| Summary: | ‘Huangguan’ pear (<i>Pyrus bretschneideri</i> Rehd. cv. Huangguan) fruit is sensitive to chilling injury (CI), which exhibits peel browning spots (PBS) during cold storage. Dehydrin (DHN) is considered to be related to cold tolerance in plants, but its function in postharvest pear fruit during storage remains unclear. In this study, six <i>PbDHNs</i> (<i>PbDHN1–6</i>) genes were identified and characterized, and the PbDHN proteins were sorted into Y<sub>n</sub>K<sub>n</sub>, SK<sub>n</sub> and Y<sub>n</sub>SK<sub>n</sub> according to the major conserved motifs related to the number and location of K-segments, S-segments, and Y-segments. In addition, there were five cold-responsive related <i>cis</i>-acting elements in the promoter region of the <i>PbDHNs</i>. The analysis of fruit quality suggested that compared with a storage temperature at 20 °C, a storage temperature of 0 °C results in CI in ‘Huangguan’ pear fruit, while a storage temperature of 10 °C and low temperature conditioning (LTC) alleviates the CI. Moreover, gene expression results indicated that the six <i>PbDHNs</i> were markedly enhanced at low temperatures, especially at 0 °C. The transcripts of <i>PbDHN1</i>, <i>PbDHN4</i>, <i>PbDHN5</i> and <i>PbDHN6</i> were also increased in the fruit stored at 10 °C, but they were lower than that at 0 °C except <i>PbDHN5</i>. Compared with low temperature storage at 0 °C, LTC treatment significantly depressed the expression of <i>PbDHN1</i>, <i>PbDHN2</i>, <i>PbDHN3</i>, <i>PbDHN4</i>, and <i>PbDHN6</i>, while enhanced the mRNA amount of <i>PbDHN5</i>. In conclusion, <i>PbDHN1</i>, <i>PbDHN4</i>, <i>PbDHN5</i>, and <i>PbDHN6</i> were closely related to the CI, and LTC lowered the CI by down-regulating the expression of <i>PbDHN1</i>, <i>PbDHN4</i>, and <i>PbDHN6</i> and by up-regulating <i>PbDHN5</i> in ‘Huangguan’ pear fruit.
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