Bovine leukemia virus genotype surveillance in cattle at a slaughterhouse in Aichi Prefecture,Japan, in 2019 using polymerase chain reaction combined with restriction fragment length polymorphism

Polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) is commonly used for genotyping bovine leukemia virus (BLV) in slaughterhouses. However, unclassified BLV genotypes have been sporadically reported. To assess the current status of BLV genetic characterization in cattle, PCR-RFLP was performed on blood samples of 170 cattle (84 Japanese Black, 60 Japanese Black x Holstein, and 26 Holstein) from 17 farms (5 prefectures) at a slaughterhouse in Aichi Prefecture in 2019. A total of 65 samples (38.2%) were BLV positive, and genotype 1 was the most predominant (56/65 samples), followed by genotypes 3 (6 samples) and 5 (1 sample), and two unclassified samples. No relationship between the genotypes and breeds was observed. Sequence and phylogenetic analyses demonstrated that unclassified BLV genotypes clustered with genotype 1 sequences were, therefore, not new genotypes.     

Effects of transient subsurface waterlogging on root growth, plant biomass and yield of chickpea

Root growth and proliferation are important for achieving the yield potential of chickpea in soils prone to waterlogging. Root growth characteristics and seed yield of the desi cultivar Rupali and the kabuli cultivar Almaz that differ in seed size and early vigour were investigated under well-drained and transiently-waterlogged conditions in glass-walled root boxes in a controlled-temperature glasshouse. Rooting parameters and detailed measurements of root growth and proliferation were made at 2-day intervals using a root mapping technique and by sampling the roots from the soil 14 days after the transient waterlogging ended. Although the roots of the kabuli cultivar Almaz had greater dry matter and length than the desi cultivar Rupali, the subsurface waterlogging promptly stopped the root growth of both genotypes. Root dry matter in both types of chickpea was reduced by two-thirds, 14 days after the cessation of the 12-day waterlogging treatment. The reduction resulted from an inhibition in root growth and proliferation, which led to a lower root length density down the soil profile, particularly in the top 0.6 m of the waterlogged plants. While root length and root dry matter was higher in the kabuli cultivar Almaz than in the desi cultivar Rupali after waterlogging, they were not associated with a greater above-ground dry matter or seed yield at maturity. The transient waterlogging reduced the seed yield by 54% in the kabuli cultivar Almaz and by 44% in the desi cultivar Rupali. The reduction in seed yield in the kabuli cultivar Almaz resulted from 50% decline in the number of seeds per pod while in the desi cultivar Rupali it was a consequence of less pods and seeds per pod. Subsurface waterlogging changed the rooting pattern in chickpea, inhibiting root branching and the growth of the tap root and severely reducing the growth of root branches. The release from the waterlogging induced the production of new roots rather than regrowth of existing roots.     

Root growth, available soil water, and water-use efficiency of winter wheat under different irrigation regimes applied at different growth stages in North China

Field experiments were conducted at the Luancheng Agro-Ecosystem Experimental Station of the Chinese Academy of Sciences during the winter wheat growing seasons in 2006-2007 and 2007-2008. Experiments involving winter wheat with 1, 2, and 3 irrigation applications at jointing, heading, or milking were conducted, and the total irrigation water supplied was maintained at 120 mm. The results indicated that irrigation during the later part of the winter wheat growing season and increase in irrigation frequency decreased the available soil water; this result was mainly due to the changes in the vertical distribution of root length density. In ≤30-cm-deep soil profiles, 3 times irrigation at jointing, heading, and milking increased the root length density, while in >30-cm-deep soil profiles, 1 time irrigation at jointing resulted in the highest root length density. With regard to evapotranspiration (ET), there was no significant (LSD, P < 0.05) difference between the regimes wherein irrigation was applied only once at jointing; 2 times at jointing and heading; and 3 times at jointing, heading, and milking. Compared with 1 and 3 times irrigation during the winter wheat growing season, 2 times irrigation increased grain yield and 2 times irrigation at jointing and heading produced the highest water-use efficiency (WUE). Combining the results obtained regarding grain yield and WUE, it can be concluded that irrigation at the jointing and heading stages results in high grain yield and WUE, which will offer a sound measurement for developing deficit irrigation regimes in North China.     

基于微根管技术的玉米根系生长监测

为了研究玉米根系生长规律,该文利用固城农业气象试验站内设置的大型根剖面系统,采用微根管观测法,对试验地上玉米主要生育期的根系生长动态进行定期直接跟踪监测,并以方形整段标本法作为参照标准,对试验数据采用MATLAB软件辅助图像处理和现代统计方法进行分析。结果表明：微根管法与方形整段标本法对得出的根长密度随深度增加呈递减型有较好的一致性,两者相关系数达到0.83以上,通过0.05的显著性检验;由观测数据建立的回归方程能较好地反映土壤中玉米根系生长规律,进一步表明微根管法是一种破坏性较小、可准确定位跟踪植物根系在土壤中生长动态变化的先进技术,对植物根系生长研究有较好的推广应用价值。     

Correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress

AIM:To explore the correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress (CIS). METHODS:Healthy male Sprague-Dawley (SD) rats (n=48) were randomly divided into control group and CIS group. The rats in CIS group were subjected to 3 h of immobilization stress a day for 21 consecutive days, and the rats in control group were kept for 21 d without stress intervention. The behaviors in open-field test (OFT) and elevated plus-maze test (EPM test), the sucrose consumption, the serum D-xylose content, and the small bowel transit rate were detected. The fecal metabolites were determined by ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR) technique, and differential metabolites in the rats of 2 groups were analyzed by multivariate statistics. The correlation between body weight/food intake and above indexes of CIS rats were observed by Pearson correlation analysis. RESULTS:Compared with the control rats, the body weight of CIS rats was increased slowly and the food intake was decreased significantly (P<0.01). In the OFT, both the total and central distance covered in CIS rats were reduced significantly than those in control group within 5 min (P<0.01). In the EPM test, the residence time in open-arms of CIS rats within 5 min was shortened dramatically than those in the control group (P<0.01). The content of serum D-xylose and the sucrose consumption of the rats after stress for 21 d were decreased markedly (P<0.05). The small bowel transit rate of CIS rats was lower than that of control rats, but no statistical difference was observed (P>0.05). Acetate, butyrate, glucose, propionate, glutamate, ribose, pimelate, lactate, alanine, valerate, total 10 kinds of differential metabolites in fecal samples were detected, and the 10 kinds of metabolites in CIS rats were higher than that of the control rats (P<0.05). Pearson correlation analysis showed that food intake of CIS rats was negatively correlated with metabolites of acetate and pimelate (P<0.05), and no correlation between body weight and above indexes was found. CONCLUSION:Under the CIS condition, there are certain correlations between food intake and metabolites of acetate and pimelate, but the mechanism still need further study.     

特定土壤条件下“新温185”核桃根施氮磷钾肥细根根长密度效应研究

以"新温185"核桃(Juglans regia'Xinwen185')为试验材料,通过"3414"肥料效应田间试验,采用根钻取样法和图像扫描分析法,研究了特定土壤养分条件下根施氮(N)、磷(P)、钾(K)肥对"新温185"核桃细根根长密度的影响,以期为"新温185"核桃土壤养分的科学管理提供依据。结果表明:"新温185"核桃细根根长密度(C)的正平方根(Sqrt C)同P肥与K肥的交互作用(P×K)、N肥的施用量(纯氮量,N)、N肥施用量的自乘(N^2)存在极显著(P=0.000)的线性相关关系,即■。特定土壤条件下(碱解N 77.7 mg·kg^-1,有效P 14.3 mg·kg^-1,速效K 77.3 mg·kg^-1),根施P、K肥对核桃的细根根长密度效应不显著,P、K肥的交互作用对细根根长密度存在负效应,当N肥施用量(纯量)小于1.34 kg·株^-1时,对"新温185"核桃细根根长密度存在正效应,反之则存在负效应。     

Changes in DNA methylation patterns affect ripening time in Satsuma mandarin fruit

Differences in DNA methylation patterns might lead to differences in fruit maturation time in the citrus Satsuma, but the underlying mechanism is unclear. Here, we explored the differences in methylation patterns during fruit ripening in Satsuma among 20 early‐ and late‐maturing Satsuma varieties and compared DNA methylation patterns in two Satsuma cultivars (Ooita wase and Aoshima unshiu) at different developmental stages using methylation‐sensitive fragment length polymorphism (MSAP) analysis. We cloned and sequenced DNA from different bands to identify differentially methylated genes involved in fruit ripening. The internal methylation of CCGG sequences occurred more frequently in the early‐maturing Satsuma cultivars (8.47%) than the late‐maturing cultivars (6.74%), whereas the external methylation of CCGG sequences occurred less frequently in the early‐maturing cultivars (24.98%) compared to the late‐maturing types (27.27%). Genes encoding the G protein α subunit and zinc‐binding protein of the histidine triad (HIT) family and two unknown genes homologous to expressed sequence tag (EST) sequences (CX052976.1 and CX071135.1) were found to be modified by methylation during the fruit ripening process. These findings suggest that DNA methylation might play important roles in regulating fruit ripening in Satsuma. Our results lay the foundation for analysing the molecular mechanism underlying fruit ripening in this important citrus crop.     

玉米粒长性状主基因+多基因遗传分析

玉米粒长是培育优良玉米品种的重要选择性状。选取粒长性状表现差异显著的玉米自交系铁7922和E28,及其组建的6个世代群体P₁、F₁、P₂、B₁、B₂和F₂为材料,运用主-多基因混合模型遗传分析方法进行分析,研究玉米粒长的遗传规律。结果表明：粒长性状在F₁表现为超亲优势,符合两对加性-显性-上位性主基因+加性-显性-上位性多基因遗传的E-1-0模型,主基因遗传率为41.22%~80.58%,多基因遗传率为17.68%~24.95%,环境因素决定粒长表型变异的19.42%~41.10%,控制玉米粒长性状的主基因效应高于多基因效应,并且主基因的加性累积效应明显,该性状在育种中可以通过世代累积进行选择。     

利用人工合成小麦RIL群体进行小麦穗长和穗宽性状的QTL分析

为了挖掘小麦穗长和穗宽性状相关QTL,并为人工合成小麦优异基因资源的开发利用奠定基础,以普通小麦品种西农389×人工合成小麦材料KU98的F_(7∶8) RIL群体为试验材料,基于小麦55K SNP芯片对F_(7∶8)群体分型结果绘制的遗传连锁图谱及2018和2019年调查统计的F_7群体表型数据,对小麦穗长和穗宽性状进行了QTL定位分析。结果表明,在1A、2D、3A、5A和7B染色体上检测到10个与穗长性状相关的QTL,在2D、4D、5A、6A和7D染色体上检测到10个与穗宽性状相关的QTL,其中与穗长相关的 qSL-2D.1和与穗宽相关的 qSW-4D.1、 qSW-5A.1在两年中均被检测到,标记区间分别为AX-111939856～AX-111497351、AX-169335104～AX-110618708、AX-108792246～AX-111048027。 qSW-5A.1连续两年均为主效QTL,且与 qSL-5A.2在同一标记区间,推测该位点具有一因多效的遗传效应或连锁遗传效应。     

暴雨细沟侵蚀的调查研究

本文通过对1988年8月4～5日和1989年7月16日陕北安塞水土保持试验站出现的两次大暴雨细沟侵蚀的分析研究,得出了野外大暴雨条件下细沟侵蚀量随坡长增加近线性增大;与坡度的关系为,当坡度小于25°时,随坡度增大而增大,当坡度大于25°时,随坡度增大而减小;细沟侵蚀量在不同农耕地的变化为,翻耕后麦地>荞麦地>水平沟谷地>一般耕作豆地,细沟侵蚀量在坡面总侵蚀量中所占的比重为50%～75%。