兰州市草坪禾草根腐病的发生及病原菌鉴定

2007-2008年对兰州市13个小区混播草坪禾草根腐病症状表现和发病情况进行了调查。结果表明,发病严重的草坪禾草根腐病发病率为83.33%,病情指数为36.67。该病在草坪禾草不同部位上引起的症状不同,将其归纳为3种症状类型:叶尖黄化型、叶片中部缢缩型和根茎部褐变腐烂型。经对草坪禾草根腐不同发病部位进行分离培养,致病性测定等确定了引起草坪禾草根腐病的主要致病菌为腐霉属(Pythium spp.)的瓜果腐霉(P. aphanidermatum),根茎部病原菌分离频率达100%。潜育期测定结果表明在温度35℃,湿度90%的条件下该病原菌的潜育期最短为14～15 h。     

卡特兰水培技术研究

为研究名贵兰花的水培技术,促进水培兰花的生产与消费,以兰科卡特兰为试材,从卡特兰水生根系诱导,营养液培养,筛选出水培卡特兰诱导根系的最适宜的NAA浓度和营养液配方,在培养的过程中,防治根腐烂和水藻的生成。结果表明,低浓度NAA（5mg/L）对诱导水生根系具有促进作用;KC营养液是水培卡特兰较好的营养液;加强根部通气有利于防止卡特兰根系的腐烂,在培养过程中添加2～3滴含氯霉素的滴眼液有助于防止藻类的生长。     

小麦β-1,3-葡聚糖酶性质及其对小麦根腐离蠕孢菌的抑菌作用

为了明确小麦根腐离蠕孢菌（Bipolaris sorokinianum）侵染小麦后被诱导表达的β-1,3-葡聚糖酶基因所编码的β-1,3-葡聚糖酶的性质及其与抗病性的关系,采用生物信息学的方法对β-1,3-葡聚糖酶的一级结构、信号肽和跨膜结构进行了预测分析。结果表明β-1,3-葡聚糖酶是一种分泌型碱性蛋白酶,主要存在于胞外。将克隆到的β-1,3-葡聚糖酶基因构建成重组质粒并转化大肠杆菌BL21,经IPTG诱导后,分离纯化得到了原核表达的β-1,3-葡聚糖酶,对其在体外对小麦根腐离蠕孢菌生长的抑制作用的研究发现,β-1,3-葡聚糖酶对小麦根腐离蠕孢具较强抑菌活性。     

不同生境中荻草根状茎扩展速率及地上茎生长的研究

[目的]研究不同生境中获草根状茎的生长特性。[方法]对2种不同生境（山地、平原）中获草根状茎的扩展速率及动态进行研究,同时对获草地上茎的生长动态、高度和密度进行比较。[结果]山地和平原生境中获草根状茎的平均扩展速率分别为82．3、125．6cm／a,扩展较快的时段均为水热条件较好的5～8月份;2种生境中获草地上茎的密度均在8月份达到最大（平均为54．2、76．5株／m2）,高度均在11月份达到最大（平均为127．2、168．5cm）。[结论]平原生境中荻草根状茎的扩展速率和地上茎的生长速率均快于山地生境中。     

一串红菌核病病原鉴定及其主要生物学特性研究

[目的]明确引起广东省中山市一串红茎基部腐烂的病原菌种类及其主要生物学特性。[方法]对一串红病株进行了病原菌分离纯化,研究了其形态特征、致病性、主要生物学和分子生物学特性。[结果]该菌在多种培养基上均可生长;生长温度范围为5～30℃,最适生长温度为加～25℃。在供试碳源中,病原菌对葡萄糖利用最好;在供试的氮源中,对硫酸铵利用最好;菌丝在pH2—9均可生长,生长的最佳pH值为3～6;同时筛选出几种对病原菌有明显抑制作用的杀菌剂。[结论]引起一串红茎基腐菌核病的病原菌鉴定为核盘菌,这在中国大陆首次报道。     

Screening of cultivated and wild adzuki bean for resistance to race 3 of <Emphasis Type="Italic">Cadophora gregata</Emphasis> f. sp. <Emphasis Type="Italic">adzukicola</Emphasis>, cause of brown stem rot

Two diseases of adzuki bean, brown stem rot (BSR, caused by Cadophora gregata f. sp. adzukicola) and adzuki bean Fusarium wilt (AFW, caused by Fusarium oxysporum f. sp. adzukicola), are serious problems in Hokkaido and have been controlled using cultivars with multiple resistance. However, because a new race of BSR, designated race 3, was identified, sources of parental adzuki bean for resistance to race 3 were needed. Therefore, we examined 67 cultivars and lines of cultivated and wild adzuki bean maintained at the Tokachi Agricultural Experiment Station using a root-dip inoculation method. Consequently, nine adzuki bean cultivars, one wild adzuki bean accession and 30 lines (including two lines resistant to all the three races of BSR and AFW) were confirmed to be resistant or tolerant to race 3 of BSR, and we found a cultivar Akamame as well as a wild adzuki bean Acc2515 to be a new source for a resistance gene to the race 3. This cultivar also holds promise as a source of resistance against other races of BSR and AFW.     

Identification of an ISR‐related metabolite produced by rhizobacterium Klebsiella oxytoca C1036 active against soft‐rot disease pathogen in tobacco

BACKGROUND: Klebsiella oxytoca C1036 (C1036) causes induced systemic resistance (ISR) activity against the soft‐rot pathogen Pectobacterium carotovorum subsp. carotovorum SCC1 (SCC1). However, microbial metabolites from C1036 involved in ISR activity remain unknown. The present study was performed to identify an ISR‐related metabolite produced by C1036. RESULTS: The supernatants of C1036 cultures grown on Luria‐Bertani medium were subjected to solvent extraction, repeated column chromatography and preparative liquid chromatography for isolation of an ISR‐related metabolite. High‐resolution mass spectrometer analysis of the isolated metabolite indicated a C₉H₁₅O₃N compound with a mass of 185.11. Low‐resolution mass spectrometer analysis of the metabolite showed a molecular ion peak at 185 and its fragment ions at 84 and 56. Nuclear magnetic resonance spectrometer analyses characterised all protons and carbons of the isolated metabolite. Based on the data, the isolated metabolite was determined to be butyl 2‐pyrrolidone‐5‐carboxylate (BPC). BPC at 12 mM significantly suppressed the disease symptoms in ISR bioassays against SCC1. CONCLUSION: This is the first report identifying BPC as an ISR‐related metabolite produced by C1036. C1036 may play a role in promoting plant growth because it produces ISR‐related metabolites against the plant pathogen SCC1. Copyright © 2009 Society of Chemical Industry     

戊唑·多菌灵·乙膦铝乳胶液对苹果枝干轮纹病的防治效果

近年,在矮砧密植苹果园发现苗木栽植后幼树主干上的枝干轮纹病发生严重,急需有效的防治方法。针对生产中的需求,本研究对幼树枝干轮纹病的防治方法进行了探索,结果显示:用乳胶液配制的戊唑·多菌灵·乙膦铝混合剂对枝干轮纹病防治效果显著高于同种药剂的水溶液,对剪锯口枝干轮纹病防治效果可达63.7%~100%,是药剂水溶液防效的2~3倍;生长季施用2次,对枝干轮纹病病斑的铲除率为45.2%,是药剂水溶液防效的9.6倍以上。结果表明,戊唑·多菌灵·乙膦铝乳胶液对枝干轮纹病防治效果显著,可以用于苗木剪锯口的防护,以及新建果园中幼树枝干轮纹病的治疗。研究结果为生产中幼树枝干轮纹病的防治提供了有效的方法。     

甘薯爪哇黑腐病的病原鉴定

甘薯爪哇黑腐病是甘薯贮藏期的一种真菌性病害,是全球热带和亚热带地区甘薯贮藏期的重要病害之一。2013年我们从广东湛江采集的甘薯中,发现病薯薯块由两端向中间变黑变硬,切开发病薯块,在伤口处会逐渐长出黑色或灰色的菌丝。发病薯块室内放置30d后表面龟裂,裂口处有大量的黑色粉末溢出,显微镜下观察发现大量褐色有隔膜孢子。经对病原菌进行分离,采用柯赫氏法则回接验证,依据病原菌的形态特征和rDNA-ITS及β-tubulin基因序列,确定该病害为甘薯爪哇黑腐病,病原菌为可可毛色二孢(Lasiodiplodia theobromae)。致病性测定发现该病具有较强致病性,对于贮藏期甘薯具有较大威胁。这是国内首次对该病进行的报道。     

口红吊兰菌核病病原鉴定及其生物学特性分析

为鉴定1株分离自口红吊兰叶部病斑上的疑似核盘菌菌株,利用柯赫氏法则验证其致病性并通过形态观察和ITS序列分析对该病原菌进行分类鉴定,结合温度、酸碱度等生理指标研究其生物学特性,并利用菌丝生长速率法测定了扑海因、多菌灵、苯醚甲环唑、腐霉利4种药剂对该病原菌的抑制作用。结果显示:在PDA平板上该病原菌菌丝为白色,均匀生长;约7 d后开始产生菌核,直径3~5 mm;菌核萌发后可产生1~3个子囊盘,内含8个大小为8.0~12.0μm×4.0~5.5μm的子囊孢子。该菌株ITS序列系统进化分析结果显示,其与核盘菌的同源性高达99%。综上所述,初步确定该菌株为核盘菌Sclerotinia sclerotiorum。该病原菌在PDA培养基上的最适生长温度为20~25℃、最适生长p H为5~7。室内毒力测定发现供试4种药剂中扑海因对该病原菌菌丝生长有较好的抑制效果,且其EC_(50)最小,仅为0.62 mg/L,证明扑海因对核盘菌毒力最强。