Myrosin cells are differentiated directly from ground meristem cells and are developmentally independent of the vasculature in Arabidopsis leaves

Abstract

Myrosin cells accumulate myrosinases in their vacuoles to catalyze the production of toxic compounds when tissues are damaged by herbivores. Myrosin cells are positioned adjacent to the abaxial side of the vasculature but their origin is unclear. To determine whether the myrosin cells are differentiated from vascular precursor cells, we generated a transgenic Arabidopsis line that expressed a myrosin cell reporter together with one of 3 vascular precursor cell reporters. The myrosin-positive cells were discontinuously distributed while the vascular precursor-positive cells were continuously distributed. The fluorescent signals of the myosin and vascular reporters did not overlap. Furthermore, the shape of myrosin-positive cells was different from the shape of vascular precursor-positive cells. These results indicate that myosin cells develop independently of the vasculature.

Sugar Transporter STP7 Specificity for l-Arabinose and d-Xylose Contrasts with the Typical Hexose Transporters STP8 and STP12

“…In nonfloral tissues, GUS staining was observed only in leaves (Fig. 5, A and B), where it was restricted to a patchy pattern along the vasculature, which might indicate an expression in myrosin cells (Shirakawa et al, 2016). No GUS staining was observed in any of the other vegetative tissues.…”

The Cellular and Subcellular Organization of the Glucosinolate–Myrosinase System against Herbivores and Pathogens

“…Myrosin cells are found along veins in Arabidopsis and other Brassicales plants [74][75][76]. Based on the close proximity of myrosin cells to vascular precursor cells and phloem cells [50,75,76], myrosin cells could belong to a vascular cell lineage and differentiate from vascular and vascular precursor cells. More recent studies, however, have provided evidence against this hypothesis.…”

The Cell Differentiation of Idioblast Myrosin Cells: Similarities With Vascular and Guard Cells

“…This observation provoked the question of whether myrosin cells differentiate from vascular precursor cells (procambium cells). Two groups compared the spatiotemporal expression patterns of a myrosin cell reporter and a procambium reporter and showed that myrosin cells do not differentiate from procambium cells and, rather, directly differentiate from ground meristem cells, which are stem cell-like cells in inner tissue ( Li and Sack, 2014 ; Shirakawa et al, 2016b ). Ground meristem cells are also mother cells of mesophyll cells and procambium cells.…”