Immunohisto- and cytochemical localization of PR-10 proteins induced by heavy metals in lupine roots

R Przymusiński,J Gzyl

doi:10.1007/s11738-012-1177-6

Abstract

Most of the data concerning PR-10 proteins accumulation in plants under various environmental stress conditions are derived from biochemical analysis of transcript expression or polypeptide accumulation. In the current study, we examined the localization of PR (L1–L6) proteins, belonging to the PR-10 class family, in the root tips of yellow lupine seedlings using histo- and cytochemical methods. Immunohistochemical localization revealed the presence of PR-proteins in all examined yellow lupine root tip tissue, and lead treatment did not change the distribution of proteins in the roots. However, the metal induced a significant increase in the accumulation of PR-proteins in the meristematic cells and procambium tissue. An immunocytochemical approach with immunogold method demonstrated the cytoplasmic nature of the PR-proteins and their increased accumulation after copper treatment. The results confirmed the affiliation of PR (L1–L6) to PR-10 class family proteins, as well as their intracellular localization.

Highlights

One of the plant responses to metal ion toxicity is the synthesis of specific proteins and polypeptides, which increase cell tolerance to an excess of metal ions through modification of the cell metabolism
We examined the localization of PR (L1–L6) proteins, belonging to the PR-10 class family, in the root tips of yellow lupine seedlings using histo- and cytochemical methods
The presence or accumulation of pr10 genes expression products, mostly under stress conditions, has been demonstrated in roots and leaves (Bantignies et al 2000; Przymusinski et al 2004; Utriainen et al 1998), hypocotyls (Gzyl et al 1997), tuber (Flores et al 2002), stems, seeds (Iturriaga et al 1994), fruits (Andersen et al 2011), embryos and pollen (Swoboda et al 1994), stigma (Constabel and Brisson 1995), calluses (Moiseyev et al 1997), and cell suspension (Carpin et al 1998). These data suggest that PR-10 proteins might be potentially accumulated in all organs of plants and are in line with our earlier study (Przymusinski et al 2001) in which the localization of PR (L1–L6) proteins with a tissue printing method was investigated in 12-day-old lupine seedlings, but excluding the root tips

Summary

Introduction

One of the plant responses to metal ion toxicity is the synthesis of specific proteins and polypeptides, which increase cell tolerance to an excess of metal ions through modification of the cell metabolism. This group of proteins comprises phytochelatins, heat shock and desiccation proteins, various enzymes involved in the antioxidant defense system, and pathogenesis-related class 10 proteins (Clemens 2006; Nagajyoti et al 2010; Sobkowiak and Deckert 2006). Sequence analysis of 20 N-terminal amino acids indicated that all these polypeptides show a high degree of homology to the 10 class family of pathogenesisrelated proteins (Przymusinski and Gwozdz 1999). Members of the PR-10 group share several conserved features, including a lack of signal peptides and hydrophobic helices, acidic pI values of 4.5–6.5, and a high resistance to protease activity

Objectives

Methods

Results