Molecular characterization and overexpression of the difenoconazole resistance gene CYP51 in Lasiodiplodia theobromae field isolates

Stem-end rot (SER) caused by Lasiodiplodia theobromae is an important disease of mango in China. Demethylation inhibitor (DMI) fungicides are widely used for disease control in mango orchards. The baseline sensitivity to difenoconazole of 138 L. theobromae isolates collected from mango in the field in 2019 was established by the mycelial growth rate method. The cross-resistance to six site-specific fungicides with different modes of action were investigated using 20 isolates randomly selected. The possible mechanism for L. theobromae resistance to difenoconazole was preliminarily determined through gene sequence alignment and quantitative real-time PCR analysis. The results showed that the EC50 values of 138 L. theobromae isolates to difenoconazole ranged from 0.01 to 13.72 µg/mL. The frequency of difenoconazole sensitivity formed a normal distribution curve when the outliers were excluded. Difenoconazole showed positive cross-resistance only with the DMI tebuconazole but not with non-DMI fungicides carbendazim, pyraclostrobin, fludioxonil, bromothalonil, or iprodione. Some multifungicide-resistant isolates of L. theobromae were found. Two amino acid substitutions (E209k and G207A) were found in the CYP51 protein, but they were unlikely to be related to the resistance phenotype. There was no alteration in the promoter region of the CYP51 gene. However, difenoconazole significantly increased the expression of the CYP51 gene in the resistant isolates compared to the susceptible isolates. These results are vital to develop effective mango disease management strategies to avoid the development of further resistance.

A Zeroth-Order Adaptive Learning Rate Method to Reduce Cost of Hyperparameter Tuning for Deep Learning

Due to powerful data representation ability, deep learning has dramatically improved the state-of-the-art in many practical applications. However, the utility highly depends on fine-tuning of hyper-parameters, including learning rate, batch size, and network initialization. Although many first-order adaptive methods (e.g., Adam, Adagrad) have been proposed to adjust learning rate based on gradients, they are susceptible to the initial learning rate and network architecture. Therefore, the main challenge of using deep learning in practice is how to reduce the cost of tuning hyper-parameters. To address this, we propose a heuristic zeroth-order learning rate method, Adacomp, which adaptively adjusts the learning rate based only on values of the loss function. The main idea is that Adacomp penalizes large learning rates to ensure the convergence and compensates small learning rates to accelerate the training process. Therefore, Adacomp is robust to the initial learning rate. Extensive experiments, including comparison to six typically adaptive methods (Momentum, Adagrad, RMSprop, Adadelta, Adam, and Adamax) on several benchmark datasets for image classification tasks (MNIST, KMNIST, Fashion-MNIST, CIFAR-10, and CIFAR-100), were conducted. Experimental results show that Adacomp is not only robust to the initial learning rate but also to the network architecture, network initialization, and batch size.

The Correlation between temperature and COVID-19 Incidence: An ecologic study

Background It has been hypothesized that the COVID-19 is less prevalent in regions with warm climates. Here we investigated the correlation between temperature and the cumulative COVID-19 incidence rate. Method Daily data of the temperature and the cumulative COVID-19 incidence rate were obtained from meteorological stations’ reports and CORONALAB database, respectively, for every 36 counties of Fars province, southern Iran. Results A decreasing pattern in the cumulative incidence rate of COVID-19 was occurred at 20-25°C and 25-35°C for counties with the cold climate and counties with the warm climate, respectively; while it was increased at both upper and lower temperatures. Conclusion It appears that higher rates of disease transmission at temperatures below 20°C and above 35°C might be linked to people’s indoor gatherings, coupled with insufficient ventilation.

PROJECT-BASED INCIDENT RATE BASED ON WEIGHTED AVERAGE METHOD

The incident rate has been widely used to indicate safety performance. The incident rate of a company can be compared with the national or international incident rate within similar industry or among different type of industries. The comparison is particularly very useful as a safety benchmark to gauge performance with other companies in the same business area. However, many existing methods produce the annual incident rate, which has been formulated on an annual basis. This will lead to incompatibility of the method used in calculating the incident rate for a project that runs for a specific period. This is because the annual incident rate does not consider the duration of the project; it becomes less meaningful in indicating the safety performance of project-based activities such as those in construction industries. The proposed method which is Project-Based Incident Rate (PIR) is found to be able to reflect the actual situation of project-based companies better than the existing annual incident rate method, and it is also can be expressed both on a monthly and yearly basis.

Synthesis of Novel Thiazolyl Hydrazine Derivatives and Their Antifungal Activity

A series of novel thiazolyl hydrazine derivatives 3a–3o were synthesized and evaluated for their in vitro antifungal activity against six phytopathogenic strains, namely, Botryosphaeria dothidea (B. d.), Gibberella sanbinetti (G. s.), Fusarium oxysporum (F. o.), Thanatephorus cucumeris (T. c.), Sclerotinia sclerotiorum (S. s.), and Verticillium dahliae (V. d.), by the classical mycelial growth rate method. Biological assessment results showed that most of these target compounds showed good antifungal activity toward tested strains. Especially, compound 3l showed excellent antifungal activities against B. d. and G. s. with relatively lower EC50 values of 0.59 and 0.69 µg/mL, respectively, which were extremely superior to those of commercial fungicides fluopyram, boscalid, and hymexazol and were comparable to those of carbendazim. Given the excellent bioactivity of designed compounds, this kind of thiazolyl hydrazine framework can provide a suitable point for exploring highly efficient antifungal agents.

A Fuzzy Method for Joint Resource Allocation and Stable Pairing in D2D Communications with Applications in COVID-19 Patient Information Management

In this paper, a device-to-device (D2D) communication multiple-metric scenario for resource allocation and pairing is proposed. To improve the stability of the D2D connection, a fuzzy method based on the data-rate and battery levels of potential D2D pairs is studied so that the set of D2D transmitters is considered as a fuzzy set. A single-cell scenario with a cellular user and some co-channel D2D nodes consisting of D2D receivers and transmitters is considered. A stable fuzzy pairing criterion is proposed for the selection of the best D2D transmitter. The proposed method is compared to three other pairing methods: maximum sum-rate, constant, and random pairing methods. The simulation results show that the proposed pairing method outperforms the other three methods in terms of stability and fairness criteria and follows the maximum sum-rate method from the sum-rate criteria point of view.

Molecular Characterization and Overexpression of CYP51 gene of Difenoconazole Resistance in Lasiodiplodia Theobromae Field Isolates

Stem-end rot (SER) caused by Lasiodiplodia theobromae is an important disease of mango in China. Demethylation inhibitor (DMI) fungicide are widely used for diseases control in mango orchards. The baseline sensitivity to difenoconazole of 138 isolates collected in the field in 2019 from mango were established by the mycelial growth rate method. The cross-resistance to six site-specific fungicides with different modes of action were investigated using 20 isolates randomly selected. The possible reasons for L. theobromae resistance to difenoconazole were preliminarily determined through gene sequence alignment and quantitative real-time PCR analysis. The results showed that the EC50 values of 138 L. theobromae isolates to difenoconazole ranged from 0.01 to 13.72 µg/ml. The frequency of difenoconazole sensitivity formed a normal distribution curve when the outliers were excluded. Difenoconazole showed positive cross-resistance only with the DMI tebuconazole, but not with non-DMI carbendazim, pyraclostrobin, fludioxonil, bromothalonil, or iprodione. Some multifungicide-resistant isolates of L. theobromae were found. Two amino acid substitutions (E209k and G207A) were found in CYP51 protein, but they were not likely related to the resistance phenotype. There was no alteration in promoter region of the CYP51 gene. However, difenoconazole significantly increased the expression of the CYP51 gene in the resistant isolates when compared to the susceptible isolates. This study is important references to explore resistance mechanism. These results are vital to make effective mango diseases management strategies in order to avoid the development of further resistance.