Plant Morphogenesis Research Articles

Peripheral straightness leads to shape diversification during formations of entire leaves

The ways to read out positional information are essential to determine final shapes in developmental processes. Relative shaping to different sizes of positional information enables robust morphogenesis; however, the same difference sometimes causes diversity. Different responses to a positional information will enable such switching of identical/diverse shapes, though detail mechanisms remain unknown.In this paper, we describe growing forms by constructing the contour of a two-dimensional object using propagating points and segments connecting them. In plant morphogenesis that lacks almost cell movements, tissue growth accompanied by cell divisions is central. We focused on peripheral cell composition in leaf formation as a frame. The growth with or without cell division on the periphery was analyzed with simple algorithms. We calculated the shapes of entire leaves with different ovality using combined growth algorithms as a model. Responces of the respective algorithms to simple positional information were explored to seek the origin of the shape diversification.The algorithm for “growth with cell divisions” maintained identical shapes; however, diverse shapes were generated by the algorithm “growth without cell division” with gradients. The simplified model allowed us to interpret the oval shape diversity due to slants on edges. We concluded that peripheral straightness can generate shape diversity, at least in leaf morphogenesis.

SlSPA3 regulates the nuclear abundance of SlUVR8 in tomato.

Tomato (Solanum lycopersicum L.) is an important model plant species in photomorphogenesis research. Ultraviolet B (UV-B) induces the dissociation of homodimers of the photoreceptor UV RESISTANCE LOCUS8 (UVR8) into monomers, which translocate into the nucleus. Nuclear accumulation of UVR8 is a prerequisite for its signaling function. Previous studies have reported that SUPPRESSOR OF PHYTOCHROME A-105 (SPA) family members may regulate UV-B signaling in Arabidopsis (Arabidopsis thaliana); however, the underlying mechanism is unknown. Here, we show that the tomato genome encodes four SPA (SlSPA) orthologs. Genome-edited Slspa3 mutants exhibited enhanced photomorphogenic responses in white light, suggesting that SlSPA3 inhibits general photomorphogenesis. By contrast, UVR8-mediated gene expression in response to UV-B was compromised in Slspa3 mutants, suggesting that SlSPA3 promotes UV-B signaling. UV-B-induced nuclear accumulation of UVR8, which is essential for UV-B signaling, was reduced in the Slspa3 mutants. Moreover, UV-B-induced nuclear accumulation of UVR8 was also reduced in the Arabidopsis spa1 spa2 spa3 and spa1 spa2 spa4 triple mutants, indicating a conserved mechanism in these two species. Notably, spa1 spa2 spa4 exhibited normal UV-B-induced interaction between UVR8 and the plant morphogenesis repressor CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1). This suggests that the well-established mechanisms of UVR8 nuclear retention remained unaffected in spa1 spa2 spa4. Thus, our work uncovered a potentially unrecognized mechanism by which SPA proteins regulate UV-B signaling through the promotion of UVR8 nuclear abundance in land plants.

The Potential Role of PeMAP65-18 in Secondary Cell Wall Formation in Moso Bamboo.

Microtubule-associated proteins (MAPs) play a pivotal role in the assembly and stabilization of microtubules, which are essential for plant cell growth, development, and morphogenesis. A class of plant-specific MAPs, MAP65, plays largely unexplored roles in moso bamboo (Phyllostachys edulis). This study identified 19 PeMAP65 genes in moso bamboo, systematically examining their phylogenetic relationships, conserved motifs, gene structures, collinearity, and cis-acting elements. Analysis of gene expression indicated that PeMAP65s exhibit tissue-specific expression patterns. Functional differentiation was investigated among the members of different PeMAP65 subfamilies according to their expression patterns in different development stages of bamboo shoots. The expression of PeMAP65-18 was positively correlated with the expression of genes involved in secondary cell wall (SCW) biosynthesis. Y1H and Dual-LUC assays demonstrated that the transcription of PeMAP65-18 was upregulated by PeMYB46, a key transcription factor of SCW biosynthesis. The result of subcellular localization showed that PeMAP65-18 was located in cortical microtubules. We speculate that PeMAP65-18 may play a crucial role in the SCW deposition of moso bamboo. This comprehensive analysis of the MAP65 family offers novel insights into the roles of PeMAP65s in moso bamboo, particularly in relation to the formation of SCWs.

Plasma membrane and cytoplasmic compartmentalization: a dynamic structural framework required for pollen tube tip growth.

Rapid, unidirectional pollen tube tip growth is essential for fertilization and is widely employed as a model of polar cell expansion, a process crucial for plant morphogenesis. Different proteins and lipids with key functions in the control of polar cell expansion are associated with distinct domains of the plasma membrane (PM) at the pollen tube tip. These domains need to be dynamically maintained during tip growth, which depends on massive secretory and endocytic membrane trafficking. Very little is currently known about the molecular and cellular mechanisms responsible for the compartmentalization of the pollen tube PM. To provide a reliable structural framework for the further characterization of these mechanisms, an integrated quantitative map was compiled of the relative positions in normally growing Nicotiana tabacum (tobacco) pollen tubes of PM domains 1) enriched in key signaling proteins or lipids, 2) displaying high membrane order, or 3) in contact with cytoplasmic structures playing important roles in apical membrane trafficking. Previously identified secretory and endocytic PM domains were also included into this map. Internalization of regulatory proteins or lipids associated with PM regions overlapping with the lateral endocytic domain was assessed based on brefeldin A (BFA) treatment. These analyses revealed remarkable aspects of the structural organization of tobacco pollen tube tips, which 1) enhance our understanding of cellular and regulatory processes underlying tip growth, and 2) highlight important areas of future research.

Multifaceted roles of TCP transcription factors in fate determination.

Fate determination is indispensable for the accurate shaping and specialization of plant organs, a process critical to the structural and functional diversity in plant kingdom. The TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) family of transcription factors has been recognized for its significant contributions to plant organogenesis and morphogenesis. Recent research has shed light on the pivotal roles that TCPs play in fate determination. In this review, we delve into the current understanding of TCP functions, emphasizing their critical influence on fate determination from the organelle to the cell and organ levels. We also consolidate the molecular mechanisms through which TCPs exert their regulatory effects on fate determination. Additionally, we highlight intriguing points of TCPs that warrant further exploration in future research endeavors.

Unveiling the Power of Flax Lignans: From Plant Biosynthesis to Human Health Benefits.

Flax (Linum usitatissimum L.) is the richest plant source of lignin secondary metabolites. Lignans from flax have been applied in the fields of food, medicine, and health due to their significant physiological activities. The most abundant lignan is secoisolariciresinol, which exists in a glycosylated form in plants. After ingestion, it is converted by human intestinal flora into enterodiol and enterolactone, which both have physiological roles. Here, the basic structures, contents, synthesis, regulatory, and metabolic pathways, as well as extraction and isolation methods, of flax lignans were reviewed. Additionally, the physiological activity-related mechanisms and their impacts on human health, from the biosynthesis of lignans in plants to the physiological activity effects observed in animal metabolites, were examined. The review elucidates that lignans, as phenolic compounds, not only function as active substances in plants but also offer significant nutritional values and health benefits when flax is consumed.

A CC-NB-ARC-LRR Gene Regulates Bract Morphology in Cotton.

Bracts are leaf-like structures in flowering plants. They serve multiple functions such as attracting pollinators, aiding tolerance of abiotic stressors, and conducting photosynthesis. While previous studies extensively examine bract function, the molecular mechanisms underlying bract growth remain unknown. Here, the map-based isolation and characterization of a crucial factor responsible for cotton bract development, identified from a mutant known as frego bract (fg), discovered by Frego in 1945 are presented. This gene, named Ghfg, encodes a CC-NB-ARC-LRR (CNL) family protein. Through analysis of bract form in plants with virus-induced gene silencing (VIGS) and transgenic plants, this gene is confirmed to be the causal gene under the fg locus. Furthermore, high-resolution single-cell transcriptomic landscape of cotton bracts is generated, which reveals differences related to auxin in proliferating cells from TM-1 and T582; differences in auxin distribution and ROS accumulation are experimentally verified. These findings suggest that GhFG is in a self-activated state in the fg mutant, and its activity leads to ROS accumulation that impacts auxin distribution and transport. Finally, an island cotton variety with the frego bract trait is developed, demonstrating a novel solution for reducing the high impurity rate caused by bract remnants.

The people behind the papers - Isabella Burda and Adrienne Roeder.

Morphogenesis in plants is often robust, resulting in a reproducible organ size and shape across organisms. In a new study, Adrienne Roeder and colleagues investigate this robustness in the developing Arabidopsis thaliana sepal. They find that the robustness is not affected by changes in the amount of cell division, but the variability of cellular growth rate must be uncorrelated or anti-correlated for robust development to occur. To find out more about the work, we caught up with first author Isabella Burda and corresponding author Adrienne Roeder, Associate Professor at Cornell University, USA.

Phloem sap from melon plants contains extracellular vesicles that carry active proteasomes which increase in response to aphid infestation.

The morphogenesis of higher plants requires communication among distant organs throughout vascular tissues (xylem and phloem). Numerous investigations have demonstrated that phloem also act as a distribution route for signalling molecules being observed that different macromolecules translocated by the sap, including nucleic acids and proteins, change under stress situations. The participation of extracellular vesicles (EVs) in this communication has been suggested, although little is known about their role. In fact, in the last decade, the presence of EVs in plants has originated a great controversy, where major concerns arose from their origin, isolation methods, and even the appropriate nomenclature for plant nanovesicles. Phloem sap exudates from melon plants, either aphid-free or infested with Aphis gossypii, were collected by stem incision. After sap concentration (Amicon), phloem EVs (PhlEVs) were isolated by size exclusion chromatography. PhlEVs were characterised using Nanoparticle Tracking Analysis, Transmission electron microscopy and proteomic analysis. Here we confirm the presence of EVs in phloem sap in vivo and the detection of changes in the particles/protein ratio and composition of PhlEVs in response to insect feeding, revealing the presence of typical defence proteins in their cargo as well as components of the proteasome complex. PhlEVs from infested plants showed lower particles/protein ratio and almost two times more proteolytic activity than PhlEVs from aphid-free plants. In both cases, such activity was inhibited in a dose-dependent manner by the proteasome inhibitor MG132. Our results suggest that plants may use this mechanism to prepare themselves to receive infectious agents and open up the possibility of an evolutionary conserved mechanism of defence against pathogens/stresses in eukaryotic organisms.

The biomechanics of turgor pressure

If you ever forget to water your houseplant, you may find its leaves getting soft and droopy - if you water it again in time, the leaves may stiffen, spring back up, and resist gravity. During this recovery, plant cells absorb water and build up an intracellular pressure, called turgor pressure, similar to inflating a balloon. Turgor pressure is an intrinsic component of plant physiology, and its biomechanical role as the 'hydroskeleton' is generally appreciated either statically in structural stability, like leaves resisting gravity, or dynamically in rapid motions, like Venus flytrap snapping, Mimosa closing, or stomatal opening. Slow but non-static processes like plant cell expansion also rely on turgor pressure, and it has been increasingly realized that turgor pressure and water fluxes in plant tissues play active roles in plant growth and morphogenesis. But where does turgor pressure come from, and how does it interact with other biomechanical properties of a plant cell? This primer aims to answer these questions by taking a brief tour from osmosis, to pressure vessel theory, then plant cell rheology. Although this primer is centered around intracellular pressure in plant cells, the biomechanical concepts are generally applicable to other organisms like bacteria and fungi, and even animal cells, which do not have cell walls, but are either embedded in stiff extracellular matrix (ECM) or are contracting (see the following section). To explain some of these concepts, we included a few equations, most of which are not hard to derive at all. We encourage readers to check the included examples, try for themselves, and look up derivations in suggested further reading materials.

Plant biology: Mapping meristem morphogenesis in Marchantia

The use of state-of-the-art imaging, underpinned by molecular data, for the first time provides a clear understanding of two fundamental processes in liverworts- the establishment of dorsoventrality and origin of apical meristems. This work opens the door to exploring many new facets of plant morphogenesis.

Sucrose-responsive osmoregulation of plant cell size by a long non-coding RNA

In plants, sugars are the key source of energy and metabolic building blocks. The systemic transport of sugars is essential for plant growth and morphogenesis. Plants evolved intricate molecular networks to effectively distribute sugars. The dynamic distribution of these osmotically active compounds is a handy tool for regulating cell turgor pressure, an instructive force in developmental biology. In this study, we have investigated the molecular mechanism behind the dual role of the receptor-like kinase CANAR. We functionally characterized a long non-coding RNA, CARMA, as a negative regulator of CANAR. Sugar-responsive CARMA specifically fine-tunes CANAR expression in the phloem, the route of sugar transport. Our genetic, molecular, microscopy, and biophysical data suggest that the CARMA–CANAR module controls the shoot-to-root phloem transport of sugars, allows cells to flexibly adapt to the external osmolality by appropriate water uptake, and thus adjust the size of vascular cell types during organ growth and development. Our study identifies a nexus of plant vascular tissue formation with cell internal pressure monitoring, revealing a novel functional aspect of long non-coding RNAs in developmental biology.

Influence of izatison on growth and development of Kalanchoe daigremontiana (Raim.-Hamet & Perrier) A. Berger

Aim. The investigation was performed to studying of the influence of Izatison on the adaptiv morphogenesis in plants. Kalanchoe Daigremontiana was chosen as the model. Methods. The plants, obtained from the plantlets of same age and origin, were grown as a soil culture in separate pots. The mature leaves from the middle layer of the plants were used for the investigation. The first versions of Izatison dilutions were used. Results. The statistically reliable increase of the initiated plantlets on the leaf (P<0.05) was detected in the version with the greatest dilution for 5 days of exposition of the Kalanchoe leaves in the water suspensions of Izatison. The statistically reliable of the accelerated emergence of second pair of the leaves (P<0.05; P<0.01) was shown in tenth day in the versions with the middle ant the greatest dilutions. It was detected earlier emergence of the third pair of the leaves for 11–17 days (P<0,05; P<0,001) in the versions with the greatest dilutions. Conclusions. It was shown the possibility of Izatison to stimulate the initiation of plantlets and accelerate their differentiation and the growth depending from its concentration.

Transcriptome sequencing-based analysis of primary vein development in Betula pendula ‘Dalecarlica’

Keymessage The study revealed the major biological processes occurred at three developmental stages and identified candidate genes involved in primary vein development of birch plants.Vascular tissues usually mirror the surrounding leaf shape and its development plays a fundamental role in plant performance. However, the information of vascular development in birch trees, especially primary vein development, remains unclear. Therefore, we conducted the anatomical observation on primary veins from leaves at different development stages in Betula pendula ‘Dalecarlica’. With the development of primary vein, dynamic changes in mechanical tissue thickness and primary vein diameter were consistent with each other, and the sum of phloem, xylem and cambium thickness was significantly varied. Transcriptome analysis indicated that primary vein development could be divided into three stages, namely Stage I, II and III, which were in aggreement with anatomical observation. Expression of marker genes associated with vascular tissues revealed that pro-vasculature development occurred at Stage I and II, and phloem development occurred at Stage III. GO enrichment analysis of differentially expressed genes (DEGs) showed that shared DEGs at Stage II were mainly engaged in cell division and cell cycle, and shared DEGs at Stage III were mainly engaged in phosphorylation. Decreased cell division and cell cycle as well as activation of lignin biosynthesis might contribute to primary vein development. Combining phenotypic traits, we performed weighted gene co-expression network analysis and identified a cytochrome P450 84A (CYP84A) family gene (BpF5H1). Based on analyses of gene families, expression patterns and yeast-two hybrid assay results, we proposed a potential electron transfer pathway involving BpF5H1 and three cytochrome b5 proteins during primary vein development in B. pendula ‘Dalecarlica’. These results could shed some light on which biological processes occurred during primary vein formation and provide some valuable clues for vascular morphogenesis in woody plants.

Genome-wide identification of the AP2/ERF gene family from Limonium bicolor and functional characterization of LbAP2/ERF32 under salt stress

AP2/ERF transcription factors (TFs) play important roles in plant growth and development, plant morphogenesis and response to environmental stresses. However, their biological roles in recretohalophytes are still not fully revealed. Limonium bicolor L. is a typical recretohalophyte, which secretes excessive salt ions through the salt glands on the epidermis. Here, 64 LbAP2/ERF genes were identified in L. bicolor genome, which were unevenly distributed on the eight chromosomes. Cis-elements related to growth and development, stress response and phytohormone response are distributed in multiple LbAP2/ERF promoters. Expression analysis indicated that LbAP2/ERF genes responsed to NaCl, PEG and ABA. And the salt gland density, salt secretion of leaves and overall salt tolerance of LbAP2/ERF32 silenced lines were significantly reduced. In agreement, the genes related to salt gland development and ion transport were significantly changed in LbAP2/ERF32-silenced lines. Our findings provided fundamental information on the structure and evolutionary relationship of LbAP2/ERF gene family in salt gland development and salt secretion of L. bicolor and gave theoretical guideline for further functional study of LbAP2/ERF genes in response to abiotic stress.

Distribution Patterns and Environmental Determinants of Invasive Alien Plants on Subtropical Islands (Fujian, China)

Plant invasions threaten the biodiversity of islands, causing serious impacts on their ecosystems. To investigate the distribution patterns of invasive alien plants on subtropical islands, the environmental determinants of species richness, and the growth forms of invasive alien plants, this study analyzed the composition and origin of invasive alien plants on 77 islands in Fujian. The similarity in the distribution of invasive alien plants between islands was assessed using the UPGMA. Moreover, feature selection, best-subset regression, and variance decomposition were performed using 19 environmental variables characterizing climate, anthropogenic disturbance, and landscape/geography, as well as the species richness and growth forms of invasive alien plants. Through the analysis, the main environmental factors affecting the species richness and growth forms of invasive alien plants on the Fujian islands were identified. The results showed 142 species of invasive alien plants in 38 families and 102 genera on 77 islands in Fujian. Annual herbs constituted the most representative growth form of invasive alien plants and tropical America was the main origin of invasive alien plants. The distribution of invasive alien plants across the 77 islands in Fujian showed a high degree of similarity, suggesting a nested pattern in their distribution. The proportions of building and farmland area (BFA), island area (A), and maximum elevation (ME) were the main driving factors of species richness and growth forms for invasive alien plants. In particular, BFA played a key role in driving plant invasion. The results of this study can help establish an early warning mechanism for invasive alien plants and better implement island ecological management, which are important for the protection of subtropical island ecosystems.

Transcriptomic profiling and discovery of key transcription factors involved in adventitious roots formation from root cuttings of mulberry

ARs plays a crucial role in plant morphogenesis and development. The limited and inefficient rooting of scions poses a significant challenge to the efficiency and quality of clonal propagation of forest trees in silvicultural practices. Building on previous research conducted by our team, we found that applying IBA at a concentration of 1000 mg/L significantly enhanced mulberry rooting. This study aims to uncover the molecular mechanisms underlying this effect by analyzing RNA sequencing data from mulberry phloem before and after treatment with IBA over time intervals of 10, 20, 30, and 40 days. We identified 5226 DEGs, which were then classified into GO terms and KEGG pathways, showing significant enrichment in hormone signaling processes. Using WGCNA, we identified eight co-expression modules, two of which were significantly correlated with the IBA treatment. Additionally, 18 transcription factors that potentially facilitate ARs formation in mulberry were identified, and an exploratory analysis on the cis-regulatory elements associated with these transcription factors was conducted. The findings of this study provide a comprehensive understanding of the mechanisms of ARs in mulberry and offer theoretical support for the discovery and utilization of exceptional genetic resources within the species.

A Study on the Functional Identification of Overexpressing Winter Wheat Expansin Gene TaEXPA7-B in Rice under Salt Stress.

Expansin is a cell wall relaxant protein that is common in plants and directly or indirectly participates in the whole process of plant root growth, development and morphogenesis. A well-developed root system helps plants to better absorb water and nutrients from the soil while effectively assisting them in resisting osmotic stress, such as salt stress. In this study, we observed and quantified the morphology of the roots of Arabidopsis overexpressing the TaEXPAs gene obtained by the research group in the early stage of development. We combined the bioinformatics analysis results relating to EXPA genes in five plants and identified TaEXPA7-B, a member of the EXPA family closely related to root development in winter wheat. Subcellular localization analysis of the TaEXPA7-B protein showed that it is located in the plant cell wall. In this study, the TaEXPA7-B gene was overexpressed in rice. The results showed that plant height, root length and the number of lateral roots of rice overexpressing the TaEXPA7-B gene were significantly higher than those of the wild type, and the expression of the TaEXPA7-B gene significantly promoted the growth of lateral root primordium and cortical cells. The plants were treated with 250 mM NaCl solution to simulate salt stress. The results showed that the accumulation of osmotic regulators, cell wall-related substances and the antioxidant enzyme activities of the overexpressed plants were higher than those of the wild type, and they had better salt tolerance. This paper discusses the effects of winter wheat expansins in plant root development and salt stress tolerance and provides a theoretical basis and relevant reference for screening high-quality expansin regulating root development and salt stress resistance in winter wheat and its application in crop molecular breeding.

Bio-solubilization of Rock Phosphate Using Acidophilic Bacteria and Effect of Bio-Organic-Phosphate Composite on the Growth of Wheat

Acidophilic sulfur and iron oxidizing bacteria, such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, play a crucial role in releasing nutrients into the soil. This study utilized a mixture of these bacteria to solubilize phosphorus from phosphate rock. Acidophilic bacteria were enriched from soil samples taken from the collection pond of a coal heap constructed for biodesulfurization studies. Rock phosphate sample was supplemented with elemental sulfur (So) and pyrite (FeS2) as energy substrates for bioleaching of phosphorus. The effect of different pulp densities of the rock phosphate on biosolubilization of phosphorus elucidated that the pulp density and rock phosphate solubilization are negatively correlated. The mixture of acidophilic microorganisms solubilized 40.76% P2O5 at 10 g/L pulp density during 30 days of leaching. A comparative study showed that a two-step process is more effective for the phosphorus leaching from rock phosphate. In pot experiments under net house conditions, the acidophilic bacterial composite increased wheat grain yield by 2% and seed phosphorus content by 3%, while reducing the need for DAP fertilizer by 20%. Treating soil with BOP (a combination of phosphate rock and acidophilic bacteria) proves to be an efficient method for converting frugally soluble phosphorus compounds into readily available forms for plants.

Three ways to confirm the correctness of the biomechanical model of the morphogenesis of spiral phyllotaxis

The mystery of the phyllotaxis phenomenon has been inspiring inquiry among generations of botanists and mathematicians. Of particular interest is the fact that the number of visible spirals is equal to the numbers from the Fibonacci series. The article proposes three methods to prove the adequacy of the biomechanical model of the morphogenesis of spiral phyllotaxis: mathematical, simulation software, and experimental. Evidence of the biomechanical model leads to a critical rethinking of the understanding of plant morphogenesis.