玉米与赤霉素对向日葵列当种子萌发、防除以及对后茬作物向日葵生长的影响

向日葵列当(Orobanche cumana Wallr.)是一种根寄生草本植物,对向日葵等经济作物造成严重危害。为了减少向日葵列当对向日葵的寄生,降低土壤中向日葵列当种子库,本试验以新疆地区广泛种植的玉米品种‘京糯一号’和‘新玉57号’为研究材料,通过穴盘试验研究在不同时期(出苗后10 d和15 d)施加两种不同浓度赤霉素(10~(-4 )mol·L~(-1)和10~(-5 )mol·L~(-1))对上述两个品种玉米生长发育和分泌列当萌发刺激物质的影响;24 d后收集并提取玉米根系分泌物,用其进行刺激向日葵列当种子的萌发试验,从而筛选出刺激向日葵列当种子萌发能力较强的玉米品种进行盆栽试验。通过盆栽试验,在玉米种植后的不同时期(20 d和40 d)喷施10~(-4 )mol·L~(-1)赤霉素以探究玉米与赤霉素共同防除向日葵列当种子的效果,收获时(105 d后)采集玉米地上部、根和根际土样品,用其甲醇浸提液刺激向日葵列当种子萌发;次年在种植过玉米的盆中种植后茬作物向日葵,收获时测定向日葵的农艺指标并统计向日葵列当的出土数。结果表明:穴盘试验中施加赤霉素对玉米的株高有显著增高作用,对玉米根系分泌萌发刺激物质没有抑制作用,即在玉米生长时期可以施加10~(-4 )mol·L~(-1)和10~(-5 )mol·L~(-1)赤霉素。此外,‘新玉57号’根系分泌物的100倍稀释液刺激向日葵列当种子的萌发率显著高于‘京糯一号’,因此选取‘新玉57号’作为盆栽试验的玉米品种。盆栽试验中不同时期施加10~(-4 )mol·L~(-1)赤霉素,玉米株高同样显著高于对照,增长率分别为22.5%、19.1%。次年种植后茬作物向日葵,在第20 d向玉米施加赤霉素处理的盆中种植的向日葵的花盘直径比对照(种植玉米时不施加赤霉素)显著增加57.1%。与对照相比,在种植玉米后的20 d和40 d施加赤霉素的处理种植向日葵,向日葵列当的出土数分别是1.3个·盆~(-1)、1.8个·盆~(-1),分别降低76.4%和67.3%。因此,可以在玉米种植的后20 d和40 d施加10~(-4 )mol·L~(-1)赤霉素,与玉米共同诱导向日葵列当种子"自杀发芽",以减少向日葵列当对向日葵植株的危害。     

加工番茄田列当致病菌的筛选与鉴定

【目的】 筛选对加工番茄列当具有强致病力的菌株,丰富加工番茄列当生物防治菌株资源。【方法】采集新疆加工番茄田间自然发病列当,组织分离获得菌株。采用滤纸平板法,测试菌株发酵液和粗毒素提取液对列当种子萌发抑制效果;针刺、涂抹和喷雾接种法,测试菌株对列当植株致病性;盆栽实验测试菌株孢子悬浮液对列当出土抑制效果;用形态学并辅以分子生物学方法鉴定菌株。【结果】22个菌株中14个菌株粗毒素提取液母液对列当种子萌芽抑制效果在90%以上,其中7个在PDA培养基上产孢量大菌株孢子悬浮液均对列当植株具有致病性,菌株2016-42 、2016-36和2017-6孢子悬浮液在3种接种方式下均可致病。盆栽实验中菌株2017-6孢子悬浮液对列当出土抑制效果最高,为94.65%,其他两个菌株对列当出土抑制效果较低。形态学观察辅以分子生物方法鉴定菌株2017-6为尖孢镰孢Fusarium oxysporum。【结论】筛选的菌株2017-6粗毒素提取液对加工番茄田列当种子萌芽具有抑制作用、其孢子悬浮液对列当植株具有强致病性,对列当出土具有较好抑制效果。     

列当生防菌Br-2的DsRed红色荧光标记及定殖

为探明生防菌Br-2在分枝列当体内及番茄根围的定殖能力,采用PEG-CaCl_2介导的原生质体转化体系将红色荧光蛋白基因DsRed转入到菌株Br-2中,并构建其生长曲线,测定其对分枝列当种子萌发的抑制率,通过共聚焦显微镜观察其在分枝列当茎内及番茄根围的定殖情况。结果表明:通过原生质体转化体系得到了标记菌株Br-2-DsRed,继代培养5代后,其在共聚焦显微镜下仍可观察到亮红色荧光,经PCR检测带有DsRed基因,证明其稳定性好。标记菌株Br-2-DsRed与野生菌株Br-2的生长曲线基本一致,对分枝列当种子萌发的抑制率分别为75.86%和74.14%,无显著差异。显微观察发现,标记菌株Br-2-DsRed接种1 d后即能够侵染分枝列当的茎部表皮,3 d后主要分布在茎表皮和厚壁细胞间隙,5 d后侵染到厚壁细胞及维管束细胞内部并导致茎部腐烂;而标记菌株Br-2-DsRed不能侵染番茄根尖的内部,主要定殖在番茄根尖表面。     

Crenate broomrape control in pea by foliar application of benzothiadiazole (BTH)

Parasitic plants are becoming a severe constraint on major agricultural crops in Mediterranean and tropical countries and the efficacy of available means of control is minimal. The problem is particularly severe in field pea, which is very sensitive to standard glyphosate treatments and in which little resistance has been identified. Systemic Acquired Resistance (SAR) has proven to be effective as a tool for controlling plant pathogens, including fungi, bacteria and viruses, but only recently has this phenomenon started to be evaluated as a control strategy against parasitic weeds. The present studies were conducted to evaluate the potential of SAR activation for broomrape control in pea. The effect of salicylic acid, glutathione and benzothiadiazole (BTH) in three different application methods was studied. Foliar application of 0.6–1.0 mM BTH, in the form of Bion 50 (50% a.i.), reduced broomrape infection under controlled conditions (growth chamber and greenhouse) by limiting the success in attachment and retarding the development of established tubercles. http://www.phytoparasitica.org posting Dec. 1, 2003.     

Proteomics: a promising approach to study biotic interaction in legumes. A review

Summary During the 1990s and early 2000s, the genomes of different organisms have been completely sequenced. Nowadays, biological research is directed to understand gene expression and function. Proteomics, understood as protein biochemistry on an unprecedented and high-throughput scale, is becoming a promising and active approach in this post-genomic period. However, its application to plants is still rather limited as compared to other biological systems. After having referred to the most recent plant proteomic reviews, we focused on legume proteomics including studies with the model species Medicago truncatula. This review is aimed at providing to non-proteomic specialists a global overview of what might be expected in entering this field.     

Evaluation of Differential Lines and a Collection of Sunflower Parental Lines for Resistance to Broomrape (Orobanche cernua) in Spain

Broomrape (Orobanche cernua Loelf.) is a sunflower parasite which has become a potential threat to this crop in Spam with an increasing incidence in recent last years. In order to investigate the racial situation of the parasite in Spam and to evaluate the resistance of differentials and inbred lines currently used in breeding programmes, two experiments were carried out. In the first, two sets of European sunflower differentials were inoculated with three broomrape populations from different geographical origin. The second experiment studied the reaction to the parasite of 38 inbred lines in comparison with resistant and susceptible checks. Reactions of differential lines resistant to known European broomrape races ranged from complete immunity of lines P-1380-2A and ‘Jdanovski 8281’ to complete susceptibility of ‘Record’ and the universal suscepts. These results confirmed the existence of several physiological races of broomrape in Spain and a different racial composition from that of Eastern Europe. Results from the second experiment showed good resistance of half the restorer lines tested and 36 % of the maintainers and cms lines. This material together with the resistant differential lines constitutes good starting material to be used in developing cultivars resistant to broomrape populations in Spain.