Diverse accumulation of several dehydrin-like proteins in cauliflower (Brassica oleracea var. botrytis), Arabidopsis thaliana and yellow lupin (Lupinus luteus) mitochondria under cold and heat stress.

Michal Rurek

doi:10.1186/1471-2229-10-181

Abstract

BackgroundDehydrins represent hydrophilic proteins acting mainly during cell dehydration and stress response. Dehydrins are generally thermostable; however, the so-called dehydrin-like (dehydrin-related) proteins show variable thermolability. Both groups immunoreact with antibodies directed against the K-segment of dehydrins. Plant mitochondrial dehydrin-like proteins are poorly characterized. The purpose of this study was to extend previous reports on plant dehydrins by comparing the level of immunoprecipitated dehydrin-like proteins in cauliflower (Brassica oleracea var. botrytis), Arabidopsis thaliana and yellow lupin (Lupinus luteus) mitochondria under cold and heat stress.ResultsAll the analyzed plant species showed constitutive accumulation of thermostable mitochondrial putative dehydrins ranging from 50 to 70 kDa. The mitochondrial dehydrin-like proteins observed in cauliflower and Arabidopsis ranged from 10 to 100 kDa and in lupin imbibed seeds and hypocotyls - from 20 to 90 kDa. Cold treatment increased mainly the accumulation of 10-100 kDa cauliflower and Arabidopsis dehydrin-like proteins, in the patterns different in cauliflower leaf and inflorescence mitochondria. However, in lupin mitochondria, cold affected mainly 25-50 kDa proteins and seemed to induce the appearance of some novel dehydrin-like proteins. The influence of frost stress on cauliflower leaf mitochondrial dehydrin- like proteins was less significant. The impact of heat stress was less significant in lupin and Arabidopsis than in cauliflower inflorescence mitochondria. Cauliflower mitochondrial dehydrin-like proteins are localized mostly in the mitochondrial matrix; it seems that some of them may interact with mitochondrial membranes.ConclusionsAll the results reveal an unexpectedly broad spectrum of dehydrin-like proteins accumulated during some abiotic stress in the mitochondria of the plant species analyzed. They display only limited similarity in size to those reported previously in maize, wheat and rye mitochondria. Some small thermolabile dehydrin-like proteins were induced under stress conditions applied and therefore they are likely to be involved in stress response.

Highlights

Dehydrins represent hydrophilic proteins acting mainly during cell dehydration and stress response
Accumulation of dehydrin-like proteins in cauliflower and Arabidopsis mitochondria To analyse accumulation of dehydrin-like proteins in cauliflower mitochondria under control and stress conditions, the mitochondria from leaves as well as from young inflorescences were isolated and their purity was assayed by transmission electron microscopy (Figure 1A)
The mitochondria obtained from cauliflower inflorescences of plants grown under standard conditions showed similar pattern of dlps immunoreacting with Ksegment specific antibodies

Summary

Introduction

Dehydrins represent hydrophilic proteins acting mainly during cell dehydration and stress response. Dehydrins are generally thermostable; the so-called dehydrin-like (dehydrin-related) proteins show variable thermolability. Both groups immunoreact with antibodies directed against the K-segment of dehydrins. Stress acclimation in plants is associated with the appearance of characteristic cellular, biochemical and gene expression alterations [1]. It is generally assumed that dehydrins protect the rapidly growing plant organs against damage. They are present both in the nucleus and in the cytoplasm and close to the elements of cytoskeleton as well as in the vicinity of the plasma membrane and tonoplast [9,10,11,12,13]. The data concerning potential associations of dehydrins with other cell compartments are still limited and need more verification

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