PsDUF6A from Populus simonii enhances drought tolerance in transgenic Arabidopsis and poplar by increasing ROS scavenging

Abstract

Domain of unknown function (DUF) proteins play roles in a range of plant biological processes, including growth and development, and adaptation to abiotic stresses. However, their function was largely unknown in woody plants. Populus simonii is a notable native tree species in northern China and is highly tolerance to drought stress. In this study, PsDUF6A was isolated and functionally characterized from P. simonii. This gene was highly expressed in mature leaves and its expression was induced under drought condition. Transgenic Arabidopsis and 84 K poplar lines overexpressing PsDUF6A were constructed to investigate the function of PsDUF6A in drought tolerance. Under drought conditions, the survival rate and relative water content were higher in PsDUF6A-overexpressing Arabidopsis than in wild-type Arabidopsis, whereas the opposite trend was observed for relative electrical conductivity, indicative of increased drought tolerance. Compared with 84 K poplar, transgenic poplar had a higher photosynthetic activity, lower water loss rate, and higher root biomass. Moreover, PsDUF6A-overexpressing increased antioxidant enzyme activities and the reactive oxygen species scavenging. In addition, the yeast one-hybrid assay indicated that PsC2H213, PsC2H214, PsC2H215, PsC2H217, and PsC2H218 can directly bind to PsDUF6A promoter. These results indicated that PsDUF6A enhances drought tolerance by maintaining ROS homeostasis, and its expression might regulate by C2H2-type ZFPs. These findings revealed the positive contributions of PsDUF6A to drought tolerance and provided insights into the underlying regulatory network of P. simonii response to drought stress.