Unveiling the Heat Shock Protein Network in Sugar Beet: Comprehensive Genome-Wide Identification, Characterization, and Stress-Induced Expression Patterns

Abstract

Heat shock proteins (Hsps) are vital for plant responses to abiotic stress, serving as molecular chaperones that maintain protein stability under adverse conditions. This study supplies a comprehensive genome-wide analysis of Hsp family members in the sugar beet (Beta vulgaris) genome and Hsp family gene expression patterns in three genotypes: drought-tolerant, drought-sensitive, and wild beet (Beta maritima). 334 Hsp genes belonging to six major families (sHsp, Hsp40, Hsp60, Hsp70, Hsp90, and Hsp100) were identified. Abundant tandem and segmental duplication events were observed, particularly within the Hsp70 and Hsp100 families, indicating a potential role in stress adaptation. Gene expression analysis under heat, drought, and combined stress conditions revealed significant upregulation of BvHsp70-22, BvHsp90-03, and BvHsp60-28 in the drought-tolerant genotype, indicating their critical roles in stress recovery. In contrast, the drought-sensitive genotype displayed upregulation of BvHsp60-01 and BvHsp90-03, exhibiting a potentially less robust stress response. BvsHsp-34 and BvsHsp-38 were highly expressed under drought stress in the wild beet, suggesting unique adaptive mechanisms. Synteny and phylogenetic analyses demonstrated conserved genetic linkages between sugar beet Hsp genes and orthologs in Arabidopsis thaliana, Oryza sativa, and Glycine max, indicating evolutionary conservation. Gene ontology analysis highlighted their roles in protein folding, binding, and stress response processes. This research sheds light on the molecular mechanisms behind heat shock protein-driven tolerance to abiotic stress in sugar beet, and identifies BvHsp70-22, BvHsp90-03, and BvHsp60-28 as promising candidate genes for future breeding strategies aimed at enhancing stress resilience.