Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor 4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly 2,000 common target genes, and synergistically regulate many of these target genes, including the PRE family helix-loop-helix factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, enabling plant growth co-regulation by the steroid and environmental signals.

/pdf/interaction-between-bzr1-and-pif4-integrates-brassinosteroid-3q3nv3as0b.pdf

Interaction between BZR1 and PIF4 integrates brassinosteroid and environmental responses

Brassinosteroid and gibberellin promote many similar developmental responses in plants; however, their relationship remains unclear. Here we show that BR and GA act interdependently through a direct interaction between the BR-activated BZR1 and GA-inactivated DELLA transcription regulators. GA promotion of cell elongation required BR signalling, whereas BR or active BZR1 suppressed the GA-deficient dwarf phenotype. DELLAs directly interacted with BZR1 and inhibited BZR1-DNA binding both in vitro and in vivo. Genome-wide analysis defined a BZR1-dependent GA-regulated transcriptome, which is enriched with light-regulated genes and genes involved in cell wall synthesis and photosynthesis/chloroplast function. GA promotion of hypocotyl elongation requires both BZR1 and the phytochrome-interacting factors (PIFs), as well as their common downstream targets encoding the PRE-family helix-loop-helix factors. The results demonstrate that GA releases DELLA-mediated inhibition of BZR1, and that the DELLA-BZR1-PIF4 interaction defines a core transcription module that mediates coordinated growth regulation by GA, BR and light signals.

/pdf/brassinosteroid-gibberellin-and-phytochrome-impinge-on-a-33vc4662q6.pdf

Brassinosteroid, gibberellin and phytochrome impinge on a common transcription module in Arabidopsis.

Opposite Roles of Salicylic Acid Receptors NPR1 and NPR3/NPR4 in Transcriptional Regulation of Plant Immunity

The efficient extraction of targets from complex surfaces is vital for technological applications ranging from environmental pollutant monitoring to analysis of explosive traces and pesticide residues. In our present study, we proposed a proof-of-concept surface enhance Raman scattering (SERS) active substrate serving directly to the rapid extraction and detection of target molecules. The novel substrate was constructed by decorating the commercial tape with colloidal gold nanoparticles (Au NPs), which simultaneously provides SERS activity and “sticky” of adhesive. The utility of SERS tape was demonstrated by directly extracting pesticide residues in fruits and vegetables via a simple and viable “paste and peel off” approach. The obtained strong and easily distinguishable SERS signals allow us to detect various pesticide residues such as parathion-methyl, thiram, and chlorpyrifos in the real samples with complex surfaces including green vegetable, cucumber, orange, and apple.

Flexible and Adhesive Surface Enhance Raman Scattering Active Tape for Rapid Detection of Pesticide Residues in Fruits and Vegetables.

†These authors contributed equally. SUMMARY The plant vacuole is an important organelle for storing excess iron (Fe), though its contribution to increasing the Fe content in staple foods remains largely unexplored. In this study we report the isolation and functional characterization of two rice genes OsVIT1 and OsVIT2, orthologs of the Arabidopsis VIT1. Transient expression of OsVIT1:EGFP and OsVIT2:EGFP protein fusions revealed that OsVIT1 and OsVIT2 are localized to the vacuolar membrane. Ectopic expression of OsVIT1 and OsVIT2 partially rescued the Fe 2+ - and Zn 2+ -sensitive phenotypes in yeast mutant Dccc1 and Dzrc1, and further increased vacuolar Fe 2+ ,Z n 2+ and Mn 2+ accumulation. These data together suggest that OsVIT1 and OsVIT2 function to transport Fe 2+ ,Z n 2+ and Mn 2+ across the tonoplast into vacuoles in yeast. In rice, OsVIT1 and OsVIT2 are highly expressed in flag leaf blade and sheath, respectively, and in contrast to OsVIT1, OsVIT2 is highly responsive to Fe treatments. Interestingly, functional disruption of OsVIT1 and OsVIT2 leads to increased Fe/Zn accumulation in rice seeds and a corresponding decrease in the source organ flag leaves, indicating an enhanced Fe/Zn translocation between source and sink organs, which might represent a novel strategy to biofortify Fe/Zn in staple foods.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-313X.2012.05088.x

Vacuolar membrane transporters OsVIT1 and OsVIT2 modulate iron translocation between flag leaves and seeds in rice

Protoplasts isolated from leaves are useful materials in plant research. One application, the transient expression of recombinant genes using Arabidopsis mesophyll protoplasts (TEAMP), is currently commonly used for studies of subcellular protein localization, promoter activity, and in vivo protein-protein interactions. This method requires cutting leaves into very thin slivers to collect mesophyll cell protoplasts, a procedure that often causes cell damage, may yield only a few good protoplasts, and is time consuming. In addition, this protoplast isolation method normally requires a large number of leaves derived from plants grown specifically under low-light conditions, which may be a concern when material availability is limited such as with mutant plants, or in large scale experiments. In this report, we present a new procedure that we call the Tape-Arabidopsis Sandwich. This is a simple and fast mesophyll protoplast isolation method. Two kinds of tape (Time tape adhered to the upper epidermis and 3 M Magic tape to the lower epidermis) are used to make a "Tape-Arabidopsis Sandwich". The Time tape supports the top side of the leaf during manipulation, while tearing off the 3 M Magic tape allows easy removal of the lower epidermal layer and exposes mesophyll cells to cell wall digesting enzymes when the leaf is later incubated in an enzyme solution. The protoplasts released into solution are collected and washed for further use. For TEAMP, plasmids carrying a gene expression cassette for a fluorescent protein can be successfully delivered into protoplasts isolated from mature leaves grown under optimal conditions. Alternatively, these protoplasts may be used for bimolecular fluorescence complementation (BiFC) to investigate protein-protein interactions in vivo, or for Western blot analysis. A significant advantage of this protocol over the current method is that it allows the generation of protoplasts in less than 1 hr, and allows TEAMP transfection to be carried out within 2 hr. The protoplasts generated by this new Tape-Arabidopsis Sandwich method are suitable for the same range of research applications as those that use the current method, but require less operator skill, equipment and time.

/pdf/tape-arabidopsis-sandwich-a-simpler-arabidopsis-protoplast-3b70fy6iyx.pdf

Fu Hui Wu

Papers

Tape-Arabidopsis Sandwich - a simpler Arabidopsis protoplast isolation method