Portal de Periódicos da CAPES

Maize HSFA 2 and HSBP 2 antagonistically modulate raffinose biosynthesis and heat tolerance in Arabidopsis

2019; Wiley; Volume: 100; Issue: 1 Linguagem: Inglês

10.1111/tpj.14434

1365-313X

Lei Gu, Tao Jiang, Chunxia Zhang, Xudong Li, Chunmei Wang, Yumin Zhang, Tao Li, Lynnette M.A. Dirk, A. Bruce Downie, Tianyong Zhao,

Plant Molecular Biology Research

Summary Raffinose is thought to play an important role in plant tolerance of abiotic stress. We report here that maize HEAT SHOCK FACTOR A2 (Zm HSFA 2) and HEAT SHOCK BINDING PROTEIN 2 (Zm HSBP 2) physically interact with each other and antagonistically modulate expression of GALACTINOL SYNTHASE 2 ( Zm GOLS 2 ) and raffinose biosynthesis in transformed maize protoplasts and Arabidopsis plants. Overexpression of Zm HSFA 2 in Arabidopsis increased the expression of Arabidopsis At GOLS 1 , At GOLS 2 and At RS 5 ( RAFFINOSE SYNTHASE ), increased the raffinose content in leaves and enhanced plant heat stress tolerance. Contrary to Zm HSFA 2 , overexpression of Zm HSBP 2 in Arabidopsis decreased expression of At GOLS 1 , At GOLS 2 and At RS 5 , decreased the raffinose content in leaves and reduced plant heat stress tolerance. Zm HSFA 2 and Zm HSBP 2 also interact with their Arabidopsis counterparts At HSBP and At HSFA 2 as determined using bimolecular fluorescence complementation assays. Furthermore, endogenous Zm HSBP 2 and Rluc , controlled by the Zm HSBP 2 promoter, are transcriptionally activated by Zm HSFA 2 and inhibited by Zm HSBP 2 in maize protoplasts. These findings provide insights into the transcriptional regulation of raffinose biosynthetic genes, and the tolerance their product confers to plant heat stress.