Streptomyces rochei D74菌剂对向日葵、列当及其根际微生物的影响北大核心

【目的】研究娄彻氏链霉菌(Streptomyces rochei)D74菌剂促进向日葵生长和抑制列当寄生的作用,及其对根际微生物的影响。【方法】通过构建向日葵-列当-S.rochei D74共培养体系,观察D74菌株对列当寄生的影响;采用田间小区试验,测定D74菌剂接种对向日葵植物生理指标和列当出土数的影响;测定向日葵产量指标,研究D74菌剂对向日葵籽粒品质及产量的影响;利用16S rRNA基因高通量测序技术和传统微生物培养方法,分析添加D74菌剂对向日葵根际微生物群落结构的影响。【结果】D74菌剂能够促进向日葵生长[茎秆重和花盘重分别显著增加(P<0.05)37%-40%和21%-37%],同时抑制28%-46%(P<0.05)的列当出土;还可以提高向日葵籽粒中粗蛋白含量5%-9%、大粒占比约66%(P<0.05)和百粒重8%-18%,并且通过产量测定表明,D74菌剂可增产约30%(P<0.05),这对提高农民经济收益具有深远意义。D74菌剂对向日葵根际微生物群落具有显著影响,调节了群落有益微生物数量。【结论】D74菌剂可以显著降低向日葵根部列当寄生病害的发生,促进花盘生长,使籽粒饱满,具有实际应用价值和推广意义。     

土壤条件对向日葵列当寄生的影响

以高感列当的向日葵品种‘龙食葵2号’为试验材料,采用室内接种列当温室培养的方法,研究土壤条件对向日葵列当寄生与生长的影响。结果表明：（1）土壤质地对向日葵列当的寄生具有显著影响,培养50 d时,沙壤土、壤土、粘土中列当的出土数分别为 32.2、19.5和4.6个,平均单株寄生列当数量分别为38.8、24.0和8.2个,说明通透性好的沙壤土有利于列当瘤的形成与生长。（2）在沙壤土条件下,随着处理温度的上升,列当的出土数量和寄生数量均呈先升高后降低的趋势;当培养温度为25 ℃和30 ℃时,向日葵列当有较高的寄生数量与生长速度,列当出土数和平均单株寄生列当数量分别为30.4、31.6和39.8、39.4个。（3）在沙壤土条件下,随着土壤湿度的增加,列当的出土数量和寄生数量呈先升高后降低的变化趋势,并在土壤湿度为60%和70%达到较高值,列当出土数和平均单株寄生列当数量分别为32.6、30.9和39.9、40.9个,而在高湿条件下列当的寄生数量显著减少。（4）在沙壤土条件下,随着土壤pH值的增加,列当的出土数量和寄生数量也呈先升高后降低的变化趋势,并均在土壤pH值为8时达到最大值,列当出土数和平均单株寄生列当数量分别为47.5和51.1个,即列当在偏碱性的土壤环境中有着较高的寄生数量。研究发现,当土壤类型为沙壤土、土壤温度为25~30 ℃、土壤湿度为60%~70%、土壤 pH为8时有利于向日葵列当的寄生与生长;在实际生产中应选择中性或偏酸性的非沙壤土地种植向日葵,并注意调整播期和控制田间灌水量,以降低向日葵列当的危害。     

列当寄生对不同品种向日葵幼苗生长及抗氧化酶活性的影响

采用连作重茬含向日葵列当的土壤,进行不同列当抗性向日葵品种苗期盆栽试验,调查播种后第30、50和70天向日葵幼苗根系列当的寄生率、幼苗地上部和地下部干物质量及株高,并测定其叶片丙二醛(MDA)、苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性。结果表明:不同向日葵品种苗期对列当抗性明显不同,其中油葵品种‘T012244’和‘MGS’对向日葵列当寄生免疫,‘S31’和‘白杂9号’为高抗,而‘星火大白边’和‘白杂6号’为敏感。列当寄生后明显抑制敏感品种向日葵幼苗生长,而对免疫品种和高抗品种的影响较小。列当寄生后的敏感性品种‘星火大白边’幼苗叶片MDA含量迅速上升,PAL活性也大幅度增加,列当对幼苗生长伤害加重;而苗期免疫品种"T012244"和高抗品种"S31"MDA含量下降,PAL活性则变化不大。随接种时间延长,不同抗性向日葵品种苗期SOD、POD和CAT活性均呈现先升高后降低的变化趋势,且免疫品种的保护酶活性变化幅度大于敏感品种,说明列当寄生对敏感向日葵品种造成了逆境胁迫,诱导其幼苗叶片保护酶系统产生防御响应。     

不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响

以对向日葵列当抗性不同的向日葵幼苗为材料,利用水培法收集其根系分泌物,经二氯甲烷萃取后结合硅胶柱色谱分离法,研究不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响。结果表明:(1)在一定浓度范围内,向日葵根系分泌物对向日葵列当种子萌发具有低浓度促进、高浓度抑制的作用;二氯甲烷萃取的向日葵根系分泌物浓度为0.1mg/mL时,其向日葵列当萌发率高于其他浓度的作用。(2)‘星火大白边’和‘白葵杂9号’根系分泌物提取物作用下向日葵列当萌发率最高分别为46.92%和43.88%,显著高于免疫品种‘MGS’根系分泌物提取物作用下列当的萌发率(27.81%)。(3)根系分泌物提取物正己烷-乙酸乙酯1∶1洗脱组分的萌发刺激活性显著高于其他组分,‘星火大白边’、‘白葵杂9号’和‘MGS’的该组分作用下向日葵列当最高萌发率分别为49.90%、45.66%和30.00%。(4)‘MGS’的根系分泌物提取物与GR24或脱氢木香内酯共同作用时种子萌发率显著低于GR24或脱氢木香内酯的单独作用,说明‘MGS’根系分泌物中可能含有抑制GR24或脱氢木香内酯刺激向日葵列当种子萌发的物质,使其对向日葵列当表现出免疫特性。     

绿色木霉TV41对尖孢镰刀菌FW0在西瓜植株空间分布和枯萎病防控效果的影响

【目的】为进一步探究盆栽试验条件下绿色木霉TV41 (Trichoderma viride TV41)对尖孢镰刀菌FW0 (Fusarium oxysporum FW0)在西瓜植株空间分布的影响以及对西瓜枯萎病的防控效果。【方法】通过定期检测不同处理西瓜根际/根表尖孢镰刀菌的数量、西瓜植株根内/茎内尖孢镰刀菌的数量以及植株侧根被侵染比例和尖孢镰刀菌在植株内的侵染进程,进行多次盆栽试验并统计发病率。【结果】当绿色木霉和尖孢镰刀菌接种量均为5×105孢子/g基质时,绿色木霉TV41在西瓜根际/根表的定殖数量明显高于尖孢镰刀菌FW0的数量,接种了绿色木霉TV41的处理,根际/根表尖孢镰刀菌的数量(103/g基质)显著低于仅接种FW0的对照(104/g基质);绿色木霉TV41不仅能够有效减缓尖孢镰刀菌在西瓜植株内的侵染进程,而且能够有效降低西瓜植株根内、茎内尖孢镰刀菌的数量。与对照(只接种FW0)相比,接种绿色木霉后西瓜枯萎病的发病率从66%降低到27%。【结论】绿色木霉TV41能够通过影响尖孢镰刀菌FW0在西瓜植株的空间分布,从而有效防控西瓜枯萎病的发生,防控效果达到60%。     

‘锦苗标靶’诱抗剂抑制列当寄生向日葵的机制研究

该研究通过对2个向日葵品种(LD5009 和JK103)根系浇灌‘锦苗标靶’诱抗剂,于浇灌处理后0、24、48 和72 h分别对根系取样进行组织化学分析,测定根系H₂O₂含量、ROS清除酶活性以及抗性相关基因表达,并于浇灌处理后20 d检测向日葵生长指标和根瘤结数量,以明确‘锦苗标靶’对向日葵抑制列当寄生的诱抗机制。结果显示：(1)与对照(施用清水)相比,LD5009在‘锦苗标靶’处理后,列当瘤结数减少了95.5个,寄生率降低了98.20%;瘤结的鲜质量和干质量分别降低了94.60%和81.63%,而向日葵株高和茎粗分别相应增加了2.09 cm和0.52 mm,增长率分别为14.92%和15.29%;JK103在‘锦苗标靶’处理后,列当瘤结数较对照减少了37.5个,寄生率降低了98.04%,瘤结的鲜质量和干质量也分别降低了97.06%和82.69%,而向日葵的株高和茎粗分别增加了2.07 cm和0.39 mm,增长率分别为12.26%和9.70%。(2)‘锦苗标靶’诱抗剂浇灌处理后,2个向日葵品种根系中胼胝质的沉积量均有增加,但以JK103在处理48 h后增加幅度最为明显;JK103和LD5009中H₂O₂含量在处理24 h后均达到最大值,分别为3.53和2.68 μmol·g^-1,与对照相比,LD5009的H₂O₂含量增幅较大,为208.05%。(3)2个品种的ROS清除酶活性在处理后均呈先升高后降低的趋势,且均在处理48 h后达到最大值;JK103+锦苗标靶处理较清水对照的SOD、POD、CAT、PPO活性分别增加了69.77 U·g^-1、5.44 U·g^-1·min^-1、1.88 U·g^-1·min^-1和527 U·g^-1·min^-1,而LD5009+锦苗标靶处理后,上述4种酶的活性分别增加了25.91 U·g^-1、13.16 U·g^-1·min^-1、0.50 U·g^-1·min^-1和313 U·g^-1·min^-1。(4)抗性相关基因转录水平的检测结果显示,施用诱抗剂后2个品种抗性基因的转录水平都不同程度地被诱导,但以LD5009+锦苗标靶样本中被诱导的幅度最为明显,特别是CAT、Mn SOD和XTH6基因,其转录水平比对照均上调了50倍之多。研究表明,诱抗剂‘锦苗标靶’对向日葵列当的寄生有显著的抑制效果,且在向日葵列当寄生前(瘤结未形成)施用效果更佳;‘锦苗标靶’可促进向日葵根系细胞中胼胝质的沉积量增加,在结构水平上抵御列当对向日葵根系的侵染,并能够诱导向日葵根系ROS清除酶活性以及CAT、PAL、Mn SOD和XTH6等基因表达的提高,从而建立向日葵对列当寄生的获得性抗性,但诱导的程度由于品种不同而存在一定的差异。     

基于RNA-Seq的向日葵脂肪酸合成基因筛选与分析

向日葵(Helianthus annuus L.)是世界四大油料作物之一。为解析向日葵主要脂肪酸组分的生物合成分子机制,选用高油酸自交系J9、低油酸自交系P50为研究材料;采用错期播种同期采样试验,以液相色谱测定授粉后不同样品籽粒的脂肪酸组分与含量;利用RNA-Seq技术,对不同样品测序,获得各样品与脂肪酸合成相关的基因表达数据,以气象学数据、液相色谱数据、向日葵基因组数据和转录组数据为基础,采用生物信息学方法分析相关数据。结果表明：(1)高油酸向日葵材料脂肪酸组分和含量受温度影响小,而低油酸材料易受温度影响;(2)J9和P50的12个样本的高表达基因数在7500个左右,而中、低表达基因数相当,是高表达基因的两倍,约15000个;(3)品种特异性表达基因和品种间特异表达基因去除重复后,在J9和P50在-CK和S数据集得到15885个,GO功能富集获得的与脂质代谢直接相关的403个DEGs 映射到与的脂质代谢相关的KEGG代谢通路,累计29个DEGs直接参与了19条相关KEGG通路。本研究将为深入解析向日葵脂肪酸代谢分子机制提供新信息。     

吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的转录组影响分析

【背景】金黄色葡萄球菌是目前食品和临床引起感染的重要病原菌,迫切需要开发新型抗菌药物。【目的】分析吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的转录组影响和主要代谢信号通路。【方法】采用液体稀释法测定P-FAH-Cu-phen作用金黄色葡萄球菌的最低抑菌浓度(minimum inhibitory concentration, MIC)和最低杀菌浓度(minimum bactericidal concentration, MBC)。将终浓度2 μg/mL的配合物分别作用于对数生长期的金黄色葡萄球菌30 min和2 h,进行转录组测序及分析。【结果】 P-FAH-Cu-phen作用金黄色葡萄球菌的MIC和MBC分别为2 μg/mL和4 μg/mL。与空白对照相比,配合物处理细菌30 min后,其差异基因共有356个,其中上调表达180个、下调表达176个;配合物处理细菌2 h后,其差异基因共有23个,其中上调表达3个、下调表达20个。差异基因功能主要富集于膜的组成部分、细胞质、质膜、ATP结合、发病机制、金属离子结合、组氨酸生物合成过程、DNA结合、水解酶活性、跨膜转运蛋白活性、硝酸盐同化、硝酸盐代谢过程、硝酸还原酶复合物、硝酸还原酶活性等。差异基因涉及的信号通路主要有双组分系统、群体感应、氮代谢、三羧酸循环、氨基酸代谢等。【结论】影响细菌质膜组成、毒素生成、生物膜形成、细胞壁合成、能量代谢等可能是吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的主要抑菌作用。研究为揭示吡唑啉酮铜配合物抑制金黄色葡萄球菌分子机制提供了理论依据。     

基于RNA-Seq分析MpigE在红曲霉色素生物合成中的转录调控

【目的】分析MpigE的缺失在转录水平对红曲色素产生的影响。【方法】对实验室保存的野生型紫色红曲霉(Monascus purpureus)Mp-21和△MpigE菌株进行高通量转录组测序、注释、表达差异基因功能富集分析和基因通路富集分析,在转录水平揭示MpigE缺失后红曲霉色素产量变化的原因。【结果】通过RNA-Seq测序,每个样品获得7.5–8.5 Gb的原始数据,经过拼接后得到7219个转录本(Unigenes),其中成功注释的为5692个。差异基因表达富集分析发现基因缺失菌株△MpigE相较于野生型菌株Mp-21上调差异基因达到199个,下调差异基因为293个。【结论】MpigE的缺失能够促进红曲霉中中央碳代谢和乙酰辅酶A代谢相关基因的表达以此影响色素生物合成。     

向日葵对苯胺废水的光合生理响应及净化效果

为探讨向日葵对苯胺废水的耐受性及其应用于苯胺污染废水植物修复的可行性,采用水培试验方法,以美国油葵1号为材料,研究了不同苯胺浓度胁迫对向日葵光合和叶绿素荧光参数的影响,以及向日葵对苯胺的吸收、积累和净化效果。研究发现:100 mg/L的苯胺对向日葵的净光合速率(P_n)、气孔导度(L_s)和蒸腾速率(T_r)有显著的促进作用,而对生长与叶绿素荧光相关参数无显著的影响。当苯胺浓度升高到200—400 mg/L时,向日葵的鲜重、净光合速率(P_n)、实际光化学效率(Φ_(PSⅡ)),最大光化学效率(F_v/F_m)以及光化学淬灭系数(qP)比对照组显著降低,而胞间CO_2浓度(C_i)显著升高,NPQ呈现出先升高后降低的趋势,并在苯胺浓度为200 mg/L时达到最大值。综合分析表明,当苯胺浓度升高到200 mg/L到400 mg/L时,苯胺对向日葵的净光合速率的抑制以非气孔因素为主。当苯胺浓度为500 mg/L时,导致向日葵死亡。另外,向日葵对100 mg/L苯胺废水中苯胺的去除率最高,达到80.97%。苯胺主要在向日葵的地上部分积累,随着苯胺浓度的升高,向日葵中叶片苯胺的浓度逐渐升高,茎中的苯胺含量变化不显著,而根中的苯胺含量较低。     

Development of SCAR markers linked to the gene Or5 conferring resistance to broomrape (Orobanche cumana Wallr.) in sunflower

A consensus molecular linkage map of 61.9 cM containing the Or5 gene, which confers resistance to race E of broomrape orobanche cumana, five SCAR markers (three dominant, two codominant) and one RAPD marker were identified based on segregation data scored from two F₂ populations of susceptible×resistant sunflower line crosses. Bulked segregant analysis was carried out to generate the five SCAR markers, while the single RAPD marker in the group was identified from 61 segregating RAPD markers that were directly screened on one of the two F₂ populations. The five SCAR markers, RTS05, RTS28, RTS40, RTS29 and RTS41, were significantly (LOD≥4.0) linked to the Or5 gene and mapped separately at 5.6, 13.6, 14.1, 21.4 and 39.4 cM from the Or5 locus on one side, while the RAPD marker, UBC120_660, was found at 22.5 cM (LOD=1.4) on the opposite side. These markers should facilitate the efficient transfer of the resistance gene among sunflower breeding lines. As the first report on molecular markers linked to a broomrape resistance gene, the present work provides a starting point to study other genes and to examine the hypothesis of the clustering of broomrape resistance genes in sunflower. Received: 16 September 1998 / Accepted: 22 June 1999     

Several Mechanisms are Involved in Resistance of Helianthus to Orobanche cumana Wallr.

Orobanche cumana(broomrape) poses a serious threat to sunflowercultivation in many countries since there is no effective methodof controlling the pathogen. It is known that wild species ofthe genusHelianthus show resistance to different pathogens.Our goal was to identify resistant wild species and derivedinterspecific hybrids (wild Helianthus x sunflower) and to characterizethe resistance mechanisms involved. After identification ofkey stages (germination, fixation, tubercule formation and development)in the resistance of Helianthus to O. cumana, several germplasmswere tested. Development of a hydroponic co-culture system allowedrapid screening of new Helianthus germplasms and a more accuratestudy of the resistance phenomenon. Several resistance mechanisms,such as cell wall deposition, vessel occlusion and broomrapecellular disorganization were demonstrated in the resistantsunflower genotype LR1 by histological observation of the host-parasiteinterface. In contrast, no reaction was observed in the susceptiblecultivated genotype 2603. H. debilis debilis(the wild parentof LR1) exhibited an encapsulation layer which prevented intrusionof the parasite into the cortex. Severe reduction in the rootand apex biomass of sunflower was observed in the susceptibleline (2603) indicating strong competition between broomrapeand sunflower sinks. This large loss of sunflower biomass wascompensated by broomrape biomass. In resistant genotypes LR1and 92B6, the effect of broomrape infestation on sunflower biomasswas much more limited.¹⁴CO₂radiolabelling showed differencesbetween resistant and susceptible sunflower genotypes in nutrientflux from the host to broomrape. Copyright 2001 Annals of BotanyCompany Carbon transfer, Helianthus, Orobanche cumana, resistance, sunflower     

Some Soybean Cultivars Have Ability to Induce Germination of Sunflower Broomrape

Sunflower broomrape is a noxious parasitic weed which has caused severe damage to crop ecosystems. Trap crops can release a mixture of allelochemicals to induce the germination of sunflower broomrape. We studied the allelopathic effects of soybean on sunflower broomrape. Fourteen common soybean cultivars were grown in pots. Samples were collected from soybean plants and rhizosphere soil at five growth stages (V1, V3, V5, R2, and R4). The allelopathic effects of soybean reached highest at the V3 stage. Methanolic extracts of soybean roots induced higher broomrape germination than methanolic extracts of stems or leaves. The germination rates induced by root extracts (10-fold dilution) were positively correlated with germination rates induced by stem (10-fold dilution) and leaf extracts (10-fold dilution). The broomrape germination rates induced by root extracts were also positively correlated with soybean nodule diameter and dry weight. The results indicated that soybeans could induce sunflower broomrape germination. We conclude that soybean has the potential to be used as a trap crop for sunflower broomrape.     

Conditioning duration and agents involved in broomrape seeds responding to germination stimulants

Weedy broomrape species, such as sunflower broomrape (Orobanche cumana Wallr.) and Egyptian broomrape [Phelipanche aegyptiaca Pers. (syn. O. aegyptiaca)], require a period of pre-conditioning before they can respond to germination stimulants. Thus, the sensitivity of weedy broomrape seeds to germination stimulants could be an important factor for broomrape control. In this study, the influence of conditioning agents, conditioning period (0–21 days) and germination stimulants on the germination of sunflower broomrape and Egyptian broomrape seeds was analyzed. Without conditioning, the sunflower and Egyptian broomrape seeds exhibited negligible germination responses to the stimulants. The germination rate of the broomrape seeds increased rapidly with conditioning period and reached a maximum under a conditioning period of 4–10 days; further prolonged conditioning resulted in a decrease in the germination rate. Gibberellic acid (GA₃) could not only break the dormancy of the sunflower and Egyptian broomrape seeds but also maintained the high sensitivity of these seeds even after 21 days of conditioning. Furthermore, 100 µM of GA₃ induced the germination of the Egyptian broomrape seeds. The stimulants that induced Egyptian broomrape germination were ranked in decreasing order as GR24 (76.8?%), strigol (76.1?%), tobacco root exudates (49.5?%), dehydrocostus lactones (DCL, 39.2?%), and maize root exudates (18?%). In contrast, GA₃ did not directly induce sunflower broomrape seed germination, which responded to strigol (62.8?%)?>?maize root exudates (58.2?%)?>?GR24 (57.9?%)?>?tobacco root exudates (41.6?%)?>?DCL (41.3?%). These results indicate specialized recognition of germination stimulants by sunflower and Egyptian broomrape. This study may contribute to a better understanding of parasitic weed germination and may lead to improved control strategies.     

向日葵列当生物学特性及抗列当向日葵分子育种研究进展

向日葵是世界各国重要的油料作物,也是供食用的重要经济作物。向日葵列当是危害向日葵生长极为严重的一类草害,在全球均有发生,且列当种子生活力极强,难以根除。向日葵列当研究和抗列当向日葵育种是农业科研人员研究的重点。本文综述了向日葵列当的生物学特性、寄生与传播特点、为害症状、预防和控制措施,以及近来年抗列当向日葵分子育种研究进展,并对抗列当向日葵育种研究发展前景作分析和展望。     

Comparative analysis of gene expression profiles of acute hepatic failure and that of liver regeneration in rat

To explore the relevance of rat liver regeneration (LR) to acute hepatic failure (AHF), Rat Genome 230 2.0 Array was used to detect their gene expression profiles in this study, and the reliability of the detection results was confirmed by real-time-PCR. 1012 genes were found to be significantly changed in AHF occurrence and 948 genes in LR. Hierarchical clustering analysis showed that physiological activities of AHF and those of LR had no time correlation. Hierarchical clustering analysis (which is performed to group genes based on the similarity of expression patterns) showed that physiological activities of AHF and those of LR had no time correlation. K-means clustering analysis (which is used to check the difference in the relevant predictor variables between different groups is significant or not) demonstrated that gene expression trend of C1 group (genes relate to categories of stimulus–response and cell apoptosis, etc.) in AHF and in LR was extremely similar, that those of their C2 group (categories of regulation of homeostasis and hormone stimulation, etc.) were contrary, and that those of their C3 (material and energy metabolism and oxidation reduction, etc.), C4 (Cell cycle-related genes) and C5 (cell proliferation-related genes) groups were also similar with the gene expression changes of LR more abundant. GO classifications and functional clustering analysis (which was used to statistics the numbers or composition of proteins or genes at a function level) revealed that cellular processes including immune response, inflammatory reaction, cell migration and adhesion, etc. were increased both in AHF and in LR, whereas material and energy metabolism were decreased. Of them, stimulus response, inflammatory reaction and regulation of apoptosis, etc. were stronger in AHF occurrence than in LR, but ion homeostasis, hormonal response, regulation of cell division and proliferation, etc. were weaker in AHF occurrence. Gene expression changes and physiological activities of AHF and those of LR not only have similarities but also differences.     

Differential gene expression in two potato lines differing in their resistance to Phytophthora infestans

Horizontal resistance to late blight in the potato is a primary objective of many breeding programs. Knowledge of the physiological and biochemical mechanisms underlying it, however, is scarce. The purpose of the present study was the identification of these physiological and biochemical factors in plant material obtained by crossing a late blight resistant Solanum phureja clone with a susceptible dihaploid of S. tuberosum subsp. tuberosum. The mRNA RT-PCR differential display method was used to compare the gene expression patterns of a resistant hybrid with that of a susceptible one. By sequence homology, we identified several genes with diverse functions, including genes known to be involved in resistance or stress responses and genes known to be involved in primary or secondary metabolism.