Increased symplasmic permeability in barley root epidermal cells correlates with defects in root hair development.

M Marzec,M Melzer,A Muszynska,E U Kurczynska,H Sas-Nowosielska

doi:10.1111/plb.12066

Abstract

It is well known that the process of plant cell differentiation depends on the symplasmic isolation of cells. Before starting the differentiation programme, the individual cell or group of cells should restrict symplasmic communication with neighbouring cells. We tested the symplasmic communication between epidermal cells in the different root zones of parental barley plants Hordeum vulgare L., cv. ‘Karat’ with normal root hair development, and two root hairless mutants (rhl1.a and rhl1.b). The results clearly show that symplasmic communication was limited during root hair differentiation in the parental variety, whereas in both root hairless mutants epidermal cells were still symplasmically connected in the corresponding root zone. This paper is the first report on the role of symplasmic isolation in barley root cell differentiation, and additionally shows that a disturbance in the restriction of symplasmic communication is present in root hairless mutants.

Highlights

IntroductionIn a time where there is a rapid increase in human population and the absence of new areas under cultivation, improvement of cereals and other crops is a major task of plant research
Barley (Hordeum vulgare L.) is one of the major cereals cultivated worldwide
The obtained results suggest that in both mutants all epidermal cells in the differentiation zone were symplasmically connected, whereas in the parental variety, root hair cells and non-root hair cells were symplasmically isolated from neighbouring cells (Table 1)

Summary

Introduction

In a time where there is a rapid increase in human population and the absence of new areas under cultivation, improvement of cereals and other crops is a major task of plant research. Root systems play a critical role in plant growth and development, since they are responsible for water and nutrient uptake from the soil (Cailloux 1972; Itoh & Barber 1983; Fo€hse et al 1991). One morphological strategy to increase root–soil (rhizosphere soil) contact is to develop root hairs, the tubular outgrowths of specialised root epidermal cells, called trichoblasts (Grabov & Bottger 1994; Lauter et al 1996). It has been proved that barley cultivars with longer root hairs absorb more phosphorus from rhizosphere soil than cultivars with shorter root hair (Gahoonia et al 2001). An analysis of the root hairless mutant brb (bald root barley) and its parental variety ‘Pallas’ revealed almost twofold depletion of inorganic and organic phosphorus fractions compared to mutants without root hairs (Gahoonia et al 2001)

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Discussion

Conclusion