Effects of bean rust (Uromyces appendiculatus) epidemics on host dynamics of common bean (Phaseolus vulgaris)

Epidemics of bean rust ( Uromyces appendiculatus ) and their effects on host dynamics of common bean ( Phaseolus vulgaris ) were studied in three controlled greenhouse experiments, with and without fungicide sprays, on two susceptible bean cultivars, Dufrix and Duplika. Bean plants were artificially inoculated with a suspension of 10⁵ U. appendiculatus urediniospores mL⁻¹ water and temporal disease progress, as well as host growth dynamics (leaf size and defoliation), were monitored on a leaflet basis in comparison with non-inoculated plants, which were sprayed with deionized water. Progress curves of bean rust, expressed as the proportion of leaf area occupied by pustules (uredinia), or as the proportion occupied by total lesion area (= halo areas + pustule area), were well described by logistic functions with maximum disease levels clearly lower than 1. Bean rust epidemics substantially affected host growth by reducing the total leaf area formed by 17·4–35·6% and 35·3–46·2% compared with healthy plants for cvs Dufrix and Duplika, respectively. Fungicide sprays mitigated the negative effect of bean rust, leading to a gain in leaf area of 17–21% compared with unsprayed plants in both cultivars in two experiments, while in another experiment, disease control had no effect in Dufrix, but a clear effect in Duplika. In addition to the growth depression, bean rust also led to pronounced losses of leaf area as a result of reduced leaf size (leaf shrivelling) and accelerated defoliation.     

Control of bean common mosaic by deployment of the dominant gene I

The deployment of the dominant gene I for the control of bean common mosaic predisposes a bean crop to the risk of death by black root if one or more recessive genes to prevent the hypersensitive plant reaction are lacking. However, during 3 years of observation in Kenya black root occurred only exceptionally to more than 10%, and in such cases the yields from crops having the dominant gene I exceeded significantly those from mosaic-susceptible crops. The use of the dominant resistance factor in Kenya is therefore recommended, but continued caution and monitoring of the disease situation are required. Broadening the resistance basis by adding recessive genes to control black root is advisable.Samenvatting Het gebruik van het dominante gen I voor de bestrijding van de virusziekte bonerolmozaïek stelt een bonengewas bloot aan het gevaar van systemische necrose, als niet een of meer recessieve genen aanwezig zijn om deze overgevoeligheidsreactie van de planten te voorkomen. Gedurende een periode van drie jaar werden waarnemingen verricht om na te gaan hoe vaak deze necrose optrad. Slechts bij uitzondering bleek meer dan 10% van de planten te worden aangetast. In die gevallen werd de opbrengst toch aanmerkelijk verhoogd door de aanwezigheid van het dominante gen I. Het gebruik van dit gen ter bestrijding van het bonerolmozaïek wordt daarom voor Kenya aanbevolen. Voortdurend moet echter worden nagegaan in welke mate necrose-inducerende stammen van het virus voorkomen. Een verbreding van de erfelijke basis van de resistentie ter voorkoming van de necrotische reactie door introductie van recessieve resistentiegenen is raadzaam.

---

Résumé L'emploi du gène dominant I pour la lutte préventive contre la mosaïque commune du haricot, en I'absence d'un ou plusiers gènes récessifs pour éviter une réaction hypersensible de la plante, entraine un danger de mort de la plante par racines noires. Néanmoins, pendant les 3 ans d'observations au Kénya, les cas de racines noires ne sont apparus qu'exceptionnellement à un taux superieur à 10%, et, dans de tels cas, le rendement du végétal ayant le gène dominant I était, de façon significative, supérieur à celui des végétaux prédisposées à la mosaïque. L'utilisation au Kénya du facteur de résistance dominant est par conséquent recommendé mais une attention et une surveillance permanentes de I'évolution de la maladie sont nécessaires. On peut conseiller I'élargissement de la base de résistance par addition de gènes récessifs pour le contrôle de la maladie des racines noires.

     

Characterization of the rust resistance gene present in the common bean cultivar Ouro Negro,the main rust resistance source used in Brazil

The main goal of the present work was to characterize the rust resistance (RR) gene present in the Mesoamerican common bean cultivar Ouro Negro, temporarily named Ur‐OuroNegro or Ur‐ON, which is the main RR source used in Brazil. The RR spectrum presented by cv. Ouro Negro was compared with those of other bean lines harbouring known RR genes when inoculated with nine selected races of Uromyces appendiculatus, the causal agent of bean rust. In addition, all bean lines were screened with molecular markers linked to Ur‐ON in order to identify additional evidence for the presence of alleles for this locus in the screened RR sources. The allelic relationships of Ur‐ON were tested with previously characterized RR genes from lines resistant to at least one race of the pathogen. Allelism tests were also carried out between cv. Ouro Negro and cvs CNC and CSW 643, important RR sources in Brazil harbouring unnamed RR genes. The results showed that the major dominant gene conditioning RR in cv. Ouro Negro is positioned at a locus distinct from those with which it was compared. It is proposed that this gene – or complex gene locus – is unique and be designated Ur‐14.     

不同小豆抗性品种对锈菌侵染的生化响应和防卫反应基因的表达特征

为探究小豆应答锈菌侵染的生理机制,以不同小豆抗性品种与豇豆单胞锈菌Uromyces vignae互作为研究对象,采用紫外分光光度法和实时荧光定量PCR技术分析锈菌侵染后不同抗性品种中防御酶活性及防卫反应基因表达的变化特征。结果表明,接种豇豆单胞锈菌后小豆抗病品种叶片内过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和多酚氧化酶(polyphenol oxidase,PPO)活性均比感病品种显著提高;接种192 h后,小豆抗病品种中CAT和SOD活性最高,分别为16.93 nmol·g^-1·s^-1和950.89 U/g,较对照提高了496.13%和89.61%,小豆感病品种中CAT和SOD活性分别在接种192 h和120 h后达到峰值,分别为10.54 nmol·g^-1·s^-1和884.51 U/g,较对照增加了256.08%和55.50%,增加幅度小于抗病品种;接种12 h后,小豆抗病品种和感病品种...     

蚕豆和豌豆锈病病原菌的分子鉴定

为明确我国热带和亚热带地区蚕豆Vicia faba和豌豆Pisum sativum锈病的病原菌种类,通过致病性测定和ITS序列系统发育分析对来自我国云南省玉溪市的4份豌豆锈菌分离物及云南、广西、重庆和四川省(区、市)的5份蚕豆锈菌分离物进行系统鉴定。结果显示,分离自豌豆的锈菌WX1分离物对蚕豆和豌豆均具有高致病性,在侵染叶片上产生大量锈子器;分离自蚕豆的锈菌CX3分离物仅对蚕豆具有高致病性,能在叶片上产生大量夏孢子,而对豌豆的致病性相对较低,仅产生少量的夏孢子堆;分离物WX1和CX3对小扁豆和鹰嘴豆不具有致病性。基于ITS序列系统发育分析表明,所有不同寄主来源的蚕豆单胞锈菌分离物均聚类于一个系统发育组,但分离自蚕豆和豌豆的分离物分别聚类在不同的亚组。表明分离自云南省玉溪市豌豆上的蚕豆单胞锈菌Uromyces viciae-fabae应为豌豆专化型,定名为U. viciae-fabae ex P. sativaum,而来源于云南、广西、重庆和四川省(区、市)的蚕豆锈病病原菌为蚕豆专化型U. viciae-fabae ex V. faba。     

Changes in biochemistry and cellular ultrastructure support different resistance mechanisms to Phytophthora sojae in nonhost common bean and host soybean

Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease affecting soybean production worldwide. In nature, soybean is the only economically important cultivated host of P. sojae. The aim of this study was to explain different resistance mechanisms to P. sojae in nonhost common bean and host soybean as a basis for the control of Phytophthora root and stem rot of soybean via nonhost resistance. Observations and measurements of disease resistance-related variables showed slight differences in structural and biochemical resistance mechanisms between common bean and soybean. P. sojae infection induced a stronger hypersensitive response in nonhost common bean than in host resistant soybean. Moreover, phytoalexin phaseollidin synthesis-related vestitone reductase gene was extremely highly up-regulated, and phytoalexin glyceollin synthesis-related isoflavone reductase gene was slightly less up-regulated in common bean than in soybean, which resulted in a higher level of phaseollidin and a lower level of glyceollin in common bean. Phaseollidin had stronger inhibitory effects on mycelial growth and oospore formation of P. sojae than glyceollin, and more cell wall depositions and callose accumulated in common bean, which are probably related to the stronger resistance of nonhost common bean to P. sojae.     

超高效液相色谱-串联质谱法快速检测菜豆及土壤中的灭蝇胺残留

建立了采用超高效液相色谱-串联质谱仪(UPLC-MS/MS)快速检测分析菜豆及其土壤中灭蝇胺残留的方法。样品经5 mmol/L的乙酸铵-乙腈溶液[V(乙酸铵):V(乙腈)=1:4]提取、定容,N-丙基乙二胺(PSA)净化后用UPLC-MS/MS在正离子模式下以多反应监测扫描方式进行测定,外标法定量。结果表明:在0.05～1 mg/kg添加水平范围内,灭蝇胺在菜豆和土壤中的平均回 收率为80.1%～95.2%,相对标准偏差(RSD)为1.9%～9.1%,检出限(LOD)为3.8～5.9 μg/kg,定量限(LOQ)为50 μg/kg。该方法操作简单、灵敏度高、定量准确且测定浓度范围宽,适用于菜豆及土壤中灭蝇胺的残留分析。     

Evaluation of fungicide application rates,spray schedules and alternative management options for rust and angular leaf spot of snap beans in Uganda

Yield losses due to rust and angular leaf spot (ALS) of snap beans may reach 100% in Eastern Africa. Where susceptible varieties are grown, farmers control these diseases with routine fungicide applications. To determine an optimum application rate and spray schedule for Orius® (tebuconazole 250 g/L), we sprayed 10 mL and 20 mL Orius® per 15 L spray water twice at two trifoliate leaf stage and 50% flowering, and three times at the same stages, with an additional application at pod initiation. In farmers’ fields, we tested the effect of fungicide sprays, use of resistant variety, intercropping, increased plant spacing and farmyard manure on rust and ALS diseases. Application three times of 20 mL Orius® per 15 L spray water reduced rust severity scores by 5.7 and 2.4 in 2010 and 2011, respectively. Lowest rust and ALS severities were observed when a resistant variety, fungicide or farmyard manure was used. Pod yield increments due to disease management ranged between 13% and 242%. Prophylactic fungicide application, use of resistant varieties and farmyard manure can be used to reduce disease severity and improve snap bean quality on smallholder farms.     

褪黑素诱导小豆抗锈病机理的初步研究

为明确外源褪黑素诱导小豆抗锈性的作用及机理,以感病小豆品种‘宝清红’为材料,采用叶面喷施不同浓度褪黑素激发处理小豆真叶,而后对真叶挑战接种锈菌夏孢子,结果表明,低浓度(11.61 mg/L)褪黑素可显著提升小豆对锈病的抗性。夏孢子萌发试验表明,褪黑素对夏孢子萌发及芽管生长无显著抑制作用,表明褪黑素无抑菌活性。进一步的基因表达分析发现,与对照相比,褪黑素激发诱导了水杨酸(SA)通路关键基因NPR1于接种后24 h显著上调表达,且病程相关蛋白PR1、几丁质酶(CHI)、β-1,3-葡聚糖酶(GLU)及PR5均于接种后24～120 h被显著诱导表达,说明褪黑素可能通过诱导NPR1表达,进而激活下游PR蛋白的高水平应答,使感锈病小豆品种获得对锈病的抗性。     

小豆AP2/ERF基因家族鉴定及其应答锈菌侵染的表达分析

 为明确小豆VaAP2/ERF家族基因在小豆应答豇豆单胞锈菌(Uromyces vignae)侵染中的作用,本研究采用生物信息学方法从小豆基因组中鉴定VaAP2/ERFs家族基因186个,包括AP2(24个)、RAV(2个)、Soloist(1个)及ERF(159个)四个亚家族,其中ERF亚家族又可分为DREB和ERF两个亚类。基因结构分析发现,68.3%的VaAP2/ERFs基因不具内含子。保守基序分析发现,各亚族成员保守域组成类似,可作为基因家族分类的重要依据。前期转录组测序发现VaAP2/ERF中的6个成员接种后24 h显著上调,进一步应用qPCR技术对其在‘1-D-3’(免疫)及‘宝清红’(感病)中应答锈菌侵染的表达分析发现,免疫品种中6个成员均于接种后6 h及120 h显著上调,另有2个于接种后12 h也显著上调,表明上述基因均在小豆抗锈病中发挥正调控作用。     

Life-table analysis of faba bean rust

In controlled near-optimum conditions (18 °C), monocyclic sporulation capacity and spore infection efficiency were assessed for faba bean rust on the first and second leaves of field bean. After a latency period of 8–10 days, lesions sporulated duringc. 50 days. Spore production on the second leaf,c. 9×10⁴ spores per lesion, was two times as high as spore production on the first leaf. Infection efficiency was similar for both leaf layers, with a mean value of 0.11 lesion per inoculated spore. Infection efficiency decreased strongly when spores originated from mother lesions older than 20 days. Three life-table statistics (the net reproduction numberR _o , the mean generation timeT _g , and the maximum relative growth rater _max ) were calculated.R _o was larger andT _g was longer for the second than for the first leaf, butr _max was nearly the same for both leaf layers (0.31–0.33 day^–1).r _max was compared with the exponential growth rater measured in a field experiment. From the difference between the two rates, the fraction of inoculum lost in field conditions was estimated at 0.54–0.94. The life-table statistics were also compared to those of other legume rusts, and implications of life-table analysis for comparative epidemiology were discussed.     

不同覆膜方式对山旱地菜豆土壤水分及利用效率的影响

以秋季和春季半膜平覆、全膜平覆、全膜双垄沟6种覆膜方式为处理,研究了不同覆膜方式对山旱地菜豆土壤水分及其利用率等的影响.结果表明,秋季全膜双垄沟和秋季全膜平覆较春季全膜双垄沟、秋季半膜平覆、春季全膜平覆和对照春季半膜平覆在播种时0～ 100 cm土层中土壤贮水量分别提高7.62％～14.20％、7.44％～14.02％...     

Integration of partial resistance,plant density and use of fungicide for management of white mould in common bean

In-row plant densities have not been studied for common beans with type II growth habit and contrasting reactions to white mould. Advanced breeding lines with partial resistance or susceptibility to white mould were combined with 4, 7, 10 or 13 plants m⁻¹ and with or without fungicide at a constant between-row spacing of 0.5 m in five sprinkler-irrigated field trials conducted during the autumn–winter season in Brazil. White mould pressures in the trials covered the whole range from zero to moderate/high (46–60% of white mould severity index). In all trials, means of white mould incidence, severity and yield did not vary significantly between 7 and 13 plants m⁻¹ for the partially resistant line, regardless of the fungicide levels. For the susceptible line, 13 plants m⁻¹ increased white mould incidence and severity under moderate disease, regardless of the fungicide levels, and decreased yield compared with 10 plants m⁻¹ when fungicide was applied twice under moderate/high disease pressure. For the susceptible line, 7 or 10 plants m⁻¹ maximized yield in all trials, with or without fungicide applications. The results suggest that the current recommendation of 11–13 plants m⁻¹ could be used for type II beans with partial resistance to white mould in either a conventional or organic system. For susceptible genotypes, 7–10 plants m⁻¹ seems to be the most appropriate in-row plant density. This study may improve the recommendation of in-row plant density for type II beans cultivated under white mould pressure.     

小麦持久抗条锈病品种Champlein的抗性遗传分析

小麦条锈病是小麦生产中最重要的病害,培育抗病品种是防治条锈病最经济、有效、安全的措施。‘Cham-plein’引自法国,对条锈菌生理小种表现良好持久抗性。为了明确其抗性遗传特点,以感病品种‘铭贤169’与其杂交、自交和回交获得了F1、F2、F3和BC1代,人工接种小麦条锈菌生理小种CY32,在温室和田间对‘Champlein’进行遗传分析。结果表明:苗期‘Champlein’对CY32的抗病性由1对显性基因控制;成株期‘Champlein’对CY32的抗病性由2对显性和1对隐性抗条锈病基因以互补方式控制;系谱分析表明基因可能来源于‘Vilmorin27’。     

Spread of faba bean rust over a discontinuous field

Spatio-temporal progress of an epidemic of faba bean rust was monitored over a discontinuous field. Trap plots were sown at increasing distances from a source plot, in the centre of which plants were inoculated. Disease spread in the source plot followed a focal pattern, with a radial velocity of expansion slightly lower than 0.1 m per day. At the end of the experiment, all trap plots had been infected, and two of the most distant ones showed unexpected high disease severity. Using a three-dimension model of disease progress, we showed that the epidemics on the scales of the source plot and of the trap plots could not be combined into a single epidemic on the whole-field scale. The epidemics had equivalent infection rates on both scales, but changing the scale dramatically affected their distance parameter. The epidemic in the source plot could have been caused by a short-distance, high-frequency, deterministic mechanism of spore dispersal, whereas infection of the trap plots could have been caused by a long-distance, low-frequency stochastic mechanism of spore dispersal. Although our results agreed with the predictions of a simulation model postulating these two mechanisms, alternative hypotheses which could also explain the observed disease pattern remained to be tested.     

谷子抗病基因同源序列的克隆与分析

谷子锈病是谷子上的一种流行性强、毁灭性大的病害,严重影响谷子生产.种植抗病品种是防治锈病最经济有效的方法,但谷子抗锈病种质资源非 常贫乏,而且高抗锈病的材料其农艺性状又很差.很难通过传统育种方法培育抗锈病品种,因此克隆谷子抗锈病基因尤为重要.目前克隆到的许多植 物抗病基因编码的氨基酸序列都有一定的保守结构域.根据抗病基因保守结构域,已克隆的抗病基因主要分为5类,其中最主要的是NBS-LRR(nu- leotide-binding site leucine-rich epeat)和STK(Se-rine／Threonine protein kinase)类.因而根据抗病基因保守结构域设计引物,从植物的DNA中扩增植物的抗病基因同源序列RGA(resistance geneanalogs)更加快捷有效,目前通过RGA方法克隆植物抗病基因已有报道[1,2].     

小麦持久抗性品种对中国条锈菌(系)抗病性特点的分析

小麦品种抗性谱鉴定、田间病情系统观察和抗性组分测定等结果表明,小麦持久抗条锈品种具显著的抗性特征,即成株期抗性谱很宽,有的品种甚至全生育期都表现抵抗,田间病情消长很慢且轻,成株期一般表现侵染机率低、病斑面积小、潜育期长。试验在控制条件下进行,便于操作,可用于小麦品种持久抗条锈性鉴定研究。     

小麦持久抗条锈性品种N.strampelli苗期抗性遗传分析

 小麦条锈病是世界范围内小麦上发生最为普遍的重要病害之一,种植抗病品种是防治该病的首选。N.strampelli是1974年我国从意大利引进的,在甘肃省陇南小麦条锈病常发易变区大面积种植30余年仍然保持良好抗病性,是一个典型的持久抗条锈性品种。为了测定其遗传特性,利用小麦条锈菌生理小种CY29、CY30和菌系Su-14在温室对N.strampelli与铭贤169及其杂交F₁、F₂和BC₁代接种进行遗传分析。结果表明:N.strampelli对CY29的抗病性由2对隐性基因独立或重叠作用控制,不受胞质效应的影响,属核遗传;对CY30的抗病性由1对显性基因和1对隐性基因互补控制,属核遗传;对Su-14菌系的抗病性由2对隐性基因累加作用控制,属核遗传。研究结果表明,N.strampelli应做为抗源用于小麦的抗病育种中。     

小豆白粉病菌的鉴定与小豆品种抗白粉病评价

为明确小豆白粉病病原菌的种类以及小豆种质资源对白粉病的抗性,采用形态学和系统发育学方法对近年来在北京市发生的小豆白粉病病原菌种类进行鉴定,并采用室内苗期人工接种法评价小豆常见栽培品种（系）对白粉病的抗性。结果表明,从北京市采集的感白粉病小豆病样中培养获得病原菌BJ1,该菌能在小豆叶片和茎上产生明显的白色粉斑,分生孢子梗直立,不分枝,分生孢子单细胞,成链状着生于分生孢子梗上,呈椭圆形或卵圆形。通过rDNA-ITS序列系统发育分析,小豆白粉病菌BJ1被鉴定为白粉菌目白粉菌科的苍耳叉丝单囊壳Podosphaera xanthii。室内苗期人工接种条件下,19个供试小豆品种（系）接种小豆白粉病菌BJ1后均可发病,其中9个审定品种均表现为中度感病或高度感病,10个优良品系发病略轻。