PlMAPK1 facilitates growth and photosynthesis of herbaceous peony (Paeonia lactiflora Pall.) under high-temperature stress

Herbaceous peony (Paeonia lactiflora Pall.) is a traditional famous flower in China that prefers cold climates and is not tolerant of high summer temperatures. Mitogen-activated protein kinase (MAPK) is widely involved in plant signal transduction to various environmental stresses. In order to clarify the role of PlMAPK1 in response to high-temperature stress, it was cloned, and its open reading frame was 1215 bp, encoding 405 amino acids. Quantitative real-time PCR (qRT-PCR) analysis showed that when the plant was severely damaged by high temperatures, the expression level of PlMAPK1 was at its peak. Moreover, based on a systematic study of exogenous yeast, it was found that the yeast strain overexpressing PlMAPK1 grew better than the control under high-temperature stress. In addition, PlMAPK1 was transiently silenced by virus induced gene silencing tech-nology (VIGS) in P. lactiflora. And under high-temperature stress, the leaves of transgenic plants wilted signifi-cantly, the accumulation of reactive oxygen species increased and the photosynthetic capacity decreased significantly. These findings suggested that PlMAPK1 might play a positive regulatory role in the response of P. lactiflora to high-temperature stress, laying a theoretical groundwork for P. lactiflora high-temperature tolerance breeding.