CONTENTS: Summary 737 I. Chilling and freezing: two different stresses requiring different solutions 738 II. Identification of a major cis‐element in the control of cold gene expression 739 III. The ...CBF transcription factors (TFs) and their regulation 739 IV. Events downstream of CBFs 740 V. A post‐genomic view on global transcript changes in response to low temperature 741 VI. The effect of light and circadian signals on cold gene expression 742 VII. Post‐transcriptional regulation 742 VIII. A receptor for cold? 742 IX. What are the characteristics of plant cell thermometer(s)? 744 X. Low‐temperature signalling downstream of perception 744 XI. Unresolved questions 747 Acknowledgements 748 References 748 SUMMARY: Plant species exhibit a range of tolerances to low temperatures, and these constitute a major determinant of their geographical distribution and use as crops. When tolerance is insufficient, either chilling or freezing injuries result. A variety of mechanisms are employed to evade the ravages of extreme or sub‐optimal temperatures. Many of these involve cold‐responsive gene expression and require that the drop in temperature is first sensed by the plant. Despite intensive research over the last 100 yr or longer, we still cannot easily answer the question of how plants sense low temperature. Over recent years, genomic and post‐genomic approaches have produced a wealth of information relating to the sequence of events leading from cold perception to appropriate and useful responses. However, there are also crucial and significant gaps in the pathways constructed from these data. We describe the literature pertaining to the current understanding of cold perception, signalling and regulation of low‐temperature‐responsive gene expression in higher plants, raising some of the key questions that still intrigue plant biologists today and that could be targets for future work. Our review focuses on the control of gene expression in the pathways leading from cold perception to chilling and freezing tolerance.
This article challenges the implicit assumption of many cross-national studies that gender-role attitudes fall along a single continuum between traditional and egalitarian. The authors argue that ...this approach obscures theoretically important distinctions in attitudes and renders analyses of change over time incomplete. Using latent class analysis, they investigate the multidimensional nature of gender-role attitudes in 17 postindustrial European countries. They identify three distinct varieties of egalitarianism that they designate as liberal egalitarianism, egalitarian familism, and flexible egalitarianism. They show that while traditional gender-role attitudes have precipitously and uniformly declined in accordance with the “rising tide” narrative toward greater egalitarianism, the relative prevalence of different egalitarianisms varies markedly across countries. Furthermore, they find that European nations are not converging toward one dominant egalitarian model but rather, remain differentiated by varieties of egalitarianism.
Land subsidence as a result of groundwater overpumping in the San Joaquin Valley, California, is associated with the loss of groundwater storage and aquifer contamination. Although the physical ...processes governing land subsidence are well understood, building predictive models of subsidence is challenging because so much subsurface information is required to do so accurately. For the first time, we integrate airborne electromagnetic data, representing the subsurface, with subsidence data, mapped by interferometric synthetic aperture radar (InSAR), to model deformation. By combining both data sets, we are able to solve for hydrologic and geophysical properties of the subsurface to effectively model the complex spatiotemporal process of deformation. The resulting model reveals that roughly 3 m of subsidence has occurred at one location of our study area from 1990 to 2018. This model also allows us to predict subsidence more accurately under future hydrologic scenarios, which is needed to develop plans for sustainable groundwater use.
Key Points
InSAR and AEM data are combined to produce accurate deformation models at three locations in the San Joaquin Valley of California
The model can be used to predict the impact of future droughts or managed aquifer recharge on land subsidence
The method of model development could be extended to much larger areas due to the ability to acquire both data sets rapidly
Working with 5 years (2015–2019) of high quality interferometric synthetic aperture radar (InSAR) data covering the Central Valley of California, we developed a new approach to isolate the ...poroelastic component in InSAR data by estimating and removing the hydrologic loading component. K‐means clustering was used to identify the InSAR deformation time series dominated by the loading response and those dominated by the poroelastic response. The former time series include seasonal oscillations of uplift and subsidence related to mass changes in snow and ice in the adjacent mountain range, while the latter include interannual deformation and seasonal oscillations related to changing head in the valley. The loading component accounts for, on average, 56 ± 12% of the deformation in the Central Valley. Without correcting for the loading response, the deformation due to the poroelastic response (and therefore any derived estimate of change in head) is underestimated by 50%–60% in areas of the valley.
Plain Language Summary
In the Central Valley of California, changes in ground elevation, often referred to as surface deformation, are mainly due to two hydrologic changes in the system: the changes in groundwater head, which result in a poroelastic response and the changes in mass of water, snow, and ice, which result in a hydrologic loading response. Interferometric synthetic aperture radar (InSAR) provides a powerful way to map this surface deformation with an unprecedented level of resolution in space and time. The close connection between the InSAR data and changes in head has created great interest in using the InSAR data for mapping and monitoring changes in groundwater head, information that is of critical importance for groundwater management. However, without the removal of the loading response in the InSAR data, changes in head derived from the InSAR data can include significant errors that could impact decisions for groundwater management. Working with the 5 years of publicly available InSAR data in the Central Valley, we developed a new approach that can remove the loading component thereby advancing the ability to use InSAR data to monitor changes in groundwater head.
Key Points
Developed a new approach to isolate the poroelastic component in interferometric synthetic aperture radar (InSAR) data by removing the hydrologic loading component
Provided the first detailed analysis of the loading response in InSAR data
Found that the loading response on average represents 56 ± 12% of the deformation in InSAR measurements in the Central Valley
Nonalcoholic fatty liver disease (NALFD) is now a leading cause of chronic liver disease worldwide, in part, as a consequence of rapidly rising levels of obesity and metabolic syndrome and is a major ...risk factor for cirrhosis, hepatocellular carcinoma, and liver-related mortality. From NAFLD stems a myriad of clinical challenges related to both diagnosis and management. A growing body of evidence suggests an intricate linkage between the gut microbiome and the pathogenesis of NAFLD. We highlight how our current knowledge of the gut-liver axis in NAFLD may be leveraged to develop gut microbiome-based personalized approaches for disease management, including its use as a non-invasive biomarker for diagnosis and staging, as a target for therapeutic modulation, and as a marker of drug response. We will also discuss current limitations of these microbiome-based approaches. Ultimately, a better understanding of microbiota-host interactions in NAFLD will inform the development of novel preventative strategies and precise therapeutic targets.
Sharpton et al. review our current understanding of the gut-liver axis in nonalcoholic fatty liver disease (NAFLD). They highlight potential opportunities for the development of gut microbiome-based personalized approaches for NAFLD management, including its use as a non-invasive biomarker for diagnosis and staging, as targets for therapeutic modulation, and as markers of drug response.
The ethylene response factor (ERF) family in Arabidopsis thaliana comprises 122 members in 12 groups, yet the biological functions of the majority remain unknown. Of the group IX ERFs, the IXc ...subgroup has been studied the most, and includes ERF1, ERF14 and ORA59, which play roles in plant innate immunity. Here we investigate the biological functions of two members of the less studied IXb subgroup: ERF5 and ERF6. In order to identify potential targets of these transcription factors, microarray analyses were performed on plants constitutively expressing either ERF5 or ERF6. Expression of defense genes, JA/Et-responsive genes and genes containing the GCC box promoter motif were significantly upregulated in both ERF5 and ERF6 transgenic plants, suggesting that ERF5 and ERF6 may act as positive regulators of JA-mediated defense and potentially overlap in their function. Since defense against necrotrophic pathogens is generally mediated through JA/Et-signalling, resistance against the fungal necrotroph Botrytis cinerea was examined. Constitutive expression of ERF5 or ERF6 resulted in significantly increased resistance. Although no significant difference in susceptibility to B. cinerea was observed in either erf5 or erf6 mutants, the erf5 erf6 double mutant showed a significant increase in susceptibility, which was likely due to compromised JA-mediated gene expression, since JA-induced gene expression was reduced in the double mutant. Taken together these data suggest that ERF5 and ERF6 play positive but redundant roles in defense against B. cinerea. Since mutual antagonism between JA/Et and salicylic acid (SA) signalling is well known, the UV-C inducibility of an SA-inducible gene, PR-1, was examined. Reduced inducibilty in both ERF5 and ERF6 constitutive overexepressors was consistent with suppression of SA-mediated signalling, as was an increased susceptibility to avirulent Pseudomonas syringae. These data suggest that ERF5 and ERF6 may also play a role in the antagonistic crosstalk between the JA/Et and SA signalling pathways.
Despite multiple associations between the microbiota and immune diseases, their role in autoimmunity is poorly understood. We found that translocation of a gut pathobiont,
, to the liver and other ...systemic tissues triggers autoimmune responses in a genetic background predisposing to autoimmunity. Antibiotic treatment prevented mortality in this model, suppressed growth of
in tissues, and eliminated pathogenic autoantibodies and T cells. Hepatocyte-
cocultures induced autoimmune-promoting factors. Pathobiont translocation in monocolonized and autoimmune-prone mice induced autoantibodies and caused mortality, which could be prevented by an intramuscular vaccine targeting the pathobiont.
-specific DNA was recovered from liver biopsies of autoimmune patients, and cocultures with human hepatocytes replicated the murine findings; hence, similar processes apparently occur in susceptible humans. These discoveries show that a gut pathobiont can translocate and promote autoimmunity in genetically predisposed hosts.
The immune system responds vigorously to microbial infection while permitting lifelong colonization by the microbiome. Mechanisms that facilitate the establishment and stability of the gut microbiota ...remain poorly described. We found that a regulatory system in the prominent human commensal
modulates its surface architecture to invite binding of immunoglobulin A (IgA) in mice. Specific immune recognition facilitated bacterial adherence to cultured intestinal epithelial cells and intimate association with the gut mucosal surface in vivo. The IgA response was required for
(and other commensal species) to occupy a defined mucosal niche that mediates stable colonization of the gut through exclusion of exogenous competitors. Therefore, in addition to its role in pathogen clearance, we propose that IgA responses can be co-opted by the microbiome to engender robust host-microbial symbiosis.
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