通讯机构:
[Houxiang Kang] S;State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
关键词:
Cell division;CRISPR;Cas9 gene editing;Genetic architecture of rice leaf width;Genome-wide association study;Gibberellin;Rice leaf width;Vein width
摘要:
Abstract: Rice leaf width (RLW) is a crucial determinant of photosynthetic area. Despite the discovery of several genes controlling RLW, the underlying genetic architecture remains unclear. In order to better understand RLW, this study conducted a genome-wide association study (GWAS) on 351 accessions from the rice diversity population II (RDP-II). The results revealed 12 loci associated with leaf width (LALW). In LALW4, we identified one gene, Narrow Leaf 22 (NAL22), whose polymorphisms and expression levels were associated with RLW variation. Knocking out this gene in Zhonghua11, using CRISPR/Cas9 gene editing technology, resulted in a short and narrow leaf phenotype. However, seed width remained unchanged. Additionally, we discovered that the vein width and expression levels of genes associated with cell division were suppressed in nal22 mutants. Gibberellin (GA) was also found to negatively regulate NAL22 expression and impact RLW. In summary, we dissected the genetic architecture of RLW and identified a gene, NAL22, which provides new loci for further RLW studies and a target gene for leaf shape design in modern rice breeding. Keywords: Cell division; CRISPR/Cas9 gene editing; Genetic architecture of rice leaf width; Genome-wide association study; Gibberellin; Rice leaf width; Vein width
关键词:
Color fading;Cut flower;Sucrose;Transcript regulation
摘要:
As fresh ornamental crops, vase life and post-harvested quality of cut flowers have attracted much attention. Flower color fading is the prominent defect in red and purple cut flowers, especially in cut chrysanthemum which have a relative long vase life. Here, the effect of sucrose on change in anthocyanin contents during the vase life of 'Dante Purple' cut chrysanthemum was studied. Results showed that 500 mM sucrose as holding solution could significantly delay the decrease in anthocyanin content and maintain the ornamental value for as long as 38 vase days. Moreover, the sucrose also increased the flower diameter, soluble sugar contents and total antioxidant capacity, while decreasing the malondialdehyde contents. Further studies suggested that the transcript levels of anthocyanin biosynthetic genes and transcription factors, CmMYB6 and CmMYB#7, had continuously decreased during the vase life. The changes in these genes expression patterns was retarded by the sucrose treatment, except for CmMYB#7 which is a repressor of anthocyanin biosynthesis gene expression. The decline in relative expression of CmMYB#7 was accelerated by sucrose. These results have supplied clues to study the mechanism whereby sucrose serves as a signal molecule to regulate anthocyanin biosynthesis.
摘要:
The current neural networks for tomato leaf disease recognition have problems such as large model parameters, long training time, and low model accuracy. To solve these problems, a lightweight convolutional neural network (LBFNet) is proposed in this paper. First, LBFNet is established as the base model. Secondly, a three-channel attention mechanism module is introduced to learn the disease features in tomato leaf disease images and reduce the interference of redundant features. Finally, a cascade module is introduced to increase the depth of the model, solve the gradient descent problem, and reduce the loss caused by increasing the depth of the model. The quantized pruning technique is also used to further compress the model parameters and optimize the model performance. The results show that the LBFNet model achieves 99.06% accuracy on the LBFtomato dataset, with a training time of 996 s and a single classification accuracy of over 94%. Further training using the saved weight file after quantized pruning enables the model accuracy to reach 97.66%. Compared with the base model, the model accuracy was improved by 28%, and the model parameters were reduced by 96.7% compared with the traditional Resnet50. It was found that LBFNet can quickly and accurately identify tomato leaf diseases in complex environments, providing effective assistance to agricultural producers.
摘要:
Chromium picolinate (Cr(pic)3) is widely used for feeding animals. Most Cr(pic)3 administered to animals is excreted without change. The land use of animal waste introduces Cr(pic)3 to the environment. Transformation of Cr(pic)3 in the environment releases hexavalent chromium (Cr(VI)), posing a chromium contamination risk. Because chromium (in trivalent valent) is complexed by picolinic acid (pic), removal of chromium in Cr(pic)3 form via direct adsorption and precipitation methods is rather difficult. Release of chromium from Cr(pic)3 first and then removal of it through the combination of adsorption and precipitation is advisable. To this end, the treatment of Cr(pic)3 using the Fenton process was first investigated in this work. Treatment parameters were optimized for Cr(pic)3 degradation and chromium removal (i.e., initial and final pH of 3.0 and 7.0, and the molar ratio of Fe(II) and H2O2 was 1:2). Adverse effects of the water constituents could be mitigated by flexible adjustment of the Fenton reagent dosages and the external addition of iron ions. The residual chromium in the aqueous phase was simultaneously lowered to the required standard, and Cr(VI) was barely detected in the aqueous phase. Mechanisms of Cr(pic)3 degradation and chromium removal were proposed by the intermediates determined. The results obtained indicate that the Fenton process is robust for degrading Cr(pic)3 and removing chromium simultaneously and is promising for treating Cr(pic)3-containing wastewater.
摘要:
Abstract: In recent years, considerable attention has been paid to the volatile organic compounds (VOCs) that might lead to serious environmental problems, yet few studies relate to the insecticide application during agricultural process. As there appears to be a notable lack of research on the VOCs pollution of insecticides, we aimed to assess the occurrence of insecticide VOCs in the laboratory and during the agricultural process in China that have not been previously investigated. We discuss the estimation of VOCs emission potentials (EPs) and actual emissions (AEs) posed by insecticide applications. For this purpose, nine insecticide formulations were collected for testing and were analyzed via a thermogravimetric analyzer (TGA) and a pump-suction photoionization detection (PID) gas detector. The results showed that the EPs of nine insecticide samples ranged from 12.30% to 81.30%, with a median of 41.59% and a mean of 45.41%. The average actual emission ratio (AER) for the different formulations ranged from 48.76% to 72.12%. AER value was significantly positively correlated with temperature, but significantly negatively correlated with relative humidity and atmospheric pressure. The results of this study provide a technical reference for establishing the corresponding emission inventory and determining the total amount of pesticide VOCs. Keywords: insecticide application; pesticide VOCs; meteorological factors; emission characterization
摘要:
The components of a protein complex involved in recognizing the histone modification H3K27me3 and transcriptional repression function in an epigenetic module that negatively regulates the N‐hydroxypipecolic acid biosynthesis gene FLAVIN‐DEPENDENT MONOOXYGENASE 1. ABSTRACT N‐Hydroxypipecolic acid (NHP) is a signaling molecule crucial for systemic acquired resistance (SAR), a systemic immune response in plants that provides long‐lasting and broad‐spectrum protection against secondary pathogen infections. To identify negative regulators of NHP biosynthesis, we performed a forward genetic screen to search for mutants with elevated expression of the NHP biosynthesis gene FLAVIN‐DEPENDENT MONOOXYGENASE 1 (FMO1). Analysis of two constitutive expression of FMO1 (cef) and one induced expression of FMO1 (ief) mutants revealed that the AIPP3–PHD2–CPL2 protein complex, which is involved in the recognition of the histone modification H3K27me3 and transcriptional repression, contributes to the negative regulation of FMO1 expression and NHP biosynthesis. Our study suggests that epigenetic regulation plays a crucial role in controlling FMO1 expression and NHP levels in plants.
摘要:
Southwest China is one of the largest contiguous karst areas in the world. Due to the particularity of geological conditions, extreme rainfall events and unreasonable land use, this region is experiencing severe soil erosion. Therefore, the main purpose of this study is to evaluate the influences of vegetation type and rainfall regime on runoff and soil loss in southwest China. The recording of 143 rainfall events from 2006 to 2015 have been divided into 5 rainfall regimes by K-means clustering method. The vegetation type included soil and water conservation forest, grassland, cropland and economic fruit forest. Results showed that vegetation type and rainfall regime both had significant influences on runoff and soil loss. Among the four vegetation types, the cropland produced the largest runoff and soil loss, and the minimum runoff and soil loss were observed in grassland. The rainfall regime I with the shortest duration and highest rainfall intensity produced the largest runoff, accounting for 45% of the total runoff. The rainfall regime IV with shorter duration and higher rainfall intensity generated the greatest soil loss, occupying about 41% of the total soil loss. The general linear model indicated that the main factors affecting runoff were vegetation type, maximum 30-minute rainfall intensity (I30) and rainfall duration, while the soil loss is highly linked to vegetation type and I30. This study suggested that grassland is a good choice to control soil erosion when land use conversion is implemented. Furthermore, replacing soil and water conservation forest with economic fruit forest can not only effectively control soil erosion, but also increase the income of residents in karst regions. Due to the low soil formation rate in karst areas, the soil erosion risk is still high and great efforts should be paid to control soil erosion and rock desertification in this region.