中国、日本和菲律宾水稻白叶枯病菌遗传多样性比较分析

用IS-PCR和Rep-PCR对19个来自中国、日本和菲律宾的水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae)群体进行遗传多样性分析.4个专化引物中的IS1113和ERIC能较好的区分三国水稻白叶枯病菌.UPGMA聚类结果表明,三国菌株主要呈现第2簇和第3簇遗传型;中国和菲律宾菌株在第2簇和笫3簇遗传型基础上有各自的特异性分化.病原菌的遗传分簇与致病群之间没有相关性.     

中国、日本和菲律宾水稻白叶枯病菌遗传多样性比较分析

用IS-PCR和Rep-PCR对19个来自中国、日本和菲律宾的水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae)群体进行遗传多样性分析。4个专化引物中的IS1113和ERIC能较好的区分三国水稻白叶枯病菌。UPGMA聚类结果表明, 三国菌株主要呈现第2簇和第3簇遗传型;中国和菲律宾菌株在第2簇和第3簇遗传型基础上有各自的特异性分化。病原菌的遗传分簇与致病群之间没有相关性。     

水稻白叶枯细菌致病力差异的鉴别及其生理生化反应的研究

辽宁省水稻白叶枯病,1964年从庄河县开始发生以来,各地曾进行一些调查和防治研究工作.但对菌株致病力的鉴别,以及白叶枯细菌的生理生化反应等研究,省内未见报导。本研究开展了这方面的一些工作。对于白叶枯菌致病力的鉴别,本实验选用了辽宁省代表性的5个菌株,吉林1个菌株,黑龙江2个菌株,并用江苏1个菌株比较。以7—11个鉴别品种,于苗期和孕穗期两个阶段、用东北水稻白叶枯菌株做接种试验,以测定这些白叶枯菌株致病力的差异。初步结果:可分弱、中及略强的菌系类群,其中表现中等致病力的菌株较多,表现致病力略强的菌株有LN-2(营口菌株)、LN-3(丹东菌株)及JL-IA(吉林菌株)。辽宁等地水稻白叶枯细菌的生理生化测定,使用糖及其它碳素化合物16个,用硝酸盐还原等生理生化测定项目13项。进行了重复观察,初步了解到东北的水稻白叶枯细菌和国内外研究报导基本相同。但还有一些反应存在差异。如对麦芽糖、甘露糖、阿拉伯糖利用得充分,有些菌株利用乳糖、甘油、甘露糖醇和山梨糖醇。有些菌株硝酸盐还原为阳性等。但对明胶液化、淀粉水解、吲哚产生、V.P.测定和M.R.测定,亦均表现阴性,和前人报导一致。以上试验初步结果,对于品种抗病鉴定、抗病育种以及本病原细菌的鉴定分类,或可提供一些依据。     

水稻白叶枯病菌udgH基因的功能研究

水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,以下简称Xoo)是水稻病原菌的一种,其引起的水稻白叶枯病(bacterial leaf blight,BLB)可致使水稻大量减产。本研究发现一个假定的udg H基因的插入突变致使致病力急剧下降,并且胞外多糖、抗逆性、生物膜、游动性等几种生理表型与野生型相比发生了明显变化。互补菌株的致病力能恢复至80%以上,其他生理表型基本能恢复至野生型。本研究为进一步研究udg H基因的致病分子机理提供了研究线索。     

水稻白叶枯病菌广西分离株K74中主效TAL效应物的鉴定

水稻是世界上主要的粮食作物之一。水稻白叶枯病(Bacterial leaf blight)是危害水稻最严重的细菌性病害,可使水稻减产20%以上,严重时甚至绝产,给农业生产和经济造成巨大影响。水稻白叶枯病由水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae, Xoo)的侵染造成,而TAL效应物是Xoo的重要致病因子。近年来,该病在广西也有多发的趋势。2007年从防城港疫区分离得到Xoo K74菌株,经前期研究表明该菌株中有18个tal基因。本研究中,我们对K74菌株中的TAL效应物进行了功能研究。通过基因同源整合突变及互补等研究,我们鉴定到了K74菌株一个与致病力相关的主效TAL效应物。     

水稻白叶枯病菌pxo_04104基因功能的初步分析

水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,Xoo)是一种重要的植物病原细菌,可以引起水稻白叶枯病,使水稻减产。本研究通过对Xoo K74 Tn5插入突变体库进行致病力检测、质粒拯救定位发现pxo_04104基因与Xoo致病相关,pxo_04104基因编码periplasmic beta-glucosidase(周质β-葡萄糖苷酶)。该基因的缺失突变体及其互补菌株生理生化表型检测显示缺失突变体致病力、抗渗透压能力显著下降,其互补菌株致病力可恢复到野生型水平的84.2%,抗渗透压能力也可恢复。本研究为深入研究pxo_04104基因致病分子机理提供了线索。     

水稻抗白叶枯病基因及其应用研究进展

由黄单胞菌水稻变种Xanthomonas oryzae pv.Oryzae（Xoo）引起的白叶枯病是水稻重要病害之一。目前,已有37个水稻白叶枯抗性基因被鉴定并报道,其中28个被定位到染色体上,7个被克隆。本文简要综述了水稻白叶枯抗性基因的鉴定、定位和克隆的进展,并讨论了合理利用抗性基因防治白叶枯病的前景。     

水稻抗白叶枯病基因的鉴定、定位和克隆进展

由水稻黄单胞菌水稻变种Xoo引起的水稻白叶枯病是全球性的重要病害之一。已有31个水稻白叶枯抗性基因被鉴定并报道,其中18个被定位到染色体上,5个被克隆。简要综述了水稻白叶枯抗性基因的鉴定、定位和克隆的进展,并讨论了合理利用抗性基因防治白叶枯病的前景。     

含有绿色荧光蛋白基因的质粒载体的构建及其在水稻白叶枯细菌中的表达

本文用绿色荧光蛋白基因（green fluorescent protein）标记水稻白叶枯细菌,观察其在白叶枯细菌中的表达情况。光激发后,白叶枯细菌发出绿色荧光,表明gfp在白叶枯细菌中得到了高效表达。后续工作意在利用gfp所发出的绿色荧光,来追踪白叶枯细菌侵染水稻的路径,以及检测水稻在遭受白叶枯病害时的一些生理生态变化,进一步探讨水稻对白叶枯细菌的抗生机理,希望能够为水稻抗性品种的检测提供新的理论依据。文中重点介绍了对质粒pM2464的改造过程,经gfp标记后的水稻白叶枯细菌,在紫外或蓝光的激发下,发出绿色荧光,证明了用标记有gfp基因的白叶枯细菌来观察其侵染水稻过程的想法是可行的。     

水稻白叶枯病菌opsX基因功能的初步分析

水稻白叶枯病(bacterial leaf blight,BLB)是水稻生产中最严重的细菌性病害之一。本研究发现水稻白叶枯病菌广西菌株K74(Xanthomonas oryzae pv.Oryzae K74,Xoo K74)的ops X基因缺失突变后致病力基本完全丧失,研究还证明该基因与胞外多糖分泌、铜离子耐受、苯耐受、氯化钠耐受、生物膜合成等相关,此外还发现突变体对氧化物及表面活性剂SDS更为敏感。互补菌株的相关表型和致病力基本可以回复至野生型水平。本研究为ops X基因进一步分子水平的研究提供了线索。     

Status of Streptomycin Resistance Development in Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola in China and their Resistance Characters

Rice leaves with bacterial blight or bacterial leaf streak symptoms were collected in southern China in 2007 and 2008. Five hundred and thirty‐four single‐colony isolates of Xanthomonas oryzae pv. oryzae and 827 single‐colony isolates of Xanthomonas oryzae pv. oryzicola were obtained and tested on plates for sensitivity to streptomycin. Four strains (0.75%) of X. oryzae pv. oryzae isolated from the same county of Province Yunnan were resistant to streptomycin, and the resistance factor (the ratio of the mean median effective concentration inhibiting growth of resistant isolates to that of sensitive isolates) was approximately 226. The resistant isolate also showed streptomycin resistance in vivo. In addition to resistant isolates, isolates of less sensitivity were also present in the population of X. oryzae pv. oryzae from Province Yunnan. However, no isolates with decreased streptomycin‐sensitivity were obtained from the population of X. oryzae pv. oryzicola. Mutations in the rpsL (encoding S12 protein) and rrs genes (encoding 16S rRNA) and the presence of the strA gene accounting for streptomycin resistance in other phytopathogens or animal and human pathogenic bacteria were examined on sensitive and resistant strains of X. oryzae pv. oryzae by polymerase chain reaction amplification and sequencing. Neither the presence of the strA gene nor mutations in the rpsL or rrs were found, suggesting that different resistance mechanisms are involved in the resistant isolates of X. oryzae pv. oryzae.     

Pathotypic variation of Xanthomonas oryzae pv. oryzae in Bangladesh

Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of rice. Altogether, 96 isolates of Xoo were collected from 19 rice growing districts of Bangladesh in irrigated and rainfed seasons during 2014 to assess pathotypic variation. Pathotypic analyses on a set of 12 Near Isogenic Lines (NILs) of rice containing resistance genes viz. Xa1, Xa2, Xa3, Xa4, Xa5, Xa7, Xa8, Xa10, Xa11, Xa13, Xa14 and Xa21 and two check varieties IR24 and TN1 by leaf clip-inoculation technique. A total of 24 pathotypes were identified based on their virulence patterns on NILs tested. Among these, pathotypes VII, XII, and XIV considered as major, containing maximum number of isolates, (9.38% each) frequently distributed in North to Mid-Eastern districts of Bangladesh. Most virulent pathotype I recorded from Habiganj and Brahmanbaria. This pathotypic variation explained the pathogenic relatedness of X. oryzae pv. oryzae populations from diverse geographic areas in Bangladesh.     

Involvement of Gluconeogenic Pathway in Virulence of Xanthomonas oryzae pv. oryzae

Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, one of the most widespread and destructive bacterial diseases of rice. A phosphoenolpyruvate synthase (ppsA)‐disrupted mutant OSPAM was generated by homologous suicide plasmid integration. The mutant was unable to grow in medium with pyruvate or C₄‐dicarboxylates as the sole carbon source, compared with the wild‐type, indicating a disruption in ppsA function. The mutant showed a reduction in virulence on rice but still induced a hypersensitive response in tobacco. When the mutant was complemented, the response was recovered to wild‐type. These results suggested that X. oryzae pv. oryzae possesses only PPSA route in gluconeogenesis, which is necessary for virulence.     

Rapid inhibition of protein histidine phosphorylation by UV-irradiation in Xanthomonas oryzae pv. oryzae

Abstract Exposure of Xanthomonas oryzae pv. oryzae cells to 254 nm UV radiation resulted in an alteration of protein phosphorylation. Labelling of the phosphohistidine-containing proteins with molecular masses of 81 and 32 kDa, named p81 and p32, was rapidly reduced following UV irradiation in the early exponential cells, but the decrease was not detected in mid-exponential cells. Mitomycin C, a DNA replication inhibitor, and rifampicin, a drug generally used to inhibit RNA synthesis and DNA replication, were also found to reduce the histidyl phosphorylation. However, this alteration of protein phosphorylation was not hindered by chloramphenicol treatment. A possible role for these histidyl phosphopfoteins in sensing UV light is proposed.     

水稻黄单胞菌hrp基因簇中致病相关基因hpaB的鉴定水稻黄单胞菌 TAIL-PCR hrp基因簇 hpaB基因

由水稻黄单胞菌引起的水稻白叶枯病是水稻最严重的细菌性病害.通过筛选18000个Xoo Tn5转座子插入突变体,得到其中一个致病力缺失的突变体XOG11.TAIL-PCR方法分离该突变体中插入转座子的侧翼序列,发现转座子插入到位于hrp基因簇的hpaB基因中.对该基因进一步的分析表明该基因编码一个含有156个氨基酸,等电点为4.28,亮氨酸含量为14.4%的蛋白HpaB.Southern blot和PCR验证表明Tn5在该突变体中为单拷贝插入且未发生转座子携带侧翼序列的转移.将hpaB克隆到具有广泛寄主的质粒pHM1中,转化重组质粒进入突变体后,突变体恢复了在其寄主水稻IR24上的致病力,而转化空质粒pHM1后的突变体仍然表现为致病力缺失.证实了水稻黄单胞菌中hpaB基因与该细菌的致病力相关,在侵染水稻的过程中起着不可缺失的作用.     

Identification of a H+/glucose and galactose symporter gene glt from Xanthomonas oryzae pv. oryzae

We identified a glucose and galactose transporter gene from the plant-pathogenic bacterium Xanthomonas oryzae pv. oryzae. Sequence analysis indicated that the gene, named glt, encoded a polypeptide of 592 amino acid residues and the product was significantly homologous with members of the Na+/glucose cotransporter (SGLT) family from mammalian and bacterial origin, especially with vSGLT from Vibrio parahaemolyticus (50% identity). GLT functioned as a glucose and galactose transporter in an Escherichia coli mutant deficient in glucose and galactose transport activity. A protonophore inhibited the transport activity, suggesting that GLT is a H+-coupled glucose/galactose symporter.     

中国、日本和菲律宾水稻白叶枯病菌的母株与单细胞系的遗传与致病性差异的分析

以J3、IS1112、IS1113和ERIC为引物对17组(56株)来自中国、日本和菲律宾的水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae)代表菌株和它们的单细胞系进行IS-PCR和Rep-PCR扩增以及田间致病性鉴定,研究母株和单细胞系之间的遗传和致病性变异.结果表明:1)母株与单细胞系属于同一分子谱型的比率依次为:52.9%(J3)、23.5%(IS1112)、29.4%(IS1113)和35.3%(ERIC); 2)综合4个引物的PCR扩增结果,采用UPGMA聚类,母株与其全部单细胞系相似率在90%以上的组群占29.4%,差异率达到30%～41%的组群占参试组群的52.9%;以带位相似率80%为簇界,参试菌可以划分为15簇,来自中国、日本和菲律宾的9个组的母株和单细胞系聚合在同一簇中,占参试菌的52.9%,说明三国病菌在遗传上存在高度相关性;三国病菌都存在簇群差异,以菲律宾茵系变异最大,如Pxo79和Pxo112母株和单细胞系各分在不同的3簇中,Pxo79、Pxo86、Pxo99和Pxo112等菌系的母株和单细胞系之间的差异率达到了41%;结果证明:母株是"由遗传上有不同程度差异的细胞"组成的混合体.3)田问致病性测定表明,母株与其单细胞系毒力不同的有15组,占88.2%,说明母株是由毒力不同的单细胞系组成的混合体,但病原菌的分子谱型以及遗传分簇与致病型之间没有相关性.     

OsSERK1 regulates rice development but not immunity to Xanthomonas oryzae pv. oryzae or Magnaporthe oryzae

Somatic embryogenesis receptor kinase (SERK) proteins play pivotal roles in regulation of plant development and immunity. The rice genome contains two SERK genes, OsSerk1 and OsSerk2. We previously demonstrated that OsSerk2 is required for rice Xa21-mediated resistance to Xanthomonas oryzae pv. oryzae (Xoo) and for normal development. Here we report the molecular characterization of OsSerk1. Overexpression of OsSerk1 results in a semi-dwarf phenotype whereas silencing of OsSerk1 results in a reduced angle of the lamina joint. OsSerk1 is not required for rice resistance to Xoo or Magnaporthe oryzae. Overexpression of OsSerk1 in OsSerk2-silenced lines complements phenotypes associated with brassinosteroid (BR) signaling defects, but not the disease resistance phenotype mediated by Xa21. In yeast, OsSERK1 interacts with itself forming homodimers, and also interacts with the kinase domains of OsSERK2 and BRI1, respectively. OsSERK1 is a functional protein kinase capable of auto-phosphorylation in vitro. We conclude that, whereas OsSERK2 regulates both rice development and immunity, OsSERK1 functions in rice development but not immunity to Xoo and M. oryzae.