*Article* **Genome-Wide Identification and Characterization of Warming-Related Genes in** *Brassica rapa* **ssp.** *pekinensis*

**Hayoung Song 1,†, Xiangshu Dong 2,† ID , Hankuil Yi <sup>1</sup> , Ju Young Ahn <sup>1</sup> , Keunho Yun <sup>1</sup> , Myungchul Song <sup>3</sup> , Ching-Tack Han <sup>3</sup> and Yoonkang Hur 1,\***


Received: 11 May 2018; Accepted: 6 June 2018; Published: 11 June 2018

**Abstract:** For sustainable crop cultivation in the face of global warming, it is important to unravel the genetic mechanisms underlying plant adaptation to a warming climate and apply this information to breeding. Thermomorphogenesis and ambient temperature signaling pathways have been well studied in model plants, but little information is available for vegetable crops. Here, we investigated genes responsive to warming conditions from two *Brassica rapa* inbred lines with different geographic origins: subtropical (Kenshin) and temperate (Chiifu). Genes in Gene Ontology categories "response to heat", "heat acclimation", "response to light intensity", "response to oxidative stress", and "response to temperature stimulus" were upregulated under warming treatment in both lines, but genes involved in "response to auxin stimulus" were upregulated only in Kenshin under both warming and minor-warming conditions. We identified 16 putative high temperature (HT) adaptation-related genes, including 10 heat-shock response genes, 2 transcription factor genes, 1 splicing factor gene, and 3 others. *BrPIF4*, *BrROF2*, and *BrMPSR1* are candidate genes that might function in HT adaptation. Auxin response, alternative splicing of *BrHSFA2*, and heat shock memory appear to be indispensable for HT adaptation in *B. rapa*. These results lay the foundation for molecular breeding and marker development to improve warming tolerance in *B. rapa*.

**Keywords:** warming; BrHSFA2; BrHSP18.2s; transcriptome; alternative splicing; Kenshin
