Search Results (9)

The red plant phenotype of R1 cotton is a genetic marker produced by light-induced anthocyanin accumulation. GhPAP1D controls this trait. There are two 228 bp tandem repeats upstream of GhPAP1D in R1 cotton. In this study, GUS staining assays in transgenic Arabidopsis thaliana (L.) Heynh. demonstrated that tandem repeats in the GhPAP1D promoter-enhanced transcriptional activity. GhPAP1D is a homolog of A. thaliana AtPAP1. AtPAP1’s expression is regulated by photomorphogenesis-related transcription factors such as AtHY5 and AtBBXs. We identified the homologs of A. thaliana AtHY5, AtBBX21, and AtBBX24 in R1 cotton, designated as GhHY5, GhBBX21, and GhBBX24, respectively. Y1H assays confirmed that GhHY5, GhBBX21, and GhBBX24 each bound to the GhPAP1D promoter. Dual-luciferase reporter assays revealed that GhHY5 weakly activated the promoter activity of GhPAP1D. Heterologous expression assays in A. thaliana indicated that GhBBX21 promoted anthocyanin accumulation, whereas GhBBX24 had the opposite effect. Dual-luciferase assays showed GhBBX21 activated GhPAP1D transcription, while GhBBX24 repressed it. Further study indicated that GhHY5 did not enhance GhBBX21-mediated transcriptional activation of GhPAP1D but alleviates GhBBX24-induced repression. Together, our results demonstrate that GhBBX21 and GhBBX24 antagonistically regulate anthocyanin accumulation in R1 cotton under GhHY5 mediation, providing insights into light-responsive anthocyanin biosynthesis in cotton. Full article

Leonurus sibiricus L. has great ethnobotanical and ethnomedicinal significance. This study aimed to assess the antioxidant and anti-inflammatory properties of Leonurus sibiricus L. transgenic roots extracts transformed by Rhizobium rhizogenes, with and without the AtPAP1 transcriptional factor. The study determined the total phenolic and flavonoid contents, as well as in vitro antioxidant assays, including hydrogen peroxide and nitric oxide scavenging activity. In addition, in silico computational studies and molecular docking were conducted to evaluate the antioxidant and anti-inflammatory potential of the identified compounds. The ligands were docked to NADPH oxidase, cyclooxygenase 2,5-lipoxygenase, inducible nitric synthase and xanthine oxidase: enzymes involved in the inflammatory process. The total phenolic and flavonoid contents ranged from 85.3 ± 0.35 to 57.4 ± 0.15 mg/g GAE/g and 25.6 ± 0.42 to 18.2 ± 0.44 mg/g QUE/g in hairy root extracts with and without AtPAP1, respectively. H₂O₂ scavenging activity (IC₅₀) was found to be 29.3 µg/mL (with AtPAP1) and 37.5 µg/mL (without AtPAP1 transcriptional factor), and NO scavenging activity (IC₅₀) was 48.0 µg/mL (with AtPAP1) and 68.8 µg/mL (without AtPAP1 transcriptional factor). Leonurus sibiricus L. transformed root extracts, both with and without AtPAP1, are a source of phytochemicals belonging to different classes of molecules, such as flavonoids (catechin and rutin), phenolic compounds (caffeic acid, coumaric acid, chlorogenic acid, ferulic acid) and phenylpropanoid (verbascoside). Among the radicals formed after H removal from the different -OH positions, the lowest bond dissociation enthalpy was observed for rutin (4′-OH). Rutin was found to bind with cyclooxygenase 2, inducible nitric synthases and xanthine oxidase, whereas chlorogenic acid demonstrated optimal binding with 5-lipoxygenase. Therefore, it appears that the Leonurus sibiricus L. transformed root extract, both with and without the AtPAP1 transcriptional factor, may serve as a potential source of active components with antioxidant and anti-inflammatory potential; however, the extract containing AtPAP1 demonstrates superior activities. These properties could be beneficial for human health. Full article

PAPs (purple acid phosphatases) belong to the metallo-phosphoesterase superfamily and play important roles in developmental processes, phosphorus foraging, and recycling. However, the specific functions of BrPAPs in Brassica rapa are poorly understood. In this study, 39 BrPAPs were identified and divided into three major clades and nine subgroups. In 8 of the 39 BrPAPs, some invariant amino acid residues were lost or shifted. Based on an expression profiling analysis, BrPAP11, 14, 20, 24, 29, and 34 were specifically expressed in fertile floral buds, indicating their critical roles during pollen development. A total of 21 BrPAPs responded to Pi deprivation in either shoots or roots. Of these, BrPAP4, 5, 19, and 21 were upregulated in roots under Pi depravation conditions, while BrPAP12 was upregulated in the roots in normal conditions. BrPAP28 was upregulated in shoots under Pi depravation conditions, indicating its function shifted compared with its Arabidopsis homolog, AtPAP26. The present work contributes to further investigation of BrPAPs as candidate genes for genetic improvement studies of low phosphorus tolerance as well as for creating male sterile lines based on gene editing methods in Brassica rapa. Full article

Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2), which is anchored to the outer membranes of chloroplasts and mitochondria, affects carbon metabolism by modulating the import of some preproteins into chloroplasts and mitochondria. AtPAP9 bears a 72% amino acid sequence identity with AtPAP2, and both proteins carry a hydrophobic motif at their C-termini. Here, we show that AtPAP9 is a tail-anchored protein targeted to the outer membrane of chloroplasts. Yeast two-hybrid and bimolecular fluorescence complementation experiments demonstrated that both AtPAP9 and AtPAP2 bind to a small subunit of rubisco 1B (AtSSU1B) and a number of chloroplast proteins. Chloroplast import assays using [³⁵S]-labeled AtSSU1B showed that like AtPAP2, AtPAP9 also plays a role in AtSSU1B import into chloroplasts. Based on these data, we propose that AtPAP9 and AtPAP2 perform overlapping roles in modulating the import of specific proteins into chloroplasts. Most plant genomes contain only one PAP-like sequence encoding a protein with a hydrophobic motif at the C-terminus. The presence of both AtPAP2 and AtPAP9 in the Arabidopsis genome may have arisen from genome duplication in Brassicaceae. Unlike AtPAP2 overexpression lines, the AtPAP9 overexpression lines did not exhibit early-bolting or high-seed-yield phenotypes. Their differential growth phenotypes could be due to the inability of AtPAP9 to be targeted to mitochondria, as the overexpression of AtPAP2 on mitochondria enhances the capacity of mitochondria to consume reducing equivalents. Full article

Energy metabolism in plant cells requires a balance between the activities of chloroplasts and mitochondria, as they are the producers and consumers of carbohydrates and reducing equivalents, respectively. Recently, we showed that the overexpression of Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2), a phosphatase dually anchored on the outer membranes of chloroplasts and mitochondria, can boost the plant growth and seed yield of Arabidopsis thaliana by coordinating the activities of both organelles. However, when AtPAP2 is solely overexpressed in chloroplasts, the growth-promoting effects are less optimal, indicating that active mitochondria are required for dissipating excess reducing equivalents from chloroplasts to maintain the optimal growth of plants. It is even more detrimental to plant productivity when AtPAP2 is solely overexpressed in mitochondria. Although these lines contain high level of adenosine triphosphate (ATP), they exhibit low leaf sucrose, low seed yield, and early senescence. These transgenic lines can be useful tools for studying how hyperactive chloroplasts or mitochondria affect the physiology of their counterparts and how they modify cellular metabolism and plant physiology. Full article

Black nightshade (Solanum nigrum) belongs to the Solanaceae family and is used as a medicinal herb with health benefits. It has been reported that the black nightshade plant contains various phytochemicals that are associated with antitumor activities. Here we employed a genetic approach to study the effects of overexpression of Arabidopsis thaliana production of anthocyanin pigment 1 (AtPAP1) in black nightshade. Ectopic expression of AtPAP1 resulted in enhanced accumulation of anthocyanin pigments in vegetative and reproductive tissues of the transgenic plants. Analysis of anthocyanin revealed that delphinidin 3-O-rutinoside-5-O-glucoside, delphinidin 3,5-O-diglucoside, delphinidin 3-O-rutinoside, petunidin 3-O-rutinoside (cis-p-coumaroyl)-5-O-glucoside, petunidin 3-(feruloyl)-rutinoside-5-glucoside, and malvidin 3-(feruloyl)-rutinoside-5-glucoside are highly induced in the leaves of AtPAP1 overexpression lines. Furthermore, ectopic expression of AtPAP1 evoked expression of early and late biosynthetic genes of the general phenylpropanoid and flavonoid pathways that include phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), chalcone isomerase (CHI), and quinate hydroxycinnamoyl transferase (HCT), which suggests these genes might be transcriptional targets of AtPAP1 in black nightshade. Concomitantly, the total content of anthocyanin in the transgenic black nightshade plants was higher compared to the control plants, which supports phenotypic changes in color. Our data demonstrate that a major anthocyanin biosynthetic regulator, AtPAP1, can induce accumulation of anthocyanins in the heterologous system of black nightshade through the conserved flavonoid biosynthesis pathway in plants. Full article

As the current cancer treatment success rate is not sufficient, interest has grown in plants as possible sources of anti-cancer compounds. One such plant with a broad spectrum of activity is Lenourus sibiricus of the family Lamiaceae. This study investigates for the first time both the genotoxic and cytotoxic activities of TR (transformed) and AtPAP1 TR (with over-expression of transcriptional factor) root extracts of Lenourus sibiricus against various cancer cell lines (CCRF-CEM, K-562 and A549). Both tested extracts showed a cytotoxic effect on CCRF-CEM and K-562 cell lines, but strongest activity was observed for the AtPAP1 TR extract. No cytotoxic effect was observed against the A549 cell line in the tested concentration range, and it was found that both tested extracts may induce apoptosis by decreasing mitochondrial membrane potential and inducing nDNA damage lesion in the TP53 region and mtDNA in ND1 (mitochondrially encoded NADH: ubiquinone oxidoreductase core subunit 1) and ND5 (mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 5) regions in K-562 and CCRF-CEM. Our results confirmed that TR and AtPAP1 TR root extracts from L. sibiricus are cytotoxic and genotoxic against different model cell lines (CCRF-CEM and K-562). However, the observed genotoxicity of both extracts needs to be confirmed by additional studies. These preclinical observations support the use of L. sibiricus with other pharmacological purposes. Full article

Purple acid phosphatases (PAPs) play various physiological roles in plants. AtPAP2 was previously shown to localize to both chloroplasts and mitochondria and to modulate carbon metabolism in Arabidopsis. Over-expression of AtPAP2 resulted in faster growth and increased biomass in several plant species, indicating its great potential for crop improvement of phosphate use and yield. Here, we studied the localization of AtPAP2 by transient expression in tobacco leaves. The results showed AtPAP2 was localized to the plasma membrane through the secretory pathway, which is different from previous studies. We also found that AtPAP2 had a close relationship with fungal PAP2-like proteins based on phylogenetic analysis. In addition, the C-terminal transmembrane domain conserved in land plants is unique among other AtPAPs except AtPAP9, which is a close homolog of AtPAP2. Taken together, our results provide information for further study of AtPAP2 in understanding its special function in crop improvement. Full article

To improve the production of chlorogenic acid (CGA) in hairy roots of Platycodon grandiflorum, we induced over-expression of Arabidopsis thaliana transcription factor production of anthocyanin pigment (AtPAP1) using an Agrobacterium rhizogenes-mediated transformation system. Twelve hairy root lines showing over-expression of AtPAP1 were generated. In order to investigate the regulation of AtPAP1 on the activities of CGA biosynthetic genes, the expression levels of seven P. grandiflorum CGA biosynthetic genes were analyzed in the hairy root line that had the greatest accumulation of AtPAP1 transcript, OxPAP1-1. The introduction of AtPAP1 increased the mRNA levels of all examined CGA biosynthetic genes and resulted in a 900% up-regulation of CGA accumulation in OxPAP1-1 hairy roots relative to controls. This suggests that P. grandiflorum hairy roots that over-express the AtPAP1 gene are a potential alternative source of roots for the production of CGA. Full article