Plant photoreceptors regulate various developmental processes. Among the photoreceptors, phytochromes, red and far-red light receptors, regulate light responses through many signaling components, including phytochrome-interacting proteins. The functional relationships among phytochromes and their interacting proteins, however, have not been clearly established. Here, we sought to identify a functional relationship between phytochromes and phytochrome interacting factor 3 (PIF3). We demonstrate that PIF3 is polyubiquitinated rapidly and subsequently degraded in PHYA and PHYB-mediated light signaling. We also show that the degradation of PIF3 is mediated by the 26S proteasome. Our data indicate that light-stimulated phytochromes cause the degradation of their interacting protein, PIF3, by the 26S proteasome.

a b s t r a c tIn this paper we use the conformable fractional derivative and integral to discuss the fractional Newtonian mechanics. The fractional version of the calculus of variations is introduced and the fractional Euler-Lagrange equation is constructed. Some mechanical problems such as fractional harmonic oscillator problem, the fractional damped oscillator problem and the forced oscillator problem are discussed in the one-dimensional fractional dynamics.

SUMMARYIn yeast and animals, tri-and dimethylation of histone H3 at lysine 4 (H3K4me3/2) are markers of transcriptionally active genes that have recently been shown to be primary ligands for the plant homeodomain (PHD) finger. However, PHD fingers able to bind to H3K4me3/2 have not been identified in plants. Here, we identify 83 canonical PHD fingers in the Arabidopsis proteome database that are supported by both SMART and Pfam prediction. Among these, we focus on PHD fingers in ING (inhibitor of growth) homologues (AtING) and Alfin1-like (AL) proteins, which are highly similar to those in human ING2 and bromodomain PHD finger transcription factor (BPTF), based on predicted tertiary structures. ING proteins are found in yeast, animals and plants, whereas AL proteins exist only in plants. In vitro binding experiments indicated that PHD fingers in AtING and AL proteins in Arabidopsis can bind to H3K4me3, and, to a lesser extent, to H3K4me2. In addition, mutational analysis confirmed that a predicted aromatic cage and a specific conserved acidic residue are both crucial for binding to H3K4me3/2. Finally, we demonstrate that AtING and AL proteins are nuclear proteins that are expressed in various tissues of the Arabidopsis plant. Thus, we propose that ING and AL proteins are nuclear proteins that are involved in chromatin regulation by binding to H3K4me3/2, the active histone markers, in plants.

Plants have diversified their leaf morphologies to adapt to diverse ecological niches. The molecular components responsible for regulating leaf morphology, however, have not been fully elucidated. By screening Arabidopsis activation-tagging lines, we identified a dominant mutant, which we designated longifolia1-1D (lng1-1D). lng1-1D plants were characterized by long petioles, narrow but extremely long leaf blades with serrated margins, elongated floral organs, and elongated siliques. The elongated leaves of the mutant were due to increased polar cell elongation rather than increased cell proliferation. Molecular characterization revealed that this phenotype was caused by overexpression of the novel gene LNG1, which was found to have a homolog, LNG2, in Arabidopsis. To further examine the role of the LNG genes, we characterized lng1 and lng2 loss-of-function mutant lines. In contrast to the elongated leaves of lng1-1D plants, the lng1 and lng2 mutants showed slightly decreased leaf length. Furthermore, the lng1-3 lng2-1 double mutant showed further decreased leaf length associated with less longitudinal polar cell elongation. The leaf widths in lng1-3 lng2-1 mutant plants were similar to those in wild type, implying that the role of LNG1 and LNG2 on polar cell elongation is similar to that of ROTUNDIFOLIA3 (ROT3). However, analysis of a lng1-3 lng2-1 rot3-1 triple mutant and of a lng1-1D rot3-1 double mutant indicated that LNG1 and LNG2 promote longitudinal cell elongation independently of ROT3. Taken together, these findings indicate that LNG1 and LNG2 are new components that regulate leaf morphology by positively promoting longitudinal polar cell elongation independently of ROT3 in Arabidopsis.

P-type two-dimensional steep-slope negative capacitance field-effect transistors are demonstrated for the first time with WSe as channel material and ferroelectric hafnium zirconium oxide in gate dielectric stack. F4-TCNQ is used as p-type dopant to suppress electron leakage current and to reduce Schottky barrier width for holes. WSe negative capacitance field-effect transistors with and without internal metal gate structures and the internal field-effect transistors are compared and studied. Significant SS reduction is observed in WSe negative capacitance field-effect transistors by inserting the ferroelectric hafnium zirconium oxide layer, suggesting the existence of internal amplification (∼10) due to the negative capacitance effect. Subthreshold slope less than 60 mV/dec (as low as 14.4 mV/dec) at room temperature is obtained for both forward and reverse gate voltage sweeps. Negative differential resistance is observed at room temperature on WSe negative capacitance field-effect-transistors as the result of negative capacitance induced negative drain-induced-barrier-lowering effect.