Climate change is profoundly reshaping sweet cherry production, increasing the frequency of abiotic stress events such as heat waves, salinity, and drought, which negatively affect vegetative growth, productivity, and fruit quality.
Understanding the molecular mechanisms that enable sweet cherry trees to adapt to unfavorable environmental conditions is therefore a crucial step, also for the development of breeding strategies.
A recent study provided the first comprehensive genomic characterization of the HSP70 and HSP90 (Heat Shock Protein) gene families in sweet cherry, highlighting their structure, evolutionary organization, and role in responses to environmental stresses.
HSPs represent one of the major classes of molecular chaperones found in living organisms.
Their function is to promote the correct folding of newly synthesized proteins, prevent the accumulation of denatured proteins, and maintain cellular homeostasis under stressful conditions.
Through a genome-wide analysis, the researchers identified 17 genes belonging to the two major families: 11 HSP70 genes and 6 HSP90 genes.
These genes are distributed across six of the eight (n = 8) sweet cherry chromosomes and exhibit highly conserved structural characteristics within their respective subfamilies, indicating a high degree of evolutionary conservation.
Phylogenetic analysis further classified them into three major groups shared with the corresponding families in Arabidopsis and wheat, suggesting that these genes have retained essential biological functions throughout plant evolution.
Analysis of the promoter regions revealed a high abundance of regulatory elements associated with responses to light, drought, temperature, and phytohormones such as abscisic acid, salicylic acid, jasmonates, and gibberellins.
The different distribution of these elements suggests that individual genes may be regulated in a stress- or developmental stage-specific manner, thereby contributing to a highly specialized adaptive response.
Gene expression was subsequently analyzed in different organs of ‘Gisela 6’.
The results showed marked tissue specificity: numerous HSP70 genes were more highly expressed in stems, whereas several HSP90 genes exhibited higher expression levels in mature leaves.
Some genes, including PavHSP70-3 and PavHSP90-5, instead showed constitutive expression across all organs examined, indicating a potential role in maintaining normal cellular functions in addition to their involvement in stress responses.
qRT-PCR experiments confirmed that numerous genes are rapidly activated following exposure to 37°C or salt stress (150 mM NaCl).
In particular, PavHSP70-5, PavHSP70-3, and especially PavHSP90-5 showed marked transcriptional induction, indicating their potential direct involvement in cellular protection mechanisms.
In parallel, a progressive accumulation of sodium was observed in roots and leaves during salt treatment, supporting a relationship between stress intensity and the transcriptional response of HSP genes.
Additional cellular localization experiments demonstrated that PavHSP70-1, PavHSP70-3, and PavHSP90-5 are predominantly localized to the plasma membrane, a strategic position for sensing and transducing environmental stress signals.
Overall, the study provides a genomic basis for understanding the functions of HSP proteins in sweet cherry.
The identification of genes showing the strongest responses to heat and salt stress, together with the characterization of their regulatory and interaction networks, represents a valuable genomic resource for future breeding programs aimed at improving sweet cherry resilience to climate-related stresses.
Source: Liu, A., et al. (2026). Genome-Wide Characteristics and Responsive Expression of HSP Family Genes in Sweet Cherry (Prunus avium L.). Russian Journal of Plant Physiology, 73(2), 87. https://doi.org/10.1134/S102144372560686X
Image source: Stefano Lugli
Andrea Giovannini
PhD in Agricultural, Environmental and Food Science and Technology - Arboriculture and Fruitculture, University of Bologna, IT
17 Apr 2026
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