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Stem strength plays a crucial role in the growth and development of plants, as well as in their flowering and fruiting. It not only impacts the lodging resistance of crops, but also influences the ornamental value of ornamental plants. Stem development is closely linked to stem strength; however, the roles of the SPL transcription factors in the stem development of herbaceous peony (Paeonia lactiflora Pall.) are not yet fully elucidated. In this study, we obtained and cloned the full-length sequence of PlSPL14, encoding 1085 amino acids. Quantitative real-time PCR (qRT-PCR) analysis revealed that the expression level of PlSPL14 gradually increased with the stem development of P. lactiflora and was significantly expressed in vascular bundles. Subsequently, utilizing the techniques of virus-induced gene silencing (VIGS) and heterologous overexpression in tobacco (Nicotiana tabacum L.), it was determined that PlSPL14-silenced P. lactiflora had a thinner xylem thickness, a decreased stem diameter, and weakened stem strength, while PlSPL14-overexpressing tobacco resulted in a thicker xylem thickness, an increased stem diameter, and enhanced stem strength. Further screening of the interacting proteins of PlSPL14 using a yeast two-hybrid (Y2H) assay revealed an interactive relationship between PlSPL14 and PlSLR1 protein, which acts as a negative regulator of gibberellin (GA). Additionally, the expression level of PlSLR1 gradually decreased during the stem development of P. lactiflora. The above results suggest that PlSPL14 may play a positive regulatory role in stem development and act in the xylem, making it a potential candidate gene for enhancing stem straightness in plants. [ABSTRACT FROM AUTHOR]

The herbaceous peony (Paeonia lactiflora Pall.) is widely cultivated as an ornamental, medicinal and edible plant in China. Drought stress can seriously affect the growth of herbaceous peony and reduce its quality. In our previous research, a significantly differentially expressed gene, PM19L, was obtained in herbaceous peony under drought stress based on transcriptome analysis, but little is known about its function. In this study, the first PM19L that was isolated in herbaceous peony was comprised of 910 bp, and was designated as PlPM19L (OP480984). It had a complete open reading frame of 537 bp and encoded a 178-amino acid protein with a molecular weight of 18.95 kDa, which was located in the membrane. When PlPM19L was transferred into tobacco, the transgenic plants had enhanced tolerance to drought stress, potentially due to the increase in the abscisic acid (ABA) content and the reduction in the level of hydrogen peroxide (H2O2). In addition, the enhanced ability to scavenge H2O2 under drought stress led to improvements in the enzyme activity and the potential photosynthetic capacity. These results combined suggest that PlPM19L is a key factor to conferring drought stress tolerance in herbaceous peony and provide a scientific theoretical basis for the following improvement in the drought resistance of herbaceous peony and other plants through genetic engineering technology. [ABSTRACT FROM AUTHOR]

Herbaceous peony (Paeonia lactiflora Pall.) is a traditional Chinese medicinal herb with roots; however, the flowers, specifically the stamens have not been exploited. In this study, the main active components of P. lactiflora stamens (PLS) were identified, and in vitro antioxidant, in vivo anti-aging and stress resistance properties were examined using the nematode Caenorhabditis elegans. Our results showed that PLS contains 350 active components including flavonoids, phenolic acids, terpenoids, alkaloids, and others. PLS extracts at concentrations of 0.2–1.2 mg·mL−1 had strong antioxidant activity in vitro and showed a linear increase of concentration. The value of absorbance, scavenging activity of ·OH, DPPH and ABTS was 0.84, 31.55%, 84.67%, and 99.49% at 1.2 mg·mL−1, respectively. Moreover, PLS extracted at the same concentrations had no toxic effects on C. elegans, and the treatment with 1.2 mg·mL−1 PLS extract significantly extended C. elegans lifespan that was not at the expense of reducing its reproduction and Escherichia coli OP50 growth. Furthermore, the same treatment extract enhanced their locomotion behavior and decreased their intestinal autofluorescence during the aging process. Additionally, the stress resistance of C. elegans under both heat and oxidative stress conditions were significantly induced by 1.2 mg·mL−1 PLS extract treatment. Collectively, these results demonstrated that PLS extract exerted both in vitro antioxidant and in vivo anti-aging together with stress resistance properties, which could provide the theoretical basis for its production and popularization in China. [ABSTRACT FROM AUTHOR]

Oil bodies (OBs) are organelles of lipid storage in plants. In order to clarify the properties of OBs development in herbaceous peony (Paeonia lactiflora Pall.) seeds, this research had studied anatomical structures, particle size, zeta potential, the stability of OBs and characteristics of oleosin gene (OLE). It showed that OB particle size increased gradually during seed development, OBs accumulated in the endosperm cells, and their zeta potential firstly decreased and then increased. Temperature had not affected the stability of OBs, they could be maintained stably under the conditions of neutral and alkaline pH and less than 50 mM NaCl. Subsequently, P. lactiflora OLE was isolated, it had 824 bp in full-length and a 435-bp open reading frame encoding 144 amino acids with isoelectric point 9.40, which had three transmembrane domain and did not has a signal peptide, and belonged to the stable protein. Alpha helix was the main part of the secondary structure, no glycosylation site and 14 potential phosphorylation sites were found. Additionally, the express level of OLE initially increased and then decreased, and reached the highest on 60 days after flowering. These results could contribute to understand the properties of OBs development and characteristics of OLE in P. lactiflora seeds. [ABSTRACT FROM AUTHOR]

microRNAs (miRNAs) play critical regulatory roles in plant growth and development. In the present study, the function of herbaceous peony ( Paeonia lactiflora Pall.) miR156e-3p in the regulation of color formation has been investigated. Firstly, P. lactiflora miR156e-3p precursor sequence (pre-miR156e-3p) was isolated. Subsequently, the overexpression vector of pre-miR156e-3p was constructed and transformed into Arabidopsis thaliana. Moreover, the medium screening, GUS staining, polymerase chain reaction (PCR) of the GUS region and real-time quantitative PCR (qRT-PCR) of miR156e-3p all confirmed that the purpose gene had been successfully transferred into Arabidopsis plants and expressed, which resulted in apparent purple lateral branches. And this change in color was caused by the improved anthocyanin accumulation. In addition, expression analysis had shown that the level of miR156e-3p transcript was increased, while transcription level of target gene squamosa promoter binding protein-like gene ( SPL1), encoding SPL transcription factor that negatively regulated anthocyanin accumulation, was repressed in miR156e-3p-overexpressing transgenic plants, and its downstream gene dihydroflavonol 4-reductase gene ( DFR) that was directly involved in anthocyanin biosynthesis was strongly expressed, which resulted in anthocyanin accumulation of Arabidopsis lateral branches. These findings would improve the understanding of miRNAs regulation of color formation in P. lactiflora. [ABSTRACT FROM AUTHOR]

• PlMAPK1 was cloned in Paeonia lactiflora and could respond to high-temperature stress. • Overexpression of PlMAPK1 in yeast system boosted high-temperature tolerance. • Silence of PlMAPK1 made plant injury more severe under high-temperature stress. Herbaceous peony (Paeonia lactiflora Pall.) is a traditional famous flower in China that prefers cold climates and is not tolerant of high summer temperatures. Mitogen-activated protein kinase (MAPK) is widely involved in plant signal transduction to various environmental stresses. In order to clarify the role of PlMAPK1 in response to high-temperature stress, it was cloned, and its open reading frame was 1215 bp, encoding 405 amino acids. Quantitative real-time PCR (qRT-PCR) analysis showed that when the plant was severely damaged by high temperatures, the expression level of PlMAPK1 was at its peak. Moreover, based on a systematic study of exogenous yeast, it was found that the yeast strain overexpressing PlMAPK1 grew better than the control under high-temperature stress. In addition, PlMAPK1 was transiently silenced by virus induced gene silencing technology (VIGS) in P. lactiflora. And under high-temperature stress, the leaves of transgenic plants wilted significantly, the accumulation of reactive oxygen species increased and the photosynthetic capacity decreased significantly. These findings suggested that PlMAPK1 might play a positive regulatory role in the response of P. lactiflora to high-temperature stress, laying a theoretical groundwork for P. lactiflora high-temperature tolerance breeding. [ABSTRACT FROM AUTHOR]

• PlbHLH87 was cloned in Paeonia lactiflora and could respond to high-temperature stress. • PlbHLH87 was localized in the nucleus and exhibited transcriptional activation activity. • Overexpressing PlbHLH87 enhanced high-temperature tolerance, while silencing it caused severe damage. Herbaceous peony (Paeonia lactiflora Pall.) exhibits captivating floral displays, however, its intolerance to high-temperature stress has seriously inhibited its popularization in the middle and lower reaches of the Yangtze River and its southern regions in China. The bHLH transcription factor family is widely distributed in plants and plays a crucial role in stress response. In this study, a bHLH transcription factor PlbHLH87 was isolated from P. lactiflora , and it was exhibited nuclear localization and transcriptional activation ability, indicating its involvement in gene regulation. PlbHLH87 showed increased expression levels in response to high-temperature stress, and transgenic plants with PlbHLH87 overexpression showed strengthened high-temperature resistance, while plants with silenced PlbHLH87 suffered severe damage under high-temperature stress. Various physiological indices demonstrated that PlbHLH87 could help to reduce reactive oxygen species accumulation, maintain the integrity of cell membranes and protect Photosystem II. These findings highlighted the critical role of PlbHLH87 in conferring high-temperature stress tolerance, which would be useful for molecular breeding of enhanced high-temperature tolerance in P. lactiflora. [ABSTRACT FROM AUTHOR]