大豆根瘤内抗棉花枯萎病菌株的筛选及其防病试验

【目的】采用优良抗病性内生菌资源来控制棉花枯萎病是一种有效的措施。本研究从大豆根瘤中筛选棉花枯萎病拮抗性内生细菌,探索其对棉花枯萎病菌丝的抑制作用和代表菌株特性,为发掘和应用防病、抗逆优良菌株提供理论基础。【方法】采用对峙法和代谢液培养法对大豆根瘤内生细菌进行棉花枯萎病菌抑菌性筛选,显微观察法研究筛选菌株引起病原菌菌丝变化,通过菌株培养特征、理化特性和16S r DNA序列同源性分析确定菌株系统发育地位,比色法测定DD174耐盐碱性,盆栽试验验证防病效果。【结果】经复筛和代谢液试验有5株拮抗性较强菌株,被作用病原菌菌丝畸形、细胞壁消失、自溶,菌丝基部加粗、分支增多,呈树根状;菌丝被菌苔包埋而溶解、断裂,菌丝末端球形膨大。对棉花枯萎病菌的抑制作用主要通过菌体产生胞外代谢物发挥作用。菌株DD174、DD176和DD179最相似菌株分别为Bacillus oceanisediminis H2T(GQ292772)和B.thuringiensis ATCC 10792T(AF290545),菌株DD165和DD166最相似菌株均为Stenotrophomonas maltophilia LMG 958T(X95923)。DD174能耐受6%盐浓度,p H 10生长良好,具有一定耐盐碱能力。DD174处理组防治效果达76.32%,其他防效均在62%以上,可作为棉花枯萎病的生防菌株资源。【结论】大豆根瘤内存在棉花枯萎病内生拮抗细菌,其中有些菌株具有一定耐盐碱能力,对棉花枯萎病病原菌及病害有一定抑菌和防病作用。     

棉花内生细菌数量动态及其对棉花黄、枯萎病菌的拮抗作用

摘要：【目的】了解棉花内生细菌数量动态,从棉花中获得拮抗黄、枯萎病菌的内生细菌资源【方法】对棉花根、茎、叶表面灭菌,采用稀释平板法分离棉花内生细菌;通过对峙培养法体外鉴定分离的棉花内生细菌对棉花黄、枯萎病菌的拮抗作用,并对拮抗棉花黄、枯萎病菌的内生细菌16S rDNA序列进行了分析【结果】棉花根中内生细菌的数量显著高于茎、叶;根的苗期总体内生细菌数量低于开花期、吐絮期,茎、叶中的内生细菌数量在不同生育期呈现一定的波动性,但趋势性不明显;6个棉花品种根中内生细菌平均数量差异并不显著,但茎、叶中内生细菌数量不同品种间呈现一定程度差异。平板对峙鉴定显示:棉花根中具有较高比例的拮抗棉花黄、枯萎病菌的内生细菌,拮抗强致病落叶型黄萎病菌（V107）的内生细菌比例不仅低于枯萎病菌（F108）,而且低于非落叶型黄萎病菌（V396）。同时拮抗棉花黄、枯萎病菌的内生细菌有44株,16S rDNA分子序列分析表明：这些拮抗内生细菌的类群包括了两个门(变形杆菌门、拟杆菌门)8个属,其中10个菌株与已报道菌株相似性<97%,可能是新的种（属）,优势种群为肠杆菌属（18株）、泛菌属（15株）。【结论】棉花的品种、生育期与器官影响棉花内生细菌数量;棉花拮抗黄、枯萎病菌的内生细菌具有优势种群,且具多样性。     

烟草赤星病菌拮抗性大豆根瘤内生菌的筛选及抑制作用

以烟草赤星病菌为供试病原菌,采用对峙法、代谢液培养法对分离自大豆根瘤的内生细菌进行抑菌筛选,对筛选菌株作用的病原菌菌丝进行显微观察,研究筛选菌株细胞培养特征及生理生化特性、16S rDNA测序序列、系统发育,以及进行温室接种防病试验.结果表明: 大豆根瘤内生菌经初筛、复筛,对烟草赤星病菌抑菌率42%以上的有7株菌,分别属于芽孢杆菌属、假单胞菌属、中华根瘤菌属和寡养单胞菌属.显微观察表明,在拮抗性内生菌作用下病原菌菌丝末端出现明显畸形,呈珊瑚状分枝、球状膨大等;代谢液试验表明,内生菌对病原菌的抑制作用主要是内生菌代谢产生的胞外物质在发挥作用;对峙试验表明,芽孢杆菌可迅速形成生物薄膜,有效阻碍病原菌丝生长和延伸.盆栽防病试验表明,拮抗性内生菌处理下烟草病情指数显著低于对照,表明筛选菌株可作为烟草赤星病的生防菌株资源.     

沙棘根瘤内生细菌中抑菌促生菌株的筛选和鉴定

【背景】植物内生细菌可产生具有抑菌和促生活性的物质,既能抑制植物病原菌对寄主植物的侵染,也能促进植物的生长。沙棘根瘤内生细菌是根瘤内除共生固氮的弗兰克氏菌外,与沙棘共生的一大类微生物。研究具有抑菌和促生活性的植物内生菌,可为微生物菌肥的研究提供理论基础。【目的】筛选具有优良抑菌和促生活性的沙棘根瘤内生细菌,初步研究其抑菌和促生活性,并对菌株进行鉴定。【方法】采用双层琼脂法、琼脂扩散法、双层平板对峙法、牛津杯法进行沙棘根瘤拮抗性内生细菌的筛选。选取抑菌活性较高的内生细菌,分别采用Salkowski比色法、ChromeAzurolS(CAS)平板检测法和钼锑抗比色法进行产吲哚乙酸、铁载体及溶磷能力的测定。采用发酵液灌根法测定沙棘根瘤内生细菌SR308对黄瓜促生作用的盆栽效果。通过形态和培养特征、生理生化试验及16S rRNA基因序列分析法对菌株TT201和SR308进行鉴定。【结果】从131株沙棘根瘤内生细菌中筛选出9株具有较强抑菌活性的内生细菌,其中菌株TT201抑菌性最佳、抑菌谱广;菌株SR308的促生活性最好,其发酵液对黄瓜的生长具有较强的促进作用。对具有较强抑菌和促生活性的菌株TT201和SR308进行鉴定的结果表明,菌株TT201为侧孢短芽孢杆菌(Brevibacilluslaterosporus),菌株SR308为蕈状芽孢杆菌(Bacillusmycoides)。【结论】获得2株具有优良抑菌和促生活性的沙棘根瘤内生细菌,为进一步开发微生物农药及菌肥提供了资源。     

骏枣内生生防细菌的分离、筛选与鉴定

选择交城骏枣(Zizyphus jujube cv.Jiaocheng Junzao)作为分离内生细菌的材料,从中共分离到18株内生菌株,运用平板对峙法从中筛选出5株对大枣病原菌及部分植物病原菌有拮抗作用的内生细菌。抑菌试验结果表明:筛选出的5株细菌对刺盘胞菌Colletotrichum gloeosporides、链格孢菌Alternaria alternata、尖孢镰刀菌Fusarium oxysporium、烟草赤星病菌Alternarial longipes、稻瘟病菌Pyricularia oryzae、人参立枯病菌Rhizoctonia solani、人参菌核病菌Sclerotinia schinseng和小麦根腐病菌Bipolaris sorokiniana均有一定的抑菌活性。对这5株内生细菌进行了形态特征观察和生理生化鉴定。     

水稻恶苗病拮抗菌的筛选、鉴定及其抑菌活性

从水稻根际土壤中筛选出拮抗水稻恶苗病的菌株,初步研究其抑菌作用及生防效果。采用平板稀释法从水稻根际土壤中分离获得菌株,以水稻恶苗病菌为靶标菌采用平板对峙法筛选出拮抗菌;通过形态学特征、生理生化特征及16S r DNA序列分析对筛选出的拮抗菌进行鉴定;检测拮抗菌无菌发酵液对水稻恶苗病菌菌丝生长的影响,同时测定拮抗菌的抑菌谱及进行盆栽实验。分离得到6株拮抗菌,其中有一株对水稻恶苗病菌拮抗作用较强的菌株SH15,经鉴定菌株SH15为多粘类芽孢杆菌。菌株无菌发酵液对水稻恶苗病菌菌丝生长有显著抑制作用;菌株SH15抑菌谱广,对水稻恶苗病菌、层出镰孢菌、棉花枯萎病菌、辣椒疫病菌、棉花黄萎病、黄瓜黑斑病菌均有一定的抑菌活性。水稻盆栽实验表明,接种多粘类芽孢杆菌SH15可显著降水稻恶苗病的发病指数,平均防效高达65.68%。因此,多粘类芽孢杆菌SH15在水稻恶苗病的生物防治方面具有一定的应用价值。     

枸骨益生菌的筛选及其抑菌作用

采用涂布平板法分离药用植物枸骨可培养内生细菌,采用对峙法和发酵滤液培养法筛选对植物病原菌具高抑制作用的菌株,通过镜检和显微摄影观察处理组菌丝的变化,对16SrDNA PCR产物进行测序和同源性分析菌株的系统发育关系,通过形态、生理生化特征和16SrDNA序列比对确定菌株的分类地位.从枸骨健康植株的根、茎、叶及果实中分离得到85株内生细菌,筛选出对烟草赤星病菌、稻瘟病菌、棉花枯萎病菌等有较强抑菌作用的10株菌,初步鉴定为4属7种.其中,抑菌效果最强的GG78(60.3％)、GG31 (48.1％)、GG3(61.0％)分别属于阴沟肠杆菌、路德维希肠杆菌和蜡样芽孢杆菌.受抑制病原菌菌丝均发生畸形、扭曲,局部膨大形成原生质浓缩球、菌丝基部出现毛发状细分支等现象,可能与内生菌分泌到胞外具有一定抑菌或杀菌作用的代谢物质如抗生素、水解酶类、生物碱等有关.     

稻瘟病菌拮抗性大豆根瘤内生细菌的筛选及抑制效果

【目的】从河南大豆根瘤的内生细菌资源中筛选对稻瘟病菌有拮抗作用的菌株,初步探讨其抑菌效果,为进一步研究其抑菌机理提供菌种资源。【方法】以稻瘟病菌为供试病原菌,采用对峙法进行拮抗性菌株筛选,显微观察法研究受抑制病原菌菌丝变化,对筛选拮抗性菌株进行细胞形态学及生理生化特性试验、16S rRNA基因测序和系统发育分析及接种防效试验。【结果】经复筛有17株内生菌拮抗效果较明显,最高抑制率为62.16%;受抑制病原菌丝呈现弯曲打结、断裂、原生质浓缩等畸形状态。拮抗性筛选过程中内生菌快速生长形成生物薄膜,包埋菌丝并使其断裂。拮抗菌株分布在7属9种,稻瘟病拮抗性大豆根瘤内生菌呈现种属多样性。防效试验表明内生菌处理组稻苗发病率和病情指数均显著降低,防治效果最高达74.19%。【结论】大豆根瘤内生拮抗性菌株具有种属多样性,拮抗性菌株处理组稻苗发病率和病情指数均显著降低,防治效果显著,为进一步研究其抑菌机理提供菌种资源。     

苹果树内生菌筛选及其对苹果腐烂病防治效果

为了获得苹果腐烂病菌的内生拮抗菌株,并初步研究其拮抗特性以及防治效果,用平板对峙法从苹果树根部、茎部、叶片筛选到具有拮抗作用的内生菌,明确其无菌滤液的抑菌效果,并测定拮抗菌株对苹果离体果实腐烂病害的防治效果。从分离纯化的56株内生菌中筛选出12株苹果腐烂病菌的拮抗菌,其中G2、G9、J32和Y40的抑菌效果比较明显,分别为69.64%、58.93%、67.86%、67.88%,当G2和G9的无菌滤液浓度达到8%时,其抑制率最高,分别达到了78.26%、76.29%,J32和Y40的无菌滤液浓度达到8%时抑制率均达到72.33%;在苹果果实离体试验中,G2、Y40的抑制率分别达到32.56%和26.89%;所筛选的这4株菌株对小麦赤霉病菌(Fusa Hum graminearum)、番茄灰霉病菌(Botrytis cinerea)、烟草赤星病菌(Alternaria longipes)、棉花枯萎病菌(Fusarium oxysporun f.sp.vasinfectum)、稻瘟病菌(Pyricularia oryzae Cav)、黄瓜枯萎病菌(Fusarium oxysporum f.sp.cucumerium)、西瓜枯萎病菌(Fusarium oxysporum f.sp.niveum)均有一定的抑制作用,其中抑制率最高达79.65%;4株菌对苹果腐烂病病原菌的抑制大多数会导致病原菌菌丝畸形。试验结果表明拮抗真菌G2、G9、J32和Y40均对苹果腐烂病菌有较强拮抗作用,为进一步开展苹果主要病害的生物防治研究提供了潜在资源菌。     

拮抗棉花枯萎病菌的地黄内生细菌筛选、鉴定和促生潜能

【目的】为了筛选棉花枯萎病菌拮抗性菌株资源,从药用植物地黄根块中分离内生细菌,分析优良菌株的促植物生长特性和耐盐碱特性,发掘优良菌株资源,为研发棉花枯萎病生防菌剂提供参考价值。【方法】采用平板对峙法对分离内生细菌进行棉花枯萎病菌拮抗性试验,荧光显微镜观察法研究病原菌菌丝的变化、分光光度计法测定吲哚乙酸(IAA)含量和1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性、平板培养法测定溶磷特性、分隔培养法测定产生挥发性物质抑菌性、比浊法测定内生菌的耐盐碱特性、通过测定代表菌株理化特性、16S rDNA序列并分析系统发育地位、盆栽接种试验验证防病效果。【结果】地黄内生细菌对棉花枯萎病菌具有拮抗性,其中菌株DH9、DH66、DH92拮抗作用较强。与对照组菌丝对比,处理组菌丝出现打结、弯曲和断裂现象,菌丝末端分枝明显增多,多数边缘菌丝呈珊瑚状分枝,存在明显被菌体包埋等现象。菌株DH83、DH66、DH92、DH9、DH56产生挥发性物质对棉花枯萎病菌均有抑制作用,但抑制效果不明显。产生IAA含量均大于1.32 mg/L的有7株(DH92、DH30、DH71、DH83、DH93、DH9、DH56),其中DH92产量最高,为34.696mg/L。菌株DH92和DH30产生ACC脱氨酶活力分别为118.612μmol/(mg·h)和103.795μmol/(mg·h)。菌株DH92无机磷溶磷能力最强,溶磷圈直径/菌落直径(D/d)为1.51;菌株DH71溶解有机磷能力最强,D/d为4.50。菌株DH9和DH56分别能够耐受在7%、3%NaCl盐浓度,在pH 8–10均能生长,具有一定耐盐碱性。结合菌株培养特征、生理生化特性和16S rDNA测序及系统发育分析,结果表明DH30最相似菌株为沙福芽孢杆菌(Bacillus safensis),DH9最相似菌株为枯草芽孢杆菌(Bacillussubtilis),DH92最相似菌株为菠萝泛菌(Pantoea ananatis)。DH92处理组防治效果达77.29%,其他防效在63%以上,可作为棉花枯萎病的生防菌株资源。【结论】药用植物地黄根块中存在棉花枯萎病菌拮抗性菌株资源,其中菠萝泛菌DH92从地黄根块中分离未曾见报道。优良地黄内生细菌具有促进植物生长特性和一定耐盐碱性,为防治棉花枯萎病和研发生物防治菌剂提供了基础。     

苦豆子提取物对黄瓜和番茄病原菌的抑制作用

苦豆子主要分布在我国西北沙漠地区,是一种抗逆性极强的豆科多年生药用植物。本实验采用带毒平板菌丝生长法和琼脂打孔药剂扩散法测定了苦豆子地上部分乙醇粗提物及其石油醚、氯仿、正丁醇和水层的不同极性溶剂萃取物对瓜果腐霉、黄瓜枯萎病菌、番茄枯萎病菌、番茄早疫病菌、黄瓜角斑病菌和番茄疮痂病菌的抗菌活性。结果表明,正丁醇萃取部分和氯仿萃取部分对真菌生长有较强的抑制活性,正丁醇萃取部分对细菌亦有较强的抑制活性,推测苦豆子中的生物碱是主要的抗真菌成分,存在于正丁醇萃取部分的黄酮和三萜类配糖体等成分同时具有抗真菌和抗细菌活性。     

Evaluation of antimicrobial activity of endophytic fungi from Camptotheca acuminata (Nyssaceae)

Agricultural research of plant-derived endophytic fungi has grown in recent decades. We isolated 26 endophytic fungi from the leaves, stems and fruits of "the tree of life", Camptotheca acuminata, and tested them for antimicrobial activities based on growth inhibition measurements in a modified agar diffusion method. Fermentation broths from most of the isolates exhibited antifungal activity and 50% exhibited antibacterial activity; some of them also exhibited strong broad-spectrum antimicrobial activity. The strongest antimicrobial activity was exhibited by strains XSY10 and XSY15 against Rhizoctonia solani and Fusarium oxysporum f. sp. vasinfectum, with 75% and 67% inhibition, respectively. Strain XSJ01 gave strong activity against pathogenic bacteria, with inhibition zones more than 20 mm in diameter. The isolates were identified by molecular methods as belonging to nine taxa: Nigrospora, Diaporthe, Alternaria, Colletotrichum, Pestalotiopsis, Sordariomycete, Guignardiai, Penicillium, and Zythia. Based on these results, we conclude that the endophytic fungi of C. acuminata are promising sources of novel bioactive compounds.     

银杏内生细菌的分离鉴定及抑菌活性初探

【目的】从银杏(Ginkgo biloba)茎叶中分离鉴定内生细菌, 测定其体外抑菌活性及对辣椒果疫病的防治效果。【方法】采用平板对峙法筛选出对辣椒疫霉菌(Phytophthora capsici)有拮抗作用的内生细菌, 并用平板对扣法测定其中一株防治效果较好的内生细菌产生的挥发性物质对辣椒疫霉菌生长的影响。通过生防菌液和病原菌孢子悬浮液喷雾接种辣椒果测定该菌株对辣椒果疫病的防治效果。基于形态特征、生理生化特性、16S rDNA和gyrA基因序列同源性分析鉴定该生防菌株。【结果】从银杏的茎和叶中分离获得9株内生细菌。平板对峙生长试验结果表明, 菌株W5对供试的辣椒疫霉菌、稻瘟病菌(Pyricularia grisea)、水稻纹枯菌(Rhizoctonia solani)、黄瓜枯萎病菌(Fusarium oxysporum)、荔枝霜疫霉菌(Peronophythora litchi)、荔枝酸腐菌(Geotrichum candidum)均有抑制作用, 其中对辣椒疫霉菌、稻瘟病菌和荔枝霜疫霉菌的抑菌效果显著, 抑菌率分别为88.9%、86.3%和90.2%。其产生的挥发性物质能明显抑制辣椒疫霉菌菌丝的生长。对辣椒采后果疫病的防治效果表明, 先喷雾接种W5菌悬液24 h后再接种辣椒疫霉病菌孢子悬浮液的防治效果最好, 可将辣椒果的保鲜期延长2?3 d。该菌株被鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。【结论】获得了一株对植物病原菌物有良好防治效果的银杏内生解淀粉芽胞杆菌W5, 对辣椒采后果疫病及其他病原真菌的防治具有潜在应用价值。     

木本曼陀罗内生真菌抗菌活性的筛选研究

从木本曼陀罗植物内生真菌中筛选高效抗菌活性的菌株。选择与人类和植物相关的36株病原微生物,分别对分离自木本曼陀罗(Datura arborea L.)植物的内生真菌77株进行了发酵代谢产物的抗菌活性筛选研究。结果显示:对细菌病原菌、皮肤致病真菌、植物致病真菌有抑制作用的内生真菌分别有24,9,17株,其中5株内生真菌对10种以上的供试病原菌有明显的抑制作用,活性最好的1株对20种病原菌有较强抑制活性,最大抑菌圈直径达48mm。这说明木本曼陀罗植物内生真菌抗菌能力较强,抗菌谱较广。     

Antifungal activity of rhizospheric bacteria

Fluorescent Pseudomonad spp. were isolated from the rhizosphere of potato plants (Algeria) by serial dilutions of rhizosphere soils on Kings B medium and were tested for their antifungal activity. The antifungal activity of the Pseudomonas isolated from Potatoes rhizosphere was tested against Pythium ultimum, Rhizoctonia solani and Fusarium oxysporum in dual culture with bacteria on PDA. The Petri dish was divided into tow, on one the bacteria was spread and on the opposite side fungal plugs were inoculated and incubated for one week. Fourteen bacteria were isolated; only one isolate inhibited the growth of Pythium ultimum, Rhizoctonia solani, Fusarium solani; Fusarium oxysporum f.sp. albedinis and Fusarium oxysporum f. sp. Lycopersici with inhibition zones of 39.9, 33.7, 30.8, 19.9 and 22.5 mm respectively.     

甜瓜黑斑病菌的拮抗细菌筛选、鉴定及发酵条件优化

从健康甜瓜植株的根、茎、叶和果实分离内生细菌,明确优良拮抗菌株的分类地位及其最优发酵条件。利用平板稀释法分离内生细菌,平板对峙法筛选黑斑病菌(Alternaria tenuissima)的优良拮抗细菌,通过形态学和分子生物学鉴定,并使用单因素和正交试验方法优化发酵条件。分离共得到50株内生细菌,21株对细极链格孢具有拮抗作用,11株的抑制率达到70%以上,其中菌株G2的抑菌率最高,达76.41%,室内离体防效达44.90%,经形态特征和基因序列分析鉴定为枯草芽孢杆菌(Bacillus subtilis),其最优发酵培养基为葡萄糖20 g、硝酸钠30 g、酵母膏10 g和水1 000 mL,最优发酵条件为摇床转速150 r/min,温度32℃,150 mL摇瓶装液50 mL,最佳接种量为0.2%,培养基初始pH为7.5,其最佳发酵时间为18 h。该结果为甜瓜黑斑病生物防治提供了菌种资源,也为甜瓜内生细菌G2的产业化开发提供了依据。     

Response of endophytic bacterial communities in banana tissue culture plantlets to Fusarium wilt pathogen infection

Endophytic bacteria reside within plant hosts without having pathogenic effects, and various endophytes have been found to functionally benefit plant disease suppressive ability. In this study, the influence of banana plant stress on the endophytic bacterial communities, which was achieved by infection with the wilt pathogen Fusarium oxysporum f. sp. cubense, was examined by cultivation-independent denaturing gradient gel electrophoresis analysis of 16S ribosomal DNA directly amplified from plant tissue DNA. Community analysis clearly demonstrated increased bacterial diversity in pathogen-infected plantlets compared to that in control plantlets. By sequencing, bands most similar to species of Bacillus and Pseudomonas showed high density in the pathogen-treated pattern. In vitro screening of the isolates for antagonistic activity against Fusarium wilt pathogen acquired three strains of endophytic bacteria which were found to match those species that obviously increased in the pathogen infection process; moreover, the most inhibitive strain could also interiorly colonize plantlets and perform antagonism. The evidence obtained from this work showed that antagonistic endophytic bacteria could be induced by the appearance of a host fungal pathogen and further be an ideal biological control agent to use in banana Fusarium wilt disease protection.     

黄瓜枯萎病拮抗放线菌的筛选、鉴定及发酵条件优化

【背景】黄瓜枯萎病是由尖孢镰刀菌(Fusarium oxysporum f. sp. cucumerinum)黄瓜专化型引起的土传真菌性病害,严重制约着黄瓜产业的发展。【目的】从河西走廊敦煌地区盐碱土壤中分离筛选出一株对黄瓜枯萎病病菌有良好拮抗效果的放线菌菌株,探究其分类地位及其最优发酵条件。【方法】采用稀释平板涂布法分离放线菌,平板对峙法、抑制菌丝生长速率法筛选拮抗菌株,通过培养特征、生理生化试验及16SrRNA基因序列分析确定其分类地位,利用单因素试验和正交试验方法确定其最优发酵配方及培养条件。【结果】菌株16-3-10鉴定为链霉菌属(Streptomyces sp.)菌株,最优发酵配方(g/L):小米10.0,乳糖20.0,蛋白胨1.0,NaCl 5.0,CaCO3 6.0,最优发酵条件:培养温度28°C,装瓶量50/250 mL,培养3 d,起始pH 10.0,抑菌率达82.50%,比优化前增加153.43%。【结论】菌株16-3-10对黄瓜枯萎病病菌具有显著的拮抗效果,有较好的应用前景。     

Plant growth-promoting potential of endophytic bacteria isolated from roots of coastal sand dune plants

Endophytic bacteria associated with the roots of coastal sand dune plants were isolated, taxonomically characterized, and tested for their plant growth-promoting activities. Ninety-one endophytic bacterial isolates were collected and assigned to 17 different genera of 6 major bacterial phyla based on partial 16S rDNA sequence analyses. Gammaproteobacteria represented the majority of the isolates (65.9%), and members of Pseudomonas constituted 49.5% of the total isolates. When testing for antagonism towards plant pathogenic fungi, 25 strains were antagonistic towards Rhizoctonia solani, 57 strains were antagonistic towards Pythium ultimum, 53 strains were antagonistic towards Fusarium oxysporum, and 41 strains were antagonistic towards Botrytis cinerea. Seven strains were shown to produce indole acetic acid (IAA), 33 to produce siderophores, 23 to produce protease, 37 to produce pectinase, and 38 to produce chitinase. The broadest spectra of activities were observed among the Pseudomonas strains, indicating outstanding plant growth-promoting potential. The isolates from C. kobomugi and M. sibirica also exhibited good plant growth-promoting potential. The correlations among individual plant growth-promoting activities were examined using phi coefficients, and the resulting data indicated that the production of protease, pectinase, chitinase, and siderophores was highly related.