsis NITRILASE 1 Contributes to the Regulation of Root Growth and Development through Modulation of Auxin Biosynthesis in Seedlings

“…In fact, the point that the aberrant phenotype of NIT1ox is limited to roots of young seedlings is a very compelling aspect, distinguishing NIT1ox from other well documented Arabidopsis auxin over-producing mutants, like, e.g., bus1-1 (Reintanz et al, 2001), 35S::CYP79B2 (Hull et al, 2000), and yucca (Zhao et al, 2001; Cheng et al, 2006). Here, the phenotypic changes are visible in roots as well as shoots, and leaves.…”

“…Based on these observations the most probable source for free IAN in Arabidopsis is the IG glucobrassicin. Glucobrassicin can be metabolized to IAN, and a number of publications reported a positive correlation between the levels of those two compounds (Müller and Weiler, 2000; Reintanz et al, 2001; Zhao et al, 2002). …”

Heteroatom–Heteroatom Bond Formation in Natural Product Biosynthesis

“…162 Knockout of this gene in Arabidopsis resulted in the abolishment of short chain aliphatic glucosinolate production. 163 When E. coli spheroplasts overexpressing CYP79F1 were incubated with substrate and NADPH:cytochrome P450 reductase, both E- and Z- 5-methylthio-pentanaldoxime and 6-methylthiohexanaldoxime were formed ( 55 ). CYP79F1 is specific for homoelongated methionines and did not accept L-methionine.…”

Glucose signalling positively regulates aliphatic glucosinolate biosynthesis

“…CYP79F1 and CYP79F2 are two important genes whose products catalyse accumulation of long-chain aliphatic glucosinolates, while the product of CYP79F1 also functions in the biosynthesis of short-chain aliphatic glucosinolates (Reintanz et al ., 2001; Chen et al ., 2003; Tantikanjana et al ., 2004). In addition, MYB28, MYB29, and MYB76 have been identified as transcription factors in aliphatic glucosinolate biosynthesis with partial functional redundancy.…”