Plant stem cells: what we know and what is anticipated

Spatiotemporal transcriptome and metabolome landscapes of cotton somatic embryos

Somatic embryogenesis (SE) is a developmental process related to the regeneration of tissue-cultured plants, which serves as a useful technique for crop breeding and improvement. However, SE in cotton is difficult and elusive due to the lack of precise cellular level information on the reprogramming of gene expression patterns involved in somatic embryogenesis. Here, we investigate the spatial and single-cell expression profiles of key genes and the metabolic patterns of key metabolites by integrated single-cell RNA-sequencing (scRNA-seq), spatial transcriptomics (ST), and spatial metabolomics (SM). To evaluate the results of these analyses, we functionally characterized the potential roles of two representative marker genes, AATP1 and DOX2, in the regulation of cotton somatic embryo development. A publicly available web-based resource database ( https://cotton.cricaas.com.cn/somaticembryo/ ) in this study provides convenience for future studies of the expression patterns of marker genes at specific developmental stages during the process of SE in cotton.

Maintenance of stem cell activity in plant development and stress responses

Stem cells residing in plant apical meristems play an important role during postembryonic development. These stem cells are the wellspring from which tissues and organs of the plant emerge. The shoot apical meristem (SAM) governs the aboveground portions of a plant, while the root apical meristem (RAM) orchestrates the subterranean root system. In their sessile existence, plants are inextricably bound to their environment and must adapt to various abiotic stresses, including osmotic stress, drought, temperature fluctuations, salinity, ultraviolet radiation, and exposure to heavy metal ions. These environmental challenges exert profound effects on stem cells, potentially causing severe DNA damage and disrupting the equilibrium of reactive oxygen species (ROS) and Ca2+ signaling in these vital cells, jeopardizing their integrity and survival. In response to these challenges, plants have evolved mechanisms to ensure the preservation, restoration, and adaptation of the meristematic stem cell niche. This enduring response allows plants to thrive in their habitats over extended periods. Here, we presented a comprehensive overview of the cellular and molecular intricacies surrounding the initiation and maintenance of the meristematic stem cell niche. We also delved into the mechanisms employed by stem cells to withstand and respond to abiotic stressors.

Cambial meristematic cell culture: a sustainable technology toward in vitro specialized metabolites production

Cambial meristematic cells (CMCs) culture has received a fair share of scientific and industrial attention among the trending topics of plant cell culture, especially their potential toward secondary metabolites production. However, the conventional plant cell culture is often not commercially feasible because of difficulties associated with culture dedifferentiated cells. Several reports have been published to culture CMCs and bypass the dedifferentiation process in plant cell culture. Numerous mitochondria, multiple vacuoles, genetic stability, self-renewal, higher biomass, and stable metabolites accumulation are the characteristics features of CMCs compared with dedifferentiated cells (DDCs) culture. The CMCs culture has a broader application to produce large-scale natural compounds for: pharmaceuticals, food, and cosmetic industries. Cutting-edge progress in plant cellular and molecular biology has allowed unprecedented insights into cambial stem cell culture and its fundamental processes. Therefore, regarding sustainability and natural compound production, cambial cell culture ranks among the most vital biotechnological interventions for industrial and economic perspectives. This review highlights the recent advances in plant stem cell culture and understands the cambial cells induction and culture mechanisms that affect the growth and natural compounds production.

Algal Cells-Derived Extracellular Vesicles: A Review With Special Emphasis on Their Antimicrobial Effects

Extracellular vesicles (EVs) originated from different cells of approximately all kinds of organisms, recently got more attention because of their potential in the treatment of diseases and reconstructive medicine. To date, lots of studies have been performed on mammalian-derived vesicles, but little attention has been paid to algae and marine cells as valuable sources of EVs. Proving the promising role of EVs in medicine requires sufficient resources to produce qualified microvesicles. Algae, same as its other sister groups, such as plants, have stem cells and stem cell niches. Previous studies showed the EVs in plants and marine cells. So, this study was set out to talk about algal extracellular vesicles. EVs play a major role in cell-to-cell communication to convey molecules, such as RNA/DNA, metabolites, proteins, and lipids within. The components of EVs depends on the origin of the primitive cells or tissues and the isolation method. Sufficient resources are needed to produce high-quality, stable, and compatible EVs as a drug or drug delivery system. Plant stem cells have great potential as a new controllable resource for the production of EVs. The EVs secreted from stem cells can easily be extracted from the cell culture medium and evaluated for medicinal uses. In this review, the aim is to introduce algae stem cells as well as EVs derived from algal cells. In the following, the production of the EVs¸ the properties of EVs extracted from these sources and their antimicrobial effects will be discussed.

NAL8 encodes a prohibitin that contributes to leaf and spikelet development by regulating mitochondria and chloroplasts stability in rice

BACKGROUND

Leaf morphology and spikelet number are two important traits associated with grain yield. To understand how genes coordinating with sink and sources of cereal crops is important for grain yield improvement guidance. Although many researches focus on leaf morphology or grain number in rice, the regulating molecular mechanisms are still unclear.

RESULTS

In this study, we identified a prohibitin complex 2α subunit, NAL8, that contributes to multiple developmental process and is required for normal leaf width and spikelet number at the reproductive stage in rice. These results were consistent with the ubiquitous expression pattern of NAL8 gene. We used genetic complementation, CRISPR/Cas9 gene editing system, RNAi gene silenced system and overexpressing system to generate transgenic plants for confirming the fuctions of NAL8. Mutation of NAL8 causes a reduction in the number of plastoglobules and shrunken thylakoids in chloroplasts, resulting in reduced cell division. In addition, the auxin levels in nal8 mutants are higher than in TQ, while the cytokinin levels are lower than in TQ. Moreover, RNA-sequencing and proteomics analysis shows that NAL8 is involved in multiple hormone signaling pathways as well as photosynthesis in chloroplasts and respiration in mitochondria.

CONCLUSIONS

Our findings provide new insights into the way that NAL8 functions as a molecular chaperone in regulating plant leaf morphology and spikelet number through its effects on mitochondria and chloroplasts associated with cell division.