Rice bacterial leaf blight is caused by Xanthomonas oryzae pv. oryzae (Xoo) and produces substantial losses in rice yields. Resistance breeding is an effective method for controlling bacterial leaf ...blight disease. The mutant line H120 derived from the japonica line Lijiangxintuanheigu is resistant to all Chinese Xoo races. To identify and map the Xoo resistance gene(s) of H120, we examined the association between phenotypic and genotypic variations in two F
populations derived from crosses between H120/CO39 and H120/IR24. The segregation ratios of F
progeny consisted with the action of a single dominant resistance gene, which we named Xa46(t). Xa46(t) was mapped between the markers RM26981 and RM26984 within an approximately 65.34-kb region on chromosome 11. The 12 genes predicted within the target region included two candidate genes encoding the serine/threonine-protein kinase Doa (Loc_Os11g37540) and Calmodulin-2/3/5 (Loc_Os11g37550). Differential expression of H120 was analyzed by RNA-seq. Four genes in the Xa46(t) target region were differentially expressed after inoculation with Xoo. Mapping and expression data suggest that Loc_Os11g37540 allele is most likely to be Xa46(t). The sequence comparison of Xa23 allele between H120 and CBB23 indicated that the Xa46(t) gene is not identical to Xa23.
•Deep CNNs outperform OSTU and BTS methods in identifying water bodies from SAR imagery;•Speckle noise is suppressed by deep CNNs prior to the Refined Lee filter;•The summer flooding in 2020 of the ...Poyang Lake area, China, is monitored using Multiple CNNs.
Precise monitoring of floods is significant in disaster management and loss reduction; however, remote sensing data resource and methods can largely affect the monitoring accuracy of flooded areas. In this study, we use cloud-free Sentinel-1 Synthetic Aperture Radar (SAR) imagery, preferable to the optical imagery. We have used 5 convolutional neural networks (CNNs), including HRNet, DenseNet, SegNet, ResNet and DeepLab v3 + for flood monitoring in the Poyang Lake area, and compared their performances with the traditional methods — the bimodal threshold segmentation (BTS) and the OSTU method. The HRNet has superior performance in water body identification with the highest precision and efficiency, based on a parallel structure to not only extract rich semantic information but also maintain high-resolution features in the whole process. Besides, speckle noise reduction by deep convolutional neural networks in SAR imagery is better compared with the Refined Lee filter. The CNNs are then used to monitor the temporal evolution of summer flooding (May-Nov.) in 2020. Results show the smallest water coverage of Poyang Lake in late May; it gradually increases to the maximum in mid-July, and then shows a downward trend until November.
Within the research framework of pragma-dialectics, this study analysed and assessed strategic manoeuvring by dissociation in corporate crisis communication, exemplified by the 2017 United Airlines’ ...Passenger Dragging-off Incident. As shown from the analysis of the public statements issued on its official website and Twitter, United Airlines adopted dissociation using the lexical item “volunteer” in the different stages of argumentation: bringing forward a standpoint, maintaining a standpoint and mitigating a standpoint. In so doing, the corporation strategically manoeuvred the topical potential and the presentational devices to meet the demands of its primary audience, i.e. the international general public. Whereas employing dissociation of the notion “volunteer” seemed to be reasonable and served the corporation’s interests best, its argumentative effectiveness was called into question based upon the general rules for critical discussion and the institutional context.
Background
The rice (
Oryza sativa
) gene
Xa7
has been hypothesized to be a typical executor resistance gene against
Xanthomonas oryzae
pv.
oryzae
(
Xoo
), and has conferred durable resistance in the ...field for decades. Its identity and the molecular mechanisms underlying this resistance remain elusive.
Results
Here, we filled in gaps of genome in
Xa7
mapping locus via BAC library construction, revealing the presence of a 100-kb non-collinear sequence in the line IRBB7 compared with Nipponbare reference genomes. Complementary transformation with sequentially overlapping subclones of the BACs demonstrated that
Xa7
is an orphan gene, encoding a small novel protein distinct from any other resistance proteins reported. A 27-bp effector binding element (EBE) in the
Xa7
promoter is essential for AvrXa7-inducing expression model. XA7 is anchored in the endoplasmic reticulum membrane and triggers programmed cell death in rice and tobacco (
Nicotiana benthamiana
). The
Xa7
gene is absent in most cultivars, landraces, and wild rice accessions, but highly homologs of XA7 were identified in
Leersia perrieri
, the nearest outgroup of the genus
Oryza
.
Conclusions
Xa7
acts as a trap to perceive AvrXa7 via EBE
AvrXa7
in its promoter, leading to the initiation of resistant reaction. Since EBE
AvrXa7
is ubiquitous in promoter of rice susceptible gene
SWEET14
, the elevated expression of which is conducive to the proliferation of
Xoo
, that lends a great benefit for the
Xoo
strains retaining AvrXa7. As a result, varieties harboring
Xa7
would show more durable resistance in the field.
Xa7
alleles analysis suggests that the discovery of new resistance genes could be extended beyond wild rice, to include wild grasses such as
Leersia
species.
The scientific understanding of climate change is based on a solid physical-theoretical foundation, and long-term observation and research. By analyzing the accelerated rise of the global climate and ...its wide-ranging effects on the risk of natural ecosystems and the social economy, and, particularly in view of the stringent targets of 1.5 degrees set by the Paris Agreement to limit global temperature rise, this study contends that climate security has become a new, non-traditional, security issue. The fundamental approach to implementing the objectives of the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement is to develop clean energy vigorously and to accelerate energy transformation. Furthermore, building a global energy interconnection is emphasized as one of the solutions to promoting energy transformation. Keywords: Climate Change, Scientific basis, Effects and risk, Addressing pathways, Energy transition
The frequent occurrence of extreme precipitation events notably affects the middle and lower reaches of the Yangtze River (MLYR) during the Mei-yu period. Based on meteorological station data from ...the China Meteorological Administration collected from 1970 to 2019, we employed nonlinear time series analysis and the state transition networks (STN) to identify the spatiotemporal and evolution characteristics of 10 extreme precipitation indices (EPIs). Although previous studies have largely focused on investigating the spatiotemporal characteristics, the suitability of STN for extreme precipitation has not been extensively explored. This study focused on not only the spatiotemporal characteristics of extreme precipitation but also its evolution using the STN. The results showed that the periodic oscillations in extreme precipitation ranged from 2 to 5 years and an abrupt change occurred primarily around 1990. Extreme precipitation displayed similar network parameters, yet different network structures and transition probabilities. The evolution of extreme precipitation exhibited from decreasing to increasing from 1970 to 2019, with an increasing trend after 1990. Similar network structures tended to exhibit higher Pearson correlations. Spatially, high EPIs values were mainly concentrated in the central region of the MLYR. This study could provide new methods and perspectives for studying the characteristics of extreme precipitation.
Reference evapotranspiration (ET
0
) is an important parameter of agricultural activity and hydro-meteorological studies. In this study, we used the Food and Agriculture Organization Penman–Monteith ...equation to evaluate ET
0
, and to investigate the change point of ET
0
in the Loess Plateau region from 1960 to 2013. The results showed that a change point was detected at approximately the year 1990 for annual ET
0
series from 108 meteorological stations using Cramer’s statistical test. The annual ET
0
decreased significantly (
p
< 0.05) by −1.22 mm year
−1
from 1960 to 1990, especially during the summer months, which contributed the most to the total annual reduction, while it increased significantly (
p
< 0.001) by 1.15 mm year
−1
from 1991 to 2013, with the spring months contributing the most. The ET
0
and its trend in the five integrated management divisions of the Loess Plateau have significant spatial heterogeneity. The highest and lowest ET
0
were found in the third and fifth divisions from 1960 to 2013. The ET
0
decreased significantly in the first division and increased in the fourth divisions (1960–1990 and 1991–2013, respectively). Using differential equations to quantitatively evaluate the contribution of various factors, the wind speed was mostly responsible for the variability in the ET
0
trend from 1960 to 1990, followed by solar radiation and vapor pressure. The positive effect of air temperature on ET
0
trend was offset by the other three factors, and the combined effects of the four climatic variables led to the decrease in the ET
0
trend. However, the rapidly increasing air temperature became the predominant factor in the change in the ET
0
trend after 1990. A spatiotemporal variation of predominant contribution to the ET
0
trend was identified. The temperature dominant region changed from the third to the first division for 1960–1990 and 1991–2013. Radiation did not change. Vapor pressure changed from the first to the fourth and the wind speed changed from the forth to the third. This study could contribute to a better understanding of the response of the spatial and temporal variation of ET
0
to increased climate change. Additionally, this research also provides scientific support to regional planning and management.
Drought is a complex natural hazard that affects various regions of the world, causing significant economic and environmental losses. Accurate and timely monitoring and forecasting of drought ...conditions are essential for mitigating their impacts and enhancing resilience. Satellite-based drought indices have the advantage of providing spatially continuous and consistent information on drought severity and extent. A new drought product was developed from the thermal infrared observations of the Fengyun (FY) series of satellites. We proposed a data fusion algorithm to combine multiple FY satellites, including FY-2F, FY-2G, and FY-4A, to create a long time series of a land surface temperature (LST) data set without systematic bias. An FY drought index (FYDI) is then derived by coupling the long-term LST data set with the surface–atmospheric energy exchange model at 4 km spatial resolution over China from 2013 to present. The performance and reliability of the new FYDI product are evaluated in this study by comparing it with the Meteorological-drought Composite Index (MCI), one of the authoritative drought monitoring indices used in the Chinese meteorological services. The main objectives of this paper are: (1) to evaluate the performance of the FYDI in capturing the spatiotemporal patterns of drought events over China; (2) to quantitively analyze the consistency between the FYDI and MCI products; and (3) to explore the advantages and limitations of the FYDI for drought monitoring and assessment. The preliminary results show that the FYDI product has good agreement with the MCI, indicating that the FYDI can effectively identify the occurrence, duration, severity, and frequency of drought events over China. These two products have a strong correlation in terms of drought detection, with a correlation coefficient of approximately 0.7. The FYDI was found to be particularly effective in the regions where ground observation is scarce, with the capability of reflecting the spatial heterogeneity and variability of drought patterns more clearly. Overall, the FYDI can be a useful measure for operational drought monitoring and early warning, complementing the existing ground-based MCI drought indices.
Global warming and its associated changes in temperature and precipitation have significantly affected the ecosystem in Southwest China, yet studies that integrate temperature and precipitation ...changes are inadequate for quantitatively assessing the impacts of extreme events on ecosystems. In this study, the return period of concurrent climate extremes characterized by precipitation deficit and extreme temperature and the spatial and temporal dynamic patterns of their impacts on ecosystems were assessed by using high-precision temperature and precipitation data, as well as NDVI and NPP data collected for the 1985–2015 period. The results show that the 2009 concurrent event had a return period of about 200 years. The return periods of individual climate factors are significantly overestimated or underestimated. Concurrent events significantly reduced the spring and annual Normalized Difference Vegetation Index (NDVI) and net primary productivity (NPP) in Southwest China. The magnitude of the reduction in vegetation greenness and productivity increased with the intensity of concurrent events. Concurrent events beginning in autumn 2009 reduced spring NDVI and NPP by 8.8% and 23%, and annual NDVI and NPP by 2.23% and 7.22%, respectively. Under future climate scenarios, the return period of concurrent events could be significantly shortened, which would have a more severe impact on regional ecosystems.
PDF
