亚硝基谷胱甘肽还原酶 GSNOR1正调控植物对疫霉菌的抗性

疫霉属（ Phytophthora）卵菌引致马铃薯晚疫病等作物灾难性病害，严重威胁作物的可持续生产。由于病菌毒性变异，导致品种抗病性丧失问题突出。因此，挖掘植物广谱和持久抗病基因，并探索其在抗病育种中的有效利用具有重要的科学意义。亚硝基谷胱甘肽还原酶1（GSNOR1）是植物氮信号通路中高度保守的关键还原酶，其参与调节r基因介导的植物抗性和非寄主抗性。然而， GSNOR1参与抗疫霉菌的免疫功能和作用机理尚不清楚。本研究中，借助拟南芥与寄生疫霉菌互作的模式体系，首先发现拟南芥T-DNA插入突变体 gsnor1-3对寄生疫霉菌呈现感病表型。进一步利用病毒诱导的基因沉默（VIGS）降低烟草叶片中 GSNOR1同源基因的表达量，在此基础上，通过抗病表型分析以及一系列抗性相关功能的检测，结果表明，沉默本氏烟草 GSNOR1同源基因能够在寄生疫霉菌侵染植物的过程中削弱植物体内的活性氧（ROS）迸发、病程相关基因（PR genes）的诱导表达以及MAPK信号转导，从而增强了植物对疫霉菌的感病性。本研究揭示了植物 GSNOR1对疫霉菌具有高度保守的抗性功能，并初步解析了 GSNOR1正调控植物抗疫霉菌的作用机理，为进一步探索 GSNOR1在马铃薯抗晚疫病中的功能及其在抗病育种中的有效利用奠定了重要的理论 基础。     

Effects of Feeding Frequency on Apparent Energy and Nutrient Digestibility/Availability of Channel Catfish,Ictalurus punctatus,Reared at Optimal and Suboptimal Temperatures

This study examined the effects of feeding frequency (daily versus every other day [EOD]) on nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal (30 C) and suboptimal (24 C) temperatures. A 28% protein practical diet was used as the test diet, and chromic oxide was used at 0.75% of the diet as a maker. Twenty channel catfish of a mean weight of 141 g/fish were stocked into 12 flow‐through aquaria (110 L). Fish were fed daily or EOD to apparent satiation for 7 d before fecal samples were collected by the dissection method. Fish fed EOD to apparent satiation consumed more diet on days fed than those fed daily, and fish reared at 30 C consumed more diet than those reared at 24 C. Neither feeding frequency nor water temperature significantly affected apparent digestibility coefficients for energy and protein and apparent availability coefficients for total amino acids. Results show no advantage by feeding EOD over feeding daily on nutrient digestibility and diet utilization efficiency.     

香型水稻新品种武优6号高产栽培技术

武优6号是四川华丰种业有限责任公司以香型不育系武香A与高产恢复系华恢016配组育成的高产稳产香型杂交水稻新组合,于2018年通过贵州省农作物品种审定委员会审定。描述了武优6号特征特性,在区域试验人工栽培技术的基础上融合现代机械化栽培技术,总结出了武优6号高产栽培技术。     

The efficiency of nitrogen in cattle manures when applied to a double‐annual forage cropping system

The use of cattle manure (CM) for fertilization presents challenges for optimizing nitrogen (N) use. Our work aimed to assess N efficiencies, in a 6‐year experiment with three biennial rotations of four crops: oat–sorghum (first year) and ryegrass–maize (second year) in a rainfed humid Mediterranean area of Spain. Fertilization treatments included the following: control (no N), 250 kg mineral N ha^?1 year^?1 (250MN), three CM rates (supplying 170, 250 and 500 kg N ha^?1 year^?1) and four treatments where the two lowest CM rates were complemented with either 80 or 160 kg mineral N ha^?1 year^?1. Treatments were distributed randomly in each of three blocks. Maximum dry‐matter yield (~44–49 t ha^?1 rotation^?1) was achieved in the third rotation, and only the control and the 170CM yielded significantly less. Within the limitations of the EU Nitrate Directive, the N steady state supply of 170CM always requires a complement of mineral N (80 kg N ha^?1) to maximize N agronomic efficiency. The maximum N‐fertilizer replacement value (250CM vs. 250MN) was 0·67, without significant differences between the two treatments in other N‐related efficiency indexes, which indicates that plants took advantage of residual‐N effects. Nitrogen losses by leaching in the 250CM treatment were around 5–7% of the N applied. This reinforces the sustainability of manure recycling in long cropping seasons.     

糯玉米新品种桂糯615的选育及栽培技术

桂糯615是广西壮族自治区农业科学院玉米研究所以桂糯系255作母本、桂京糯31作父本杂交选育而成的糯玉米新品种。株高239cm,穗位高83cm,果穗筒型,具有高产、稳产、抗病性强、适应性广、果穗外观品质好、蒸煮口感糯性柔软等特点,2018年通过广西农作物品种审定委员会审定,审定编号:桂审玉2018027号,适宜在广西及东南甜糯玉米区域种植。     

极端暴雨条件下黄土丘陵沟壑区土壤蓄水能力和入渗规律

黄土高原退耕还林还草工程实施后,下垫面环境条件的变化可能对流域水文过程、水文通量、水量平衡以及生态系统产生十分重要的影响。研究极端暴雨条件下剖面土壤蓄水能力和入渗规律,对于阐明流域产汇流过程和影响机制具有重要的科学价值。采用土壤墒情仪对陕北"7·26"特大暴雨事件下黄土丘陵沟壑区草地剖面土壤水分进行了实时动态监测,分析了极端暴雨条件下剖面土壤水分的动态变化和蓄水过程,利用Horton入渗模型模拟了剖面土壤水分湿润锋的运动过程,揭示了极端暴雨条件下剖面土壤水分的入渗规律。结果表明:(1)极端暴雨条件下,黄土丘陵沟壑区坡面草地不同深度层次土壤水分与降雨过程的响应不同,具有层次性和明显的滞后效应,其中,0～140 cm是影响该地区土壤水文过程的关键层次;(2)土壤水分再分配结束时,湿润锋最深深度达140 cm,土壤蓄水量达225.99 mm,较降雨前95.37 mm增加了1.37倍;(3)极端暴雨过程中湿润锋的运动随时间呈对数递减关系,其稳渗速率随容重增加而减小,呈指数函数递减;(4)极端降雨过程中该地区坡面草地的产流机制仍以超渗产流为主,对于揭示流域的产汇流机制和完善水文预报模型具有重要的科学意义。     

Silage and total mixed ration hygienic quality on commercial farms: implications for animal production

Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.     

A genetic linkage map in southern‐by‐spring oat identifies multiple quantitative trait loci for adaptation and rust resistance

We developed 178 recombinant inbred lines from a southern‐by‐spring oat population designated as “TxH.” These lines were genotyped to generate a high‐quality linkage map that resolved 6,902 markers into 21 linkage groups that matched closely with the latest hexaploid oat consensus map. Three major quantitative trait loci (QTLs) affecting heading date were found in locations that are consistent with known QTLs and candidate genes, and two other QTLs affecting heading date were found in novel locations. Five QTLs affecting plant height were found. Both sets of QTLs are responsible for transgressive segregation observed for these two traits. Four QTLs affecting resistance to crown rust, caused by the pathogen Puccinia coronata f. sp. avenae, were identified. Two of these QTLs are consistent with known clusters of rust resistance genes, while two may represent new locations of novel rust resistance genes. A complete set of SNP sequences suitable for generating markers for molecular selection is provided.