transcritional analysis of cherry rootstock under waterlogging

Waterlogging is a huge threat for crop yield and quality, which occurs more frequently these years due to climate change. Cherry, a fruit tree with high economic value, is sensitive to waterlogging stress. One of the most effective methods to enhance waterlogging tolerance of cherry is to select waterlogging-tolerant cherry rootstock. However, the evaluation of various cherry rootstocks responding to waterlogging stress has not been done, and the mechanism of waterlogging tolerance of cherry rootstock remains to be uncharacterized. In this study, we compared the differences among five cherry rootstock cultivars Y1, Colt, Gisela 5, Gisela 6 and Gisela 12 under waterlogging conditions with or without oxygenating. Gisela 12 was the most waterlogging-sensitive cultivar among five and Colt was the most tolerant one, based on their morphological and physiological changes under waterlogging. Meanwhile, oxygenating can obviously alleviate the influences of waterlogging treatment for all five cultivars. Then, we chose the moderately waterlogging-tolerant cultivar Gisela 6 to further explore the mechanism underlying the cherry rootstock response to waterlogging with or without oxygenating. Gisela 6 subjected to waterlogging had lower relative water content, Fv/Fm value, net photosynthetic rate and antioxidant enzyme activities, whereas the group with oxygenating performed better in all these aspects. RNA-Seq analysis of leaf samples at 8 DAT with waterlogging treatment, T1, with waterlogging treatment and oxygenating, T2, and under control, CK, was conducted to investigate the genes involved in waterlogging stress response. DEGs under T1 was drastically more than that under T2, suggesting the waterlogging stress relieving effect of oxygenating. Further analysis of DEGs elucidated that many of them were involved in energy production, antioxidant metabolism, hormone metabolism pathway, stress-related transcription factors and proteins. In summary, our study intended to make a comparison in waterlogging tolerance among five varieties of cherry rootstock and provide new insights into the mechanism underlying waterlogging responses of cherry rootstock, thus finding approaches to enhance waterlogging tolerance of cherry and leading to higher yield and quality of sweet cherry.