Weaning performance of potato microplants following bacterization and mycorrhization

Summary Commercial mycorrhizal inoculants andPseudomonas fluorescens isolates CHAO and IP10 have been shown to promote microplant growth during and after weaning. The fluorescent pseudomonads also protected against the soil-borne potato pathogenRhizoctonia solani. The potential benefits of inoculation in vitro with mycorrhizal fungi and helper/biocontrol bacteria are discussed.     

Effects of Pseudomonas fluorescens CHA0 on the Resistance of Wheat Seedling Roots to the Take-all Fungus Gaeumannomyces graminis var. tritici

Abstract

The aim of this study was to verify that wheat seedlings treated with Pseudomonas fluorescens CHA0 (CHA0 hereafter) before inoculation with Gaeumannomyces graminis var. tritici (Ggt), a pathogen of take-all, acquire induced resistance to Ggt. The soil with wheat seedlings growing on it was drenched with a suspension of CHA0 cells and inoculated with Ggt 24 h later. Then, the seedlings were grown in a glasshouse, and severity of take-all disease, fresh weights of root and shoot and lengths of root and shoot, and also the activities of soluble peroxidase (SPOX), ionically cell-wall-bound peroxidase (CWPOX), β-1,3-glucanase, β-1,4-glucanase and the concentration of total phenolic compounds in the root of the seedlings were examined. The results indicated that the treatment with CHA0 before inoculation with Ggt mitigated the disease severity significantly, and increased the root and shoot lengths and root and shoot fresh weights. The treatment with CHA0 increased the activities of SPOX, CWPOX, β-1-3-glucanase, β-1,4-glucanase and phenolic compounds in the wheat roots and the activities of SPOX and β-1,4-glucansee activities were highest at day 4 and those of CWPOX and β-1,3-glucanase at day 6 after inoculation with Ggt. The concentration of total phenolic compounds was also highest at day 6 after the inoculation with Ggt. The results suggest that the take-all suppressing effect of CHA0 may be related to enhanced defense response of the wheat roots.     

内生枯草芽孢杆菌BS-2防治荔枝霜疫病及其生化机理

研究内生枯草芽孢杆菌BS-2(Bacillus subtilis)菌株对荔枝采后果实霜疫病的防治效果,及其对体内活性氧代谢(SOD、POD、CAT、MDA、超氧阴离子自由基的产生速率)和病程相关蛋白(β-1,3葡聚糖酶活性、几丁质酶活性)等的影响。结果表明,BS-2菌株对荔枝霜疫病具有较好的防治效果,接种处理后6d,其防治效果为37.83%;经内生细菌处理的荔枝果皮的β-1,3葡聚糖酶活性、几丁质酶活性、CAT和SOD酶活性均比病菌处理的高,而POD、PPO酶活性以及膜透性、MDA含量与超氧阴离子自由基的产生速率却比病菌处理的低。当接种后6d,经内生细菌处理的荔枝果皮的β-1,3葡聚糖酶活性、几丁质酶活性和SOD酶活性分别比病菌处理的高70.73%、30.76%和297.43%;而POD、PPO酶活性和超氧阴离子自由基的产生速率却分别比病菌处理的低15.11%、4.96%和28.95%。     

水稻抗稻瘟病菌防卫反应的细胞学分析与防卫基因表达

对水稻类病变坏死突变体 lmm1　(LmmKaty)与原亲本及双单倍体YT14和YT16接种稻瘟病菌24 h内的抗病反应、细胞学和分子作用机理进行了研究。人工接种实验表明,与原亲本相比,该突变体对稻瘟病菌具有更强的抗性。突变体接种20~24 h后,自动荧光检测到细胞死亡,而对照则未检测到。表明该突变体通过细胞程序性死亡阻止稻瘟病菌的蔓延,从而提高了抗病性。Northern blotting结果发现,抗病品系YT14中的防卫相关基因、苯丙氨酸解氨酶基因和β 葡聚糖酶基因在人工接种稻瘟病菌6 h后开始表达,16~24 h后上述基因表达量快速增加;而病程相关蛋白基因 PR 1和几丁质酶基因在人工接种稻瘟病菌24 h后才开始表达。与YT14相比,感病品系中上述基因的表达明显延迟。表明在人工接种稻瘟病菌24 h内水稻可启动抗病防卫反应,从而对稻瘟病菌产生抗性。     

不同地区花生网斑病菌致病性鉴定及环境条件对致病力的影响

为了探明不同地区的花生网斑病菌致病力和筛选快速稳定的接种方法,以来自山东、云南和辽宁的6个不同地区的花生网斑病菌为材料,用孢子悬浮液对离体叶片和花生植株进行接种,结果表明致病力最强的菌株是WB-SY（分离自辽宁省沈阳市）。最佳接种条件为：开花末期使用高浓度孢子悬浮液（106/mL）,接种湿度保持在90%～100%之间持续保湿36h以上,温度在25～28℃之间,接种前黑暗处理24h,接种后近紫光（波长340～380nm）处理。本文筛选出的菌株和快速稳定的接种方法,将为抗病品种的筛选奠定基础。     

六个SMV毒株在大豆不同品种上病毒浓度的变化与比较

分属於三个株系群的SMV119、245、86—9、87—02、87—44及173毒株,接种到大豆不同品种上,於接种后48小时、10、15、20、25、30、35、40、50、60天用酶联检测植株体内的病毒浓度。结果证明:条件适宜时,接种后48小时各毒株都能在部分顶芽内测出病毒。接种后25天及50为植株体内病毒浓度含量的两个高峰。一个植株内以第一复叶的浓度最高。各毒株以87—02浓度最高,119次之,245最低。病株的病毒浓度并不和外观症状严重程度成正相关。     

对SMV不同抗性的大豆品种体内过氧化物酶活性变化的研究

采用ＳＭＶ－ａ析系为毒源接种３人不同抗性类型的大豆品种，在接种后８，２４，４８，７小时及在３，６，９，１２，１５，１８ １１次连续取样与相应ＣＫ一并测定过氧化物酶的活性后发现：未经接种的抗感品种体内ＰＯ酶活性差异较大，病品种中ＰＯ酶活性水平高于抗性品种２倍以上。     

水稻细菌性条斑病种子劳菌检测技术研究：Ⅱ.离体检测法

 经3年研究建立了一套用离体稻叶检测稻种带细条病菌的方法，应用该方法成功地将44份自然发病的细条病病种接种到离体稻叶上并产生菌脓。甩1％水琼脂加90 ppm无毒苯口并咪唑．在30℃下可使水稻幼苗的离体叶保持15～20 d，可满足细条病接种发病的时间需要。应用纯菌测定该方法的灵敏度，最低可检测浓度为5×10^3 Cells／ml。由于选择了最佳的温度、湿度/光照、苗龄及其它有关环境条件， 使1．2～4．0 g的病种经研碎浸泡后浓缩针刺接种干离体稻叶上在3 d后出现病斑，5.5～8.5 d后产生菌脓，与其它血清学检测方法相比，离体检测法具有直观、可靠、简便、稳定等优点。特别可避免由于种子携带丧失活性的细条病菌或其它病菌而引起的误诊。     

金龟子绿僵菌对红棕象甲的室内致病力测定

在室内用喷雾法测定13株绿僵菌对红棕象甲的致病力。结果表明,菌株致病力强弱与菌株种类有密切关系,菌株的浓度与累计死亡率成线性关系。菌株对红棕象甲的致病力由强到弱的顺序为：Red2＞Red3＞Gre1＞Yx7＞Yx4＞Gre3＞Red1＞Yx1＞Gre2＞Yx6＞Gre4＞Gre5＞Yx3。接种Red2菌株在孢子浓度为1.0×108个/mL水悬浮剂情况下,对4龄红棕象甲幼虫的LT50为5.23 d。用不同浓度的Red2菌株的孢子油悬浮剂涂抹法接种4龄幼虫,发现其LC50为7.32×106个/mL。另外,经试     

海南西番莲茎腐病病原的分离与鉴定

为解决若干病原菌引起的西番莲茎基腐病症状类似,难从症状方面辨别病原菌的问题,采用经典方法即常规鉴定法,对引起海南省琼海市西番莲基腐的病原菌进行鉴定。配制选择性PDA、PDA、V-8、选择性V-84种培养基,对样本中的病原物进行分离、纯化,根据分离菌的各项形态特征描述和分离菌株的主要生长温度测定结果,以及有关文献提供的原理方法进行该分离菌鉴定。结果表明:①分离到1种疫霉菌菌株;②该菌株在选择性PDA、PDA、选择性V-8培养基生长的诸方面特征一样。菌落圆形均一,气生菌丝不丰富。孢子囊形态为侧梨形、柠檬形或椭圆形,基部钝圆,长×宽为24.5～44.3μm×22.8～34.5μm,冷冻后释放游动孢子,未见厚垣孢子。③菌株最低生长温度8～10℃,最适生长温度28℃,最高生长温度36～40℃。④28℃下,分离菌在V-8上日生长量为16.2mm,而在PDA上则为13.7mm。⑤该病原物疫霉菌属于[Phytophthora nicotianae Breda de Haan(parasitica Dastur)]。     

香草兰根腐病生防菌筛选及防治试验

室内平板对峙培养测定显示,枯草杆菌（Ｂａｃｉｌｌｕｓ ｓｕｂｔｉｌｉｓ（ＯＢＳ－２和１．９３６菌株对尖镰孢香草兰专化型（Ｆｕｓａｒｉｕｍ ｏｘｙｓｐｏｒｕｍ ｆ．ｓｐ．ｖａｎｉｌｌａｅ）和腐皮镰孢（Ｆ．ｓｏｌａｎｉ）产生明显的拮抗带。在盆栽生防试验中,ＯＢＳ－２菌株水剂浸根＋ＯＢＳ－２甘蔗渣制剂或稻杆制处理３０ｄ的防效分别为８２．１％和９３．７％,１．９３６菌株作同样处理的防效分别是５４．１％和４     

甘薯抗薯瘟病的水杨酸与活性氧的代谢变化

研究不同抗性甘薯品种受薯瘟病菌侵染后水杨酸(SA)和活性氧(ROS)的代谢变化.结果表明,感染薯瘟病菌12 h后甘薯叶片中SA含量增加,增加量与品种抗性呈正相关;接菌后过氧化氢(H2O2)含量增加,过氧化氢酶(CAT)活性下降,抗病品种变化幅度大于感病品种;接菌后抗病品种提高了与产生H2O2相关的酶过氧化物酶(POD)、超氧化物歧化酶(SOD)的活性,而感病品种与此相反,积累H2O2的能力下降,影响系统获得抗性(SAR)的建立.     

白僵菌与苏云金芽胞杆菌水悬浮剂研制及田间防治玉米螟研究

通过室内生物测定,研究球孢白僵菌和苏云金芽胞杆菌联合防治玉米螟的效果。研究表明,确定白僵菌与苏云金芽胞杆菌浓度分别为1.0×106孢子/mL、1.0×109孢子/mL条件下,杀虫效果达到最佳,LT90为6.64(±0.07)d,较1.0×109的Bb LT90缩短26.06%。通过助剂悬浮率、乳化效果以及助剂对微生物活性影响等确定1个白僵菌与苏云金芽孢杆菌水悬浮剂剂型配方。田间防治玉米螟结果表明,两种生防菌均在防治过程中起作用,田间玉米受害株数、活虫数均明显低于未施药对照,防治效果优于单一使用白僵菌或苏云金芽胞杆菌。     

Evaluation of bean (Phaseolus vulgaris) seeds inoculation with Rhizobium phaseoli and plant growth promoting rhizobacteria on yield and yield components

To study the effect of co-inoculation with plant growth-promoting rhizobacteria (PGPR) and Rhizobium, on yield and yield components of common bean (Phaseolus vulgaris L.) cultivars was investigated in 2 consecutive years under field condition of plant growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. PGPR strains Pseudomonas fluorescens P-93 and Azospirillum lipoferum S-21 as well as two highly effective Rhizobium strains were used in this study. Common bean seeds of three cultivars were inoculated with Rhizobium singly or in a combination with PGPR to evaluate their effect on growth characters. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Treatment with PGPR significantly increased pod per plant, number of seeds per pod, weight of 100 seed, weight of seeds per plant, weight of pods per plant, total dry matter in R6 as well as seed yield and protein content. Co-inoculation with Rhizobium and PGPR demonstrated a significant increase in the yield and yield components. The results showed that all treatments of bacteria increased yield; however, strains Rb-133 with Pseudomonas fluorescens P-93 gave the highest seed yield, number of pods per plant, weight of 100 seed, seed protein yield, number seed per pod, seed protein yield.     

A root inoculation technique to screen potato seedlings for resistance toPseudomonas solanacearum

A seedling inoculation technique for screening potato progenies for resistance toPseudomonas solanacearum was devised, and the effect of certain treatment variables on efficiency of the technique was determined. Concentration of inoculum and age of seedlings were critical factors; with very young seedlings (16 days old) or low concentration of inoculum (10⁵ cells/ml for isolate K-60) many seedlings escaped infection. With older seedlings (25 days old) and high concentrations of inoculum (10⁹ cells/ml), very few or none of the seedlings survived. Inocula containing mixtures of the most virulent isolates, such as S-207, S-213, and S-123, even at relatively low populations (ca. 10⁵ cells/ml), killed most of the susceptible seedlings. In the standard procedure, true seed was sown in rows 3.2 cm apart in 50 x 35 cm flats and seedlings were grown for 20 days in a growth room at 22 C and a 14-hr photoperiod. For inoculation, 5 liters of a cell suspension of two pathogenic isolates ofP. solanacearum (S-207 and S-213, or S-207 and S-123) were added to each flat, and roots were cut immediately with a knife run between and across the rows of seedlings. Inoculated seedlings were incubated in a growth room at 28 C for 2 weeks, and survivors then were moved to the greenhouse for propagation. Stem inoculation of 20 clones derived from plants that survived the standard procedures showed that 16 of them had clear-cut resistance to the bacterium. Tests with 39 hybrid families from crosses of resistant clones with susceptible Mexican and Colombian cultivars showed a relatively high survival rate in progeny from crosses involving three specific resistant parents.     

杂交水稻及其亲本抗细菌性条斑病的研究初报

水稻细菌性条斑病（以下简称细条病）在热带和中国南方已上升为一种主要病害。为探讨杂交水稻及其亲本对该病的抗性规律，笔者在国际水稻所曾用Ｘａｎｔｈｏｍｏｎａｓ ｃａｍｐｅｓｔｒｉｓＰＶ．ｏｒｙｚｉｃｏｌａ的两个菌株（９３和３３５号）喷雾接种于五个杂交组合及其亲本上。结果表明，杂交水稻对细条病表现出不同程度的抗病反应，其抗性值接近双亲平均值，且属水平抗性。杂种一 代的抗性在很大程度上决定于恢复杂的抗性水平。     

水稻穗瘟离体接种技术研究

水稻品种叶瘟鉴定,先后已应用了喷雾、注射、钳叶、针刺、涂抹等多种接种方法,鉴定效果良好。但在自然状态下采用注射、喷雾、湿棉球包穗等接种方法鉴定穗瘟,还遇到品种间抽穗期不一致和接种条件难以控制的难题。因此,目前常以诱发叶瘟的抗性来评价品种抗瘟性。叶瘟和穗瘟抗性虽有较高的相关性,但也存在一定的差异,使叶瘟鉴定结果并不能完全反映穗瘟抗生。但品种抗性的评价以穗瘟抗性最为重要,因此,研究穗瘟抗性鉴定的简易技术十分必要。     

不同毒性玉米大斑病菌侵染对感病玉米叶片PAL活性的影响

利用从自然界中分离纯化的156株玉米大斑病菌菌株中筛选得到的强毒菌株YC和弱毒菌株01-23T分别接种感病玉米叶片,测定玉米叶片苯丙氨酸解氨酶(PAL)活性的动态变化。结果表明,与不接种对照相比,接种强毒菌株YC 1~2 d时,玉米叶片PAL活性显著降低;接种3~4 d时,PAL活性略有上升但差异不显著;接种5 d时,PAL活性又显著降低。接种弱毒菌株01-23T 1~2 d时,玉米叶片PAL活性略有降低但差异不显著,接种3~5 d时,PAL活性上升但差异仍不显著。PAL是玉米抵抗玉米大斑病的一种重要防御酶,在侵染初期,只有降低玉米叶片的PAL活性玉米大斑病菌才能达到成功定殖的目的,可为明确玉米大斑病菌致病性的生化机制提供一定理论依据。     

感染赤霉病菌后小麦穗组织蛋白的氧化交联

为探究细胞壁组成蛋白在抗赤霉病中的作用，对接种赤霉病茵后小麦抗、感品种穗组织中离子结合型蛋白进行了分析。样品过氧化物酶比活力测定结果显示，高抗品种苏麦3号和望水白在接种赤霉病茵孢子后的6d内，过氧化物酶(POD)比活力明显高于对照，中抗品种扬麦158比对照也略有增加，而感病品种宁麦6号和安农8455则与对照无差异。用凝胶层析的方法分析了抗赤霉病程度不同的5个小麦品种穗组织盐溶成份。结果表明，2个高抗品种在接种病原物或过氧化氢处理后．洗脱体积为8ml的蛋白质(P8)的吸收峰明显增高．而在感病品种中P8蛋白变化不明显。高抗品种的对照样品在过氧化氢水浴(35℃)处理后，P8峰有所提高，表现出与赤霉病茵接种处理一致的趋势。