Single Nucleotide Polymorphisms in HSP17.8 and Their Association with Agronomic Traits in Barley

Small heat shock protein 17.8 (HSP17.8) is produced abundantly in plant cells under heat and other stress conditions and
may play an important role in plant tolerance to stress environments. However, HSP17.8 may be differentially expressed in
different accessions of a crop species exposed to identical stress conditions. The ability of different genotypes to adapt to
various stress conditions resides in their genetic diversity. Allelic variations are the most common forms of genetic variation
in natural populations. In this study, single nucleotide polymorphisms (SNPs) of the HSP17.8 gene were investigated across
210 barley accessions collected from 30 countries using EcoTILLING technology. Eleven SNPs including 10 from the coding
region of HSP17.8 were detected, which form nine distinguishable haplotypes in the barley collection. Among the 10 SNPs
in the coding region, six are missense mutations and four are synonymous nucleotide changes. Five of the six missense
changes are predicted to be deleterious to HSP17.8 function. The accessions from Middle East Asia showed the higher
nucleotide diversity of HSP17.8 than those from other regions and wild barley (H. spontaneum) accessions exhibited greater
diversity than the cultivated barley (H. vulgare) accessions. Four SNPs in HSP17.8 were found associated with at least one of
the agronomic traits evaluated except for spike length, namely number of grains per spike, thousand kernel weight, plant
height, flag leaf area and leaf color. The association between SNP and these agronomic traits may provide new insight for
study of the gene’s potential contribution to drought tolerance of barley.