Potato late blight caused by Phytophthora infestans:From molecular interactions to integrated management strategies

Over 170 years after the infamous Irish Potato Famine,potato late blight(PLB)caused by Phytophthora infestans remains the single most devastating disease of global potato production,causing up to 10 billion USD in yield loss and management costs.Through decades of research,growers and agronomists in the field as well as laboratory scientists have made significant progress in understanding the molecular pathogenesis process of this critical pathosystem and effective management strategies to control PLB.Yet,the need to feed an ever-increasing global population under changing climate demands continued improvement in efficient and sustainable PLB management schemes that can be implemented across a broad economic spectrum.In this review,we briefly summarize the current understanding of the molecular interaction between P.infestans and its host plants,highlight the current integrated pest management strategy to control PLB on local and continental scales,and discuss the potential of further improvement of sustainable PLB control through genetic enhancement of crop resistance and emerging crop protection technologies.

Control Efficacy of 45% Propamocarb·Denamidone SC against Potato Late Blight

The effects of different doses of 45% pmpamoearb · fenamidone SC on potato late blight were studied in the paper. The results showed that the overall control effect of 45% propamocarb · fenamidone SC against potato late blight on the 14^th day after the third spraying were 67.64% -83.78%. The yield of potato reached 19 972.5 -23 302.5 kg/hm^2, with higher marketable tuber rate and lower rotten tuber rate. With the increase in fungicide dose, the difference in control effect against late blight was significant, but the yield-increasing effect on potatoes was not significant. The appropriate application dosage of 45% propamecarb · fenamidone SC were 450 -675 g/hm^2.

A potato late blight resistance gene protects against multiple Phytophthora species by recognizing a broadly conserved RXLR-WY effector

Species of the genus Phytophthora,the plant killer,cause disease and reduce yields in many crop plants.Although many Resistance to Phytophthora infestans(Rpi)genes effective against potato late blight have been cloned,few have been cloned against other Phytophthora species.Most Rpi genes encode nucleotide-binding domain,leucine-rich repeat-containing(NLR)immune receptor proteins that recognize RXLR(Arg-X-Leu-Arg)effectors.However,whether NLR proteins can recognize RXLR effectors from multiple Phytophthora species has rarely been investigated.Here,we identified a new RXLR-WY effector AVRamr3 from P.infestans that is recognized by Rpi-amr3 from a wild Solanaceae species Solanum americanum.Rpi-amr3 associates with AVRamr3 in planta.AVRamr3 is broadly conserved in many different Phytophthora species,and the recognition of AVRamr3 homologs by Rpi-amr3 activates resistance against multiple Phytophthora pathogens,including the tobacco black shank disease and cacao black pod disease pathogens P.parasitica and P.palmivora.Rpi-amr3 is thus the first characterized resistance gene that acts against P.parasitica or P.palmivora.These findings suggest a novel path to redeploy known R genes against different important plant pathogens.

Development and testing of a weather-based model to determine potential yield losses caused by potato late blight and optimize fungicide application

Late blight is one of the most important potato diseases. To minimize yield losses, various protective measures are used including fungicide application. Active use of fungicides results in a contamination of the environment. Therefore, crop protection strategies optimizing the number of treatments are of great interest.Using information about late blight development in an experimental potato field recorded over 30 seasons, a simulator to forecast yield losses caused by the disease was developed based on the number of 5-d periods favorable for reinfection of plants during a vegetation season. The simulator was successfully verified using independent data on the disease development from nine unprotected potato fields in the Netherlands and Germany. The average difference between the calculated and real yield losses did not exceed 5%. Using the simulator and weather data for a period of 2007–2017, yield losses were calculated for several areas of the Bryansk, Tambov, and Orenburg Regions of Russia. The results revealed differences in disease development between these regions and may be used to develop recommendations for a frequency of fungicide applications according to the regional risk of epidemics, leading to a significant reduction in fungicide use.

Population Improvement of Resistance to Late Blight in Tetraploid Potato:A Case Study in Combination with AFLP Marker Assisted Background Selection

Cultivated potato with high level of horizontal resistance against late blight is one of the most important goals of potato breeding.The recurrent selection has been adopted to increase the level of potato horizontal resistance and a B3C1 population without R1-R11 dominant genes has been released by the International Potato Center at the short-day condition of Peru.The present research was carried out to further improve the resistance and the agronomic traits of B3C1 population under long-day condition of Hubei,China,with maximized retention of its genetic diversity.Twenty-seven individual clones of B3C1 were used to generate population B3C2 by in-population crossing with the bulk pollens aiming to elevate the frequency of late blight resistance genotypes and to improve the adaptation to local long-day conditions.The late blight resistance and the main agronomic traits including the maturity,the plant characters and the tuber traits were evaluated for the foreground selection in three years,by which 130 pedigrees were maintained as the basic population of B3C2 for further selection.A total of 312 polymorphic loci detected by 9 AFLP marker combinations were used to monitor the genetic diversity of the populations for the background selection.The B3C2 population of 51 clones was finally selected,of which the frequency of resistant genotypes increased by 23.8% points and the genetic diversity was maintained by about 96% as referred to B3C1.Our results strongly suggested that combination of the foreground selection for target traits and the background selection for the genetic diversity is an efficient strategy in the recurrent selection of tetraploid potato to improve quantitative traits.

Efficacy of Some Botanical Extracts on the Control of Late Blight Disease in Experimental Potato Field

Late blight caused by Phytophthora infestans (Mont.) De Bary is the most devastating disease of potato. This study was carried out to evaluate the efficacy of ten botanical extracts against the late blight disease incidence and severity in experimental potato field at University of Rajshahi, Bangladesh during 2019-2020. Crude aqueous extract of leaves of Syzygium cumini, Psidium guajava, Eucalyptus globusus, Carica papaya and Lawsonia inermis;fruits of Terminalia bellirica, T. chebula and Piper nigrum;flower buds of Syzygium aromaticum and cloves of Allium sativum were used at 5% (w/v) concentration for evaluation. Out of ten botanicals, Syzygium cumini leaves extract was found most effective in controlling the late blight disease incidence and severity up to 66 DAS (days after sowing) and increased the potato yield by 71.29% compare to untreated control. The efficacy of Lawsonia inermis extract against late blight disease was found promising and increased the potato yield by 48.51%. Other four botanical extracts (Terminalia chebula, Piper nigrum, Syzygium aromaticum and Carica papaya) showed moderate efficacy against the incidence and severity of late blight disease, and increased 30% more potato yield compare to control. These results suggest that botanical extract of Syzygium cumini has a great potential as an alternative of chemical fungicides to control the late blight disease of potato in eco-friendly way.

In-Vitro Evaluation of Resistance to Late Blight (Phytophthora infestans Mont. De Bary.) in Solanum Accessions Native to Chile, by Inoculation of Detached Leaflets

The objective of the present study was to evaluate the resistance of 10 accessions to P. infestans, by in-vitro inoculation of detached leaflets with a complex isolation of the fungus. Late blight, caused by the fungus Phytophthora infestans Mont. De Bary, is one of the most important diseases of the potato crop, and can destroy complete plantations in a short space of time. Chile is considered as a sub-centre of the origin of cultivated potatoes with many native potato varieties in the country. The different resistance components demonstrated that within the material of Chilean native Solanum, there was a wide range of variation to late blight. The resistant control (R-8906384) and the accessions UCT-34-Cor presented the lowest infection efficiency, small sizes of the lesions and low levels of sporulation classifying them as the most resistant. This suggests low efficiency of the infection and high resistance to penetration in these materials. The more susceptible accessions often presented a good level of resistance for one or few components. It would be of great interest to go into the genetic control of the different resistance components to know if the same level of resistance expressed for a component by different accessions is under the same genetic control or not.

117份高抗晚疫病马铃薯种质资源遗传多样性分析

以117份高抗晚疫病马铃薯种质资源为试验材料,通过遗传多样性指数、变异系数及聚类分析等方法,对117份试验材料的26个性状进行分析。结果表明,20个质量性状的遗传多样性指数变化范围为0.35~1.61,6个数量性状变异系数大小排序依次为:主茎数>块茎产量>株高>干物质含量>茎粗>淀粉含量,遗传多样性指数变化范围为0.99~1.50。通过聚类分析,117份试验材料被划分为4类,第Ⅰ类材料多样性丰富,整体性状表现优良,比较符合现有栽培品种的性状特点;第Ⅱ类材料平均产量较高,聚合了我国主栽的4个高抗晚疫病马铃薯品种,可作为晚疫病抗性育种亲本;第Ⅲ类材料主茎数较多,植株整体表现为短日照类型,可作为抗性育种的抗原材料;第Ⅳ类材料包含4份资源,产量最高,可直接用于生产和育种亲本。对117份材料进行R8分子标记检测,其中104份资源含有R8基因,可作为晚疫病抗性基因聚合育种的基础材料。

基于CARAH预警系统对8种马铃薯晚疫病新型杀菌剂的防效评估

[目的]筛选马铃薯晚疫病防控新型高效绿色杀菌剂及生物农药,为科学合理使用高效杀菌剂开展马铃薯晚疫病绿色防控提供指导。[方法]在优化的马铃薯晚疫病CARAH预警系统指导下,采用随机区组设计对6种新型杀菌剂及2种植物源农药在马铃薯主栽品种合作88上进行大春马铃薯晚疫病田间药效评估,评价不同杀菌剂对马铃薯叶部和茎部的晚疫病防效。从预测中心病株开始,晚疫病每完成一代侵染进行一次防控。[结果]预警系统预测合作88将在7月2-4日出现中心病株,田间调查显示,对照处理7月3日出现马铃薯晚疫病中心病株,优化的预警系统预测中心病株出现时间的准确率达100%;根据预警系统指导,从7月1日第一次施药至8月30日最后一次施药共开展9次防控。对马铃薯叶部和茎部晚疫病调查显示:8种杀菌剂对马铃薯叶部和茎部晚疫病的防效分别在85.50%和87.50%以上,其中31%噁酮·氟噻唑的防效最高,分别达到95.00%和96.75%;植物源杀菌剂0.3%丁子香酚的防效较高,分别达到90.50%和92.50%。预警系统指导下应用8种杀菌剂对马铃薯增产显著,增产幅度在116.29%~257.69%,对照处理的商品薯率仅为38.27%,杀菌剂防控的商品薯率为71.60%~79.94%。[结论]CARAH系统测报与田间晚疫病的实际发生高度吻合,可精准指导晚疫病防控。6种化学杀菌剂和2种植物源农药对马铃薯晚疫病均有较高防效,推荐在生产中用于晚疫病防控,尤其是植物源农药丁子香酚替代化学杀菌剂的应用可以显著减少化学杀菌剂的使用量。

中国马铃薯晚疫病监测预警系统“China-blight”的组建及运行

马铃薯晚疫病是严重威胁世界马铃薯生产和粮食安全的重要病害之一,同时也是植物病害中流行速度最快的病害之一。由于品种多不抗病,目前国内外主要依靠化学防治控制该病害。为了提高用药的时效性,将信息技术与植物病害流行学原理相结合,设计并组建了中国马铃薯晚疫病监测预警系统"China-blight"(www.china-blight.net)。该系统由"中国晚疫病实时分布"、"未来48小时不同区域晚疫病菌侵染危险性预测"和"晚疫病化学防治决策支持系统"等子系统构成,此外还包括"晚疫病防治方法"、"品种抗病性"、"化学药剂库"、"其他病虫害"、"问题与经验交流"和"用户田间管理电子档案"等知识信息与服务功能。通过对2009年我国北方马铃薯一作区6-7月份病害侵染时段出现次数与晚疫病实际发生情况进行比较,预测信息与病害实际发生程度相符,该系统可以用于对马铃薯晚疫病田间防治的指导。

地质高背景区晚疫病马铃薯根际土壤细菌群落对重金属胁迫的响应

探究地质高背景区重金属胁迫下晚疫病马铃薯根际土壤细菌群落变化及其影响因素,对马铃薯安全生产具有重要意义。采集马铃薯(‘青薯9号’‘威芋5号’和‘威芋3号’)健康植株和晚疫病发病植株根际土壤,检测土壤p H、有机质和重金属含量,用Illumina MiSeq高通量测序技术分析细菌群落;采集马铃薯块茎,测定重金属含量。试验区土壤Cd、Cr和Zn含量均值分别为2.14、170和220 mg/kg,Cd含量超过国家土壤质量标准风险管制值,Cr和Zn含量超筛选值。马铃薯块茎仅1个样品Cd含量为0.103 mg/kg,超过国家食品安全限值标准。发病马铃薯根际土壤优势细菌门及其相对丰度主要为变形菌门(Proteobacteria)33.16%~39.09%、放线菌门(Actinobacteria)13.45%~17.11%;优势菌属主要为鞘脂单胞菌属(Sphingomonas)8.78%~12.30%、芽单胞菌属(Gemmatimonas)6.22%~7.61%,发病植株优势菌相对丰度与健康植株存在差异。不同品种间细菌多样性与丰度不同,马铃薯感染晚疫病后根际土壤细菌群落多样性升高,细菌菌群丰度下降。主成分分析显示发病植株与健康植株细菌群落差异性贡献率为29.59%。冗余分析结果表明,土壤重金属和pH显著影响土壤细菌群落组成和结构,对优势菌群的影响尤为明显,健康与发病植株间细菌群落的差异受土壤Pb、Cr胁迫的影响更大。因此,地质高背景区重金属胁迫下马铃薯可实现安全生产,染病马铃薯植株根际土壤细菌群落多样性降低,丰富度上升,土壤Pb、Cr通过改变根际土壤细菌群落有益菌类而影响晚疫病的发生和发展。

利用最大熵和CARAH模型评估重庆春马铃薯晚疫病气候风险

基于2019-2023年2-6月重庆市260个地面气象观测站逐小时平均气温、平均相对湿度数据,利用CARAH晚疫病模型模拟重庆春马铃薯晚疫病侵染风险的空间分布,通过气候网格数据构建最大熵模型,筛选马铃薯晚疫病气候影响因子,评估春马铃薯晚疫病气候风险,为春马铃薯晚疫病预测与科学防控提供参考依据。结果表明:基于CARAH模型采用小时级气象数据模拟晚疫病侵染的准确性较高,空发生率为12.5%,漏发生率为18.5%,TS评分为0.73。降水量是影响重庆春马铃薯晚疫病风险分布的主导因子,相对湿度和气温是重要因子,其幼苗期、现蕾开花期气候变量对晚疫病风险的影响较大。各马铃薯熟性(早/晚)与感病性(抗病/感病)组合的晚疫病低风险区面积少于或接近1万km^(2),平均面积占比为10.2%,中风险区和高风险区面积均超过3万km^(2),平均面积占比分别为43.7%和46.1%。重庆春马铃薯晚疫病气候风险呈中间高、周边低的空间分布特征,高风险区集中于重庆的川东平行岭谷地区,中风险区主要分布于渝东北大巴山区、渝东南武陵山区以及渝西川中丘陵一带,低风险区多呈片状分散在重庆边缘地带。重庆春马铃薯生产面临较高的晚疫病气候风险,空间分异特征显著,应通过合理生产布局和改进栽培技术加以应对。

基于CARAH模型的重庆春马铃薯晚疫病侵染特征模拟分析

马铃薯晚疫病是影响马铃薯产量的首要病害,研究其在山地立体气候条件下的发生流行特征具有重要意义。本文利用重庆地区260个地面气象观测站2019年-2023年小时级温湿度数据,采用CARAH模型模拟分析了春马铃薯晚疫病侵染频度、严重程度、关键侵染周期等时空特征,并采用巫溪县2022年马铃薯田间小气候监测数据对模拟精度进行了检验。结果表明,采用小时级地面气象观测数据模拟的晚疫病侵染空报率、漏报率均在20%以内,整体精度较佳。5年气象数据模拟结果显示,重庆地区气候条件有利于春马铃薯晚疫病的发生发展,早、晚熟品种栽培期普遍发生4~8代(11~20次)、8~12代(21~40次)侵染;严重程度呈现“两极化”特点,轻度和极重度侵染次数具有明显优势。第3代第1次和第5代第1次2个关键侵染周期的开始期分别在3月上旬至4月下旬、3月下旬至5月中旬,高峰期分别为3月下旬和4月中旬。春马铃薯晚疫病侵染的空间分异特征明显,东北部主产区侵染代数、次数、极重度侵染次数均少于其他产区,是晚疫病发生最轻的地区。关键侵染周期的开始时间随海拔升高而推迟,中西部丘陵低山地区早,东部武陵山与大巴山区晚。

马铃薯StRac5、StRac7和StRac13基因的克隆及其表达模式分析

探究马铃薯基因的表达模式,为后续研究基因对马铃薯病害的抗性影响提供理论依据。以马铃薯为试验材料,克隆获得3个马铃薯内源小G蛋白基因StRac5、StRac7、StRac13,并对其进行生物信息学分析和表达模式分析。结果表明,StRac5、StRac7、StRac13与拟南芥和水稻中的小G蛋白含有相似的保守序列,均属于ROP蛋白。StRac5和StRac13的蛋白结构域与拟南芥AtRop1、AtRop3、AtRop5、AtRop6及水稻OsRac5、OsRac6、OsRac7相同,StRac7与拟南芥AtRop9的蛋白结构域相同。系统进化树分析表明,StRac7属于第Ⅱ类,与拟南芥AtRop9遗传距离最近;StRac13属于第Ⅲ类,与拟南芥AtRop7遗传距离最近;StRac5属于第Ⅳ类,与水稻OsRac5和OsRac6遗传距离最近。在马铃薯不同组织中,StRac5、StRac7、StRac13基因的相对表达量均为叶>根>茎;与其在茎中表达量比较,StRac5、StRac7和StRac13在叶中的表达量分别增加了1222.4%,2531.3%,468.2%;接种晚疫菌后,StRac5、StRac7和StRac13基因的相对表达量均出现先升高后降低的趋势,StRac5和StRac13基因的相对表达量在接菌24 h后较0 h分别上调了62.2%,40.4%,StRac7基因的相对表达量在接菌72 h后较0 h上调了827.8%;经过ABA、SA、GA和6-BA处理后,StRac5、StRac7、StRac13基因的相对表达量呈现下调的趋势;JA和IAA处理后,StRac5、StRac7、StRac13基因的相对表达量呈现上调的趋势。因此,StRac5、StRac7和StRac13基因能够响应马铃薯晚疫病的侵染,在不同组织和不同激素处理下表达模式也存在一定差异。

3种施药方案对马铃薯晚疫病的防治效果及经济效益分析

马铃薯晚疫病是马铃薯生产上的重要病害,目前化学药剂防治仍是防控该病害的重要手段。本研究共设计3种马铃薯晚疫病药剂防控方案:方案1为0.3%丁子香酚可溶液剂+10%烯酰吗啉水乳剂160 g/(667 m^(2)·次);方案2为0.3%丁子香酚SL+10%烯酰吗啉EW 120 g/(667m^(2)·次)+代森锰锌60 g/(667m^(2)·次)+增效酮梨15 g/(667m^(2)·次);方案3为代森锰锌60 g/(667m^(2)·次)+增效酮梨15 g/(667m^(2)·次)+68.75%氟菌·霜霉威悬浮剂60 mL/(667m^(2)·次)/10%氟噻唑吡乙酮可分散油悬浮剂15 mL/(667m^(2)·次)/50%氟啶胺悬浮剂30 mL/(667m^(2)·次)(其中68.75%氟菌·霜霉威悬浮剂、10%氟噻唑吡乙酮可分散油悬浮剂、50%氟啶胺悬浮剂依次交替使用),根据田间马铃薯晚疫病发病进展,并结合晚疫病预警系统信息进行田间施药,对其防治效果和防治成本进行比较评价。结果表明,在整个防控期内,3种药剂方案对马铃薯晚疫病均具有较好的防控效果,田间防效均在90%以上;3种药剂方案处理的增产效果显著,产量均极显著高于清水对照CK的产量,3种方案间防效和产量无显著性差异;方案1药剂投入成本最低,方案2投入产出比最小,其中方案1中含有0.3%丁子香酚植物源药剂,不仅节约了成本,且减少了化学农药的使用。在实际生产中几种方案可交替使用,避免长期单一使用某种农药而产生抗药性。

菌糠水提液对马铃薯致病疫霉的抑制机理

菌糠是菌菇生产后残留的物质,含有丰富的无机盐和有机质等成分。利用热水浸提法制备香菇菌糠水提液(water extract from spent mushroom substrate,WESMS),通过紫外分光光度计和Zeta电位及粒径仪对其紫外吸收情况、表面电荷和水中分散粒径进行表征,采用平板渗透法及十字交叉测量直径法计算WESMS对致病疫霉的抑制率,利用光学显微镜和扫描电镜观察病原菌细胞形态的损伤程度,并采用琼脂糖凝胶电泳法分析WESMS对致病疫霉DNA的影响。结果表明,WESMS在紫外线A(UVA,315~400 nm)、B(UVB,280~315 nm)和C(UVC,100~280 nm)波段均有吸收,在水中的分散粒径为3649.27 nm。抑菌试验表明,WESMS对病原菌的生长具有抑制作用,随着提取液体积百分浓度的增加,抑制效果更明显,在高体积百分浓度(6.25%WESMS)作用下对病原菌的抑制率近100%。经WESMS处理后病原菌的菌丝更加扭曲、扁平,且褶皱明显增多,表明WESMS可对细胞造成明显破坏;WESMS处理组的DNA条带亮度暗于对照组,损伤程度与WESMS体积百分浓度呈正相关。研究结果为菌糠的资源化利用及其对马铃薯晚疫病的有效防治提供科学依据和技术支撑。

新型8-羟基喹啉-二硫代氨基甲酸酯衍生物对马铃薯晚疫病菌的室内毒力及防效检测

设计合成了6个8-羟基喹啉-二硫代氨基甲酸酯衍生物,并采用菌丝生长速率法测定了该类衍生物对晚疫病原菌的室内生长抑制和防效.结果表明:C2、C5及C6化合物对致病疫霉菌均有显著的抑制作用,EC 50值分别为2.97、2.40μg·mL^(-1)和9.26μg·mL^(-1).选择抑菌最优的C5化合物进行晚疫病防效评估,马铃薯离体叶片接种发现C5可有效防控致病疫霉菌侵染.

马铃薯晚疫病及抗病综合防治研究进展

马铃薯晚疫病是世界范围内最严重的植物病害之一,每年造成近百亿美元的经济损失,该病具有流行快、变异快等特点,发病面积和发病程度逐年升高,已成为限制我国马铃薯产业发展的主要障碍因素。该文综述了气候条件、品种、田间管理等对马铃薯晚疫病发病的影响,以及马铃薯晚疫病防治研究进展,旨在为我国马铃薯产业可持续发展提供有效参考。

4种农药对马铃薯晚疫病的防控及增产作用

为筛选出能够防控马铃薯晚疫病且绿色、高效、安全的新型替代药剂,采用田间药效试验法。结果表明,50%烯酰吗啉WP∶60%代森联·吡唑脂WG(1∶1)1320 g a.i./hm^(2)和18.7%烯酰·吡唑脂WG 448.8 g a.i./hm^(2)对马铃薯晚疫病的防控效果达94.88%和92.57%,可每667 m^(2)增产696.64 kg和659.89 kg,增产率达64.29%和60.90%,这说明50%烯酰吗啉WP∶60%代森联·吡唑脂WG(1∶1)和18.7%烯酰·吡唑脂WG可作为替代药剂用于马铃薯晚疫病的大田防控中。

28%唑嘧菌胺·氟吡菌胺悬浮剂防治马铃薯晚疫病田间药效试验

为明确复配药剂对马铃薯晚疫病的田间防治效果及最佳使用剂量,本研究采用茎叶喷雾处理,定期调查的方法进行田间药效试验。结果表明,28%唑嘧菌胺·氟吡菌胺悬浮剂在210.0~315.0 g·hm^(-2)的有效成分用量下,第一次施药10 d后对马铃薯晚疫病防效可达79.66%~87.56%,第二次施药10 d后对马铃薯晚疫病防效可达80.68%~88.60%,均显著优于对照药剂,且对应有效成分用量少于对照药剂;两次施药后5 d对马铃薯药害等级均为1.0,未见对马铃薯产生明显药害。比空白对照增产16.34%~24.28%,综合用药成本及效果,推荐有效成分用量为210.0~315.0 g·hm^(-2)。28%唑嘧菌胺·氟吡菌胺悬浮剂能够有效防治马铃薯晚疫病并对马铃薯具有一定的增产效果和较好的安全性。