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Duckweeds have emerged as frontier plants in research, food, and bioenergy applications. Consistency in genetic and morphological traits within species is therefore crucial for their effective use. Thailand hosts diverse duckweed populations with representatives from four of the five genera and at least four species recorded. However, the extent of genetic and morphological variation within these species in Thailand remains unclear. Here, we investigated the genetic and morphological variation in four duckweed species—Landoltia punctata, Lemna aequinoctialis, Spirodela polyrhiza, and Wolffia globosa—collected from 26 sites across Thailand. Using the multilocus sequence typing approach based on three chloroplast genes (rbcL, atpF–atpH, and psbK–psbI), we show that genetic variation in duckweed is distinct at both inter-species and intra-species levels. Among these four species, Lemna aequinoctialis exhibits the highest genetic variation, forming four distinct phylogenetic clusters. This is followed by Spirodela polyrhiza, Wolffia globosa, and Landoltia punctata. In addition, we observe that morphological variation, particularly frond aspect ratio, varies significantly among clusters but remains consistent within each cluster of each species. These findings suggest that duckweed populations in Thailand exhibit substantial genetic variation at the intraspecific level, which is closely associated with frond morphological variation.

Duckweed has attracted considerable attention for its high protein content, rapid growth, and broad potential in biotechnological applications. Understanding key phenotypic traits is crucial for unlocking and maximizing this potential. While most studies on duckweed growth have been conducted under natural or non-sterile conditions, here we minimize environmental influences and focus on the genetic component of growth by assessing growth performance under axenic culture. In this study, we measured relative growth rate (RGR) in four duckweed species, Landoltia punctata (G. Mey.) Les & D. J. Crawford, Lemna aequinoctialis Welw., Spirodela polyrhiza (L.) Schleid., and Wolffia globosa (Roxb.) Hartog & Plas. collected from various natural locations across Thailand. A total of six to seven strains were tested for each species. The relative growth rates of studied species ranged from 0.012 day−1 in S. polyrhiza to 0.162 day−1 in W. globosa. Significant intraspecific variation was observed in L. punctata, S. polyrhiza, and W. globosa, with the coefficients of variation between 9.6 to 109.9 percent. Each strain showed distinct growth characteristics: Most displayed a steady growth pattern, whereas W. globosa showed exponential growth at Day 35 after the start of experiment. The results provide the first systematic comparisons of baseline growth rate data for duckweed species in Thailand. These findings advance the understanding of strain-specific growth traits in duckweed and establish a standardized protocol for evaluating growth traits under axenic conditions, providing a basis for future research and applications.

Phenotypic diversity of flowering plants stems from common basic features of the plant body pattern with well-defined body axes, organs and tissue organisation. Cell division and cell specification are the two processes that underlie the formation of a body pattern. As plant cells are encased into their cellulosic walls, directional cell division through precise positioning of division plane is crucial for shaping plant morphology. Since many plant cells are pluripotent, their fate establishment is influenced by their cellular environment through cell-to-cell signaling. Recent studies show that apart from biochemical regulation, these two processes are also influenced by cell and tissue morphology and operate under mechanical control. Finding a proper model system that allows dissecting the relationship between these aspects is the key to our understanding of pattern establishment. In this review, we present the Arabidopsis embryo as a simple, yet comprehensive model of pattern formation compatible with high-throughput quantitative assays.

Mechanical patterns control a variety of biological processes in plants. The microviscosity of cellular structures effects the diffusion rate of molecules and organelles, thereby affecting processes such as metabolism and signaling. Spatial variations in local viscosity are also generated during fundamental events in the cell life cycle. While crucial to a complete understanding of plant mechanobiology, resolving subcellular microviscosity patterns in plants has remained an unsolved challenge. We present an imaging microviscosimetry toolbox of molecular rotors that yield complete microviscosity maps of cells and tissues, specifically targeting the cytosol, vacuole, plasma membrane, and wall of plant cells. These boron-dipyrromethene (BODIPY)-based molecular rotors are rigidochromic by means of coupling the rate of an intramolecular rotation, which depends on the mechanics of their direct surroundings, with their fluorescence lifetime. This enables the optical mapping of fluidity and porosity patterns in targeted cellular compartments. We show how apparent viscosity relates to cell function in the root, how the growth of cellular protrusions induces local tension, and how the cell wall is adapted to perform actuation surrounding leaf pores. These results pave the way to the noninvasive micromechanical mapping of complex tissues.

• Plants produce an array of specialized metabolites with important ecological functions. The mechanisms underpinning the evolution of new biosynthetic pathways are not well-understood. Here, we exploit available genome sequence resources to investigate triterpene biosynthesis across the Brassicaceae. • Oxidosqualene cyclases (OSCs) catalyze the first committed step in triterpene biosynthesis. Systematic analysis of 13 sequenced Brassicaceae genomes was performed to identify all OSC genes. The genome neighbourhoods (GNs) around a total of 163 OSC genes were investigated to identify Pfam domains significantly enriched in these regions. All-vs-all comparisons of OSC neighbourhoods and phylogenomic analysis were used to investigate the sequence similarity and evolutionary relationships of the numerous candidate triterpene biosynthetic gene clusters (BGCs) observed. Functional analysis of three representative BGCs was carried out and their triterpene pathway products were elucidated. • Our results indicate that plant genomes are remarkably plastic, and that dynamic GNs generate new biosynthetic pathways in different Brassicaceae lineages by shuffling the genes encoding a core palette of triterpene-diversifying enzymes, presumably in response to strong environmental selection pressure. • These results illuminate a genomic basis for diversification of plant-specialized metabolism through natural combinatorics of enzyme families, which can be mimicked using synthetic biology to engineer diverse bioactive molecules.

The developmental processes of multicellular organisms have long been attempted to be explained by biochemical and genetic signaling pathways. However, it has become clear that development cannot be explained solely by genetics and biochemistry, but must include the notion that mechanical signals, connecting the biological entity to the physical reality it exists in, play a central role. This has given rise to the field of mechanobiology, which aims to understand how the biological machinery of cells perceives and adapts to these physical signals. While the field of mechanobiology has seen extensive research and knowledge advancement in the animal kingdom, our understanding of mechanical signals in plant development is much less developed. This thesis aims to contribute to the expansion of our knowledge of plant mechanobiology by developing bespoke methods to discover new mechanobiological factors in plant development.

Plant external surfaces are often covered by barriers that control the exchange of molecules, protect from pathogens, and offer mechanical integrity. A key question is when and how such surface barriers are generated. Post-embryonic surfaces have well-studied barriers, including the cuticle, and late Arabidopsis embryo was shown to be protected by an endosperm-derived sheath deposited onto a primordial cuticle. Here we show that both cuticle and sheath are preceded by another structure during the earliest stages of embryogenesis. This structure, which we named the embryonic envelope, is tightly wrapped around the embryonic surface but can be physically detached by cell wall digestion. We show that this structure is composed primarily of Extensin and Arabinogalactan O-glycoproteins and lipids, which appear to form a dense and elastic crosslinked embryonic envelope. The envelope forms in cuticle-deficient mutants and in a mutant that lacks endosperm. This embryo-derived envelope is therefore distinct from previously described cuticle and sheath structures. We propose that it acts as an expandable diffusion barrier, as well as a means to mechanically confine the embryo to maintain its tensegrity during early embryogenesis. The early Arabidopsis embryo is surrounded by a proteinaceous envelope that is distinct from the cuticle or embryo sheath