香蕉枯萎病菌pacC基因的克隆与序列分析

采用PCR和RT-PCR方法扩增尖孢镰刀菌古巴专化型(Fusarium oxysporum f sp.cubense,FOC)1号和4号生理小种的pacC基因(FOC1-pacC,FOC4-pacC),对FOC1-pacC和FOC4-pacC相似序列进行搜索和比对,以及对基因编码蛋白进行结构预测,发现FOC1-pacC和FOC4-pacC开放阅读框分别为1 863、1 905 bp,编码634、620个氨基酸,2个小种之间基因序列和氨基酸序列差异明显,FOC1-pacC比FOC4-pacC缺少1个基因片段,FOC-pacC与其相似序列有显著差异,比对缺少2个基因片段;初入侵转录组表达分析说明,2生理小种pacC基因在小种侵染不同品种香蕉过程中表达有差异,FOC1-pacC基因只在粉蕉中检测到表达,而FOC4-pacC则在粉蕉和香蕉中都检测到表达,但在粉蕉中的表达量明显高于香蕉。     

香蕉枯萎病菌1号和4号生理小种菌株侵染和定殖巴西蕉和粉蕉根系的观察

尖孢镰刀菌古巴专化型1号和4号生理小种菌株对巴西蕉和粉蕉的致病性不同,其在巴西蕉和粉蕉根系的侵染和定殖过程是否不同仍未阐明。笔者将绿色荧光蛋白标记的1号（T320）和4号（B2-63）生理小种菌株分别接种巴西蕉和粉蕉,借助激光共聚焦显微镜观察侵染过程。发现这2个生理小种菌株菌丝均可沿巴西蕉和粉蕉根系表层细胞之间的凹槽生长,并进一步侵入维管束;而且B2-63侵入粉蕉根系维管束快于其侵入巴西蕉根系维管束。在接种T320 菌株15 d后,在轻微褐变的巴西蕉球茎组织中未观察到其菌丝体,而在褐变粉蕉球茎中可观察到。推测T320在粉蕉根系维管束中的扩展较其在巴西蕉根系维管束中的扩展容易。结果为进一步研究尖孢镰刀菌古巴专化型生理小种与不同基因型香蕉的互作奠定基础。     

中华补血草Syntaxin基因的克隆

[目的]对中华补血草Syntaxin基因进行克隆。[方法]以中华补血草叶片为材料,提取总RNA并进行反转录反应。依据已知Syntaxin基因5'端EST序列信息设计巢式引物,以反转录得到的cDNA为模板,利用2轮PCR扩增cDNA3'末端(3'RACE),获得Syntaxin基因3'端序列。[结果]获得1090bp的DNA片段。分析表明,该片段编码LsSyntaxin全长基因,其中开放阅读框长816bp,编码271个氨基酸。该基因编码的Syntaxin蛋白相对分子量为30254.3Da,理论等电点为5.55。[结论]为研究Syntaxin基因在补血草中的功能及其在补血草泌盐过程的作用奠定了基础。     

小麦秆锈菌新小种Ug99及其抗病育种研究进展(英文)

为帮助我国小麦研究人员全面了解秆锈菌新小种-Ug99 及其对我国小麦生产的潜在威胁,呼吁加强 Ug99 及其变异小种传播与扩散的监控,加强抗病种质创新和持久性耐病新品种选育,提前预防 Ug99 的危害。对 Ug99 小种变异、致病力、分布扩散以及小麦及其亲缘种属抗病基因发掘、连锁分子标记筛选,抗性育种策略与进展,中国 Ug99 研究现状进行了总结,由此不难看出,Ug99 是容易发生小种变异、毒力极强、扩展速度较快的秆锈菌新小种,极有可能对世界小麦生产带来的全球性危害。应该加强小麦及其亲缘种属新抗病基因的发掘与利用和持久性耐病新品种的培育,控制和预防 Ug99 及其变异小种的危害。     

Race 3, a new race of<Emphasis Type="Italic"> Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">lactucae </Emphasis>determined by a differential system with commercial cultivars

 Pathogenic variation among 26 Japanese isolates of Fusarium oxysporum f. sp. lactucae (FOL) was tested using 21 lettuce cultivars to select commercial lettuce cultivars as race differential indicators. Cultivar Costa Rica No. 4 was resistant to race 1 but susceptible to race 2, consistent with the conventional standard differential line VP1010. Cultivar Banchu Red Fire was susceptible to race 1 but resistant to race 2, which showed an opposite type of reaction as another differential line VP1013. Cultivar Patriot was susceptible to both races. The resistance reactions of the three cultivars under field conditions were identical with that observed in the seedlings. Thus cv. Costa Rica No. 4 and cv. Banchu Red Fire can be used as differential hosts to identify pathogenic races of FOL. This differential system showed that all FOL isolates obtained from diseased butterhead lettuce in Fukuoka, Japan were new races (i.e., pathogenic to three cultivars). We propose that the new race be designated race 3. Isolates of FOL, the pathogen of Fusarium wilt in lettuce, obtained from California showed the same reaction as that of race 1. Furthermore, the Japanese isolate SB1-1 (race 1) and California isolate HL-2 belonged to the same vegetative compatibility group. Our results suggest that both of the fungi are the same forma specialis. Received: March 25, 2002 / Accepted: August 26, 2002     

稻瘟病菌生理小种菌体可溶性蛋白特性初探

 采用聚丙烯酰胺凝胶等电聚焦法对来自江苏、浙江两省经全国统一鉴别寄主鉴定的稻瘟病菌7个生理小种群、12个生理小种的16个菌株菌体可溶性蛋白进行了分析比较,结果表明:供试菌株菌体可溶性蛋白电泳谱带有37~43条,谱带等电点分布范围为3.00~8.15。除个别菌株外,同一生理小种群内各生理小种问菌体可溶性蛋白电泳图谱的相似系数大于0.70,不同生理小种群的生理小种间菌体可溶性蛋白电泳图谱的相似系数一般为0.50~0.60。供试各生理小种群、生理小种乃至同一生理小种的不同菌株间,其可溶性蛋白电泳图谱存在不同程度的差异,表现为谱带数目的多少和部分谱带等电点(谱带位置)分布的不同。     

Changing allele frequencies associated with specific resistance genes to leaf blast in backcross introgression lines of Khao Dawk Mali 105 developed from a conventional selection program

Key genomic regions associated with blast resistance against a broad spectrum of isolates could be identified in backcross introgression lines developed by conventional breeding program. In this article, eighty three BC₃F₂ backcross introgression lines (BILs) derived from a cross between IR68835-98-2-B-2-1-1 (a broad spectrum blast resistance variety) and KDML105 (a susceptible variety) were developed by phenotypic selection against a mixture of six virulent blast isolates (MXL) that are widely spread out in the rainfed lowland of the North and Northeast of Thailand. The resistance spectrum of the BILs was assessed by inoculating with 12 different Magnaporthe oryzae isolates that showed differential responses on the parental cultivars and the MXL that was used for phenotypic selection. All BILs showed highly resistant reactions (low disease score) to the MXL and to two blast isolates THL48 and THL149. Four markers, i.e., RM246, RM241, RM303 and RM164 completely favoring the IR68835 allele (shifting of allele frequencies from KDML105 to IR68835) were identified on chromosomes 1, 4 and 5, respectively. Therefore, these markers could be linked to the resistance genes functioning against the MXL, THL48 and THL149. Furthermore, significant shifting of alleles was identified at six markers located on chromosomes 2, 4, 8, 9 and 12. Seven DNA markers linked to specific resistance genes were identified, in which allele from IR68835 at 6 markers, i.e., RM6, RM205, RM211, RM252, RM273 and RM342 reduced disease score (DS), against blast isolates THL16, THL329, THL458, THL831, THL868 and THL96036 while allele from KDML105 at RM208 (Pi-kd on chromosomes 2) reduce DS against THL84, THL191, THL557 and THL1108. In this study, the use of DNA markers enabled the identification of specific resistance genes in the backcross breeding materials developed from routine rice breeding program through the conventional phenotypic selection. In this experiment, the usefulness of breeding materials from conventional breeding program in identifying genes corresponding to the selection was illustrated. Linked markers and their genomic location provide necessary information for further use of marker-assisted selection to improve blast resistance in rice breeding program.     

2006～2010年黑龙江省大豆灰斑病菌生理小种监测及部分主栽品种抗性鉴定

通过对2006～2010年黑龙江省大豆灰斑病生理小种的监测,明确了大豆灰斑病生理小种出现频率和分布情况.结果表明:1号生理小种在各大豆产区出现频率最高,为50.5%,平均为40.1%;其次是7号,出现频率为35.9%,平均为26.2%.出现频率较高的还有6、10和11号生理小种,平均出现频率分别为18.8%、12.0%...     

抗病基因对大豆胞囊线虫3号生理小种的选择作用

为了解育成抗病品种抗性稳定性及胞囊线虫生理小种侵染力的变异,于2005～2008年,应用黑龙江省发生的大豆胞囊线虫3号生理小种及已经通过鉴定的抗大豆胞囊线虫3号生理小种的品种,哈尔滨小黑豆、灰皮支等8个品种和感病对照品种Lee68为材料,进行抗病基凶对大豆胞囊线虫3号生理小种选择作用研究.在盆栽条件下,强迫大豆胞囊线虫3号生理小种的群体在抗病品种上繁殖10代,选用5个标准鉴定大豆胞囊线虫生理小种的鉴别品种,重新鉴定经抗病基因选择后的大豆胞囊线虫的生理小种类型.结果表明:原来为3号生理小种的线虫群体,经在抗病品种抗线虫1号、抗线虫2号、抗线虫3号、抗线虫4号、抗线虫5号上连续选择10代之后,变为6号小种;经在厌皮支黑豆上选择之后变为10号小种;经在Peking上选择之后变为14号小种,经在哈尔滨小黑豆上选择之后变为15号小种.上述鉴定结果说明,原大豆胞囊线虫生理种群体,经过在抗病品种上连续强迫繁殖后,形成新的生理小种,并使原扰病品种变为感染品种,认为在生产上采用轮作方式是保持抗线品种抗性稳定性的有效途径.     

水稻白叶枯病数量抗性座位定位及其小种专化性

用水稻白叶枯病3个毒力不同的菲律宾小种P2、P6和P9,对供体Lemont导入到特青背景的178个近等基因导入系群体,进行白叶枯病数量抗性座位(quantitative resistance loci, QRL)定位及其小种专化性研究。供试亲本Lemont感3个小种,特青中感P2和P9,感P6。导入系群体的病斑长度呈连续正态分布。共发现影响病斑长度的10个主效QRL