Transcriptional profiling of laser-microdissected stamen abscission zones in Arabidopsis

Organ detachment occurs within cell tiers termed abscission zones (AZs). Characterizations of mutants with aberrant abscission behavior showed abscission to involve multiple signaling pathways. How such pathways are regulated is largely unknown. We examined Arabidopsis abscission zone transcriptome changes associated with floral organ detachment to identify novel shedding regulators. For genomic studies, we used laser capture microdissection (LCM) to dissect AZ cells from surrounding tissues. Because the extremely limited number, small size and close proximity of AZs limited immediate use of LCM, we developed new LCM protocols necessary for genomic studies.;Initial work showed that tape-transfer of paraffin sections to adhesive coated slides prior to LCM was superior to conventional slide mounting strategies. Electrophoresis revealed high structural integrity of RNA isolated from multiple types of tape-transferred, laser-captured cells. Optimization of transcriptional profiling methods using RNA from relatively abundant replum cells permitted linking of tape-transfer methods to LCM and GeneChip profiling in a way that allowed detection of rare gene transcripts. Replum transcriptome profiling identified a cellular shift from primary cell wall metabolism to lignin biosynthesis as siliques matured.;Techniques optimized for replums were used to profile laser-captured stamen AZs. Transcriptome changes were monitored at five floral stages from pre-pollination to organ shed. The 554 genes regulated at the highest statistical significance (p-value \u3c = 0.0001) included known abscission regulators related to ethylene and auxin signaling as well as a receptor-like kinase and extracellular ligand thought to act independent of ethylene. Functional categorization of genes showed that cell wall modifying proteins, transcription factors and extracellular regulators were disproportionately represented, and we hypothesized that such genes might encode novel abscission regulators. Functional analyses of one such gene, AtZFP2, were conducted. AtZFP2 encodes a zinc finger protein that is up-regulated in stamen AZs post-anthesis. Transgenic lines overexpressing AtZFP2 show asynchronous and delayed abscission as well as aberrant floral organ development and sterility. These data suggest that AtZFP2 might regulate abscission and other developmental processes. Future functional analyses may identify genes expressed solely or predominantly in AZs and suggest strategies to manipulate undesirable abscission behavior of agriculturally important plants

Transcriptional profiling of laser-microdissected stamen abscission zones in Arabidopsis

Organ detachment occurs within cell tiers termed abscission zones (AZs). Characterizations of mutants with aberrant abscission behavior showed abscission to involve multiple signaling pathways. How such pathways are regulated is largely unknown. We examined Arabidopsis abscission zone transcriptome changes associated with floral organ detachment to identify novel shedding regulators. For genomic studies, we used laser capture microdissection (LCM) to dissect AZ cells from surrounding tissues. Because the extremely limited number, small size and close proximity of AZs limited immediate use of LCM, we developed new LCM protocols necessary for genomic studies.;Initial work showed that tape-transfer of paraffin sections to adhesive coated slides prior to LCM was superior to conventional slide mounting strategies. Electrophoresis revealed high structural integrity of RNA isolated from multiple types of tape-transferred, laser-captured cells. Optimization of transcriptional profiling methods using RNA from relatively abundant replum cells permitted linking of tape-transfer methods to LCM and GeneChip profiling in a way that allowed detection of rare gene transcripts. Replum transcriptome profiling identified a cellular shift from primary cell wall metabolism to lignin biosynthesis as siliques matured.;Techniques optimized for replums were used to profile laser-captured stamen AZs. Transcriptome changes were monitored at five floral stages from pre-pollination to organ shed. The 554 genes regulated at the highest statistical significance (p-value < = 0.0001) included known abscission regulators related to ethylene and auxin signaling as well as a receptor-like kinase and extracellular ligand thought to act independent of ethylene. Functional categorization of genes showed that cell wall modifying proteins, transcription factors and extracellular regulators were disproportionately represented, and we hypothesized that such genes might encode novel abscission regulators. Functional analyses of one such gene, AtZFP2, were conducted. AtZFP2 encodes a zinc finger protein that is up-regulated in stamen AZs post-anthesis. Transgenic lines overexpressing AtZFP2 show asynchronous and delayed abscission as well as aberrant floral organ development and sterility. These data suggest that AtZFP2 might regulate abscission and other developmental processes. Future functional analyses may identify genes expressed solely or predominantly in AZs and suggest strategies to manipulate undesirable abscission behavior of agriculturally important plants.</p

Transcriptional profiling of laser-microdissected stamen abscission zones in Arabidopsis

Organ detachment occurs within cell tiers termed abscission zones (AZs). Characterizations of mutants with aberrant abscission behavior showed abscission to involve multiple signaling pathways. How such pathways are regulated is largely unknown. We examined Arabidopsis abscission zone transcriptome changes associated with floral organ detachment to identify novel shedding regulators. For genomic studies, we used laser capture microdissection (LCM) to dissect AZ cells from surrounding tissues. Because the extremely limited number, small size and close proximity of AZs limited immediate use of LCM, we developed new LCM protocols necessary for genomic studies. Initial work showed that tape-transfer of paraffin sections to adhesive coated slides prior to LCM was superior to conventional slide mounting strategies. Electrophoresis revealed high structural integrity of RNA isolated from multiple types of tape-transferred, laser-captured cells. Optimization of transcriptional profiling methods using RNA from relatively abundant replum cells permitted linking of tape-transfer methods to LCM and GeneChip profiling in a way that allowed detection of rare gene transcripts. Replum transcriptome profiling identified a cellular shift from primary cell wall metabolism to lignin biosynthesis as siliques matured. Techniques optimized for replums were used to profile laser-captured stamen AZs. Transcriptome changes were monitored at five floral stages from pre-pollination to organ shed. The 554 genes regulated at the highest statistical significance (p-value < = 0.0001) included known abscission regulators related to ethylene and auxin signaling as well as a receptor-like kinase and extracellular ligand thought to act independent of ethylene. Functional categorization of genes showed that cell wall modifying proteins, transcription factors and extracellular regulators were disproportionately represented, and we hypothesized that such genes might encode novel abscission regulators. Functional analyses of one such gene, AtZFP2, were conducted. AtZFP2 encodes a zinc finger protein that is up-regulated in stamen AZs post-anthesis. Transgenic lines overexpressing AtZFP2 show asynchronous and delayed abscission as well as aberrant floral organ development and sterility. These data suggest that AtZFP2 might regulate abscission and other developmental processes. Future functional analyses may identify genes expressed solely or predominantly in AZs and suggest strategies to manipulate undesirable abscission behavior of agriculturally important plants

Deoxynivalenol Degradation by Various Microbial Communities and Its Impacts on Different Bacterial Flora

Deoxynivalenol, a mycotoxin that may present in almost all cereal products, can cause huge economic losses in the agriculture industry and seriously endanger food safety and human health. Microbial detoxifications using microbial consortia may provide a safe and effective strategy for DON mitigation. In order to study the interactions involving DON degradation and change in microbial flora, four samples from different natural niches, including a chicken stable (expJ), a sheep stable (expY), a wheat field (expT) and a horse stable (expM) were collected and reacted with purified DON. After being co-incubated at 30 &deg;C with 130 rpm shaking for 96 h, DON was reduced by 74.5%, 43.0%, 46.7%, and 86.0% by expJ, expY, expT, and expM, respectively. After DON (0.8 mL of 100 &mu;g/mL) was co-cultivated with 0.2 mL of the supernatant of each sample (i.e., suspensions of microbial communities) at 30 &deg;C for 96 h, DON was reduced by 98.9%, 99.8%, 79.5%, and 78.9% in expJ, expY, expT, and expM, respectively, and was completely degraded after 8 days by all samples except of expM. DON was confirmed being transformed into de-epoxy DON (DOM-1) by the microbial community of expM. The bacterial flora of the samples was compared through 16S rDNA flux sequencing pre- and post the addition of DON. The results indicated that the diversities of bacterial flora were affected by DON. After DON treatment, the most abundant bacteria belong to Galbibacter (16.1%) and Pedobacter (8.2%) in expJ; Flavobacterium (5.9%) and Pedobacter (5.5%) in expY; f_Microscillaceae (13.5%), B1-7BS (13.4%), and RB41 (10.5%) in expT; and Acinetobacter (24.1%), Massilia (8.8%), and Arthrobacter (7.6%) in expM. This first study on the interactions between DON and natural microbial flora provides useful information and a methodology for further development of microbial consortia for mycotoxin detoxifications

Analysis of surface and vertical measurements of O-3 and its chemical production in the NCP region, China

Ozone has become a major atmospheric pollutant in the North Central Plain (NCP) of China. Comprehensive measurements concerning the vertical profiles and photochemical formation mechanisms of typical O-3 pollution episode during August 8-13, 2018 were conducted in the NCP. A maximum hourly ozone concentration of 346 mu g/m(3) was observed on Aug 10, in which the surface O-3 photochemistry was under a strong VOC-limited regime, and the ratio of VOC to NOx ranged from 4:1 to 4:3, with ethylene, toluene, xylene, and propene providing large contributions to O-3 chemical production. The vertical measurements of O-3, NOx, and the planetary boundary layer (PBL) height suggested that there were three different layers of photochemical O-3 production from the surface to 1.1 km. The first layer was from the surface to 200 m, with high NO concentrations leading to a strong conversion between O-3 and NO2. The surface O-3 concentration was significantly lower than at 220 m during nighttime and early morning, with an average O-3 of approximately 60 mu g/m(3) and the maximum vertical gradient appearing in the early morning. Diurnal variations of NO2 and NO2 were significantly inversely correlated with O-3 and O-3. In the second vertical layer between 200 m and 1000 m the value of d [O-3]/dt ranged from 10 to 40 mu g/m(3)/h, and the maximum chemical production of O-3 occurred at 300 m. The third layer was located outside the PBL height, where O-3 precursors with short chemical lifetimes rapidly decreased, producing weak chemical O(3)production

Effects of Glomalin-Related Soil Protein Driven by Root on Forest Soil Aggregate Stability and Carbon Sequestration during Urbanization in Nanchang, China

Glomalin-related soil protein (GRSP) is a hydrophobic protein released by arbuscular mycorrhizal fungi. It is an important component of the soil carbon pool, and it improves the soil aggregate structure; however, it remains unclear whether GRSP can enhance soil carbon sequestration and improve soil quality during rapid urbanization. The built-up area in Nanchang, China was the study area, and the proportion of impervious surface area was the parameter of urbanization intensity. A total of 184 plots (400 m2) were set up to collect soil samples (0–20 cm) for analysis. Aggregates of five particle sizes were sieved, and the percentage amounts of soil organic carbon (SOC) and GRSP for them were determined. The results showed that the easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP) contents of the four aggregates of p p 2 mm, 1–2 mm and <0.053 mm aggregates. The T-GRSP content showed significant correlations only with MWD, GMD, and D in the 1–2 mm aggregate. This study revealed that increasing urbanization intensity can significantly reduce the GRSP content of different sized aggregates. Moreover, the GRSP content significantly promoted SOC sequestration, and the EE-GRSP content more significantly promoted soil aggregate stability than that of the T-GRSP. These findings provide new ideas for exploring the improvement of soil quality during the process of urbanization

The Proposed Neurotoxin beta-N-Methylamino-l-Alanine (BMAA) Is Taken up through Amino-Acid Transport Systems in the CyanobacteriumAnabaenaPCC 7120

Produced by cyanobacteria and some plants, BMAA is considered as an important environmental factor in the occurrence of some neurodegenerative diseases. Neither the underlying mechanism of its toxicity, nor its biosynthetic or metabolic pathway in cyanobacteria is understood. Interestingly, BMAA is found to be toxic to some cyanobacteria, making it possible to dissect the mechanism of BMAA metabolism by genetic approaches using these organisms. In this study, we used the cyanobacteriumAnabaenaPCC 7120 to isolate BMAA-resistant mutants. Following genomic sequencing, several mutations were mapped to two genes involved in amino acids transport, suggesting that BMAA was taken up through amino acid transporters. This conclusion was supported by the protective effect of several amino acids against BMAA toxicity. Furthermore, targeted inactivation of genes encoding different amino acid transport pathways conferred various levels of resistance to BMAA. One mutant inactivating all three major amino acid transport systems could no longer take up BMAA and gained full resistance to BMAA toxicity. Therefore, BMAA is a substrate of amino acid transporters, and cyanobacteria are interesting models for genetic analysis of BMAA transport and metabolism

Review and comparison of empirical thermospheric mass density models

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