Search

Lipid remodeling is crucial for cold tolerance in plants. However, the precise alternations of lipidomics during cold responses remain elusive, especially in maize (Zea maysL.). In addition, the key genes responsible for cold tolerance in maize lipid metabolism have not been identified. Here, we integrate lipidomic, transcriptomic, and genetic analysis to determine the profile of lipid remodeling caused by cold stress. We find that the homeostasis of cellular lipid metabolism is essential for maintaining cold tolerance of maize. Also, we detect 210 lipid species belonging to 13 major classes, covering phospholipids, glycerides, glycolipids, and free fatty acids. Various lipid metabolites undergo specific and selective alterations in response to cold stress, especially mono-/di-unsaturated lysophosphatidic acid, lysophosphatidylcholine, phosphatidylcholine, and phosphatidylinositol, as well as polyunsaturated phosphatidic acid, monogalactosyldiacylglycerol, diacylglycerol, and triacylglycerol. In addition, we identify a subset of key enzymes, including ketoacyl-acyl-carrier protein synthase II (KAS II), acyl-carrier protein 2 (ACP2), male sterility33 (Ms33), and stearoyl-acyl-carrier protein desaturase 2 (SAD2) involved in glycerolipid biosynthetic pathways are positive regulators of maize cold tolerance. These results reveal a comprehensive lipidomic profile during the cold response of maize and provide genetic resources for enhancing cold tolerance in crops.

Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth, productivity and quality. Plants have evolved mechanisms to perceive these environmental challenges, transmit the stress signals within cells as well as between cells and tissues, and make appropriate adjustments in their growth and development in order to survive and reproduce. In recent years, significant progress has been made on many fronts of the stress signaling research, particularly in understanding the downstream signaling events that culminate at the activation of stress- and nutrient limitation-responsive genes, cellular ion homeostasis, and growth adjustment. However, the revelation of the early events of stress signaling, particularly the identification of primary stress sensors, still lags behind. In this review, we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.

Phagocyte NADPH oxidase, a protein complex with a core made up of NOX2 and p22 subunits, is responsible for transferring electrons from intracellular NADPH to extracellular oxygen1. This process generates superoxide anions that are vital for killing pathogens1. The activation of phagocyte NADPH oxidase requires membrane translocation and the binding of several cytosolic factors2. However, the exact mechanism by which cytosolic factors bind to and activate NOX2 is not well understood. Here we present the structure of the human NOX2–p22 complex activated by fragments of three cytosolic factors: p47, p67 and Rac1. The structure reveals that the p67–Rac1 complex clamps onto the dehydrogenase domain of NOX2 and induces its contraction, which stabilizes the binding of NADPH and results in a reduction of the distance between the NADPH-binding domain and the flavin adenine dinucleotide (FAD)-binding domain. Furthermore, the dehydrogenase domain docks onto the bottom of the transmembrane domain of NOX2, which reduces the distance between FAD and the inner haem. These structural rearrangements might facilitate the efficient transfer of electrons between the redox centres in NOX2 and lead to the activation of phagocyte NADPH oxidase.

Cold stress negatively affects maize (Zea maysL.) growth, development and yield. Metabolic adjustments contribute to the adaptation of maize under cold stress. We show here that the transcription factor INDUCER OF CBF EXPRESSION 1 (ZmICE1) plays a prominent role in reprogramming amino acid metabolome and COLD-RESPONSIVE(COR) genes during cold stress in maize. Derivatives of amino acids glutamate/asparagine (Glu/Asn) induce a burst of mitochondrial reactive oxygen species, which suppress the cold-mediated induction of DEHYDRATION RESPONSE ELEMENT-BINDING PROTEIN 1(ZmDREB1) genes and impair cold tolerance. ZmICE1 blocks this negative regulation of cold tolerance by directly repressing the expression of the key Glu/Asn biosynthesis genes, ASPARAGINE SYNTHETASEs. Moreover, ZmICE1 directly regulates the expression of DREB1s. Natural variation at the ZmICE1promoter determines the binding affinity of the transcriptional activator ZmMYB39, a positive regulator of cold tolerance in maize, resulting in different degrees of ZmICE1transcription and cold tolerance across inbred lines. This study thus unravels a mechanism of cold tolerance in maize and provides potential targets for engineering cold-tolerant varieties.

•Vip3Aa has multiple cleavage activation sites in the loop region between domain I and domain II.•Introducing additional cleavage sites between domain I and domain II of vip3Aa can significantly increase its proteolytic efficiency by midgut juice.•Increasing the proteolytic efficiency of vip3Aa can promote its insecticidal potency.

Objective: To evaluate the effect of garlicin in treating acute cerebral infarction.Methods:One hundred and one patients of acute cerebral infarction diagnosed by CT were treated with garlicin (garlicin group) and compared with another group of 53 patients treated with ligustrazine (control group). The neurologic deficiency score and neurologic function score were used for evaluation of effect.Results:The effective rates of garlicin and ligustrazine were 89. 36% and 84. 85% respectively. The improvement scores of neurologic function were 18.46±10.69 and 11.94 ± 6.79 respectively. The difference between the two groups was significant. Before treatment the serum level of MDA in the garlicin group was 6.015 ±1.26 nmol/ml, and it decreased to 4. 87 ± 1.16 nmol/ml after treatment, the change being more significant than that of the control group (from 6.02 ±0.73 nmol/ml to 6.47 ±1.04 nmol/ml). The rheological parameters and cerebral blood flow were also improved after garlicin treatment.Conclusion:Garlicin could increase the perfusion flow of brain, improve the microcirculation, and scavenge free radicals so as to relieve the ischemia and reperfusion injury of the brain.

DNA sequencing is vital for many aspects of biological research and diagnostics. Despite the development of second- and third-generation sequencing technologies, Sanger sequencing has long been the only choice when required to precisely track each sequenced plasmids or DNA fragments. Here, we report a complete set of novel barcoding and assembling system, Highly-parallel Indexed Tagmentation-reads Assembled Consensus sequencing (HITAC-seq), that could massively sequence and track the identities of each individual sequencing sample. With the cost of much less than that of single read of Sanger sequencing, HITAC-seq can generate high-quality contiguous sequences of up to 10 kilobases or longer. The capability of HITAC-seq was confirmed through large-scale sequencing of thousands of plasmid clones and hundreds of amplicon fragments using approximately 100 pg of input DNAs. Due to its long synthetic length, HITAC-seq was effective in detecting relatively large structural variations, as demonstrated by the identification of a ∼1.3 kb Copiaretrotransposon insertion in the upstream of a likely maize domestication gene. Besides being a practical alternative to traditional Sanger sequencing, HITAC-seq is suitable for many high-throughput sequencing and genotyping applications.