NHX1 and eIF4A1-stacked transgenic sweetpotato shows enhanced tolerance to drought stress
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Co-expression of Na+/H+ antiporter NHX1 and DEAD-box RNA helicase eIF4A1 from Arabidopsis positively regulates drought stress tolerance by improving ROS scavenging capacity and maintaining membrane integrity in sweetpotato.
Plants evolve multiple strategies for stress adaptation in nature. To improve sweetpotato resistance to drought stress, transgenic sweetpotato plants overexpressing the Arabidopsis Na+/H+ antiporter, NHX1, and the translation initiation factor elF4A1 were characterized for phenotypic traits and physiological performance. Without drought treatment, the NHX1–elF4A1 stacked lines (NE lines) showed normal, vigorous growth comparable to the WT plants. The NE plants showed dense green foliage with delayed leaf senescence and developed more roots than WT plants under drought treatment for 18 days. Compared to WT plants, higher level of reactive oxygen scavenging capacity was detected in NE lines as indicated by reduced H2O2 accumulation as well as increased superoxide dismutase activity and proline content. The relative ion leakage and malondialdehyde content were reduced in NE plants, indicating improved maintenance of intact membranes system. Both NE plants and NHX1-overexpressing plants (N lines) showed larger aerial parts and well-developed root system compared to WT plants under the drought stress conditions, likely due to the improved antioxidant capacity. The NE plants showed better ROS scavenging than N-line plants. All N- and NE-line plants produced normal storage roots with similar yields as WT in the field under normal growth conditions. These results demonstrated the potential to enhance sweetpotato productivity through stacking genes that are involved in ion compartmentalization and translation initiation.
KeywordsSweetpotato Drought stress NHX1 eIF4A1 Gene-stacking Overexpression Physiological parameter Phenotype
Reactive oxygen species
Quantitative reverse transcription-polymerase chain reaction
This work was supported by the grants from the National Key R&D Program of China (2018YFD1000700, 2018YFD1000705), the National Natural Science Foundation of China (31771854) and China Scholarship Council (201804910055). We thank Prof. Sitakanta Pattanaik from UK for corrections the manuscript.
Author contribution statement
YZ analyzed the data and drafted the manuscript. GD performed the majority of the experiments. WF generated the NE transgenic lines. LY revised the manuscript and provided helpful suggestions. HW and PZ coordinated and designed the study and revised the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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