Potato Plants Overexpressing SpHsfA4c Exhibit Enhanced Tolerance to High-Temperature Stress.

Plants are often subjected to heat stress during growth and development, resulting in loss of yield and quality. In order to adapt to this stress environment, plants have developed different mechanisms to endure the heat conditions. Heat shock transcription factors (Hsfs) are an important gene family, which could mediate the activation of heat-induced genes in the heat resistance. In potato, Hsfs have been identified through bioinformatics recently. However, their functions are not well understood. In this study, an Hsf gene SpHsfA4c isolated from a wild potato Solanum pinnatisectum Dun was analyzed for its function, and the results showed that SpHsfA4c gene encodes a protein with 417 amino acids, which contained DBD, OD, NES, NLS and CTD domains that are conserved characteristics of class HsfAs. SpHsfA4c gene was expressed in all tissues with higher expression levels in leaves and flowers, and the expression was induced by heat stress. To further explore the function of SpHsfA4c in heat stress, three lines A2, A7 and A11 overexpressing SpHsfA4c (OE) were constructed and identified. Under heat stress, the heat damage index of the OE lines was significantly lower than that of the control. Analysis of heat-related physiological and biochemical indices showed that SpHsfA4c over-expression improved potato's cell membrane stability, increased antioxidant capacity and osmotic adjustment ability which were consistent with phenotypic observations. All these results suggested that SpHsfA4c gene positively regulates potato heat tolerance and can be used as a candidate gene in potato breeding by genetic engineering. [ABSTRACT FROM AUTHOR]