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Abstract Background The UDP-glucuronosyltransferase 91D2 (SrUGT91D2) gene is a crucial element in the biosynthetic pathway of steviol glycosides (SGs) and is responsible for creating 1,2-β-D glucosidic bonds at the C19 and C13 positions. This process plays a vital role in the synthesis of rebaudioside M (RM) and rebaudioside D (RD). The promoter, which regulates gene expression, requires functional analysis to understand gene expression regulation. However, investigations into the function of the promoter of SrUGT91D2 (pSrUGT91D2) have not been reported. Results The pSrUGT91D2 was isolated from six S. rebaudiana lines, and subsequent multiple sequence comparisons revealed the presence of a 26 bp inDel fragment (pSrUGT91D2-B1188 type) in lines GP, GX, 110, 1114, and B1188 but not in the pSrUGT91D2 of line 023 (pSrUGT91D2-023 type). Bioinformatics analysis revealed a prevalence of significant cis-regulatory elements (CREs) within the promoter sequences, including those responsive to abscisic acid, light, anaerobic conditions, auxin, drought, low temperature, and MeJA. To verify the activity of pSrUGT91D2, the full-length promoter and a series of 5’ deletion fragments (P1–P7) and a 3’ deletion fragment (P8) from various lines were fused with the reporter β-glucuronidase (GUS) gene to construct the plant expression vector, pCAMBIA1300-pro∷GUS. The transcriptional activity of these genes was examined in tobacco leaves through transient transformation. GUS tissue staining analysis and enzyme activity assays demonstrated that both the full-length promoter and truncated pSrUGT91D2 were capable of initiating GUS expression in tobacco leaves. Interestingly, P8-pSrUGT91D2-B1188 (containing the inDel segment, 301 bp) exhibited enhanced activity in driving GUS gene expression. Transient expression studies of P8-pSrUGT91D2-B1188 and P8-pSrUGT91D2-023 in response to exogenous hormones (abscisic acid and indole-3-acetic acid) and light indicated the necessity of the inDel region for P8 to exhibit transcriptional activity, as it displayed strong responsiveness to abscisic acid (ABA), indole-3-acetic acid (IAA), and light induction. Conclusions These findings contribute to a deeper understanding of the regulatory mechanism of the upstream region of the SrUGT91D2 gene and provide a theoretical basis for future studies on the interaction between CREs of pSrUGT91D2 and related transcription factors.

Basin Vortex is a type of Southwest Vortex， which refers to the vortex generated in the Sichuan Basin on the 700 hPa isobaric surface， with two consecutive low pressures with closed Contour line or cyclonic circulation in the wind direction of three stations.It is the main system that causes precipitation in the Sichuan Basin， and the "southwest type" Basin Vortex is the most frequent and strong type of Basin Vortex.This article utilizes ERA5 （0.25°×0.25°） hourly reanalysis data， GPM satellite precipitation data， and the Southwest Low Eddy Yearbook explored the characteristics and development mechanism of a typical “southwest type” Basin Vortex that occurred in the Sichuan Basin from June 26 to 28， 2020.The results indicate that the Basin Vortex was generated in the southwestern part of the Sichuan Basin， then moved towards the northeast direction， reached the northeastern part of Sichuan， turned eastward， and disappeared after entering Chongqing， with a total life history of 48 hours.The formation and development of the Basin Vortex are closely related to its divergence zone located on the northeast side of the 200 hPa South Asian High and on the right side of the entrance area of the high-altitude jet stream， as well as the low-level decompression caused by the positive vorticity advection in front of the 500 hPa short wave trough.The southwest part of the Sichuan Basin at 700 hPa is located to the left front of the low-level jet stream， which is conducive to the development of convergent upward motion and the formation of low eddies.The high value area of frontogenesis in the northeast direction of the 700 hPa Basin Vortex， the strengthening of the low-level jet and the guidance of the southwest airflow in front of the 500 hPa high altitude trough are the main factors for the movement of the Basin Vortex towards the northeast direction.As the center of the 200 hPa South Asian High moves eastward over the Yangtze-Huaihe River and the upper level jet weakens， the 500 hPa shortwave trough moves eastward， and the Basin Vortex is located in the negative vorticity advection zone behind the trough.The vertical direction turns into a sinking motion， with surface pressure increasing and the low vortex gradually weakening and disappearing.Analysis of the vorticity budget equation reveals that low-level convergence is the main contributor to the increase in the Basin Vortex intensity， and the increase in positive vorticity of the Basin Vortex caused by low-level convergence almost runs through the entire life cycle of the vortex.In addition， the existence of high-altitude orthonormal vortices and the release of condensation latent heat from the Basin Vortex precipitation also play an important role in the development and movement of the Basin Vortex.

Many new-generation Doppler weather radars in China are located in mountainous areas with complex topography， and the problem of low elevation angle terrain occlusion is prominent.When estimating precipitation by radar in the occluded area， observations with higher elevation angles need to be used， and due to the micro-physical changes and horizontal motion of precipitation particles during their descent， the reflectivity factor at high locations of the same site is often very different from that near the surface， which will increase the estimation error when used directly for estimating surface precipitation.In this paper， we propose a method for the vertical revision of reflectivity factor.First， we establish the vertical reflectivity factor profiles （VPR） of different precipitation types in the unobstructed observation area， and then revise the observations above the height to be revised to the target height by determining the height threshold to be revised and the near-surface target height based on the vertical variation characteristics of the profiles.The comparison test results show that： the revised target reflectivity factor data are less different from the actual observed data values， and the consistency is improved； moreover， the data at low VPR are more accurate by considering the occlusion factor； since the VPR of different precipitation types are significantly different， the differentiation of precipitation types can avoid mis-correction.The proposed revision method is not only applicable to the beam blocking area， but also generally applicable to the revision of the observed data at high beam height at long distances.

Using observed hourly precipitation data and disaster records of flooding in Qinghai， we adopt the ratio weight method to construct the disaster index of flood disaster events based on the direct economic loss， disaster-affected population， collapsed houses， agricultural economic loss and agricultural disaster area.According to the percentile method， flood disasters are graded into general， heavy， severe， and extra heavy.The disaster distribution characteristics and differences of the four ranks are analyzed and compared with the precipitation characteristics in Qinghai.Principal component analysis， box-whisker plot and correlation analysis are employed to investigate the main factors that lead to flood disasters in Qinghai and the differences among regions.Results show that flood disasters occur frequently， and losses caused by floods increase.The frequency of severe and extra heavy disasters increases significantly after 2016， and the periods of July and August are the most frequent periods of flood disasters in Qinghai every year.The eastern part of Qinghai is an area of frequent floods and the most serious disasters.The Hainan Prefecture has the most flooding frequency and the Haidong City suffers the most serious disaster losses.The flooding disasters in Qinghai are mainly induced by rainfall processes that are more serious than heavy rainfall.The process of flood-causing precipitation in Qinghai can divide into two categories， one is short-lived but has a high rainfall intensity， which has a rainfall duration of 12 h and can cause high accumulated precipitation.The other can also induce high accumulated precipitation， and its rainfall duration is generally longer than 12 h.The flood disasters occurring in eastern cities like Hainan， Huangnan， Haibei， Xining and Haidong are mainly induced by the first category of precipitation process mentioned above.The second category of rainfall process is mainly found in Haixi and Yushu Prefecture， and Huangnan， Haibei， Xining and Haidong are also affected by this precipitation process.The accumulated precipitation and 24 h precipitation are closely associated with flood disaster losses， and longer precipitation duration can further aggravate flood disaster losses.

Using ERA5 （0.25°×0.25°） hourly reanalysis data， TRMM satellite precipitation data and FY-2E satellite black-body temperature （TBB） data， the circulation background and movement characteristics of the formation and development of a Qinghai-Xizang Plateau vortex （QXPV） moving out of the Tibetan Plateau from July 7 to July 9， 2017， as well as the dynamical and thermal mechanism of the heavy precipitation in the Yangtze-Huaihe River Basin were discussed， and the HYSPLIT4 model was used to track the water vapor source of the heavy precipitation in the Yangtze-Huaihe River Basin.The results show as follow： The QXPV was generated in the central part of the Tibetan Plateau， first moved to the southeast and then to the northeast after reaching the central part of Sichuan， with the life history of 39 h.At 200 hPa， the South Asian High and the upper-level jet stream were strong， and the vortex was located in the divergence region on the right side of the upper-level jet inlet area， which promoted the formation and development of the QXPV.The negative height center in the front of the vortex and the southwest airflow at the edge of the West Pacific Subtropical High lead the eastward movement and turn of the QXPV at 500 hPa.After the QXPV moved out of the Qinghai-Xizang Plateau， it was in the decompression area caused by positive vorticity advection in front of the high trough.In addition， the leeward slope of the large terrain was conducive to the enhancement of cyclonic vorticity， so the QXPV developed.The QXPV moved along the Yangtze-Huaihe shear line after it moved out of the Tibetan Plateau， and the cold air behind the trough merged with the southerly airflow carrying water vapor from the Bay of Bengal and the South China Sea.Under the action of frontogenesis， the QXPV developed into a Yangtze-Huaihe cyclone， and the rainfall rapidly increased to the standard of heavy rain.The coupling of upper-level jet and low-level jet， and the development of low-level convective instability strengthened the dynamic uplift， which was conducive to the formation of heavy precipitation over the Yangtze-Huaihe River Basin.The water vapor source of heavy precipitation was mainly the South China Sea and the Bay of Bengal.The convergence upward movement was the strongest during the period of the strongest precipitation， and the convective clouds developed vigorously to maintain the precipitation.

Knowledge of wind field characteristics and variation principles in complex topographical regions is of great importance for the development of numerical prediction models, aviation safety support, and wind energy utilization. However, there has been limited research focused on the lower-tropospheric wind fields in the Qinghai-Tibet Plateau. This paper aims to study the wind characteristics, vertical distributions, and temporal variations in the northeast of the plateau by analyzing a four-year continuous dataset collected from a Doppler wind LiDAR deployed in Xining, Qinghai Province of China. The results indicate that the prevailing horizontal wind direction in the low levels is primarily influenced by the mountain-valley wind circulation. However, as the altitude increases, the prevailing winds are predominantly affected by the westerlies. From a diurnal perspective, noticeable transition processes between up-valley and down-valley winds can be observed. The west-northwest wind (down-valley wind) dominates from late night to morning, while the east-southeast wind (up-valley wind) prevails from afternoon to early evening. The vertical winds in the low levels exhibit a downward motion during the daytime and an upward motion during the nighttime. In this plateau valley, the wind shear exponent is found to be highest in spring and lowest in winter, and it is generally lower during the daytime compared to the nighttime.

YTH domain-containing proteins are one kind of RNA-binding protein involved in post-transcriptional regulation and play multiple roles in regulating the growth, development, and abiotic stress responses of plants. However, the YTH domain-containing RNA-binding protein family has not been previously studied in cotton. In this study, a total of 10, 11, 22, and 21 YTH genes were identified in Gossypium arboreum, Gossypium raimondii, Gossypium barbadense, and Gossypium hirsutum, respectively. These Gossypium YTH genes were categorized into three subgroups by phylogenetic analysis. The chromosomal distribution, synteny analysis, structures of Gossypium YTH genes, and the motifs of YTH proteins were analyzed. Furthermore, the cis-element of GhYTH genes promoter, miRNA targets of GhYTH genes, and subcellular localization of GhYTH8 and GhYTH16 were characterized. Expression patterns of GhYTH genes in different tissues, organs, and in response to different stresses were also analyzed. Moreover, functional verifications revealed that silencing GhYTH8 attenuated the drought tolerance in the upland cotton TM-1 line. These findings provide useful clues for the functional and evolutionary analysis of YTH genes in cotton.

RNA editing, a vital supplement to the central dogma, yields genetic information on RNA products that are different from their DNA templates. The conversion of C-to-U in mitochondria and plastids is the main kind of RNA editing in plants. Various factors have been demonstrated to be involved in RNA editing. In this minireview, we summarized the factors and mechanisms involved in RNA editing in plant organelles. Recently, the rapid development of deep sequencing has revealed many RNA editing events in plant organelles, and we further reviewed these events identified through deep sequencing data. Numerous studies have shown that RNA editing plays essential roles in diverse processes, such as the biogenesis of chloroplasts and mitochondria, seed development, and stress and hormone responses. Finally, we discussed the functions of RNA editing in plant organelles.

Using the 24 h precipitation forecasts products from the ECMWF high-resolution numerical model (ECMWF-Hi) and the ECMWF ensemble model (ECMWF-EPS) and the hourly precipitation observations at more than 2 400 national meteorological stations over China from June to August of 2015 to 2017, we have conducted an evaluation of the accuracy, concentration and correlation of 24 h precipitation forecast products from ECMWF-Hi, and compared them with those from ECMWF-EPS. In addition, in order to overcome the shortcoming of describing the concentration simply by the standard deviation ratio or mean value ratio, we have established the R index which combines standard deviation ratio with mean value ratio, and used it to describe the concentration of forecast quantitatively. Results are as follows. (1) ECMWF-Hi does not show an advantage in the verification of root mean square error (RMSE), while ensemble mean of ECMWF-EPS with low horizontal resolution achieves the lowest RMSE. (2) Generally, the ECMWF-Hi is more accurate in description of concentration of precipitation forecast in the research areas. The dispersion of precipitation forecast is similar to that of the observation. The expectation of precipitation forecast of ECMWF-Hi is also the closest to that of the observation. Compared to the ensemble control forecast of ECMWF-EPS and ensemble mean of ECMWF-EPS, ECMWF-Hi is more accurate in concentration of precipitation. (3) The distribution of the R index at sites over the research area indicated that compared to the ensemble control forecast and the ensemble mean of ECMWF-EPS, ECMWF-Hi has more number of stations with under estimation of precipitation, and the concentration of those stations is generally higher than that of the observation. The precipitation forecast of ECMWF-Hi is closer to the observed precipitation. (4) The evaluation results show that the R index can not only evaluate the concentration of the forecasting of precipitation of model qualitatively, but also can describe the concentration quantitatively.

Glycerol-3-phosphate dehydrogenase (GPDH) is a key enzyme in plant glycerol synthesis and metabolism, and plays an important role in plant resistance to abiotic stress. Here, we identified 6, 7, 14 and 14 GPDH genes derived from Gossypium arboreum, Gossypium raimondii, Gossypium barbadense and Gossypium hirsutum, respectively. Phylogenetic analysis assigned these genes into three classes, and most of the genes within the family were expanded by whole-genome duplication (WGD) and segmental duplications. Moreover, determination of the nonsynonymous substitution rate/synonymous substitution rate (Ka/Ks) ratio showed that the GPDH had an evolutionary preference for purifying selection. Transcriptome data revealed that GPDH genes were more active in the early stages of fiber development. Additionally, numerous stress-related cis-elements were identified in the potential promoter region. Then, a protein–protein-interaction (PPI) network of GPDH5 in G. hirsutum was constructed. In addition, we predicted 30 underlying miRNAs in G. hirsutum. Functional validation results indicated that silencing GhGPDH5 diminished drought tolerance in the upland cotton TM-1 line. In summary, this study provides a fundamental understanding of the GPDH gene family in cotton, GhGPDH5 exerts a positive effect during drought stress and is potentially involved in stomatal closure movements.