Plant Signaling & Behavior最新文献

Different abiotic stresses induce OsTZF1, a tandem CCCH-type zinc finger domain gene, in rice. Here, we report that transgenic rice plants overexpressing OsTZF1 under own promoter (P_OsTZF1:OsTZF1-OX [for overexpression]) transferred to soil showed normal growth similar to vector control plants. The P_OsTZF1:OsTZF1-OX produced normal leaves without any lesion mimic phenotype and exhibited normal seed setting. The P_OsTZF1:OsTZF1-OX plants showed significantly increased tolerance to salt and drought stresses and enhanced post stress recovery. Microarray analysis revealed a total of 846 genes up-regulated and 360 genes down-regulated in P_OsTZF1:OsTZF1-OX salt-treated plants. Microarray analysis of P_OsTZF1:OsTZF1-OX plants showed the regulation of many abiotic stress tolerance genes. These results suggest that OsTZF1-OX under own promoter show abiotic stress tolerance and produces no pleiotropic effect on phenotype of transgenic rice plant.

Arabidopsis DYNAMIN-RELATED PROTEIN1A (AtDRP1A) and AtDRP2B are large GTPases that function together in endocytosis for effective cytokinesis, cell enlargement and development. A recent study shows that these DRPs contribute to ligand-induced endocytosis of the immune receptor FLAGELLIN SENSING2 (AtFLS2) to modulate flg22-immune signaling, and they are required for immunity against Pseudomonas syringae pv. tomato bacteria. Here, we demonstrate that atdrp1a and atdrp2b single mutants showed increased susceptibility to Botrytis cinerea indicating that AtDRP1A and AtDRP2B are necessary for effective resistance against this necrotrophic fungus. Thus, we expanded our limited understanding of clathrin endocytic accessory proteins in immunity against plant pathogens.

Over the years, many different growth media have been used to grow Arabidopsis thaliana in vitro in petri dishes. For these media the nutrient composition may vary, sugars may or may not be added, the medium may or may not be buffered and there is a choice between different gelling agents. The magnitude of possible combinations of these variables obstructs easy comparison of seedling phenotypes grown on the different media. This is especially obvious when it concerns the study of root hairs that are extremely sensitive to changes in their environment. To demonstrate this effect, we have grown Arabidopsis thaliana wild-type seeds on 18 different combinations of growth media and quantified root hair development. Comparison of root hair length and the respective root hair profiles identified the media that result in the formation of the longest root hairs. On these favored media they elongate through tip growth at a constant growth rate until they reach their final length (around 0.6 mm) at a distance of ±4 mm from the root tip.

The HD-Zip family of transcription factors is unique to the plant kingdom, and play roles in modulation of plant growth and response to environmental stresses. R. glutinosa is an important Chinese medicinal material. Its yield and quality are susceptible to various stresses. The HD-Zip transcription factors is unique to the plant, and roles in modulation of plant growth and response to environmental stresses. However, there is no relevant research on the HD-ZIP of R. glutinosa. In this study, 92 HD-Zip transcription factors were identified in R. glutinosa, and denominated as RgHDZ1-RgHDZ92. Members of RgHDZ were classified into four groups (HD-ZipI-IV) based on the phylogenetic relationship of Arabidopsis HD-Zip proteins, and each group contains 38, 18, 17, and 19 members, respectively. Expression analyses of RgHDZ genes based on transcriptome data showed that the expression of these genes could be induced by the endophytic fungus of R. glutinosa. Additionally, we showed that RgHDZ genes were differentially expressed in response to drought, waterlogging, temperature, and salinity treatments. This study provides important information for different expression patterns of stress-responsive HD-Zip and may contribute to the better understanding of the different responses of plants to biotic and abiotic stresses, and provide a molecular basis for the cultivation of resistant varieties of R. glutinosa.

The IRON-REGULATED TRANSPORTER1 (IRT1) is critical for iron uptake in roots, and its exocytosis to the plasma membrane (PM) is regulated by detergent-resistant membranes. However, studies on IRT1 exocytosis and function in response to iron status are limited. Presently, we found that the histidine-rich motif (HRM) of MxIRT1 could bind to iron directly and HRM determined the delivery of MxIRT1 to the PM, after which the cholesterol recognition amino acid consensus (CRAC) motif-regulated MxIRT1 mediated metal transport. IMAC assay revealed that H192 was the vital site for HRM binding to Fe²⁺, and metal-binding activity was stopped after the deletion of HRM (MxIRT1∆HM) or in H192 site-directed mutants (H₁₉₂A). MxIRT1∆HM or H₁₉₂A in transgenic yeast and Arabidopsis failed to localize in the PM and displayed impaired iron absorption. In the PM, Y266 in CRAC was required for metal transport; Y266A transgenic Arabidopsis displayed the same root length, Cd²⁺ flux, and Fe concentration as Arabidopsis mutant irt1 under iron-deficient conditions. Therefore, H192 in HRM may be an iron sensor to regulate delivery of MxIRT1 vesicles to the PM after binding with iron; Y266 in CRAC acts as an iron sensor for active metal transport under iron-deficient conditions.

Over 40% of arable land in the world is acidic. Al stress has become a global agricultural problem affecting plant growth and limiting crop production in acidic soils. Plants have evolved different regulatory mechanisms of adaptation to exogenous environmental challenges, such as Al stress, by altering their growth patterns. In the past decades, several key genes involved in plant response to Al stress and the mechanism of Al detoxification have been revealed. However, the signaling pathways of plant response to Al stress and the regulatory mechanism of plant Al tolerance remain poorly understood. In this review, we summarized the findings of recent studies on the plant Al tolerance mechanism and the molecular regulation mechanism of phytohormones in response to Al stress. This review improves our understanding of the regulatory mechanisms of plants in response to Al stress and provides a reference for the breeding of Al-tolerant crops.

Arbuscular mycorrhizal (AM) fungi interact with the roots of most land plants and help them to acquire various mineral resources from the soil, including potassium (K⁺). However, tracking K⁺ movement in AM symbiosis remains challenging. Recently, we reported that rubidium can be used as a proxy for K⁺ in mycorrhizal Medicago truncatula. In the present work, we investigated the possibility of using cesium (Cs⁺) as another proxy for K⁺ in AM symbiosis. Plants were placed in growing systems that include a separate compartment only accessible to the AM fungus Rhizophagus irregularis isolate 09 and in which various amounts of cesium chloride (0 mM, 0.5 mM, 1.5 mM, or 3.75 mM) were supplied. Plants were watered with sufficient K⁺ or K⁺-free nutrient solutions, and shoot and root biomass, fungal colonization, and K⁺ and Cs⁺ concentrations were recorded seven weeks after inoculation. Our results indicate that Cs⁺ accumulated in plant tissues only when K⁺ was present in the nutrient solution and when the highest concentration of Cs⁺ was used in the fungal compartment. Consequently, we conclude that Cs⁺ could be used as a proxy for K⁺ in AM symbiosis, but with serious limitations.

Root gravitropism is important for anchorage and exploration of soil for water and nutrients. It affects root architecture, which is one of the elements that influence crop yield. The mechanism of primary root gravitropism has been widely studied, but it is still not clear how lateral root gravitropism is regulated. Here, in this study, we found that Topoisomerase I α (TOP1α) repressed lateral root gravitropic growth, which was opposite to the previous report that TOP1α maintains primary root gravitropism, revealing a dual function of TOP1α in root gravitropism regulation. Further investigation showed that Target of Rapamycin (TOR) was suppressed in columella cells of lateral root to inhibit columella cell development, especially amyloplast biosynthesis. Our findings uncovered a new mechanism about lateral root gravitropism regulation, which might provide a theoretical support for improving agricultural production.

Cadmium (Cd) causes serious damage to plants. Although calcium (Ca) signal has been found to respond to certain stress, the localization of Ca and molecular mechanisms underlying Ca signal in plants during Cd stress are largely unknown. In this study, Ca²⁺-sensing fluorescent reporter (GCaMP3) transgenic duckweed showed the Ca²⁺ signal response in Lemna turionifera 5511 (duckweed) during Cd stress. Subsequently, the subcellular localization of Ca²⁺ has been studied during Cd stress by transmission electron microscopy, showing the accumulation of Ca²⁺ in vacuoles. Also, Ca²⁺ flow during Cd stress has been measured. At the same time, the effects of exogenous glutamic acid (Glu) and γ-aminobutyric (GABA) on duckweed can better clarify the signal operation mechanism of plants to Cd stress. The molecular mechanism of Ca²⁺ signal responsed during Cd stress showed that Cd treatment promotes the positive response of Ca signaling channels in plant cells, and thus affects the intracellular Ca content. These novel signal studies provided an important Ca²⁺ signal molecular mechanism during Cd stress.

The rhizomes and tubers of Curcuma kwangsiensis have extensive medicinal value in China. However, the inflorescences of C. kwangsiensis are rarely known in horticulture, because of its low field flowering rate. In order to improve the flowering rate of C. kwangsiensis, we conducted drought stress treatment on the rhizome of C. kwangsiensis. The flowering rate of rhizome was the highest after 4d of drought stress treatment, and the buds on the rhizome could be obviously swell on the 4th day of rehydration culture. In order to identify the genes regulating the flowering time of Curcuma kwangsiensis, comparative transcriptome analysis was performed on the buds on rhizomes before drought stress treatment, 4 d after drought stress treatment and 4 d after rehydration culture. During this process, a total of 20 DEGs controlling flowering time and 23 DEGs involved in ABA synthesis and signal transduction were identified, which might regulate the flowering of C. kwangsiensis under drought stress. Some floral integration factors, such as SOC1 and FTIP, were up-regulated under drought stress for 4 d, indicating that C. kwangsiensis had flowering trend under drought stress. The results of the present study will provide theoretical support for the application of Curcuma kwangsiensis in gardening.