Different Roles of Heat Shock Proteins (70 kDa) During Abiotic Stresses in Barley (Hordeum vulgare) Genotypes

Abstract

In this work, the involvement of heat shock proteins (HSP70) in barley (Hordeum vulgare) has been studied in response to drought and salinity. Thus, 3 barley genotypes usually cultivated and/or selected in Italy, 3 Middle East/North Africa landraces and genotypes and 1 improved genotype from ICARDA have been studied to identify those varieties showing the best stress response. Preliminarily, a bioinformatic characterization of the HSP70s protein family in barley has been made by using annotated Arabidopsis protein sequences. This study identified 20 putative HSP70s orthologs in the barley genome. The construction of un-rooted phylogenetic trees showed the partition into four main branches, and multiple subcellular localizations. The enhanced HSP70s presence upon salt and drought stress was investigated by both immunoblotting and expression analyses. It is worth noting the Northern Africa landraces showed peculiar tolerance behavior versus drought and salt stresses. The drought and salinity conditions indicated the involvement of specific HSP70s to counteract abiotic stress. Particularly, the expression of cytosolic MLOC_67581, mitochondrial MLOC_50972, and encoding for HSP70 isoforms showed different expressions and occurrence upon stress. Therefore, genotypes originated in the semi-arid area of the Mediterranean area can represent an important genetic source for the improvement of commonly cultivated high-yielding varieties.

Detailed Genetic Analysis for Identifying QTLs Associated with Drought Tolerance at Seed Germination and Seedling Stages in Barley

“…The overexpression of tobacco hsp70 enhanced drought stress [ 58 ]. The cytosolic hsp70 transcripts dramatically increased over 50-fold under PEG-induced drought stress in barley [ 59 ]. Moreover, HORVU6Hr1G075640 encoded the AP2-like ethylene-responsive transcription factor (AP2/ERF).…”

Molecular cloning and functional analyses of the salt‐ responsive gene KVHSP70 from Kosteletzkya virginica

“…Previous reports have attested that HSP70s are induced not only by high temperature but also by other abiotic stresses (Augustine et al, ; Landi et al, ; Qian et al, ). Consistently, our studies in this research proved this point again.…”

“…These molecular chaperones are highly conserved proteins assisting the folding and assembling of the proteins to guarantee cell survival under abiotic stress conditions (Büyük et al, ). The 70‐kDa heat shock protein (HSP70) is the most abundant and conserved heat shock protein, which has a conserved N‐terminal domain a substrate‐binding domain and a C‐terminal domain, with a slightly weaker conservative property (Landi et al, ; Zhu et al, ). It was the flexible C‐terminal endowed the different HSP70s with different subcellular localization including cytoplasm, chloroplast, mitochondria, and endoplasmic reticulum (Li et al, ; Water & Renner, ).…”

Plant Resistance to Abiotic Stresses

“…Barley is a staple cereal grown in temperate climates globally. High-yielding cultivars generated through breeding have lost tolerance to drought, salt, and heavy metal stress present in the wild ancestor Hordeum spontaneum [8]. Stress-tolerant barley landraces from the semi-arid Mediterranean region represent an important source of genetic diversity for the improvement of high-yield cultivars.…”

“…In this special issue, Landi et al (2019) investigates how different barley landraces respond to salinity and osmotic stress. Their results can be useful for breeding strategies to reintroduce stress tolerance in cultivated varieties [8].…”