| Summary: | The characterization of the PYL/RCAR ABA receptors in a great deal of plant species has dramatically advanced the study of ABA functions involved in key physiological processes. However, the genes in this family are still unclear in <i>Lycium</i> (Goji) plants, one of the well–known economically, medicinally, and ecologically valuable fruit crops. In the present work, 12 homologs of <i>Arabidopsis</i> PYL/RCAR ABA receptors were first identified and characterized from <i>Lycium</i> (L.) <i>barbarum</i> (LbPYLs). The quantitative real–time PCR (qRT–PCR) analysis showed that these genes had clear tissue–specific expression patterns, and most of them were transcribed in the root with the largest amount. Among the three subfamilies, while the Group I and Group III members were down–regulated by extraneous ABA, the Group II members were up–regulated. At 42 °C, most transcripts showed a rapid and violent up–regulation response to higher temperature, especially members of Group II. One of the genes in the Group II members, <i>LbPYL10</i>, was further functionally validated by virus–induced gene silencing (VIGS) technology. <i>LbPYL10</i> positively regulates heat stress tolerance in <i>L. barbarum</i> by alleviating chlorophyll degradation, thus maintaining chlorophyll stability. Integrating the endogenous ABA level increase following heat stress, it may be concluded that LbPYL–mediated ABA signaling plays a vital role in the thermotolerance of <i>L. barbarum</i> plants. Our results highlight the strong potential of <i>LbPYL</i> genes in breeding genetically modified <i>L. barbarum</i> crops that acclimate to climate change.
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