Loss-of-function of gynoecium-expressed phospholipase pPLAIIγ triggers maternal haploid induction in Arabidopsis.

Production of in planta haploid embryos that inherit chromosomes from only one parent can greatly increase breeding efficiency via quickly generating homozygous plants, called doubled haploid. One of the main players of in planta haploid induction is a pollen-specific phospholipase A, which is able, when mutated, to induce in vivo haploid induction in numerous monocots. However, no functional orthologous gene has been identified in dicots plants. Here, we show that loss-of-function of gynoecium-expressed phospholipase AII (pPLAIIγ) triggers maternal haploid plants in Arabidopsis, at an average rate of 1.07%. Reciprocal crosses demonstrate that haploid plants are triggered from the female side and not from the pollen, and the haploid plants carry the maternal genome. Promoter activity of pPLAIIγ shows enriched expression in the funiculus of flower development stages 13 and 18, and pPLAIIγ fused to yellow fluorescent protein reveals a plasma-membrane localization Interestingly, the polar localized PIN1 at the basal plasma membrane of the funiculus was all internalized in pplaIIγ mutants, suggesting that altered PIN1 localization in female organ could play a role in maternal haploid induction.

Phospholipase pPLAIIIα Increases Germination Rate and Resistance to Turnip Crinkle Virus when Overexpressed.

Patatin-related phospholipase As (pPLAs) are major hydrolases acting on acyl-lipids and play important roles in various plant developmental processes. pPLAIII group members, which lack a canonical catalytic Ser motif, have been less studied than other pPLAs. We report here the characterization of pPLAIIIα in Arabidopsis (Arabidopsis thaliana) based on the biochemical and physiological characterization of pPLAIIIα knockouts, complementants, and overexpressors, as well as heterologous expression of the protein. In vitro activity assays on the purified recombinant protein showed that despite lack of canonical phospholipase motifs, pPLAIIIα had a phospholipase A activity on a wide variety of phospholipids. Overexpression of pPLAIIIα in Arabidopsis resulted in a decrease in many lipid molecular species, but the composition in major lipid classes was not affected. Fluorescence tagging indicated that pPLAIIIα localizes to the plasma membrane. Although Arabidopsis pplaIIIα knockout mutants showed some phenotypes comparable to other pPLAIIIs, such as reduced trichome length and increased hypocotyl length, control of seed size and germination were identified as distinctive pPLAIIIα-mediated functions. Expression of some PLD genes was strongly reduced in the pplaIIIα mutants. Overexpression of pPLAIIIα caused increased resistance to turnip crinkle virus, which associated with a 2-fold higher salicylic acid/jasmonic acid ratio and an increased expression of the defense gene pathogenesis-related protein1. These results therefore show that pPLAIIIα has functions that overlap with those of other pPLAIIIs but also distinctive functions, such as the control of seed germination. This study also provides new insights into the pathways downstream of pPLAIIIα.

The R2R3-MYB transcription factor PgTT2 from Panax ginseng interacts with the WD40-repeat protein PgTTG1 during the regulation of proanthocyanidin biosynthesis and the response to salt stress.

Proanthocyanidins (PAs) are flavonoid compounds with important defensive roles in plants. The application of PAs in industries such as the pharmaceutical industry has led to increased interest in enhancing their biosynthesis. In Arabidopsis thaliana, PAs are biosynthesized under the regulation of an R2R3-MYB transcription factor TRANSPARENT TESTA 2 (TT2), which can interact with other proteins, including TRANSPARENT TESTA GLABRA 1 (TTG1), while also regulating a plant's response to abiotic stressors. However, the regulation of PA biosynthesis in the high-value medicinal plant Panax ginseng (ginseng) has not yet been studied. Understanding the mechanism of PAs biosynthesis regulation in ginseng may be helpful in increasing the plant's range of pharmacological applications. This study found that the overexpression of PgTT2 increased PA biosynthesis by an average of 67.3% in ginseng adventitious roots and 50.5% in arabidopsis seeds. Furthermore, transgenic arabidopsis plants overexpressing PgTT2 produced increased reactive oxygen species (ROS) scavenging ability by influencing abscisic acid synthesis and signaling. However, under high salinity stress, seed germination and growth rate of seedlings were decreased. An expression analysis of plants facing salt stress revealed increased transcripts of an ABA biosynthetic gene, NCED3, and ABA signaling genes ABI5 and ABI3. Moreover, the PgTT2 protein showed a direct interaction with PgTTG1 in yeast two-hybrid assays. This study therefore reveals novel information on the transcriptional regulation of PA production in ginseng and shows how PgTT2 influences the ABA response pathway to regulate responses to ROS and salt stress.

A group III patatin-like phospholipase gene pPLAIIIδ regulates lignin biosynthesis and influences the rate of seed germination in Arabidopsis thaliana.

The lignification of plant secondary walls is an important process that provides plants with mechanical support. However, the presence of lignin in the secondary walls affects the readily availability of cellulose required in various industries, including the biofuel, paper, and textile industries. Thus, plants with less lignin are ideal for usage in such industries. Molecular studies have identified genes that regulate plant lignification, including group III plant-specific patatin-related phospholipase genes. Recent studies have reported decreased lignin content when pPLAIIIα, pPLAIIIγ (from Arabidopsis thaliana), and pPLAIIIß (from Panax ginseng) were overexpressed in Arabidopsis. However, the role played by a closely related gene pPLAIIIδ in lignin biosynthesis has not yet been reported. In this study, we found that overexpression of the pPLAIIIδ significantly reduced the lignin content in secondary cell walls, whereas the silencing of the gene increased secondary walls lignification. Transcript level analysis showed that the key structural and regulatory genes involved in the lignin biosynthesis pathway decreased in overexpression, and increased in plants with silenced pPLAIIIδ. Further analysis revealed that pPLAIIIδ played an influential role in several physiological processes including seed germination, and chlorophyll accumulation. Moreover, the gene also influenced the size of plants and plant organs, including leaves, seeds, and root hairs. Generally, our study provides important insights toward the use of genetic engineering for lignin reduction in plants and provides information about the agronomical and physiological suitability of pPLAIIIδ transgenic plants for utilization in biomass processing industries.

Genome-wide characterization of the soybean DOMAIN OF UNKNOWN FUNCTION 679 membrane protein gene family highlights their potential involvement in growth and stress response.

The DMP (DUF679 membrane proteins) family is a plant-specific gene family that encodes membrane proteins. The DMP family genes are suggested to be involved in various programmed cell death processes and gamete fusion during double fertilization in Arabidopsis. However, their functional relevance in other crops remains unknown. This study identified 14 genes from the DMP family in soybean (Glycine max) and characterized their physiochemical properties, subcellular location, gene structure, and promoter regions using bioinformatics tools. Additionally, their tissue-specific and stress-responsive expressions were analyzed using publicly available transcriptome data. Phylogenetic analysis of 198 DMPs from monocots and dicots revealed six clades, with clade-I encoding senescence-related AtDMP1/2 orthologues and clade-II including pollen-specific AtDMP8/9 orthologues. The largest clade, clade-III, predominantly included monocot DMPs, while monocot- and dicot-specific DMPs were assembled in clade-IV and clade-VI, respectively. Evolutionary analysis suggests that soybean GmDMPs underwent purifying selection during evolution. Using 68 transcriptome datasets, expression profiling revealed expression in diverse tissues and distinct responses to abiotic and biotic stresses. The genes Glyma.09G237500 and Glyma.18G098300 showed pistil-abundant expression by qPCR, suggesting they could be potential targets for female organ-mediated haploid induction. Furthermore, cis-acting regulatory elements primarily related to stress-, hormone-, and light-induced pathways regulate GmDMPs, which is consistent with their divergent expression and suggests involvement in growth and stress responses. Overall, our study provides a comprehensive report on the soybean GmDMP family and a framework for further biological functional analysis of DMP genes in soybean or other crops.

Understanding Cannabis sativa L.: Current Status of Propagation, Use, Legalization, and Haploid-Inducer-Mediated Genetic Engineering.

Cannabis sativa L. is an illegal plant in many countries. The worldwide criminalization of the plant has for many years limited its research. Consequently, understanding the full scope of its benefits and harm became limited too. However, in recent years the world has witnessed an increased pace in legalization and decriminalization of C. sativa. This has prompted an increase in scientific studies on various aspects of the plant's growth, development, and use. This review brings together the historical and current information about the plant's relationship with mankind. We highlight the important aspects of C. sativa classification and identification, carefully analyzing the supporting arguments for both monotypic (single species) and polytypic (multiple species) perspectives. The review also identifies recent studies on suitable conditions and methods for C. sativa propagation as well as highlighting the diverse uses of the plant. Specifically, we describe the beneficial and harmful effects of the prominent phytocannabinoids and provide status of the studies on heterologous synthesis of phytocannabinoids in different biological systems. With a historical view on C. sativa legality, the review also provides an up-to-date worldwide standpoint on its regulation. Finally, we present a summary of the studies on genome editing and suggest areas for future research.

Overexpression of pPLAIIIγ in Arabidopsis Reduced Xylem Lignification of Stem by Regulating Peroxidases.

Patatin-related phospholipases A (pPLAs) are a group of plant-specific acyl lipid hydrolases that share less homology with phospholipases than that observed in other organisms. Out of the three known subfamilies (pPLAI, pPLAII, and pPLAIII), the pPLAIII member of genes is particularly known for modifying the cell wall structure, resulting in less lignin content. Overexpression of pPLAIIIα and ginseng-derived PgpPLAIIIß in Arabidopsis and hybrid poplar was reported to reduce the lignin content. Lignin is a complex racemic phenolic heteropolymer that forms the key structural material supporting most of the tissues in plants and plays an important role in the adaptive strategies of vascular plants. However, lignin exerts a negative impact on the utilization of plant biomass in the paper and pulp industry, forage digestibility, textile industry, and production of biofuel. Therefore, the overexpression of pPLAIIIγ in Arabidopsis was analyzed in this study. This overexpression led to the formation of dwarf plants with altered anisotropic growth and reduced lignification of the stem. Transcript levels of lignin biosynthesis-related genes, as well as lignin-specific transcription factors, decreased. Peroxidase-mediated oxidation of monolignols occurs in the final stage of lignin polymerization. Two secondary cell wall-specific peroxidases were downregulated following lowered H2O2 levels, which suggests a functional role of peroxidase in the reduction of lignification by pPLAIIIγ when overexpressed in Arabidopsis.

The Reduced Longitudinal Growth Induced by Overexpression of pPLAIIIγ Is Regulated by Genes Encoding Microtubule-Associated Proteins.

There are three subfamilies of patatin-related phospholipase A (pPLA) group of genes: pPLAI, pPLAII, and pPLAIII. Among the four members of pPLAIIIs (α, ß, γ, δ), the overexpression of three isoforms (α, ß, and δ) displayed distinct morphological growth patterns, in which the anisotropic cell expansion was disrupted. Here, the least studied pPLAIIIγ was characterized, and it was found that the overexpression of pPLAIIIγ in Arabidopsis resulted in longitudinally reduced cell expansion patterns, which are consistent with the general phenotype induced by pPLAIIIs overexpression. The microtubule-associated protein MAP18 was found to be enriched in a pPLAIIIδ overexpressing line in a previous study. This indicates that factors, such as microtubules and ethylene biosynthesis, are involved in determining the radial cell expansion patterns. Microtubules have long been recognized to possess functional key roles in the processes of plant cells, including cell division, growth, and development, whereas ethylene treatment was reported to induce the reorientation of microtubules. Thus, the possible links between the altered anisotropic cell expansion and microtubules were studied. Our analysis revealed changes in the transcriptional levels of microtubule-associated genes, as well as phospholipase D (PLD) genes, upon the overexpression of pPLAIIIγ. Overall, our results suggest that the longitudinally reduced cell expansion observed in pPLAIIIγ overexpression is driven by microtubules via transcriptional modulation of the PLD and MAP genes. The altered transcripts of the genes involved in ethylene-biosynthesis in pPLAIIIγOE further support the conclusion that the typical phenotype is derived from the link with microtubules.

Patatin-Related Phospholipase AtpPLAIIIα Affects Lignification of Xylem in Arabidopsis and Hybrid Poplars.

Lipid acyl hydrolase are a diverse group of enzymes that hydrolyze the ester or amide bonds of fatty acid in plant lipids. Patatin-related phospholipase AIIIs (pPLAIIIs) are one of major lipid acyl hydrolases that are less closely related to potato tuber patatins and are plant-specific. Recently, overexpression of ginseng-derived PgpPLAIIIß was reported to be involved in the reduced level of lignin content in Arabidopsis and the mature xylem layer of poplar. The presence of lignin-polysaccharides renders cell walls recalcitrant for pulping and biofuel production. The tissue-specific regulation of lignin biosynthesis, without altering all xylem in plants, can be utilized usefully by keeping mechanical strength and resistance to various environmental stimuli. To identify another pPLAIII homolog from Arabidopsis, constitutively overexpressed AtpPLAIIIα was characterized for xylem lignification in two well-studied model plants, Arabidopsis and poplar. The characterization of gene function in annual and perennial plants with respect to lignin biosynthesis revealed the functional redundancy of less lignification via downregulation of lignin biosynthesis-related genes.

Overexpression of ginseng patatin-related phospholipase pPLAIIIß alters the polarity of cell growth and decreases lignin content in Arabidopsis.

BACKGROUND: The patatin-related phospholipase AIII family (pPLAIIIs) genes alter cell elongation and cell wall composition in Arabidopsis and rice plant, suggesting diverse commercial purposes of the economically important medicinal ginseng plant. Herein, we show the functional characterization of a ginseng pPLAIII gene for the first time and discuss its potential applications. METHODS: pPLAIIIs were identified from ginseng expressed sequence tag clones and further confirmed by search against ginseng database and polymerase chain reaction. A clone showing the highest homology with pPLAIIIß was shown to be overexpressed in Arabidopsis using Agrobacterium. Quantitative polymerase chain reaction was performed to analyze ginseng pPLAIIIß expression. Phenotypes were observed using a low-vacuum scanning electron microscope. Lignin was stained using phloroglucinol and quantified using acetyl bromide. RESULTS: The PgpPLAIIIß transcripts were observed in all organs of 2-year-old ginseng. Overexpression of ginseng pPLAIIIß (PgpPLAIIIß-OE) in Arabidopsis resulted in small and stunted plants. It shortened the trichomes and decreased trichome number, indicating defects in cell polarity. Furthermore, OE lines exhibited enlarged seeds with less number per silique. The YUCCA9 gene was downregulated in the OE lines, which is reported to be associated with lignification. Accordingly, lignin was stained less in the OE lines, and the expression of two transcription factors related to lignin biosynthesis was also decreased significantly. CONCLUSION: Overexpression of pPLAIIIß retarded cell elongation in all the tested organs except seeds, which were longer and thicker than those of the controls. Shorter root length is related to auxin-responsive genes, and its stunted phenotype showed decreased lignin content.

High Physical Self-Concept Benefits on School Adjustment of Korean Student-Athletes.

Successful adjustment of student-athletes to their school is an internationally relevant issue. In Korea, school-athletes abandon their athletic activity at a rate of over 40%, suggesting an urgent need to develop measures that allow them to balance sports and academic life. Therefore, this study aimed to investigate the effect of physical self-concept on school adaptation among student-athletes. We analyzed data from 589 student-athletes, including sex and award-winning career as covariates. Then, reliability and validity of scales were obtained. The results showed that student-athletes with higher physical self-concept are more likely to be successful in school adjustment. The effects of physical self-concept on school adjustment were proven to be mediated by sex and award-winning career of student-athletes. This result provides the basis for the importance of recognizing the concept of physical self as a way for student athletes to adapt well to school life. As differences depending on gender and award experience exist, they should be taken into account when teaching student athletes.

Ginseng-derived patatin-related phospholipase PgpPLAIIIß alters plant growth and lignification of xylem in hybrid poplars.

Patatin-liked phospholipase A (pPLAs) are major lipid acyl hydrolases that participate in various biological functions in plant growth and development. Previously, a ginseng-derived pPLAIII homolog was reported to reduce lignin content in Arabidopsis. This led us to evaluate its possible usefulness as a biomass source in wood plant. Herein, we report that there are six members in the pPLAIII gene family in poplar. Overexpression of pPLAIIIß derived from ginseng resulted in a reduced plant height with radially expanded stem growth in hybrid poplars. Compared with the wild type (WT), the chlorophyll content was increased in the overexpression poplar lines, whereas the leaf size was smaller. The secondary cell wall structure in overexpression lines was also altered, exhibiting reduced lignification in the xylem. Two transcription factors, MYB92 and MYB152, which control lignin biosynthesis, were downregulated in the overexpression lines. The middle xylem of the overexpression line showed heavy thickening, making it thicker than the other xylem parts and the WT xylem, which rather could have been contributed by the presence of more cellulose in the selected surface area. Taken together, the results suggest that PgpPLAIIIß plays a role not only in cell elongation patterns, but also in determining the secondary cell wall composition.