Overexpression of a Senescence-Related Gene CpSRG1 from Wintersweet (Chimonanthus praecox) Promoted Growth and Flowering, and Delayed Senescence in Transgenic Arabidopsis

The MdCo gene encodes a putative 2OG-Fe (II) oxygenase that positively regulates salt tolerance in transgenic tomato and apple

Salinity stress is a significant environmental factor that impacts the growth, development, quality, and yield of crops. The 2OG-Fe (II) oxygenase family of enzyme proteins plays crucial roles in plant growth and stress responses. Previously, we identified and characterized MdCo, which encodes a putative 2OG-Fe (II) oxygenase, a key gene for controlling the columnar growth habit of apples. In this study, we explored the role of MdCo in salt stress tolerance. Expression analysis suggested that MdCo exhibits high expression in roots and is significantly induced by NaCl stress. Ectopic expression of MdCo exhibited enhanced salt stress tolerance in transgenic tomatoes, and these plants were characterized by better growth performance, and higher chlorophyll content, but lower electrolyte leakage and malondialdehyde (MDA), and less hydrogen peroxide (H2O2) and superoxide radicals (O2-) under salt stress. Overexpression of MdCo can effectively scavenge reactive oxygen species (ROS) by enhancing the activities of antioxidant enzymes and up-regulating the expression of stress-associated genes under salt stress, thereby enhancing salt tolerance in apple calli. Collectively, these findings provide new insights into the function of MdCo in salt stress tolerance as well as future potential application for apple breeding aimed at improving salt stress tolerance.

Functional Characterization of PoEP1 in Regulating the Flowering Stage of Tree Peony

The tree peony, a traditional flower in China, has a short and concentrated flowering period, restricting the development of the tree peony industry. To explore the molecular mechanism of tree peony flowering-stage regulation, PoEP1, which regulated the flowering period, was identified and cloned based on the transcriptome and degradome data of the early-flowering mutant Paeonia ostii 'Fengdan' (MU) and Paeonia ostii 'Fengdan' (FD). Through bioinformatics analysis, expression pattern analysis, and transgene function verification, the role of PoEP1 in the regulation of tree peony flowering was explored. The open-reading frame of PoEP1 is 1161 bp, encoding 386 amino acids, containing two conserved domains. PoEP1 was homologous to the EP1 of other species. Subcellular localization results showed that the protein was localized in the cell wall and that PoEP1 expression was highest in the initial decay stage of the tree peony. The overexpression of PoEP1 in transgenic plants advanced and shortened the flowering time, indicating that PoEP1 overexpression promotes flowering and senescence and shorten the flowering time of plants. The results of this study provide a theoretical basis for exploring the role of PoEP1 in the regulation of tree peony flowering.

ALLENE OXIDE SYNTHASE (AOS) induces petal senescence through a novel JA-associated regulatory pathway in Arabidopsis

Flowers are crucial for the reproduction of flowering plants and their senescence has drastic effects on plant-animal interactions as well as pollination. Petal senescence is the final phase of flower development which is regulated by hormones and genes. Among these, jasmonic acid (JA) has emerged as a major contributor to petal senescence, but its molecular mechanisms remain elusive. Here, the role of JA in petal senescence in Arabidopsis was investigated. We showed that petal senescence in aos mutant was significantly delayed, which also affected petal cell size and proliferation. Similar significant delays in petal senescence were observed in dad1 and coi1 mutants. However, MYB21/24 and MYC2/3/4, known downstream regulators of JA in flower development, played no role in petal senescence. This indicated that JA regulates petal senescence by modulating other unknown transcription factors. Transcriptomic analysis revealed that AOS altered the expression of 3681 genes associated, and identified groups of differentially expressed transcription factors, highlighting the potential involvement of AP-2, WRKY and NAC. Furthermore, bHLH13, bHLH17 and URH2 were identified as potential new regulators of JA-mediated petal senescence. In conclusion, our findings suggest a novel genetic pathway through which JA regulates petal senescence in Arabidopsis. This pathway operates independently of stamen development and leaf senescence, suggesting the evolution of specialized mechanisms for petal senescence.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01425-w.

Genome-wide analysis of SET domain genes and the function of GhSDG51 during salt stress in upland cotton (Gossypium hirsutum L.)

BACKGROUND

Cotton, being extensively cultivated, holds immense economic significance as one of the most prominent crops globally. The SET (Su(var), E, and Trithorax) domain-containing protein is of significant importance in plant development, growth, and response to abiotic stress by modifying the lysine methylation status of histone. However, the comprehensive identification of SET domain genes (SDG) have not been conducted in upland cotton (Gossypium hirsutum L.).

RESULTS

A total of 229 SDGs were identified in four Gossypium species, including G. arboretum, G. raimondii, G. hirsutum, and G. barbadense. These genes could distinctly be divided into eight groups. The analysis of gene structure and protein motif revealed a high degree of conservation among the SDGs within the same group. Collinearity analysis suggested that the SDGs of Gossypium species and most of the other selected plants were mainly expanded by dispersed duplication events and whole genome duplication (WGD) events. The allopolyploidization event also has a significant impact on the expansion of SDGs in tetraploid Gossypium species. Furthermore, the characteristics of these genes have been relatively conserved during the evolution. Cis-element analysis revealed that GhSDGs play a role in resistance to abiotic stresses and growth development. Furthermore, the qRT-PCR results have indicated the ability of GhSDGs to respond to salt stress. Co-expression analysis revealed that GhSDG51 might co-express with genes associated with salt stress. In addition, the silencing of GhSDG51 in cotton by the virus-induced gene silencing (VIGS) method suggested a potential positive regulatory role of GhSDG51 in salt stress.

CONCLUSIONS

The results of this study comprehensively analyze the SDGs in cotton and provide a basis for understanding the biological role of SDGs in the stress resistance in upland cotton.