Genome-Wide Analysis and Expression Profiling of the Heat Shock Factor Gene Family in Phyllostachys edulis during Development and in Response to Abiotic Stresses

Heat shock transcription factors (Hsfs) play crucial roles in regulating plant responses to heat and other stresses, as well as in plant development. As the largest monopodial bamboo species in the world, how to adapt to various stresses under the background of global climate change is very important for the sustainable development of bamboo forest. However, our understanding of the function of Hsfs in moso bamboo (Phyllostachys edulis) is limited. In this study, a total of 22 non-redundant Hsf genes were identified in the moso bamboo genome. Structural characteristics and phylogenetic analysis revealed that members of the PheHsf family can be clustered into three classes (A, B and C). Furthermore, PheHsfs promoters contained a number of stress-, hormone- and development-related cis-acting elements. Transcriptome analysis indicated that most PheHsfs participate in rapid shoot growth and flower development in moso bamboo. Moreover, the expression patterns of all 12 members of class A were analyzed under various stresses (heat, drought, salt and cold treatment) through Figurereal-time quantitative polymerase chain reaction (qRT-PCR). Within the class A PheHsf members, PheHsfA1a was expressed mainly during moso bamboo development. Expression of four PheHsfA4s and one PheHsfA2 (PheHsfA4a-1, PheHsfA4a-2, PheHsfA4d-1, PheHsfA4d-2, and PheHsfA2a-2) was up-regulated in response to various stresses. PheHsfA2a-2, PheHsfA4d-1 and PheHsfA4d-2 were strongly induced respectively by heat, drought and NaCl stress. Through co-expression analysis we found that two hub genes PheHsfA4a-2 and PheHsfA4a-1 were involved in a complex protein interaction network. Based on the prediction of protein interaction networks, five PheHsfAs (PheHsfA4a-1, PheHsfA4a-2, PheHsfA4d-1, PheHsfA4d-2, and PheHsfA2a-2) were predicted to play an important role in flower and shoot development and abiotic stress response of moso bamboo. This study provides an overview of the complexity of the PheHsf gene family and a basis for analyzing the functions of PheHsf genes of interest.