Oilseed rape seeds with ablated defence cells of the glucosinolate–myrosinase system. Production and characteristics of double haploid MINELESS plants of Brassica napus L.

Abstract

Oilseed rape and other crop plants of the family Brassicaceae contain a unique defence system known as the glucosinolate–myrosinase system or the ‘mustard oil bomb’. The ‘mustard oil bomb’ which includes myrosinase and glucosinolates is triggered by abiotic and biotic stress, resulting in the formation of toxic products such as nitriles and isothiocyanates. Myrosinase is present in specialist cells known as ‘myrosin cells’ and can also be known as toxic mines. The myrosin cell idioblasts of Brassica napus were genetically reprogrammed to undergo controlled cell death (ablation) during seed development. These myrosin cell-free plants have been named MINELESS as they lack toxic mines. This has led to the production of oilseed rape with a significant reduction both in myrosinase levels and in the hydrolysis of glucosinolates. Even though the myrosinase activity in MINELESS was very low compared with the wild type, variation was observed. This variability was overcome by producing homozygous seeds. A microspore culture technique involving non-fertile haploid MINELESS plants was developed and these plants were treated with colchicine to produce double haploid MINELESS plants with full fertility. Double haploid MINELESS plants had significantly reduced myrosinase levels and glucosinolate hydrolysis products. Wild-type and MINELESS plants exhibited significant differences in growth parameters such as plant height, leaf traits, matter accumulation, and yield parameters. The growth and developmental pattern of MINELESS plants was relatively slow compared with the wild type. The characteristics of the pure double haploid MINELESS plant are described and its importance for future biochemical, agricultural, dietary, functional genomics, and plant defence studies is discussed.

S-Nitrosylation Analysis in Brassica juncea Apoplast Highlights the Importance of Nitric Oxide in Cold-Stress Signaling

“…78 Myrosinase is an enzyme of this pathway, which hydrolyzes glucosinolates to the toxic compounds like isothiocyanates, thiocyanates, nitriles, epithionitriles, and oxazolidine-thiones. 79 It is a secretory protein and is found in the extracellular fractions. 16,80 Myrosinase (gi|127733 and gi| 4033345) is identified as a putative S-nitrosylated target in both GSNO as well as cold-treated apoplast (Tables 1 and 2).…”

Engineering Glucosinolates in Plants: Current Knowledge and Potential Uses

“…GSLs, like value-added products, primarily belong to the order Brassicales [12]. However, recently Mikkelsen et al [214] successfully engineered the glucoraphanin (AGSL) and IGSL pathways into the noncruciferous tobacco plant.…”

‘Myrosin cells’ are not a prerequisite for aphid feeding on oilseed rape (Brassica napus) but affect host plant preferences

“…Following centrifugation, soluble protein extracts were used to determine soluble myrosinase activity and protein concentration. The specific myrosinase activity was measured using the GOD‐Perid assay, as previously described (Bones & Slupphaug 1989; Borgen et al 2010; Ahuja et al. 2011).…”

“…2011). Among the plant defence mechanisms is the glucosinolate–myrosinase system, which is also known as ‘the mustard oil bomb’, and is a pre‐formed as well as an inducible defence mechanism (Matile 1980; Luthy & Matile 1984; Bones & Rossiter 1996; Ahuja et al. 2011).…”

“…These B. napus plants have been produced with transgenically ablated myrosin cells (toxic mines) and were named MINELESS (Borgen et al. 2010; Ahuja et al. 2011).…”