Changes in Ethylene, ABA and Sugars Regulate Freezing Tolerance under Low-Temperature Waterlogging in Lolium perenne

Cold Acclimation and Deacclimation of Winter Oilseed Rape, with Special Attention Being Paid to the Role of Brassinosteroids

Winter plants acclimate to frost mainly during the autumn months, through the process of cold acclimation. Global climate change is causing changes in weather patterns such as the occurrence of warmer periods during late autumn or in winter. An increase in temperature after cold acclimation can decrease frost tolerance, which is particularly dangerous for winter crops. The aim of this study was to investigate the role of brassinosteroids (BRs) and BR analogues as protective agents against the negative results of deacclimation. Plants were cold-acclimated (3 weeks, 4 °C) and deacclimated (1 week, 16/9 °C d/n). Deacclimation generally reversed the cold-induced changes in the level of the putative brassinosteroid receptor protein (BRI1), the expression of BR-induced COR, and the expression of SERK1, which is involved in BR signal transduction. The deacclimation-induced decrease in frost tolerance in oilseed rape could to some extent be limited by applying steroid regulators. The deacclimation in plants could be detected using non-invasive measurements such as leaf reflectance, chlorophyll a fluorescence, and gas exchange monitoring.

Expressing banana transcription factor MaERFVII3 in Arabidopsis confers enhanced waterlogging tolerance and root growth

Background

Waterlogging poses a significant threat to plant growth and yield worldwide. Identifying the genes responsible for mitigating waterlogging stress is crucial. Ethylene-responsive factors (ERFs) are transcriptional regulators that respond to various biotic and abiotic stresses in plants. However, their roles and involvement in responding to waterlogging stress remain largely unexplored. Hence, this study aimed to elucidate the role of ERFs in enhancing banana plant resilience to waterlogging.

Methods

We hypothesized that introducing a group VII ERF transcription factor in Arabidopsis could enhance waterlogging stress tolerance. To test this hypothesis, we isolated MaERFVII3 from banana roots, where it exhibited a significant induction in response to waterlogging stress. The isolated MaERFVII3 was introduced into Arabidopsis plants for functional gene studies.

Results

Compared with wild-type plants, the MaERFVII3-expressing Arabidopsis showed increased survival and biomass under waterlogging stress. Furthermore, the abundance of transcripts related to waterlogging and hypoxia response showed an elevation in transgenic plants but a decrease in wild-type and empty vector plants when exposed to waterlogging stress. Our results demonstrate the significant contribution of MaERFVII3 to waterlogging tolerance in Arabidopsis, providing baseline data for further exploration and potentially contributing to crop improvement programs.

Special Issue “Sugar Transport, Metabolism and Signaling in Plants”

Sucrose and its derivative hexoses are key metabolites of the plant metabolism, structural units of cell walls and stored reserves (e [...]

Comparative analysis of the potential physiological and molecular mechanisms involved in the response to root zone hypoxia in two rootstock seedlings of the Chinese bayberry via transcriptomic analysis

The negative effects of waterlogging can be effectively improved through the use of waterlogging-resistant rootstocks. However, the underlying physiological and molecular mechanisms of Chinese bayberry (Morella rubra) rootstock tolerance to waterlogging have not yet been investigated. This study aims to unravel the molecular regulation mechanisms underlying waterlogging-tolerant rootstocks. Two rootstocks, Morella cerifera (tolerant) and Morella rubra (sensitive), were selected for root zone hypoxia treatments, assessments of hormone levels and antioxidant enzyme activity, and transcriptomic analysis. While the contents of abscisic acid (ABA) and brassinosteroid (BR) in the roots of M. rubra decreased significantly after root zone hypoxia treatment, there were no significant changes in M. cerifera. Both the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content increased in M. cerifera but were decreased in M. rubra. Transcriptome sequencing identified 1,925 (928 up- and 997 downregulated) and 733 (278 up- and 455 downregulated) differentially expressed genes (DEGs) in the two rootstocks. The gene set enrichment analysis showed that 84 gene sets were enriched after root zone hypoxia treatment, including 57 (35 up- and 22 downregulated) and 14 (five up- and nine downregulated) gene sets derived from M. cerifera and M. rubra, respectively, while the remaining 13 gene sets were shared. KEGG pathway analysis showed specific enrichment in six pathways in M. cerifera, including the mitogen-activated protein kinase (MAPK), tyrosine metabolism, glycolysis/gluconeogenesis, ribosome, cyanoamino acid metabolism, and plant-pathogen interaction pathways. Overall, these results provide preliminary insights into the molecular mechanisms of Chinese bayberry tolerance to waterlogging.

Interaction between fructan metabolism and plant growth regulators

The relationship of fructan to plant growth regulators is clearly more complicated than it looks and is likely related to differences between fructan molecules in size and structure as well as localization. Fructans are a complex group of carbohydrates composed mainly of fructose units linked to a sucrose molecule. Fructans are present in plants as heterogeneous mixtures with diverse molecular structures and mass, different polymerization degrees, and linkage types between fructosyl residues. Like sucrose, they are frequently stored in leaves and other organs, acting as carbohydrate reserves. Fructans are synthesized in the cell vacuole by fructosyltransferase enzymes and catabolized by fructan exohydrolase enzymes. Several publications have shown that fructan metabolism varies with the stage of plant development and in response to the environment. Recent studies have shown a correlation between plant growth regulators (PGR), fructan metabolism, and tolerance to drought and cold. PGR are compounds that profoundly influence the growth and differentiation of plant cells, tissues, and organs. They play a fundamental role in regulating plant responses to developmental and environmental signals. In this review, we summarize the most up-to-date knowledge on the metabolism of fructans and their crosstalk with PGR signaling pathways. We identify areas that require more research to complete our understanding of the role of fructans in plants.