Plant & Cell Physiology

Plants grow in association with diverse microorganisms. During communication between plants and microbes, beneficial and phytopathogenic bacteria and fungi emit various volatile compounds (VCs). These microbial VCs (mVCs) are typically small, odorous compounds with low boiling point, high vapor pressure, and a lipophilic moiety (Schulz and Dickschat, 2007). Based on recent studies, mVCs appear to regulate plant nutrient acquisition, photosynthesis, phytohormone actions, and metabolic processes, leading to an improvement in plant performance (Fincheira et al...

Sphingolipids are ubiquitous components of eukaryotic cell membranes and are found in some prokaryotic organisms and viruses. They are composed of a sphingoid backbone that may be acylated and glycosylated. Assembly of various sphingoid base, fatty-acyl and glycosyl moieties results in highly diverse structures. The functional significance of variations in sphingolipid chemical diversity and abundance is still in the early stages of investigation. Among sphingolipid modifications, the Δ8-desaturation of the sphingoid base occurs only in plants and fungi...

As sessile organisms, land plants experience various forms of environmental stresses throughout their life span. Therefore, plants have developed extensive and complicated defence mechanisms, including a robust DNA damage response (DDR) and DNA repair systems for maintaining genome integrity. In Arabidopsis, the NAC domain family transcription factor SUPPRESSOR OF GAMMA RESPONSE1 (SOG1) plays an important role in regulating DDR. Here, we show that SOG1 plays a key role in regulating the repair of salinity-induced DNA double-strand breaks (DSBs) via the homologous recombination (HR) pathway in Arabidopsis...

Drought stress is a major threat leading to global plant and crop losses in the context of the climate change crisis. Brassinosteroids (BRs) are plant steroid hormones, and the BR signaling mechanism in plant development has been well elucidated. Nevertheless, the specific mechanisms of BR signaling in drought stress are still unclear. Here, we identify a novel Arabidopsis gene, BRZ INSENSITIVE LONG HYPOCOTYL 9 (BIL9), which promotes plant growth via BR signaling. Overexpression of BIL9 enhances drought and mannitol stress resistance and increases the expression of drought-responsive genes...

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5β-Cardenolides are pharmaceutically important metabolites of the specialized metabolism of Digitalis lanata. They were used over decades to treat cardiac insufficiency and supraventricular tachycardia. Since the 1960s, plant scientists have known that progesterone is an essential precursor of cardenolide formation. Therefore, plant progesterone biosynthesis was mainly analyzed in species of the cardenolide-containing genus Digitalis during the following decades. Today, Digitalis enzymes catalyzing the main steps of progesterone biosynthesis are known...

Nutritropism is a positive tropism towards nutrients in plant roots. An NH4+ gradient is a nutritropic stimulus in rice (Oryza sativa L.). When rice roots are exposed to an NH4+ gradient generated around nutrient sources, root tips bend towards and coil around the sources. The molecular mechanisms are largely unknown. Here, we analysed the transcriptomes of the inside and outside of bending root tips exhibiting nutritropism to reveal nutritropic signal transduction. Tissues facing the nutrient sources (inside) and away (outside) were separately collected by laser microdissection...

In response to both biotic and abiotic stresses, vascular plants transmit long-distance Ca2+ and electrical signals from localized stress sites to distant tissues through their vasculature. Various models have been proposed for the mechanisms underlying the long-distance signaling, primarily centered around the presence of vascular bundles. We here demonstrate that the non-vascular liverwort Marchantia polymorpha possesses a mechanism for propagating Ca2+ waves and electrical signals in response to wounding...

Plants undergo a series of developmental phases throughout their life cycle, each characterized by specific processes. Three critical features distinguish these phases: the arrangement of primordia (phyllotaxis), the timing of their differentiation (plastochron), and the characteristics of the lateral organs and axillary meristems. Identifying the unique molecular features of each phase, determining the molecular triggers that cause transitions, and understanding the molecular mechanisms underlying these transitions are key to gleaning a complete understanding of plant development...

Thermospermine suppresses auxin-inducible xylem differentiation, whereas its structural isomer, spermine, is involved in stress responses in angiosperms. The thermospermine synthase, ACAULIS5 (ACL5), is conserved from algae to land plants, but its physiological functions remain elusive in non-vascular plants. Here, we focused on MpACL5, a gene in the liverwort Marchantia polymorpha, that rescued the dwarf phenotype of the acl5 mutant in Arabidopsis. In the Mpacl5 mutants generated by genome editing, severe growth retardation was observed in the vegetative organ, thallus, and the sexual reproductive organ, gametangiophore...

Many terrestrial plants produce large quantities of alkanes for use in epicuticular wax and the pollen coat. However, their carbon chains must be long to be useful as fuel or as a petrochemical feedstock. Here, we focus on Nymphaea odorata, which produces relatively short alkanes in its anthers. We identified orthologs of the Arabidopsis alkane biosynthesis genes AtCER1 and AtCER3 in N. odorata and designated them NoCER1A, NoCER3A, and NoCER3B. Expression analysis of NoCER1A and NoCER3A/B in Arabidopsis cer mutants revealed that N...

Tomato torrado virus (ToTV) is a type member of the Torradovirus genus in the Secoviridae family known to cause severe necrosis in susceptible tomato varieties. ToTV also infects other Solanaceae plants, including Nicotiana benthamiana, where it induces distinctive disease symptoms: plant growth drop with the emergence of spoon-like malformed systemic leaves. Virus-induced post-transcriptional gene silencing (PTGS) is significant among plant defense mechanisms activated upon virus invasion. The PTGS, however, can be counteracted by suppressors of RNA silencing commonly found in viruses, which efficiently disrupt the antiviral defense of their host...

Sexual differentiation is a fundamental process in the life cycles of land plants, ensuring successful sexual reproduction and thereby contributing to species diversity and survival. In the dioicous liverwort Marchantia polymorpha, this process is governed by an autosomal sex-differentiation locus comprising FGMYB, a female-promoting gene, and SUF, an antisense strand-encoded long non-coding RNA (lncRNA). SUF is specifically transcribed in male plants, and suppresses the expression of FGMYB, leading to male differentiation...

Mitogen-activated protein kinase (MAPK) cascades are conserved signalling pathways that transduce extracellular signals into diverse cellular responses. Arabidopsis MAPKKK18 is a component of the MAP3K17/18-MKK3-MPK1/2/7/14 cascades, which play critical roles in ABA signalling, drought tolerance and senescence. A very important aspect of MAP kinase signalling is both its activation and its termination, which must be tightly controlled to achieve appropriate biological responses. Recently, the ubiquitin-proteasome system (UPS) has received increasing attention as a key mechanism for maintaining the homeostasis of MAPK cascade components and other ABA signalling effectors...

Phalaenopsis aphrodite can be induced to initiate spike growth and flowering by exposure to low ambient temperatures. However, the factors and mechanisms responsible for spike initiation in P. aphrodite remain largely unknown. In this study, we show that a repressor FLOWERING LOCUS T-like gene, FTL, can act as a negative regulator of spike initiation in P. aphrodite. The mRNA transcripts of PaFTL are consistently high during high ambient temperature, thereby preventing premature spike initiation. However, during low ambient temperature, PaFTL expression falls while FLOWERING LOCUS T (FT) expression increases, allowing for spike initiation...

Shoot growth directly impacts plant productivity. Plants adjust their shoot growth in response to varying environments to maximize resource capture and stress resilience. While several factors controlling shoot growth are known, the complexity of the regulation and the input of the environment are not fully understood. We have investigated shoot growth repression induced by low ambient temperatures in hybrids of Arabidopsis thaliana Kro-0 and BG-5 accessions. To continue our previous studies, we confirmed that the Kro-0 allele of DYNAMIN-RELATED PROTEIN 3B (DRP3B) causes stunted shoot growth in the BG-5 background...

Glycyrrhizin, a type of the triterpenoid saponin, is a major active ingredient contained in the roots of the medicinal plant licorice (Glycyrrhiza uralensis, G. glabra and G. inflata), and is used worldwide in diverse applications, such as herbal medicines and sweeteners. The growing demand for licorice threatens wild resources and therefore a sustainable method of supplying glycyrrhizin is required. With the goal of establishing an alternative glycyrrhizin supply method not dependent on wild plants, we attempted to produce glycyrrhizin using hairy root culture...

Heat shock transcription factors (HSFs) are crucial for regulating plant responses to heat and various stresses, as well as for maintaining normal cellular functions and plant development. HSFA9 and HSFA2 are two of the Arabidopsis class A HSFs and their expression are dramatically induced in response to heat shock (HS) stress among all 21 Arabidopsis HSFs. However, the detailed biological roles of their cooperation have not been fully characterized. In this study, we employed an integrated approach that combined bioinformatics, molecular genetics and computational analysis to identify and validate molecular mechanism that control the seed longevity and thermotolerance in Arabidopsis...

Cysteines (Cys) are chemically reactive amino acids containing sulfur that play diverse roles in plant biology. Recent proteomics investigations in Arabidopsis thaliana have revealed the presence of thiol post-translational modifications (PTMs) on several Cys residues. These PTMs are presumed to impact protein structure and function, yet mechanistic data regarding the specific Cys susceptible to modification and their biochemical relevance remains limited. To help address these limitations, we have conducted a wide-ranging analysis by integrating published datasets encompassing PTM proteomics (comparing S-sulfenylation, persulfidation, S-nitrosylation, and S-acylation), genomics, and protein structures, with a specific focus on proteins involved in plant lipid metabolism...

Plastids (including chloroplasts) and mitochondria are remnants of endosymbiotic bacteria yet maintain their own genomes, which encode vital components for photosynthesis and respiration, respectively. Organellar genomes have distinctive features, such as being present as multicopies, being mostly inherited maternally, having characteristic genomic structures, and undergoing frequent homologous recombination. To date, it has proven challenging to modify these genomes. For example, while CRISPR/Cas9 is a widely used system for editing nuclear genes, it has not yet been successfully applied to organellar genomes...