Plant Organ Shape Research Articles

Genetic Evidence of SpGH9A3 in Leaf Morphology Variation of Spathiphyllum 'Mojo'.

Leaves play a crucial role as ornamental organs in Spathiphyllum, exhibiting distinct differences across various Spathiphyllum varieties. Leaf development is intricately linked to processes of cell proliferation and expansion, with cell morphology often regulated by plant cell walls, primarily composed of cellulose. Alterations in cellulose content can impact cell morphology, subsequently influencing the overall shape of plant organs. Although cellulases have been shown to affect cellulose levels in plant cells, genetic evidence linking them to the regulation of leaf shape remains limited. This study took the leaves of Spathiphyllum 'Mojo' and its somatic variants as the research objects. We screened four cellulase gene family members from the transcriptome and then measured the leaf cellulose content, cellulase activity, and expression levels of cellulase-related genes. Correlation analysis pinpointed the gene SpGH9A3 as closely associated with leaf shape variations in the mutant. Green fluorescent fusion protein assays revealed that the SpGH9A3 protein was localized to the cell membrane. Notably, the expression of the SpGH9A3 gene in mutant leaves peaked during the early spread stage, resulting in smaller overall leaf size and reduced cellulose content upon overexpression in Arabidopsis.

Meeting reports

With the support of the Biochemical Society, I facilitated a cancer awareness and education symposium, trained health personnel on cancer screening, screened patients for cervical and prostate cancers and dispensed free prescribed drugs to patients. This was to mark the official launch of the Dove-Haven Foundation (DHF) and commemorate World Cancer Day 2021. ‘A World Without Cancer Threat’ took place at Isanlu, Kogi State, Nigeria from 1 to 6 February 2021.DHF is a non-profit organization whose programmes are designed to create awareness on early cancer screening, testing and prevention strategies and helping those already suffering from cancer. The organization has volunteers across Nigeria, and in the diaspora, and is situated in Kogi State, the only state sharing boundaries with 10 other states and thus well positioned for the engagement and impact of health intervention. Participants include government representatives such as the current Nigerian Minister of Health and former Minister of Health, as well as religious and community leaders, health professionals, oncologists, community health workers, nurses, members of the press/media, primary and tertiary healthcare staff members and students from secondary and tertiary education institutions.More than 400 people participated in the symposium, with speakers from the USA, the UK and Nigeria. Twenty-three health personnel were trained on cervical cancer screening. The community medical engagement was successful, based on the coverage, supplies, personnel, drug supply and the number of patients covered. We attended to more than 300 patients and screened over 150 people for cervical cancer and 35 people for prostate cancer. Sponsorship from the Biochemical Society was timely and useful in the production and purchase of education aid materials.Funding for this event was awarded in advance of the Biochemical Society’s decision to reserve financial support for face-to-face meetings until October 2021, regardless of international restrictions.Dynamic Cell IV was run jointly by the Biochemical Society and the British Society for Cell Biology (BSCB) in a virtual format, with emphasis on networking and social events. The meeting started with a keynote talk by Enrico Coen, with a presentation that explored the biophysics driving the emergence of plant organ shape from cell growth. This was followed by a student/postdoc session in which the quality of talks was very high, with plenty of questions and feedback from attendees. Throughout the conference we operated an anonymous question system allowing anyone in the audience to ask questions to the speaker and this worked really well to boost engagement and provide a surfeit of questions – the discussions carried on into post-session ‘meet the speaker’ talks in many cases.In the following 5 days, we heard many interesting talks by both senior and junior scientists working in the field of cell biology, with topics ranging from nematode neurons to cereal-killer fungi. We also presented one best talk prize and seven poster prizes and presented four medals from the two societies. In addition to the scientific sessions, we ran roundtable discussions spanning subjects such as grant writing, developing an independent career, communicating your science and improving the profile of minority groups in academia. We also ran a vibrant social programme each evening, with a (virtual) pub quiz, an online escape room and competitions using the drawing app Drawful2. It was great to ‘virtually’ see many attendees participating in the breakout rooms, roundtable discussions, and social events. We are planning to run this event again in 2024 or 2025.

Statistical shape analysis of tap roots: a methodological case study on laser scanned sugar beets

BackgroundThe efficient and robust statistical analysis of the shape of plant organs of different cultivars is an important investigation issue in plant breeding and enables a robust cultivar description within the breeding progress. Laserscanning is a highly accurate and high resolution technique to acquire the 3D shape of plant surfaces. The computation of a shape based principal component analysis (PCA) built on concepts from continuum mechanics has proven to be an effective tool for a qualitative and quantitative shape examination.ResultsThe shape based PCA was used for a statistical analysis of 140 sugar beet roots of different cultivars. The calculation of the mean sugar beet root shape and the description of the main variations was possible. Furthermore, unknown and individual tap roots could be attributed to their cultivar by means of a robust classification tool based on the PCA results.ConclusionThe method demonstrates that it is possible to identify principal modes of root shape variations automatically and to quantify associated variances out of laserscanned 3D sugar beet tap root models. The introduced approach is not limited to the 3D shape description by laser scanning. A transfer to 3D MRI or radar data is also conceivable.

Spatiotemporal Pattern of Ectopic Cell Divisions Contribute to Mis-Shaped Phenotype of Primary and Lateral Roots of katanin1 Mutant.

Pattern formation, cell proliferation, and directional cell growth, are driving factors of plant organ shape, size, and overall vegetative development. The establishment of vegetative morphogenesis strongly depends on spatiotemporal control and synchronization of formative and proliferative cell division patterns. In this context, the progression of cell division and the regulation of cell division plane orientation are defined by molecular mechanisms converging to the proper positioning and temporal reorganization of microtubule arrays such as the preprophase microtubule band, the mitotic spindle and the cytokinetic phragmoplast. By focusing on the tractable example of primary root development and lateral root emergence in Arabidopsis thaliana, genetic studies have highlighted the importance of mechanisms underlying microtubule reorganization in the establishment of the root system. In this regard, severe alterations of root growth, and development found in extensively studied katanin1 mutants of A. thaliana (fra2, lue1, and ktn1-2), were previously attributed to defective rearrangements of cortical microtubules and aberrant cell division plane reorientation. How KATANIN1-mediated microtubule severing contributes to tissue patterning and organ morphogenesis, ultimately leading to anisotropy in microtubule organization is a trending topic under vigorous investigation. Here we addressed this issue during root development, using advanced light-sheet fluorescence microscopy (LSFM) and long-term imaging of ktn1-2 mutant expressing the GFP-TUA6 microtubule marker. This method allowed spatial and temporal monitoring of cell division patterns in growing roots. Analysis of acquired multidimensional data sets revealed the occurrence of ectopic cell divisions in various tissues including the calyptrogen and the protoxylem of the main root, as well as in lateral root primordia. Notably the ktn1-2 mutant exhibited excessive longitudinal cell divisions (parallel to the root axis) at ectopic positions. This suggested that changes in the cell division pattern and the occurrence of ectopic cell divisions contributed significantly to pleiotropic root phenotypes of ktn1-2 mutant. LSFM provided evidence that KATANIN1 is required for the spatiotemporal control of cell divisions and establishment of tissue patterns in living A. thaliana roots.

Evolution of Lineage-Specific Gene Networks Underlying the Considerable Fruit Shape Diversity in Persimmon.

The shapes of plant organs reflect the evolution of each lineage and have been diversified according to lineage-specific adaptations to environment. Research on the molecular pathways responsible for organ shapes has traditionally been focused mainly on leaves or flowers. Thus, little is known about the pathways controlling fruit shapes, despite their diversity in some plant species. In this study, we analyzed oriental persimmon (Diospyros kaki), which exhibits considerable diversity in fruit shapes among cultivars, to elucidate the underlying molecular mechanism using transcriptomic data and quantitative evaluation. First, to filter the candidate genes associated with persimmon fruit shapes, the whole gene expression patterns obtained using mRNA-Seq analysis from 100 individuals, including a segregated population and various cultivars, were assessed to detect correlations with principal component scores for fruit shapes characterized with elliptic Fourier descriptors. Next, a gene co-expression network analysis with weighted gene co-expression network analysis (WGCNA) package revealed that class 1 KNOX family genes and SEEDSTICK function as integrators along with some phytohormone-related genes, to regulate the fruit shape diversity. On the other hand, the OVATE family genes also contribute to fruit shape diversity, of which pathway would be potentially shared with other plant species. Evolutionary aspects suggest that acquisition of a high lineage-specific and variable expression of class 1 KNOX gene, knotted-like homeobox of Arabidopsis thaliana 1 (KNAT1), in young fruit is important for establishing the persimmon-specific mechanism that determines fruit shape diversity.

Plant Organ Shapes Are Regulated by Protein Interactions and Associations With Microtubules.

Plant organ shape is determined by the spatial-temporal expression of genes that control the direction and rate of cell division and expansion, as well as the mechanical constraints provided by the rigid cell walls and surrounding cells. Despite the importance of organ morphology during the plant life cycle, the interplay of patterning genes with these mechanical constraints and the cytoskeleton is poorly understood. Shapes of harvestable plant organs such as fruits, leaves, seeds and tubers vary dramatically among, and within crop plants. Years of selection have led to the accumulation of mutations in genes regulating organ shapes, allowing us to identify new genetic and molecular components controlling morphology as well as the interactions among the proteins. Using tomato as a model, we discuss the interaction of Ovate Family Proteins (OFPs) with a subset of TONNEAU1-recruiting motif family of proteins (TRMs) as a part of the protein network that appears to be required for interactions with the microtubules leading to coordinated multicellular growth in plants. In addition, SUN and other members of the IQD family also exert their effects on organ shape by interacting with microtubules. In this review, we aim to illuminate the probable mechanistic aspects of organ growth mediated by OFP-TRM and SUN/IQD via their interactions with the cytoskeleton.

Growth Responses of Two Cultivated Okra Species (<i>Abelmoschus caillei</i> (A. Chev) Stevels and <i>Abelmoschus esculentus</i> (Linn.) Moench) in Crude Oil Contaminated Soil

The morphological distinctiveness of two cultivated Okra species- Abelmoschus caillei and Abelmoschus esculentus was investigated using six accessions; three for each species in crude oil contaminated soil. The seeds were collected from home gardens in Benin City and NIHORT. Morpho-agronomic characters such as numbers of days from sowing to germination, plant height, stem base diameter, stem color and pubescence, leaf shape and color, number of leaves produced, growth habit, branching, fruit and fruiting characters were determined. The growth response of the different accessions varied significantly (p< 0.05). Soil chemical analysis revealed decreased levels of pH, Phosphorus and Potassium in the contaminated soil. Generally, all the quantitative characters including number of flower buds and flowers produced, fruit length, height of plant and stem girth were reduced in plants (Okra) grown in the contaminated soil while most of the qualitative characters such as pigmentation and shape of plant organs were less affected. Thus, it can be suggested from the study that crude oil contamination of soil may lead to reduction in growth characteristics.Keywords: Crude oil, Soil, Morpho-agronomic characters, Abelmoschus caillei, A. esculentus.

Modeling of tomato fruits into nine shape categories using elliptic fourier shape modeling and Bayesian classification of contour morphometric data

Classification and characterization of the shape of plant organs are important tools for plant biologists, breeders and growers. Here we use boundary measurements, i.e. contour morphometric data, of scanned tomato fruits in conjunction with elliptic Fourier shape modeling and Bayesian classification techniques to find the optimum number of shape categories. Our findings show that there are nine computationally and visually distinct tomato shape categories: ellipsoid, flat, heart, long, long rectangular, rectangular, round, obovoid, and oxheart. Analyses of fruits from a diverse set of tomato accessions demonstrate that some varieties carry fruits that conform to predominantly one shape category while others carry fruits that conform to multiple shape categories. In particular the categories oxheart and long rectangular feature fruit that tend to equivalently fit several categories of shape, while the flat and obovoid categories contain fruit that consistently conform exclusively to a single category. The findings show that elliptic Fourier shape modeling and Bayesian classification provide an excellent tool for further in depth analyses of fruit shape variation that may occur across varieties and/or result from growth under different environmental conditions.

ANGUSTIFOLIA3 Signaling Coordinates Proliferation between Clonally Distinct Cells in Leaves

Coordinated proliferation between clonally distinct cells via inter-cell-layer signaling largely determines the size and shape of plant organs. Nonetheless, the signaling mechanism underlying this coordination in leaves remains elusive because of a lack of understanding of the signaling molecule (or molecules) involved. ANGUSTIFOLIA3 (AN3, also called GRF-INTERACTING FACTOR1) encodes a putative transcriptional coactivator with homology to human synovial sarcoma translocation protein. AN3 transcripts accumulate in mesophyll cells but are not detectable in leaf epidermal cells. However, we found here that in addition to mesophyll cells, epidermal cells of an3 leaves show defective proliferation. This spatial difference between the accumulation pattern of AN3 transcripts and an3 leaf phenotype is explained by AN3 protein movement across cell layers. AN3 moves into epidermal cells after being synthesized within mesophyll cells and helps control epidermal cell proliferation. Interference with AN3 movement results in abnormal leaf size and shape, indicating that AN3 signaling is indispensable for normal leaf development. AN3 movement does not require type II chaperonin activity, which is needed for movement of some mobile proteins. Taking these findings together, we present a novel model emphasizing the role of mesophyll cells as a signaling source coordinating proliferation between clonally independent leaf cells.

Patterns of Cell Division, Cell Differentiation and Cell Elongation in Epidermis and Cortex of Arabidopsis pedicels in the Wild Type and in erecta

Plant organ shape and size are established during growth by a predictable, controlled sequence of cell proliferation, differentiation, and elongation. To understand the regulation and coordination of these processes, we studied the temporal behavior of epidermal and cortex cells in Arabidopsis pedicels and used computational modeling to analyze cell behavior in tissues. Pedicels offer multiple advantages for such a study, as their growth is determinate, mostly one dimensional, and epidermis differentiation is uniform along the proximodistal axis. Three developmental stages were distinguished during pedicel growth: a proliferative stage, a stomata differentiation stage, and a cell elongation stage. Throughout the first two stages pedicel growth is exponential, while during the final stage growth becomes linear and depends on flower fertilization. During the first stage, the average cell cycle duration in the cortex and during symmetric divisions of epidermal cells was constant and cells divided at a fairly specific size. We also examined the mutant of ERECTA, a gene with strong influence on pedicel growth. We demonstrate that during the first two stages of pedicel development ERECTA is important for the rate of cell growth along the proximodistal axis and for cell cycle duration in epidermis and cortex. The second function of ERECTA is to prolong the proliferative phase and inhibit premature cell differentiation in the epidermis. Comparison of epidermis development in the wild type and erecta suggests that differentiation is a synchronized event in which the stomata differentiation and the transition of pavement cells from proliferation to expansion are intimately connected.

Comparison of digital image analysis using elliptic Fourier descriptors and major dimensions to phenotype seed shape in hexaploid wheat (Triticum aestivum L.)

Digital image analysis (DIA) is widely used for describing plant organ shape. However, the various types of shape descriptors that can be generated using DIA may identify different loci in genetic analyses. The purpose of this study was to evaluate two different DIA approaches to quantifying wheat seed shape for exploring trait correlations and quantitative trait loci (QTL) mapping. Phenotypic data were produced using the software programs ImageJ (National Institutes of Health, USA, http://rsbweb.nih.gov/ij/ ) and SHAPE (Hiroyoshi Iwata, http://lbm.ab.a.u-tokyo.ac.jp/≃iwata/shape/ ). ImageJ generates measures of length, width, perimeter, and area that can be used to describe dimensions of objects, whereas SHAPE generates elliptic Fourier descriptors (EFDs) to capture shape variation such as roughness, asymmetric skewing, or other two-dimensional aspects not encompassed by axes or distinctions in overall object area. There were significant differences in the results of the QTL analysis depending on the DIA software used. The use of EFDs to characterize horizontal measures of seed shape in wheat identified more QTL with higher LOD scores than length to width ratio. Additionally, the entire three dimensional shape of the seed described using two images in different orientations was shown to identify seed shape QTL that co-located with flour yield (FLYLD) and would go undetected based solely on a two dimensional image of the seed. Both methods identified QTL for length, width, thickness, and vertical perimeter that were co-localized with QTL for FLYLD.

Application of Digital Image Analysis System for Fine Evaluation of Varietal Differences and the Role of Ethylene in Visible Petal Senescence of Morning Glory

We detected differences in both onset and progression of visible petal senescence among morning glory cultivars by application of a digital image analysis system. The system is based on semiautomated time-lapse measurement of corolla areas. The system could also be applied to evaluate the effects of ethylene and its inhibitor on visible petal senescence. Both onset and progression of visible petal senescence were accelerated by ethylene treatment in all six cultivars tested. Treatment with aminooxyacetic acid (AOA), an ethylene biosynthesis inhibitor, prolonged time to onset of visible petal senescence in three of the six tested cultivars. In contrast, AOA treatment had no effect on duration of visible petal senescence in any tested cultivars. These data suggested differences among morning glory cultivars in the role of endogenous ethylene in controlling onset of visible petal senescence. In addition, we propose a new application of image analysis to fine quantification of time-lapse changes in the shape of plant organs.

Auxin-like activity of extract from hypertrophied tissue of Acacia eburnea infected with Ravenelia esculenta

Ravenelia esculenta Naras. and Thirum. is a rust, pathogenic to Acacia eburnea Willd. The infection leads to hypertrophy changing the morphology with bizarre shapes of plant organs. Healthy and infected tissues were subjected to extraction of IAA and indole derivatives and were estimated by spectrophotometric methods. The hypertrophy produced was presumed to be due to increase in the indole-3-acetic acid (IAA) content in the infected tissue, however, the amount of IAA in infected tissues decreased with the progression of disease. Concomitantly, the infected tissue showed the presence of a novel, slow migrating, indole derivative on TLC. Cultured shoot tips of Withania somnifera were dosed with the methanolic extract of the infected hypertrophied tissue (MEHT) (0.25, 0.5, 0.75, 1.00 and 1.25 mg/l). The stimulation in shoot growth along with profuse rooting was observed in a dose dependent manner with maximum at 1.00 and 1.25 mg/l concentration.

Quantitative evaluation of the degree of sprout leaf bending of rice cultivars using P-type Fourier descriptors and principal component analysis

In quantitative studies of the shapes of plant organs, evaluation methods based on image analysis in terms of Fourier translation and principal component analysis have been recognized as important and useful methods. However, these methods cannot be used to evaluate the degree of bending of grass-type leaves. In this study, we provide a novel quantitative evaluation method that has been developed from a new type of Fourier translation named the P-type Fourier translation. It is an effective technique for evaluating the degree of bending of grass-type leaves. We have successfully applied this method to quantitatively evaluate the degree of bending of leaves of eight rice cultivars. The degree of bending of each rice leaf was evaluated in terms of several orthogonal principal component scores of P-type Fourier descriptors (F-PCs). It has been found in the present study that a few F-PCs are sufficient to quantitatively evaluate the essential variation among different rice cultivars. These inherent essential variations among rice cultivars are mainly described by only two individual F-PCs; the other variations such as the wilt caused by sunshine damage are described by another F-PC. The results also show that the F-PCs can somewhat differentiate the reasons for variation in the degree of bending. Because the F-PCs are independent from each other, they can be used as input data for QTL analysis.

Shaping up plants

![Graphic][1] More growth at the edges than the center of leaves makes them curly. Coen/AAAS Enrico Coen (John Innes Centre, Norwich, UK) is seeing the shape of things to come. In two recent papers, he addresses how cell growth influences the shape of plant organs. The first article

Expression of the plant cyclin-dependent kinase inhibitor ICK1 affects cell division, plant growth and morphology.

The plant CDK inhibitor ICK1 was identified previously from Arabidopis thaliana with its inhibitory activity characterized in vitro. ICK1 displayed several structural and functional features that are distinct from known animal CDK inhibitors. Despite the initial characterization, there is no information on the functions of any plant CDK inhibitor in plants. To gain insight into ICK1 functions in vivo and the role of cell division during plant growth and development, transgenic plants were generated expressing ICK1 driven by the cauliflower mosaic virus 35S promoter. In comparison to control plants, growth was significantly inhibited in transgenic 35S-ICK1 plants, with some plants weighing <10% of wild-type plants at the 3 week stage. Most organs of 35S-ICK1 plants were smaller. There were also modifications in plant morphology such as shape and serration of leaves and petals. The changes were so drastic that 35S-ICK1 plants with strong phenotype no longer resembled wild-type plants morphologically. Analyses showed that increased ICK1 expression resulted in reduced CDK activity and reduced the number of cells in these plants. Cells in 35S-ICK1 plants were larger than corresponding cells in control plants. These results demonstrate that ICK1 acts as a CDK inhibitor in the plant, and the inhibition of cell division by ICK1 expression has profound effects on plant growth and development. They also suggest that alterations of plant organ shape can be achieved by restriction of cell division.

SHAPE CHARACTERS IN NUMERICAL TAXONOMY AND PROBLEMS WITH RATIOS

SummarySystematists in general, and those applying numerical methods in particular, frequently use ratios to express the shape of plant organs in order to standardize for size. However, ratios may have undesirable statistical properties and do not accurately represent the change in shape that occurs during development. Because of changes in allometric growth during development, ratios are often highly correlated with size and thus may not be effective methods of standardization. The slope of the regression line is a better measure of certain aspects of shape, and the intercept of the line can in some cases provide additional valuable information for comparative purposes. Difficulties associated with using regression analysis include the requirement for a reasonable sample size, increased computational expenses, and the disposition of cases where a low regression coefficient is obtained. Shape characters defined by regression analysis for cladistic inference may also be more suitable than ratios.