Characterization of a new cultural type (LP) of Rhizoctonia solani AG2-2 isolated from warm-season turfgrasses, and its genetic differentiation from other cultural types

Isolates of Rhizoctonia solani AG2-2 obtained from turf with symptoms of large-patch disease of warm-season turfgrasses were compared with known AG2-2 isolates belonging to cultural types IIIB and IV. Some isolates that were previously identified as type IV have been separated here and named LP isolates. Comparisons among isolates were based on cultural morphology, hyphal growth rate, pathogenicity and restriction fragment length polymorphism (RFLP) analysis in the nuclear encoded ribosomal DNA (rDNA) genes. The cultural characteristics of LP isolates varied from those of types IIIB and IV. LP isolates did not show distinct sclerotial formation and zonation, and the colour of their mycelia and pigment deposition was dark brown. LP isolates had slower hyphal growth rates than types IIIB and IV, with an optimum temperature of 25°C compared with 28°C for types IIIB and IV. LP isolates were less virulent on radish but highly virulent on zoysia grass when compared with isolates of types IIIB and IV. Genomic DNA was digested separately with Eco RI, Ban III, Xba I and Sal I, and probed with cloned rDNA from Alternaria alternata in Southern hybridizations. LP isolates had one RFLP pattern, while both IIIB and IV possessed four different patterns each. Cluster analysis of RFLPs showed that R. solani AG2-2 is divided into three genetic subgroups, consisting of the IIIB, IV and LP isolates, respectively. The polymerase chain reaction (PCR) amplified rDNA internally transcribed spacer (ITS) regions of the IIIB, IV and LP isolates had the same length but produced different restriction patterns when digested with Msp I and Taq I. These results indicate that there are three cultural types in R. solani AG2-2, namely IIIB, IV and LP.     

海南省木豆丛枝病植原体的分子检测及鉴定

 利用植原体通用引物R16mF2/R16mR1和rp (Ⅱ) F1/rp (Ⅱ) R1对海南木豆丛枝病植原体16S rDNA和部分核糖体蛋白(ribosomal protein,rp)基因序列进行PCR扩增、克隆和测序。获得海南木豆丛枝病植原体16S rDNA基因片段为1430bp,rp基因片段为1170bp。核苷酸同源性比较和系统进化树构建表明,引起海南木豆丛枝病的植原体应属于16SrⅡ组中的亚组ⅲ。本研究首次从分子水平确定了引起我国海南木豆丛枝病的病原物为植原体,明确了其分类地位,为该病害流行学研究和防治提供了理论依据。     

浙、闽、粤、琼四省棕榈科植物细须螨科调查

2009年5月至2010年10月,采用在体视显微镜下直接检查被昆虫和螨类为害所致的扭曲、畸形、黄化叶及叶背可见红色细点的叶片的方法,对我国海南、广东、福建和浙江4省12个城市的棕榈科植物进行调查。共采集江边刺葵、假槟榔和国王椰子等34种棕榈科植物240份样品,制作标本700余片,鉴定出细须螨科3属12种,为害较严重的有加州短须螨、卵形短须螨、紫红短须螨以及印度雷须螨。     

干旱河谷地区退耕还林调查与生态还林分析

退耕还林工作全面展开已经有4~5年,其执行效果如何?如何及时总结退耕还林中存在的问题和经验进行更好的退耕还林决策呢?利用遥感和地理信息系统技术结合采访调查,及时的、客观反映了退耕还林的执行情况。本文以长江上游生态脆弱区——川藏边缘的横断山区X县为例,应用“3S”技术对退耕还林的成果进行了监测,得出:由于种种原因,该地区退耕还林中可能上报的退耕面积不实,超出实际退耕面积;耕地中很大比例的坡度小于25o的耕地纳入到退耕地中。研究也分析了退耕还林对当地社会、经济等影响,调查和有关研究证实,大面积退耕还林使该地区财政收入大比例较少,农民对国家的补贴依赖性强,一旦停止钱粮补助,农民将失去生活来源,很可能导致毁林复耕。多数农户强烈表达了希望延长粮食补助的愿望,本研究认为经济补偿机制的关键应该放在如何调动农民调整产业结构和发展后续产业的积极性上,否则再长时间的连续补偿也无济于事。对已经大面积退耕的区域,加紧发展后续产业和产业结构调整势在必行,对正在计划退耕的地区,应该将退耕还林作为一个系统工程考虑,退耕还林应该是一个长期的、逐步实施的过程,必须综合各种原则和因素、分清楚轻重缓急,一步步实施,相应的经济补偿机制也需要调整。     

海南岛反季节蔬菜根际寄生线虫种类调查与分布

从海南岛10个县/市,9科31种蔬菜采集其根际土壤样本59份,用浅盘分离法分离线虫,并对其进行了系统形态学观测.结果表明,共分离得到19属寄生线虫.其中发生最普遍的线虫为肾状线虫属(Rotylenchulus),检出率为55.93％,寄主多达8科21种蔬菜;滑刃属(Aphelenchus)次之,检出率为47.46％,寄主多达9科24种;螺旋属(Helicotylenchus)、丝尾垫刃属(Filenchus)和根结属(Me loidogyne)分布相对较广,检出率分别为35.59％、33.90％和23.73％,寄主也比较多;拟滑刃属(phelenchoides)等其他14属较少或零星发生.在养心菜(Sedum aizoon)检出滑刃属线虫为国内首次报道.     

海南省温郁金炭疽病的病原鉴定

温郁金炭疽病是一种重要的真菌性病害,该病主要危害叶片,初期产生水渍状的淡黄色病斑,后逐渐扩大成圆形、椭圆形或不规则形的灰褐色病斑,上面有黑色小点,病斑外面环绕一层黄色晕圈,严重时多个病斑联合造成叶片卷缩和枯死,2016年我们从海南省的温郁金种植基地采集炭疽病样本,经病原菌的分离纯化、柯赫氏法则验证、病原菌的形态特征观察及多基因谱系分析方法,确定其病原菌为郁金炭疽菌Colletotrichum curcumae(Syd.)E.J.ButlerBisby。     

Characteristics and distribution of Colletotrichum species in coffee plantations in Hainan,China

Anthracnose caused by Colletotrichum species is a serious disease on a range of economically important hosts. To determine the Colletotrichum species in coffee plantations in Hainan, China, 55 isolates were obtained from Coffea arabica (arabica) and C. canephora var. robusta (robusta) in five counties. Initially, partial sequences of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were used to measure fungal genetic diversity. Then a subset of 23 isolates was selected to represent the range of genetic diversity, varieties and geographic origin for further multilocus phylogenetic analyses. These isolates belong to eight known Colletotrichum species from three Colletotrichum species complexes, including gloeosporioides (C. endophytica, C. fructicola, C. ledongense, C. siamense and C. tropicale), boninense (C. karstii), gigasporum (C. gigasporum), and one singleton species (C. brevisporum). Of these, C. siamense was isolated in all sampled counties and C. fructicola was identified in three counties. The other six species were isolated only in one or two counties. Only C. siamense and C. fructicola were isolated from arabica, whereas all eight species were isolated from robusta. Occurrence of C. brevisporum, C. endophytica, C. ledongense and C. tropicale in coffee has not been reported previously. Pathogenicity tests showed that all eight species were pathogenic to coffee leaves and fruit. In vitro tests showed that Colletotrichum isolates from coffee in Hainan were most sensitive to prochloraz, less sensitive to carbendazim, propiconazole and difenoconazole, and least sensitive to myclobutanil.     

海南省冬季北运蔬菜匍柄霉叶斑病病原的鉴定

2009-2011年对海南蔬菜匍柄霉叶斑病进行调查,从不同寄主上采集到68份标本,鉴定海南蔬菜匍柄霉叶斑病病原菌有7种:苦瓜匍柄霉(Stenph ylium mornordi)、菜豆匍柄霉(S.phaseolina)、番茄匍柄霉(S.lycopersici)、茄匍柄霉(S.solani)、囊状匍柄霉(S.vesicarium)、莴苣匍柄霉(S.lactucae)和菠菜匍柄霉(S.spinaciae).除番茄匍柄霉(S.lycopersici)和茄匍柄霉(S.solani)外,其他5种均为海南新记录种.     

从海南省杂草胜红蓟和假马鞭上检测到粉虱传双生病毒

 利用三抗体夹心ELISA(TAS-ELISA)及PCR检测的方法对采自海南的胜红蓟(Ageratum conyzoides)和假马鞭(Stachytarphetajamaicensis)的5个病样进行了检测,表明均为粉虱传双生病毒。PCR扩增产物克隆后进行序列测定,结果表明存在2类双生病毒,其中样品Hn2存在2类病毒的复合侵染。这是在海南首次报道存在有粉虱传双生病毒。     

甘肃陇南重要生产品种‘中梁27’抗条锈特点分析及其利用价值

运用比较形态学、同工酶和 mtDNA-PCR 对采自海南岛9个市县的南药根结线虫进行种类鉴定,结果发现有南方根结线虫、象耳豆根结线虫、爪哇根结线虫、花生根结线虫和西班牙根结线虫等5种根结线虫危害海南岛南药。5种根结线虫均能在海巴戟上寄生与危害,而南方根结线虫寄主非常广泛,可危害大多数调查的药用植物。     

海南岛南药根结线虫种类鉴定

运用比较形态学、同工酶和mtDNA-PCR对采自海南岛9个市县的南药根结线虫进行种类鉴定,结果发现有南方根结线虫、象耳豆根结线虫、爪哇根结线虫、花生根结线虫和西班牙根结线虫等5种根结线虫危害海南岛南药。5种根结线虫均能在海巴戟上寄生与危害,而南方根结线虫寄主非常广泛,可危害大多数调查的药用植物。     

海南省胡椒主要病害现状初步调查

为明确海南省胡椒主要病害种类及发生情况,对海南省琼海、文昌、万宁、海口、定安、临高、儋州、澄迈、屯昌等9个市(县)进行了调查,结果表明:(1)目前危害海南胡椒生产的主要病害有9种,其中真菌病害5种,为胡椒瘟病、胡椒枯萎病、胡椒根腐病、胡椒炭疽病和胡椒煤烟病;细菌病害1种,为胡椒细菌性叶斑病;病毒病害1种,为胡椒花叶病;其他病害2种,为胡椒根结线虫病和胡椒藻斑病。(2)分布广且危害严重的有胡椒瘟病、胡椒花叶病、胡椒根结线虫病和胡椒枯萎病。     

海南甘蔗病毒病的调查及其病原分子鉴定

 海南是我国重要的甘蔗生产省份之一,但其甘蔗主要种植区感染病毒的种类和数量尚不十分清楚,且海南甘蔗花叶病病原病毒缺乏分子水平的系统鉴定。为明确海南甘蔗病毒病的种类、数量、分布及危害情况,本研究拟建立较为完整的甘蔗病毒病检测技术体系,对海南甘蔗病毒病展开调查,为甘蔗抗病毒基因工程及健康种苗发展提供参考。     

Population structure,pathogenicity, and fungicide sensitivity of Colletotrichum siamense from different hosts in Hainan,China

Areca palm, rubber tree, and coffee are always planted adjacent to each other or intercropped with each other, and Colletotrichum siamense was found to be the dominant species of Colletotrichum from these crops in Hainan, China. To study the population structure, pathogenicity, and fungicide sensitivity of C. siamense from these three crops in Hainan, isolates were first identified by their morphological characteristics and multilocus phylogeny. Then both permutational multivariate analysis of variance (PERMANOVA) and pairwise F_ST analysis showed that the original host and geographical origin (counties) had significant effects on genetic variation in the C. siamense population, explaining 5.6% and 16.3% of genetic variation, respectively. There were significant genetic differentiations between coffee and rubber tree populations but the genetic differentiation was small (F_ST = 0.04), while significant differentiations were observed among all populations from different counties except those between Haikou and Chengmai. Pathogenicity analysis using artificial inoculation showed that isolates had significantly higher disease incidence and diseased lesion diameter on wounded leaves than on nonwounded leaves. However, the original host of an isolate and geographical origin did not significantly affect the pathogenicity of the C. siamense populations from these three hosts. In vitro tests showed that there were no significant differences in the sensitivity of C. siamense populations to carbendazim, prochloraz, difenoconazole, and propiconazole from different original hosts and geographical origins. The present study suggests that host specialization of C. siamense has not occurred yet in coffee, rubber tree, and areca palm.     

庐山外来植物调查研究

[目的]为进一步了解庐山地区现有外来植物现状,掌握庐山外来植物数据,为庐山外来植物管理提供参考依据.[方法]运用线路踏查法进行野外调查并结合相关文献、标本资料,对庐山外来植物种类、生活型、 原产地、引入途径以及外来入侵植物种类进行研究.[结果]庐山外来植物共有89科309属448种:(1)菊科植物种类最多,有69种,约...     

河南北部稻蛀茎夜蛾的发生规律研究初报

随着全球气候变暖,昆虫分布及越冬地域也在发生变化。稻蛀茎夜蛾Sesamia inferens(Walker)的越冬北限在20世纪80年代被认为不过北纬34°线,近年发现该虫在更北的黄淮海夏玉米-小麦轮作种植区新乡市(北纬35°)发生为害,为该种植模式下发生的新害虫。为了准确监测,科学、有效地制定该害虫的防治对策,本研究对河南北部地区稻蛀茎夜蛾的发生为害规律及生活史进行了初步调查。结果表明:稻蛀茎夜蛾可以在小麦-玉米轮作的条件下顺利完成生活史,其中在河南新乡该虫为害穗期玉米并顺利越冬的事实是首次报道。应用灯光监测并结合田间幼虫调查发现,当地稻蛀茎夜蛾一年发生3代。越冬代幼虫化蛹后在4月中下旬开始羽化,羽化的成虫在小麦或早春玉米上产卵,第1代幼虫主要为害春玉米和小麦,6月中旬第1代成虫开始羽化飞往夏玉米田内产卵,幼虫主要为害夏玉米幼苗。第2代幼虫化蛹后于8月初开始羽化形成第2代成虫,产卵孵化后的幼虫主要钻蛀夏玉米穗和茎秆,9月下旬幼虫陆续沿茎秆钻入玉米残桩基部越冬。综合调查结果,绘制了河南北部地区稻蛀茎夜蛾的年生活史表。     

海南玉米小斑病菌室内药剂筛选及对戊唑醇、嘧菌酯的敏感性

为明确7种杀菌剂对玉米小斑病菌CM-4的抑菌效果和玉米小斑病菌对戊唑醇和嘧菌酯的敏感性,采用菌丝生长速率法测定了7种杀菌剂对菌株CM-4的抑菌效果,并根据初筛结果,对来自海南省8个市县的36株玉米小斑病菌进行戊唑醇和嘧菌酯的敏感性测定。结果显示:7种药剂中,430g/L戊唑醇SC和250g/L嘧菌酯SC的抑菌效果较好,70%甲基硫菌灵WP和50%多灵菌WP的抑菌效果较差。敏感性测定中,430g/L戊唑醇SC的EC50均值为7.389 2μg/mL,敏感性频率分布出现了2个明显的峰值,检验结果不符合正态分布,出现敏感性下降的菌株。250g/L嘧菌酯SC的敏感性频率分布呈现单一连续性曲线,检验结果符合正态分布,其EC50均值5.699 5μg/mL可作为玉米小斑病菌对嘧菌酯的敏感性基线。敏感性基线的建立可为病原菌抗性研究和监测提供基础数据,同时指导田间用药。     

基于控制我国红火蚁危害的几点思考

针对我国红火蚁的发生危害现状以及防治中存在的主要问题,笔者结合本人对红火蚁研究的一些体会以及对美国红火蚁防治水平的总结分析,就如何控制和减轻我国红火蚁的发生危害提出4点意见:立即对我国的红火蚁发生危害区域进行普查,为制定科学的检疫、防治技术提供科学依据;制定科学、严格和具操作性的检疫措施,防止红火蚁的人为扩散;普及红火蚁的科学知识,提高人们的防范意识;研究红火蚁的发生危害规律,监测措施和防治技术,改善、提高国内现有的监测、防治水平。     

济宁市蒜田杂草种类及优势种群调查

2007—2010年对济宁市蒜田杂草进行系统调查,摸清了济宁市蒜田共有22科61种常见杂草及不同生态条件下杂草群落结构,并通过各种杂草的田间密度、频度、相对多度等因素,确定了济宁市蒜田杂草的优势种群为6科8种,次优势种群7科14种,为科学合理地制定蒜田杂草防除策略提供了科学依据。     

海南省胡椒瘟病病原鉴定及发生规律

采用形态特征观察、致病性测定及rDNA-ITS序列分析等方法,对海南省主产区胡椒瘟病病原进行鉴定,通过田间实地调查对胡椒瘟病的发生规律进行了研究。结果表明,该病病原为辣椒疫霉(Phytophthora capsici),月平均降雨量对该病的发生有着显著的影响。降雨量越大,持续降雨天数越多,发病率越高。