Mirrorless MEMS imaging: a nonlinear vibrational approach utilizing aerosol-jetted PZT-actuated fiber MEMS scanner for microscale illumination.

This study introduces a novel image capture and lighting techniques using a cutting-edge hybrid MEMS scanner system designed for compact microscopic imaging. The scanner comprises a tapered optical fiber waveguide and innovative aerosol-jet printed PZT (lead zirconate titanate) bimorph push-pull actuators on a stainless-steel substrate, effectively addressing issues that are commonly associated with PZT on silicon substrates such as fracture and layer separation. By leveraging nonlinear vibration, the scanner achieves a spiral scan pattern from a single signal input, in addition to the expected two-dimensional scanning and target illumination from two phase-shifted inputs.

Arabidopsis PDE1 confers phosphate-deficiency tolerance in primary root growth.

PDE1 acts as a mediator of primary root growth in response to Pi deficiency. Phosphorus is commonly considered as a limiting nutrient for plant growth, which is mainly due to the immobility and uneven distribution of phosphate (Pi) in soils so that available Pi is not adequate in the rhizosphere. Although various mediators have been identified in Pi sensing and response, more details need to be uncovered in plant Pi-deficiency tolerance.

CaRH57, a RNA helicase, contributes pepper tolerance to heat stress.

RNA helicases (RHs) are required for most aspects of RNA metabolism and play an important role in plant stress tolerance. Heat stress (HS) causes the deleterious effects on plant cells, such as membrane disruption and protein misfolding, which results in the inhibition of plant growth and development. In this study, CaRH57 was identified from pepper (Capsicum annuum) and encodes a DEAD-box RH.

UBC6, a ubiquitin-conjugating enzyme, participates in secondary cell wall thickening in the inflorescence stem of Arabidopsis.

Secondary cell wall (SCW) thickening in plant inflorescence stems is a complicated cellular process that is essential for stem strength and biomass. Although Arabidopsis NAC transcription factor (TF) 1 (NST1) regulates the SCW thickening in anther walls, the single T-DNA-insertion mutant (nst1) does not show disrupted SCW thickening in anther endothecium, interfascicular fibers or xylem. To better understand the regulatory mechanism of this process, we generated an ethyl methanesulfonate (EMS)-mutagenized Arabidopsis population with the nst1 background.

IRR1 contributes to de novo root regeneration from Arabidopsis thaliana leaf explants.

Plants are capable of regenerating adventitious roots (ARs), which is important for plant response to stress and survival. Although great advances in understanding AR formation of leaf explants have been made, the regulatory mechanisms of AR formation still need to be investigated. In this study, irr1-1 (impaired root regeneration) was isolated with the inhibition of adventitious rooting from Arabidopsis leaf explants.

PtoMPO1, a negative mediator, functions in poplar drought tolerance.

Drought, as one of the most severe abiotic stresses in nature, adversely affects plant growth and development. Poplar is a woody plant which is prone to water-deficit sensitivity. Therefore, it is important to improve our understanding of how poplar responds to drought stress.

Arabidopsis mitochondrial single-stranded DNA-binding proteins SSB1 and SSB2 are essential regulators of mtDNA replication and homologous recombination.

Faithful DNA replication is one of the most essential processes in almost all living organisms. However, the proteins responsible for organellar DNA replication are still largely unknown in plants. Here, we show that the two mitochondrion-targeted single-stranded DNA-binding (SSB) proteins SSB1 and SSB2 directly interact with each other and act as key factors for mitochondrial DNA (mtDNA) maintenance, as their single or double loss-of-function mutants exhibit severe germination delay and growth retardation.

Capsicum SIZ1 contributes to ABA-induced SUMOylation in pepper.

Abiotic and biotic stresses are the major factors limiting plant growth. Arabidopsis E3 SUMO ligase SIZ1 plays an essential role in plant stress tolerance. Herein, we identified a SIZ/PAIS-type protein in pepper (Capsicum annuum), namely CaSIZ1, which shares 60 % sequence identity with AtSIZ1.

Sarracenia purpurea glycerol-3-phosphate acyltransferase 5 confers plant tolerance to high humidity in Arabidopsis thaliana.

Suberin, as a lipid polyester barrier, limits the movement of gas, water, and solutes, and plays important roles in plant protection and growth. In this study, a CDS encoding glycerol-3-phosphate acyltransferase 5 (GPAT5) was cloned from Sarracenia purpurea to investigate the gene function. SpGPAT5 shares 72% identity and 80% similarity to AtGPAT5 that is required for suberin synthesis.

Arabidopsis SSB1, a Mitochondrial Single-Stranded DNA-Binding Protein, is Involved in ABA Response and Mitochondrial RNA Splicing.

A mitochondrion is a semiautonomous organelle that provides energy for life activities and balances plant growth and stress responses. Abscisic acid (ABA) regulates multiple physiological processes, including seed maturation, seed dormancy, stomatal closure and various abiotic stress responses. However, the relationship between mitochondrial activity and the ABA response is unclear.

Arabidopsis MHP1, a homologue of yeast Mpo1, is involved in ABA signaling.

Sphingolipids and their intermediates play multiple roles in biological processes. The sphingoid long-chain base component of sphingolipids has emerged as a participant in the regulation of plant biotic and abiotic stress responses. The phytohormone abscisic acid (ABA) regulates many stress responses in plants for environmental adaptation.

SIZ1-Mediated SUMOylation of ROS1 Enhances Its Stability and Positively Regulates Active DNA Demethylation in Arabidopsis.

The 5-methylcytosine DNA glycosylase/lyase REPRESSOR OF SILENCING 1 (ROS1)-mediated active DNA demethylation is critical for shaping the genomic DNA methylation landscape in Arabidopsis. Whether and how the stability of ROS1 may be regulated by post-translational modifications is unknown. Using a methylation-sensitive PCR (CHOP-PCR)-based forward genetic screen for Arabidopsis DNA hyper-methylation mutants, we identified the SUMO E3 ligase SIZ1 as a critical regulator of active DNA demethylation.

Arabidopsis glucose-sensitive mutant 3 affects ABA biosynthesis and sensitivity during early seedling development.

In plants, glucose (Glc) plays pivotal roles in development and stress responses mainly by supplying fuel for growth and regulating expression of genes essential for crosstalk with hormonal, oxidative, and defense signaling. However, the complicated relationship between Glc and plant hormones is still not very clear. In this study, gsm3 (glucose-sensitive mutant 3), an Arabidopsis mutant with Glc-sensitive phenotype, was identified.

GSM2, a transaldolase, contributes to reactive oxygen species homeostasis in Arabidopsis.

Plants are exposed to various environmental cues that lead to reactive oxygen species (ROS) accumulation. ROS production and detoxification are tightly regulated to maintain balance. Although studies of glucose (Glc) are always accompanied by ROS in animals, the role of Glc in respect of ROS in plants is unclear.

Arabidopsis GSM1 is involved in ABI4-regulated ABA signaling under high-glucose condition in early seedling growth.

In plants, sugar acts as an essential signaling molecule that modulates various aspects of metabolism, growth and development, which are also controlled by phytohormones. However, the molecular mechanism of cross-talk between sugar and phytohormones still remains to be elucidated. We have identified gsm1 (glucose-hypersensitive mutant 1) as a mutant with impaired cotyledon development that shows sensitivity to exogenous abscisic acid (ABA).

A WD40 protein, AtGHS40, negatively modulates abscisic acid degrading and signaling genes during seedling growth under high glucose conditions.

The Arabidopsis thaliana T-DNA insertion mutant glucose hypersensitive (ghs) 40-1 exhibited hypersensitivity to glucose (Glc) and abscisic acid (ABA). The ghs40-1 mutant displayed severely impaired cotyledon greening and expansion and showed enhanced reduction in hypocotyl elongation of dark-grown seedlings when grown in Glc concentrations higher than 3 %. The Glc-hypersensitivity of ghs40-1 was correlated with the hyposensitive phenotype of 35S::AtGHS40 seedlings.

Characterization of a lily anther-specific gene encoding cytoskeleton-binding glycoproteins and overexpression of the gene causes severe inhibition of pollen tube growth.

This work characterizes an anther/pollen-specific gene that encodes potential intermediate filament (IF)-binding glycoproteins in lily (Lilium longiflorum Thunb. cv. Snow Queen) anthers during the development and pollen germination.

AtRH57, a DEAD-box RNA helicase, is involved in feedback inhibition of glucose-mediated abscisic acid accumulation during seedling development and additively affects pre-ribosomal RNA processing with high glucose.

The Arabidopsis thaliana T-DNA insertion mutant rh57-1 exhibited hypersensitivity to glucose (Glc) and abscisic acid (ABA). The other two rh57 mutants also showed Glc hypersensitivity similar to rh57-1, strongly suggesting that the Glc-hypersensitive feature of these mutants results from mutation of AtRH57. rh57-1 and rh57-3 displayed severely impaired seedling growth when grown in Glc concentrations higher than 3%.

New insights into desiccation-associated gene regulation by Lilium longiflorum ASR during pollen maturation and in transgenic Arabidopsis.

LLA23, a member of the abscisic acid-, stress-, and ripening-induced (ASR) protein family, was previously isolated from lily (Lilium longiflorum) pollen. The lily ASR is induced through desiccation-associated ABA signaling transduction in the pollen. ASRs are highly hydrophilic and intrinsically unstructured proteins with molecular masses generally less than 18 kDa.

Lily ASR protein-conferred cold and freezing resistance in Arabidopsis.

The lily LLA23 protein is a member of the abscisic acid, stress and ripening-induced (ASR) protein family. Constitutive overexpression of LLA23 under the cauliflower mosaic virus 35S promoter confers cold and freezing tolerance in Arabidopsis. The phenotypical growth and survival percentage of the two transgenic 35S::LLA23 plants showed higher resistance to cold and freezing conditions than those of wild-type (WT) plants.

A conserved transcriptional regulator is required for RNA-directed DNA methylation and plant development.

RNA-directed DNA methylation (RdDM) is a conserved mechanism for epigenetic silencing of transposons and other repetitive elements. We report that the rdm4 (RNA-directed DNA Methylation4) mutation not only impairs RdDM, but also causes pleiotropic developmental defects in Arabidopsis. Both RNA polymerase II (Pol II)- and Pol V-dependent transcripts are affected in the rdm4 mutant.

An effector of RNA-directed DNA methylation in arabidopsis is an ARGONAUTE 4- and RNA-binding protein.

DNA methylation is a conserved epigenetic mark in plants and mammals. In Arabidopsis, DNA methylation can be triggered by small interfering RNAs (siRNAs) through an RNA-directed DNA methylation (RdDM) pathway. Here, we report the identification of an RdDM effector, KTF1.

NRPD4, a protein related to the RPB4 subunit of RNA polymerase II, is a component of RNA polymerases IV and V and is required for RNA-directed DNA methylation.

RNA-directed DNA methylation (RdDM) is an RNAi-based mechanism for establishing transcriptional gene silencing in plants. The plant-specific RNA polymerases IV and V are required for the generation of 24-nucleotide (nt) siRNAs and for guiding sequence-specific DNA methylation by the siRNAs, respectively. However, unlike the extensively studied multisubunit Pol II, our current knowledge about Pol IV and Pol V is restricted to only the two largest subunits NRPD1a/NRPD1 and NRPD1b/NRPE1 and the one second-largest subunit NRPD2a.

Expression and regulation of two novel anther-specific genes in Lilium longiflorum.

Two stage-specific genes have been isolated from a subtractive cDNA library constructed from developing anthers of lily (Lilium longiflorum). The proteins encoded by the two genes have a strong hydrophobic region at the N-terminus, indicating the presence of a signal peptide. The deduced LLA-67 is a new type of small cysteine-rich protein whose sequence exhibits four consecutive CX(3)CX(6-10) repeats that could form signal-receiving finger motifs, while the deduced LLA-115 protein shows significant similarities to a rice unknown protein, and putative cell wall proteins of Medicago truncatula and Arabidopsis.