Physiological and transcriptomic analysis revealed the involvement of crucial factors in heat stress response of Rhododendron hainanense.

Molecular regulatory mechanism of heat stress response (HSR) in Ericaceae remains unknown. Here, we sought to identify HSR mechanisms in Rhododendron hainanense, a Ericaceae species, through a combination of physiological and transcriptomic studies. The levels of MDA, H2O2, Pro, SOD, CAT and APX in leaves of R. hainanense were analyzed to characterize a dramatic difference in varied temperature treatment. Also, three sequencing libraries, including one control and two heat stress (HS)-treated samples, were constructed for comparative transcriptomic analysis. By Illumina sequencing and Trinity strategy, 350 million clean reads (average length = 149 bp) was assembled into 183,486 unigenes. According to analysis of differential expression genes (DEGs), a total of 2658 DEGs were obtained. Moreover, a complex interaction network of 982 DEGs was established, of which master portions were comprised of 109 transcription factors (TFs). Importantly, integrated differential expression profiling, qRT-PCR and functional analysis, several TFs of R. hainanense (ABR1, IAA26, OBF1, LUX, SCL3, DIV, NAC29, NAC72 and TCP3) and their potential regulations for the crosstalk between hormonal signal and HSR were identified. These findings will contribute to our understanding of the regulatory mechanisms of HSR in R. hainanense, breeding cultivars with improved thermotolerance.