COE 1 and GUN1 regulate the adaptation of plants to high light stress.

In order to withstand high light (HL) stress, plants have evolved both short-term defense and repair mechanisms and long-term acclimation responses. At present, however, the underlying signaling events and molecular mechanisms are still poorly understood. Analysis of the mutants coe1, coe1 gun1 double mutant and oeGUN1coe1 revealed increased sensitivity to HL stress as compared to wild type (WT), with oeGUN1 coe1 plants displaying the highest sensitivity. Accumulation of FTSH2 protein and degradation of D1 protein during the HL stress were shown to depend on both COE1 and GUN1. Overexpression of COE1 enhanced the induction of FTSH2 and the tolerance to HL stress. These results indicate that the COE1-GUN1 signaling pathway plays an important role in regulating the adaptation of plants to HL.

WRKY33-PIF4 loop is required for the regulation of H2O2 homeostasis.

The reactive oxygen species (ROS) are continuously produced and are essential for mediating the growth and development of plants. However too much accumulation of ROS can result in the oxidative damage to cells, especially under the adverse environmental conditions. Plants have evolved sophisticated strategies to regulate the homeostasis of H2O2. In this study, we generated transgenic Arabidopsis plants in the Ws ecotype (Ws) background in which WRKY33 is co-suppressed (csWRKY33/Ws). Compared with Ws, csWRKY33/Ws plants accumulate more H2O2. RNA-seq analysis indicated that in csWRKY33/Ws plants, expression of oxidative stress related genes such as ascorbate peroxidase 2 (APX2) is affected. Over-expression of APX2 can rescue the phenotype of csWRKY33/Ws, suggesting that the changes in the growth of csWRKY33/Ws is duo to the higher accumulation of H2O2. Analysis of the CHIP-seq data suggested that WRKY33 can directly regulate the expression of PIF4, vice versa. qPCR analysis also confirmed that the mutual regulation between WRKY33 and PIF4. Similar to that of csWRKY33/Ws, and the accumulation of H2O2 in pif4 also increased. Taken together, our results reveal a WRKY33-PIF4 regulatory loop that appears to play an important role in regulating the growth and development of seedlings by mediating H2O2 homeostasis.

Profiling of the Receptor for Activated C Kinase 1a (RACK1a) interaction network in Arabidopsis thaliana.

As a scaffold protein, Receptor for Activated C Kinase 1a (RACK1) interacts with many proteins and is involved in multiple biological processes in Arabidopsis. However, the global RACK1 protein interaction network in higher plants remains poorly understood. Here, we generated a yeast two-hybrid library using mixed samples from different developmental stages of Arabidopsis thaliana. Using RACK1a as bait, we performed a comprehensive screening of the resulting library to identify RACK1a interactors at the whole-transcriptome level. We selected 1065 independent positive clones that led to the identification of 215 RACK1a interactors. We classified these interactors into six groups according to their potential functions. Several interactors were selected for bimolecular fluorescence complementation (BiFC) analysis and their interaction with RACK1a was confirmed in vivo. Our results provide further insight into the molecular mechanisms through which RACK1a regulates various growth and development processes in higher plants.

Microbacterium suaedae sp. nov., isolated from Suaeda aralocaspica.

Two bacterial strains, YZYP 306T and YZGP 509, were isolated from the halophyte Suaeda aralocaspica collected from the southern edge of the Gurbantunggut desert, north-west China. Cells were Gram-stain-positive, aerobic, non-motile, short rods. Strain YZYP 306T grew at 4-40 °C, while strain YZGP 509 grew at 4-42 °C, with optimum growth at 28 °C, and they both grew at pH 6.0-12.0 and 0-15 % (w/v) NaCl. Phylogenetic analyses of the 16S rRNA gene sequences placed the two strains within the genus Microbacterium with the highest similarities to Microbacterium indicum BBH6T (97.8 %) and Microbacterium sorbitolivorans SZDIS-1-1T (97.2 %). The average nucleotide identity value between YZYP 306T and M. indicum BBH6T was 78.3 %. The genomic DNA G+C contents of strains YZYP 306T and YZGP 509 were 68.49 and 68.53 mol%, respectively. The characteristic cell-wall amino acid was ornithine. Whole-cell sugars were galactose, mannose and ribose. The acyl type of the peptidoglycan was glycolyl. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The major menaquinones were MK-10 and MK-11. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified glycolipid. These results are consistent with the classification of the two strains into the genus Microbacterium. On the basis of the evidence presented in this study, strains YZYP 306T and YZGP 509 are representatives of a novel species in the genus Microbacterium, for which the name Microbacterium suaedae sp. nov. is proposed. The type strain is YZYP 306T (=CGMCC 1.16261T=KCTC 49101T).

Microbacterium halophytorum sp. nov., a novel endophytic actinobacterium isolated from halophytes.

Two actinobacterial strains, YJYP 303T and YZYP 518, were isolated from two species of halophytes collected from the southern edge of the Gurbantunggut Desert. Cells were Gram-stain-positive, aerobic, short rods and without flagella. Growth of the two strains was found to occur at 4-44 °C, pH 6.0-12.0 and in the presence of up to 15 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains are associated with members of the genus Microbacterium. In the phylogenetic tree, the two strains shared a clade with Microbacterium halotolerans YIM 70130T (97.58 % 16S rRNA gene sequence identity) and Microbacterium populi KCTC 29152T (96.54 %). The average nucleotide identity values of strain YJYP 303T and YZYP 518 to M. halotolerans YIM 70130T were determined to be 79.97 and 80.03 %, respectively. The genomic DNA G+C contents of strains YJYP 303T and YZYP 518 were 69.72 and 70.57 %, respectively. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The predominant respiratory quinones was MK-11, followed by MK-10 and MK-12. The muramic acid type of peptidoglycan was N-glycolyl. The whole-cell sugars were mannose, ribose, rhamnose, glucose, galactose and two unidentified sugars. The cell-wall amino acids were glutamic acid, ornithine, glycine and alanine. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified glycolipid. On the basis of the evidence presented in this study, strains YJYP 303T and YZYP 518 are characterized as members of a novel species in the genus Microbacterium, for which the name Microbacteriumhalophytorum sp. nov. is proposed. The type strain is YJYP 303T (=CGMCC 1.16264T=KCTC 49100T).

Alcaligenes endophyticus sp. nov., isolated from roots of Ammodendron bifolium.

A Gram-stain-negative, rod-shaped, motile bacterium, designated AER10T, was isolated from the roots of Ammodendron bifolium collected from Takeermohuer desert in Xinjiang Uygur Autonomous Region, northwestern China. Growth was found to occur from 10 to 45 °C, at pH 5.0-9.0, and could tolerate up to 10 % (w/v) NaCl. 16S rRNA gene sequence result indicated that the strain AER10T belongs to the genus Alcaligenes and was closely related to Alcaligenes aquatilis (98.4 %), Alcaligenes faecalissubsp. parafaecalis (98.4 %), Alcaligenes faecalissubsp. faecalis (98.1 %) and Alcaligenes faecalissubsp. phenolicus (97.9 %). However, the DNA-DNA hybridization values between the strain AER10T and the above strains were less than the threshold value (below 70 %) for the delineation of genomic species. The DNA G+C content was 53.3 mol%. Ubiquinone-8 (Q-8) was the only quinone system present. The major fatty acids were summed feature 8 (C18 : 1ω7c, 25 %), C16 : 0 (24.2 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c, 19.3 %) and cyclo-C17 : 0 (10.5 %). The polar lipid profile of the strain AER10T consists of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, two unidentified aminolipids and five unknown polar lipids. On the basis of the evidence presented in this study, strain AER10T is a representative of a novel species in the genus Alcaligenes, for which the name Alcaligenes endophyticus sp. nov. is proposed. The type strain is AER10T (=DSM 100498T=KCTC 42688T).

Interdiffusion Stomatal Movement in Efficient Multiple-Cation-Based Perovskite Solar Cells.

The composition and crystallization process are essential for high-quality perovskite films. Cesium (Cs) and methylammonium chlorine (MACl) were found to affect the crystallization kinetics of perovskite, and the performance and stability of corresponding devices were greatly improved. We adopted an ion exchange method to remove MACl vapor and add Cs to form a multiple-cation-based perovskite film. With the increase of annealing time, Cl- from cesium chloride (CsCl) and MA from methylammonium bromide (MABr) formed gradually MACl vapor, and the porosity of surface morphology improved accordingly. The highly crystallized and compact CsyMAx - yFA1 - xPbI3 - xBrx perovskite film with different compositions was eventually obtained. The effects of the amount of MABr on the property of perovskite films and on the performance of the corresponding perovskite solar cells (PerSCs) were systematically studied. The PerSCs derived from 12 mg of MABr exhibit the best photovoltaic performance with a power conversion efficiency of 21.57% under 1 sun illumination.

Global Dynamic Molecular Profiling of Stomatal Lineage Cell Development by Single-Cell RNA Sequencing.

The regulation of stomatal lineage cell development has been extensively investigated. However, a comprehensive characterization of this biological process based on single-cell transcriptome analysis has not yet been reported. In this study, we performed RNA sequencing on 12 844 individual cells from the cotyledons of 5-day-old Arabidopsis seedlings. We identified 11 cell clusters corresponding mostly to cells at specific stomatal developmental stages using a series of marker genes. Comparative analysis of genes with the highest variable expression among these cell clusters revealed transcriptional networks that regulate development from meristemoid mother cells to guard mother cells. Examination of the developmental dynamics of marker genes via pseudo-time analysis revealed potential interactions between these genes. Collectively, our study opens the door for understanding how the identified novel marker genes participate in the regulation of stomatal lineage cell development.

Biodetoxification of toxins generated from lignocellulose pretreatment using a newly isolated fungus, Amorphotheca resinae ZN1, and the consequent ethanol fermentation.

BACKGROUND: Degradation of the toxic compounds generated in the harsh pretreatment of lignocellulose is an inevitable step in reducing the toxin level for conducting practical enzymatic hydrolysis and ethanol fermentation processes. Various detoxification methods have been tried and many negative outcomes were found using these methods, such as the massive freshwater usage and wastewater generation, loss of the fine lignocellulose particles and fermentative sugars and incomplete removal of inhibitors. An alternate method, biodetoxification, which degrades the toxins as part of their normal metabolism, was considered a promising option for the removal of toxins without causing the above problems. RESULTS: A kerosene fungus strain, Amorphotheca resinae ZN1, was isolated from the microbial community growing on the pretreated corn stover material. The degradation of the toxins as well as the lignocelluloses-derived sugars was characterized in different ways, and the results show that A. resinae ZN1 utilized each of these toxins and sugars as the sole carbon sources efficiently and grew quickly on the toxins. It was found that the solid-state culture of A. resinae ZN1 on various pretreated lignocellulose feedstocks such as corn stover, wheat straw, rice straw, cotton stalk and rape straw degraded all kinds of toxins quickly and efficiently. The consequent simultaneous saccharification and ethanol fermentation was performed at the 30% (wt/wt) solid loading of the detoxified lignocellulosic feedstocks without a sterilization step, and the ethanol titer in the fermentation broth reached above 40 g/L using food crop residues as feedstocks. CONCLUSIONS: The advantages of the present biodetoxification by A. resinae ZN1 over the known detoxification methods include zero energy input, zero wastewater generation, complete toxin degradation, processing on solid pretreated material, no need for sterilization and a wide lignocellulose feedstock spectrum. These advantages make it possible for industrial applications with fast and efficient biodetoxification to remove toxins generated during intensive lignocellulose pretreatment.

[Process strategy for ethanol production from lignocellulose feedstock under extremely low water usage and high solids loading conditions].

The massive water and steam are consumed in the production of cellulose ethanol, which correspondingly results in the significant increase of energy cost, waster water discharge and production cost as well. In this study, the process strategy under extremely low water usage and high solids loading of corn stover was investigated experimentally and computationally. The novel pretreatment technology with zero waste water discharge was developed; in which a unique biodetoxification method using a kerosene fungus strain Amorphotheca resinae ZN1 to degrade the lignocellulose derived inhibitors was applied. With high solids loading of pretreated corn stover, high ethanol titer was achieved in the simultaneous saccharification and fermentation process, and the scale-up principles were studied. Furthermore, the flowsheet simulation of the whole process was carried out with the Aspen plus based physical database, and the integrated process developed was tested in the biorefinery mini-plant. Finally, the core technologies were applied in the cellulose ethanol demonstration plant, which paved a way for the establishment of an energy saving and environment friendly technology of lignocellulose biotransformation with industry application potential.