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【Objective】According to the demand of scientific layout of cotton planting for climate change, the study used the species distribution model to quantitatively simulate the suitable distribution of cotton in Manas River basin and its possible response to future climate change, which helps understand the ecological suitability and environmental driving mechanism of cotton planting in arid basin.【Method】The study integrated GIS spatial analysis and MaxEnt model, using 61 cotton planting records and a total of 8 environmental factors screened by R software, and analyzed the suitable distribution range and spatial distribution characteristics of cotton in Manas River basin during the period of reference climate（1970-2000） and 2040 period（SSP245 scenario）. The contribution value of environmental factors, replacement importance value and jackknife method were used to quantitatively analyze the key environmental factors affecting cotton distribution. 【Result】（i） Under the reference climate, the moderate and the most suitable distribution areas of cotton accounted for 9.64% and 12.19% of the total area of the basin, mainly distributed in oasis area of 44°-45° north latitude, including 132, 133, 141 and 144 regiments in Shawan county, 149 and 150 regiments in Manas county, Jiahezi Reservoir and Yuejin Reservoir, and 136 regiment in Shihezi city, southern Kuytun city, northern Wusu city and northeast Karamay city;（ii）Mean diurnal range of temperature, soil pH and solar radiation were key factors affecting the suitable distribution of cotton in the basin, with a cumulative contribution rate of 74.4%. The value ranges of the three factors in the suitable distribution areas were 0.50-13.0 ℃, 5.7-8.7 and 1377-1530 KJ/（m².day）;（iii） Compared with the reference climate, the cotton suitable areas showed a significant trend of decreasing and increasing fragmentation during 2040 period, but the overall decreasing area accounted for 1.5% of the total area of the basin, and decreased to the southern and northwestern of the oasis area of Shawan county, the northeastern Karamay city, Manas county and the south edge of the oasis area of Kuytun city.【Conclusion】The results have great significance for scientific layout of crop planting and stable development in arid basin. [ABSTRACT FROM AUTHOR]

The orthogonal design was used to optimize the culture conditions, of PPV N strain in IBRS-2 cell cultivated in roller bottles to provide reference for the mass culture of PPV N attenuated vaccine. Affected factors were as follows; the pH value (7. 0, 7.2, 7.4), the time of inoculation (0, 24, 48h), the dose of toxin (0. 10 %, 1. 00 %, 10.00 %) and the time of harvesting (48, 72, 96 h). Results showed that the best culture conditions of PPV N strain IBRS-2 cells cultivated in roller bottles were as follows; pH =7. 2, synchronization inoculation, 0. 10 % inoculation dose, harvesting the virus solution 96 h after inoculation. Virus solution harvest time is the most important factor affecting the virus titer of PPV N strain. [ABSTRACT FROM AUTHOR]

[Objective] The reverse transcription polymerase chain reaction was developed to detect Poreine teschovirus in swine clinical samples in Guangxi. [Method] Based on sequence analysis of different serotypes in Gen Bank, the RT-PCR primers were designed with conservative regions at the 5’ end, and the RT-PCR assay was established after annealing temperature optimization and specificity and sensitivity-test,and to diagnosis Porcine teschovirus infection in Guangxi. [Result] This detection method had high specificity and it can amplify Poreine teschovirus, no detection appeared with Porcine epidemic diarrhea virus, Poreine pseudorabies virus, Porcine reproductive and respiratory syndrome virus, Classical swine fever virus, porcine transmissible gastroenteritis virus, Group A porcine rotavirus, Group C porcine rotavirus, porcine deltacoronavirus. The detection was high sensitive and its limit was as lower as 1.16 pg/μ1 plasmid template and 12.15 pg/μ1 cDNA template. The established RT-PCR method was used to detect 235 cases of diarrhea feces collected from pig farms in Guangxi from March 2018 to April 2019, and 24 cases were positive for PTV, with a positive rate of 10.21%. [Conclusion] The established RT-PCR was simple, specific and sensitive assay, which can be used in laboratory PTV detection and diagnosis. PTV infection has been found in some pig farms in Guangxi, so we should be vigilant, strengthen monitoring, prevention and control. [ABSTRACT FROM AUTHOR]

In order to establish a rapid multiplex RT-PCR assay for detection and differentiation of variant，classical and attenuated vaccine strains of porcine epidemic diarrhea virus (PEDV). Two pairs of specific primers were designed based on S gene sequences and 0RF3 gene sequences of variant，classical and attenuated vaccine strains PEDV published in GenBank，to amplify the partial S gene fragment and ORF3 gene fragment of different PEDV strains，the type of PEDV strain could be differentiated according to the number of the fragment and the size of the fragment. Results showed that the multiplex RT-PCR could detect and differentiate variant， classical and attenuated vaccine strains PEDV. Variant PEDV strain generated two fragments，they were 826 bp of the S gene and 234 bp of the ORF3 gene，respectively. Classical PEDV strain only amplified 234 bp of the ORF3 gene，while attenuated vaccine strain produced 185 bp of the ORF3 gene. The multiplex RT-PCR did not cross-react with TGEV，PRoVA，PKV，PRRSV，PRV，CSFV，PCV-2，JEV，TTV and PPV used in the study. Testing of the sensitivity of RT-PCR indicated as low as 2. 3 x 10 -4 ng/μl nuclear acids could be detected accurately and rapidly. Ninety-one stool specimens collected from different farms in Guangxi Province were detected by the established multiplex RT-PCR，64 samples were positive for PEDV， of which 89. 06 % (57/64 ) was variant PED V strains，4. 69 % (3/64) was classical PEDV strain and 6. 25 % (4/64) was attenuated vaccine PEDV strain. Therefore the multiplex RT-PCR could be used as an effective tool for differentiating diagnosis of PEDV in epidemiological investigations. [ABSTRACT FROM AUTHOR]