Identification and characterization of PsDREB2 promoter involved in tissue-specific expression and abiotic stress response from Paeonia suffruticosa

BnaABF3 and BnaMYB44 regulate the transcription of zeaxanthin epoxidase genes in carotenoid and abscisic acid biosynthesis

Zeaxanthin epoxidase (ZEP) is a key enzyme that catalyzes the conversion of zeaxanthin to violaxanthin in the carotenoid and abscisic acid (ABA) biosynthesis pathways. The rapeseed (Brassica napus) genome has 4 ZEP (BnaZEP) copies that are suspected to have undergone subfunctionalization, yet the 4 genes' underlying regulatory mechanisms remain unknown. Here, we genetically confirmed the functional divergence of the gene pairs BnaA09.ZEP/BnaC09.ZEP and BnaA07.ZEP/BnaC07.ZEP, which encode enzymes with tissue-specific roles in carotenoid and ABA biosynthesis in flowers and leaves, respectively. Molecular and transgenic experiments demonstrated that each BnaZEP pair is transcriptionally regulated via ABA-responsive element-binding factor 3 s (BnaABF3s) and BnaMYB44s as common and specific regulators, respectively. BnaABF3s directly bound to the promoters of all 4 BnaZEPs and activated their transcription, with overexpression of individual BnaABF3s inducing BnaZEP expression and ABA accumulation under drought stress. Conversely, loss of BnaABF3s function resulted in lower expression of several genes functioning in carotenoid and ABA metabolism and compromised drought tolerance. BnaMYB44s specifically targeted and repressed the expression of BnaA09.ZEP/BnaC09.ZEP but not BnaA07.ZEP/BnaC07.ZEP. Overexpression of BnaA07.MYB44 resulted in increased carotenoid content and an altered carotenoid profile in petals. Additionally, RNA-seq analysis indicated that BnaMYB44s functions as a repressor in phenylpropanoid and flavonoid biosynthesis. These findings provide clear evidence for the subfunctionalization of duplicated genes and contribute to our understanding of the complex regulatory network involved in carotenoid and ABA biosynthesis in B. napus.

The impact of multiple abiotic stresses on ns-LTP2.8 gene transcript and ns-LTP2.8 protein accumulation in germinating barley (Hordeum vulgare L.) embryos

Abiotic stresses occur more often in combination than alone under regular field conditions limiting in more severe way crop production. Stress recognition in plants primarily occurs in the plasma membrane, modification of which is necessary to maintain homeostasis in response to it. It is known that lipid transport proteins (ns-LTPs) participate in modification of the lipidome of cell membranes. Representative of this group, ns-LTP2.8, may be involved in the reaction to abiotic stress of germinating barley plants by mediating the intracellular transport of hydrophobic particles, such as lipids, helping to maintain homeostasis. The ns-LTP2.8 protein was selected for analysis due to its ability to transport not only linear hydrophobic molecules but also compounds with a more complex spatial structure. Moreover, ns-LTP2.8 has been qualified as a member of pathogenesis-related proteins, which makes it particularly important in relation to its high allergenic potential. This paper demonstrates for the first time the influence of various abiotic stresses acting separately as well as in their combinations on the change in the ns-LTP2.8 transcript, ns-LTP2.8 protein and total soluble protein content in the embryonal axes of germinating spring barley genotypes with different ns-LTP2.8 allelic forms and stress tolerance. Tissue localization of ns-LTP2.8 transcript as well as ns-LTP2.8 protein were also examined. Although the impact of abiotic stresses on the regulation of gene transcription and translation processes remains not fully recognized, in this work we managed to demonstrate different impact on applied stresses on the fundamental cellular processes in very little studied tissue of the embryonal axis of barley.

Genome-Wide Identification of MYC Transcription Factors and Their Potential Functions in the Growth and Development Regulation of Tree Peony (Paeonia suffruticosa)

Tree peony (Paeonia suffruticosa Andr.) is a traditional Chinese flower with significant ornamental and medicinal value. Its growth and development process is regulated by some internal and external factors, and the related regulatory mechanism is largely unknown. Myelocytomatosis transcription factors (MYCs) play significant roles in various processes such as plant growth and development, the phytohormone response, and the stress response. As the identification and understanding of the MYC family in tree peony remains limited, this study aimed to address this gap by identifying a total of 15 PsMYCs in tree peony and categorizing them into six subgroups based on bioinformatics methods. Furthermore, the gene structure, conservative domains, cis-elements, and expression patterns of the PsMYCs were thoroughly analyzed to provide a comprehensive overview of their characteristics. An analysis in terms of gene structure and conserved motif composition suggested that each subtribe had similarities in function. An analysis of the promoter sequence revealed the presence of numerous cis-elements associated with plant growth and development, the hormone response, and the stress response. qRT-PCR results and the protein interaction network further demonstrated the potential functions of PsMYCs in the growth and development process. While in comparison to the control, only PsMYC2 exhibited a statistically significant variation in expression levels in response to exogenous hormone treatments and abiotic stress. A promoter activity analysis of PsMYC2 revealed its sensitivity to Flu and high temperatures, but exhibited no discernible difference under exogenous GA treatment. These findings help establish a basis for comprehending the molecular mechanism by which PsMYCs regulate the growth and development of tree peony.

Photosynthetic and physiological responses of different peony cultivars to high temperature

In order to investigate the causes of the differences in heat tolerance ('Lu He Hong' and 'Zhi Hong'), we studied the physiological changes, photosynthetic properties and regulatory mechanism of the two peony cultivars at high temperature. The results showed that the physiological changed of different peony cultivars varied significantly under high temperature stress. With the extension of high temperature stress time, MDA content of 'Lu He Hong' increased,while 'Zhi Hong' rised first and then decreased, SOD activity of 'Lu He Hong' rised first and then decreased, that of 'Zhi Hong' kept rising, POD activity of 'Lu He Hong' kept decreasing, while 'Zhi Hong' rised. The photosynthetic instrument records the change of peony photosynthesis parameters at high temperature; the chlorophyll A (Chla) fluorescence transient is recorded using the plant efficiency analyzer (PEA), analyzed according to the JIP test (O-J-I-P fluorescence transient analysis), and several parameters were derived to explain the photosynthetic efficiency difference between different peony cultivars. The tested cultivars responded differently to the survey conditions, and the PCA analysis showed that the 'Zhi Hong' was more well tolerated and showed better thermal stability of the PSII. The reduced efficiency of the 'Lu He Hong' PSII antenna leads to higher heat dissipation values to increase the light energy absorbed by unit reaction center (ABS/RC), the energy captured by unit reaction center (TR₀/RC), and the energy dissipated by unit reaction center (DI₀/RC), which significantly leads to its lower total photosynthetic performance (PI_total). The light capture complex of the variety 'Zhi Hong' has high connectivity with its reaction center, less damage to OEC activity, and better stability of the PSII system. The results show that 'Zhi Hong' improves heat resistance by stabilizing the cell membrane, a strong antioxidant system, as well as a more stable photosynthetic system. The results of this study provide a theoretical basis for the screening of heat-resistant peonies suitable for cultivation in Jiangnan area and for the selection and breeding of heat-resistant cultivars.

Identification of an Apis cerana zinc finger protein 41 gene and its involvement in the oxidative stress response

Zinc finger proteins (ZFPs) are a class of transcription factors that contain zinc finger domains and play important roles in growth, aging, and responses to abiotic and biotic stresses. These proteins activate or inhibit gene transcription by binding to single-stranded DNA or RNA and through RNA/DNA bidirectional binding and protein-protein interactions. However, few studies have focused on the oxidation resistance functions of ZFPs in insects, particularly Apis cerana. In the current study, we identified a ZFP41 gene from A. cerana, AcZFP41, and verified its function in oxidative stress responses. Real-time quantitative polymerase chain reaction showed that the transcription level of AcZFP41 was upregulated to different degrees during exposure to oxidative stress, including that induced by extreme temperature, UV radiation, or pesticides. In addition, the silencing of AcZFP41 led to changes in the expression patterns of some known antioxidant genes. Moreover, the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and glutathione S-transferase (GST) in AcZFP41-silenced honeybees were higher than those in a control group. In summary, the data indicate that AcZFP41 is involved in the oxidative stress response. The results provide a theoretical basis for further studies of zinc finger proteins and improve our understanding of the antioxidant mechanisms of honeybees.

Identification of a 193 bp promoter region of TaNRX1-D gene from common wheat that contributes to osmotic or ABA stress inducibility in transgenic Arabidopsis

BACKGROUND

Cloning and characterizing the drought-inducible promoters is essential for their use in crop resistance's genetic improvement. Previous studies have shown that the TaNRX1-D gene participates in regulating the response of wheat to drought stress. However, its promoter has not yet been identified.

OBJECTIVE

In this study, we aimed to characterize the promoter of the TaNRX1-D gene.

METHODS

The promoter of TaNRX1-D (named P0, 2081 bp) was isolated from common wheat with several cis-acting elements that regulate in response to abiotic stresses and some core cis-acting elements. Functional verification of the promoter, eight 5'-deletion fragments of TaNRX1-D promoter, was fused to the β-glucuronidase (GUS) gene P0::GUS ~ P7::GUS and transformed into Arabidopsis, respectively. Agrobacterium-mediated GUS transient assay the P6a and P6b promoter regions in tobacco leaves under normal, osmotic or ABA stress.

RESULTS

Activity analysis of the full-length promoter (P0) showed that the intensity of stronger β-glucuronidase (GUS) staining in the roots and leaves was obtained during the growth of transgenic Arabidopsis. P0::GUS displayed the GUS activity was much higher in the roots and leaves than in other parts of the transgenic plant under normal conditions, which was similarly within wheat. Analysis of the 5'-deletion fragments revealed that P0::GUS ~ P6::GUS responded well upon exposure to osmotic (polyethylene glycol-6000, PEG6000) and abscisic acid (ABA) stress treatments and expressed significantly higher GUS activity than the CaMV35S promoter (35S::GUS), while P7::GUS did not. GUS transient assay in tobacco leaves showed that the GUS activities of P6a and P6b were lower than P6 in the PEG6000 and ABA stresses.

CONCLUSION

The 193 bp (P6) segment was considered the core region of TaNRX1-D responding to PEG6000 or ABA treatment. GUS activity assay in transgenic Arabidopsis showed that this segment was sufficient for the PEG6000 or ABA stress response. The identified 193 bp promoter of TaNRX1-D in this study will help breed osmotic or ABA tolerant crops. The 36 bp segment between P6 and P6b (-193 to -157 bp) was considered the critical sequence for the TaNRX1-D gene responding to PEG6000 or ABA treatment.

Germplasm resources and genetic breeding of Paeonia: a systematic review

Members of the genus Paeonia, which consists of globally renowned ornamentals and traditional medicinal plants with a rich history spanning over 1500 years, are widely distributed throughout the Northern Hemisphere. Since 1900, over 2200 new horticultural Paeonia cultivars have been created by the discovery and breeding of wild species. However, information pertaining to Paeonia breeding is considerably fragmented, with fundamental gaps in knowledge, creating a bottleneck in effective breeding strategies. This review systematically introduces Paeonia germplasm resources, including wild species and cultivars, summarizes the breeding strategy and results of each Paeonia cultivar group, and focuses on recent progress in the isolation and functional characterization of structural and regulatory genes related to important horticultural traits. Perspectives pertaining to the resource protection and utilization, breeding and industrialization of Paeonia in the future are also briefly discussed.