Ethylene-responsive element binding factors (ERFs) are involved in regulation of various stress responses in plants, but their biological functions in waterlogging stress are largely unclear. In this study, we identified a petunia (Petunia × hybrida) ERF gene, PhERF2, that was significantly induced by waterlogging in wild-type (WT). To study the regulatory role of PhERF2 in waterlogging responses, transgenic petunia plants with RNAi silencing and overexpression of PhERF2 were generated. Compared with WT plants, PhERF2 silencing compromised the tolerance of petunia seedlings to waterlogging, shown as 96% mortality after 4 days waterlogging and 14 days recovery, while overexpression of PhERF2 improved the survival of seedlings subjected to waterlogging. PhERF2-RNAi lines exhibited earlier and more severe leaf chlorosis and necrosis than WT, whereas plants overexpressing PhERF2 showed promoted growth vigor under waterlogging. Chlorophyll content was dramatically lower in PhERF2-silenced plants than WT or overexpression plants. Typical characteristics of programmed cell death (PCD), DNA condensation, and moon-shaped nuclei were only observed in PhERF2-overexpressing lines but not in PhERF2-RNAi or control lines. Furthermore, transcript abundances of the alcoholic fermentation-related genes ADH1-1, ADH1-2, ADH1-3, PDC1, and PDC2 were reduced in PhERF2-silenced plants, but increased in PhERF2-overexpressing plants following exposure to 12-h waterlogging. In contrast, expression of the lactate fermentation-related gene LDH was up-regulated in PhERF2-silenced plants, but down-regulated in its overexpressing plants. Moreover, PhERF2 was observed to directly bind to the ADH1-2 promoter bearing ATCTA motifs. Our results demonstrate that PhERF2 contributes to petunia waterlogging tolerance through modulation of PCD and alcoholic fermentation system.
The effects of waterlogging on antioxidant enzyme activities responses in five different lines, i.e. ABA-deficient mutant (0673) and its control (0535), two ABA over-production transgenic rd29A:NCED1 lines (#2, #7) and Mill. L. cv. New Yorker (WT) were investigated. The waterlogging was mimicked by treating pot plants with flooding. The malondialdehyde (MDA) content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity in the leaves were evaluated in all treatments. The results showed that after 7 days waterlogging treatment, the malondialdehyde (MDA) was increased in all plants, especially in LA0673. Compared with the LA0673, #2 and #7 significantly increase the activities of SOD, POD and CAT under waterlogging stress. Therefore, ABA could improve the waterlogging tolerance of tomato by increasing the activities of antioxidant enzymes under waterlogging stress.
Ethylene-responsive element binding factors (ERFs) are widely involved in the regulation of plant responses to different abiotic stresses. In petunia (Petunia × hybrida), PhERF2 belonging to the subfamily Ⅶ of ERF transcription factors participates in the response to waterlogging stress. In this study, we investigated waterlogging tolerance variation of WT and transgenic petunia plants with RNAi silencing and overexpression of PhERF2 through photosynthetic and physiological performance. Chlorophyll content and root vigor declined continuously in both WT and PhERF2 transgenic lines under waterlogging stress, but the extent of the fall in PhERF2-overexpressing lines was less than that in WT and PhERF2-RNAi lines. At the end of waterlogging treatment, soluble protein levels in PhERF2-overexpressing lines were significantly higher than those in WT and PhERF2-RNAi lines, while the latter showed a higher malondialdehyde content overall. Different degrees of reductions in Pn, Gs, and Tr levels occurred in both WT and PhERF2 transgenic lines upon exposure to waterlogging. The Ci levels of PhERF2-overexpressing lines decreased after 3 hours of waterlogging treatment, and the Ci levels of WT and PhERF2-RNAi lines gradually increased from 6 to 72 hours of waterlogging treatment. These data suggested that non-stomatal factors were the primary limiting factors for Pn in WT and PhERF2-RNAi lines under severe stress, while the stomatal opening was the main factor limiting Pn in PhERF2-overexpressing lines. Our results demonstrated that the contribution of PhERF2 to the waterlogging tolerance of petunia appears to depend on the regulation of physiological and photosynthetic responses. PhERF2 represents a hopeful candidate gene for enhancing waterlogging tolerance of ornamental plants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.