根癌农杆菌介导的轮枝镰孢菌遗传转化及T-DNA插入突变体的筛选

建立并优化了农杆菌介导转化轮枝镰孢菌Fusarium verticillioides获得T-DNA插入突变体的体系,在镰孢菌孢子浓度106个/mL、农杆菌OD600=0.15-0.20、乙酰丁香酮浓度为200μmol/mL的条件下共培养36h转化率最高,可达60-120个/106个孢子。共获得转化子1000多个,连续转接5代能够稳定遗传。PCR验证潮霉素B抗性基因已整合进转化子基因组DNA中,部分转化子表现为生长和形态异常。该转化体系的建立为研究该菌的致病机制和功能基因分析奠定了基础。     

根癌农杆菌介导的轮枝镰孢菌遗传转化及T-DNA插入突变体的筛选

建立并优化了农杆菌介导转化轮枝镰孢菌Fusarium verticillioides获得T—DNA插入突变体的体系,在镰孢菌孢子浓度10^6／mL、农杆菌OD600=0．15—0．20、乙酰丁香酮浓度为200μmol／mL的条件下共培养36h转化率最高,可达60—120个／10^6个孢子。共获得转化子1000多个,连续转接5代能够稳定遗传。PCR验证潮霉素B抗性基因已整合进转化子基因组DNA中,部分转化子表现为生长和形态异常。该转化体系的建立为研究该菌的致病机制和功能基因分析奠定了基础。     

农杆菌介导生防棘孢木霉菌转化体系的优化

目的:实现棘孢木霉菌T4的遗传转化并优化其转化体系.方法:以潮霉素抗性为选择标记,利用农杆菌转化法介导转化棘孢木霉菌.结果:潮霉素基因成功整合到受体菌基因组中,转化子抗性基因可稳定遗传.结论:最优的转化体系和条件为:IM和CM培养基中AS浓度为200 μg/mL,棘孢木霉T4孢子浓度为106/mL,农杆菌浓度为200 μL( OD600约0.8),共培养时间为48 h,转化效率约为50个转化子/106个孢子.     

农杆菌介导的获取疏绵状嗜热丝孢菌插入突变体体系的建立

[目的]建立疏绵状嗜热丝孢菌的稳定遗传转化体系并获得插入突变体.[方法]利用农杆菌介导的方法建立疏绵状嗜热丝孢菌的遗传转化体系 ;分别通过Southern杂交、克隆转移DNA(T-DNA)侧翼序列来确定T-DNA在疏绵状嗜热丝孢菌基因组中的拷贝数和插入位点.[结果]成功建立了可靠的疏绵状嗜热丝孢菌的遗传转化体系.共培养过程中使用萌发孢子是成功建立疏绵状嗜热丝孢菌遗传转化体系的必要条件.疏绵状嗜热丝孢菌萌发的孢子与农杆菌在28℃共培养48h时,转化效率最高.乙酰丁香酮(AS)在农杆菌预培养及疏绵状嗜热丝孢菌萌发的孢子与农杆菌的共培养阶段都是必需的,且在共培养阶段当AS浓度为500 μM时转化效率最高.Southern杂交验证表明,79.2％的转化子为T-DNA单拷贝插入,且通过热不对称PCR (TAIL-PCR)分析得出T-DNA在该菌基因组中的插入位点是随机的.通过该转化系统筛选到部分表型突变体.[结论]我们首次报道了利用ATMT技术成功转化嗜热真菌-疏绵状嗜热丝孢菌,证明了该方法是一种简单有效的获得插入突变体的方法,并为该嗜热真菌进行基因定位提供了工具.     

橡胶树胶孢炭疽菌T-DNA插入突变体库构建及其致病缺陷转化子筛选

【目的】进一步研究橡胶树胶孢炭疽菌致病分子机理。【方法】通过含ILV1基因(具氯嘧磺隆抗性)的pSULF.gfp双元载体农杆菌AGL-1介导进行橡胶树胶孢炭疽菌遗传转化,利用氯嘧磺隆抗性标记筛选转化子,对转化子PCR验证及荧光显微观察;采用离体古铜期橡胶树叶无伤接种法进行致病性缺陷转化子筛选,并对转化子进行遗传稳定性检测。【结果】获得含3 721个转化子的T-DNA插入突变体库,转化效率为150 400个转化子/106孢子,从3 721个转化子中筛选得到致病性缺陷转化子25个;随机选取20个转化子进行遗传稳定性测定,在不含氯嘧磺隆PDA平板上继代培养10次后仍保持氯嘧磺隆抗性,且表型稳定,表明插入外源基因能够稳定遗传。【结论】可以利用根癌农杆菌介导橡胶孢炭疽菌转化,构建橡胶树胶孢炭疽菌T-DNA插入突变体库,筛选致病缺陷突变菌,为进一步研究该菌致病相关基因提供材料。     

根癌农杆菌介导的白腐丝状真菌——黄孢原毛平革菌的转化

利用农杆菌介导的方法成功地对黄孢原毛平革菌（Phanerochaete chrysosporium）进行了遗传转化。将含有潮霉素磷酸转移酶融合基因的双元质粒pCH61300转入根癌农杆菌（Agrobacterium tumefaciens）208中,然后用该转化菌分别感染黄孢原毛平革菌的分生孢子和原生质体,获得16株可能的转化子,经复筛,共获得6株潮霉素抗性水平为100μg/mL的稳定转化子,分生孢子和原生质体的转化频率没有明显差别。PCR检测结果显示,抗性基因已导入黄孢原毛平革菌细胞中;Southern杂交表明,TDNA以单拷贝形式整合到黄孢原毛平革菌基因组中。其中的一个转化子菌落形态与原野生型菌株相比有所不同,菌丝稀薄,分生孢子较少。利用分生孢子转化更为简便易行,无需特殊的设备和制备原生质体,此方法为深入开展该菌的遗传转化研究奠定了基础。     

农杆菌介导的甜瓜蔓枯病菌遗传转化体系的建立

甜瓜蔓枯病是当前危害瓜类的主要病害,严重影响甜瓜的产量和品质,但是蔓枯病菌Didymella bryoniae病原学研究还非常落后,关于该菌功能基因的研究还未见报道。本研究以携带潮霉素B磷酸转移酶基因(hph)的pBIG2RHPH2作为转化载体,根癌农杆菌C58C1作为转化介体,转化甜瓜蔓枯病菌的强致病菌株DB11。研究发现,甜瓜蔓枯病菌的最优转化体系为:甜瓜蔓枯病菌的分生孢子悬浮液浓度为1×106个孢子/mL,农杆菌悬浮液OD600为0.15,共培养时间48h,诱导培养基中添加200μg/mL乙酰丁香酮,选择培养基添加100μg/mL潮霉素B、200μg/mL头孢噻肟钠、200μg/mL氨苄青霉素和200μg/mL四环素。1×105个蔓枯病菌分生孢子可以产生45个左右的转化子,随机挑取3个转化子进行PCR和RT-PCR检测发现,在不含潮霉素B的PDA培养基平板上转化子连续培养5代后,hph基因仍能稳定存在和转录,Southern blotting检测发现,T-DNA都是单拷贝插入3个转化子的染色体内。本研究建立的甜瓜蔓枯病菌的转化体系将为该病菌的功能基因研究和寄主与病原菌的互作研究提供重要技术支撑。     

根癌农杆菌介导的赭曲霉遗传转化体系的建立

赭曲霉在工业上用于甾体C-11α羟基化。为了对现有赭曲霉生产菌株进行遗传改造,以农杆菌LBA4404作为侵染菌株,以赭曲霉(TCCC41060)作为受体菌株,以潮霉素B基因作为筛选标记,成功建立了根癌农杆菌介导的赭曲霉遗传转化体系并对其转化效率的主要影响因素,如农杆菌浓度、孢子浓度、共培养时间和温度等进行了分析。在最佳条件下,转化效率可以达到57个转化子/108个分生孢子。随机挑选的8个阳性转化子10代连续培养结果表明所获得的转化子能稳定遗传。该遗传转化体系的建立为赭曲霉菌株的定向遗传改造提供了重要的操作平台。     

农杆菌介导的粘帚菌遗传转化北大核心CSCD

【目的】建立分离自西藏林芝的能够产生一系列具有抗肿瘤活性的二酮哌嗪类化合物(epipolythiodioxopiperazine,ETP)的一株冬虫夏草定殖真菌——粘帚菌(Gliocladium sp.)6.102的遗传转化体系。【方法】利用农杆菌介导的方式建立了粘帚菌的遗传转化体系;用正交试验研究了影响转化效率的因素,包括共培养所用农杆菌与真菌孢子的比例、共培养的时间、pH值和乙酰丁香酮的浓度。【结果】成功建立了农杆菌介导的粘帚菌的遗传转化体系,得到了转化的最佳条件,其转化效率为50-100个转化子/106真菌孢子。通过农杆菌介导的方式分别将潮霉素B磷酸转移酶基因(hph)和绿色荧光蛋白基因(egfp)转入粘帚菌中,实现了表达并且可以稳定存在。【结论】首次建立了农杆菌介导的粘帚菌遗传转化体系,为研究ETP化合物的生物合成及其调控机制奠定了基础。     

根癌农杆菌介导里氏木霉转化体系的建立和条件优化

目的:采用根癌农杆菌介导的转化方法实现丝状真菌里氏木霉的遗传转化,并优化转化条件.方法:构建含潮霉素抗性基因(hph)的双元载体pCAM-hph后,转化根癌农杆菌LBA4404获得转化菌株.将根癌农杆菌的转化菌株和里氏木霉的分生孢子共培养后在含100μg/mL潮霉素的抗性平板上筛选里氏木霉转化子,并采用PCR扩增和序列测定对转化子中的插入片段进行了分析.结果:使用根癌农杆菌介导的转化方法转化里氏木霉,每106个分生孢子可获得25.8个转化子.最佳的转化条件为:农杆菌初始浓度为OD660约为0.8,孢子数为106个,共培养时间为48h,pH为5.0～5.5,培养温度为28℃.结论:建立了根癌农杆菌介导的里氏木霉转化方法,并获得了最佳的转化条件.     

根癌农杆菌介导转化红曲菌及转化子发酵性能的研究

利用根癌农杆菌介导转化技术成功将潮霉素抗性基因转入发白红曲菌中,优化了抗生素浓度,发白红曲菌孢子浓度,根癌农杆菌浓度,共培养温度及时间,以及乙酰丁香酮浓度等转化条件,最终转化效率可达52个转化子/105个红曲孢子.将转化子在含有潮霉素B的培养基继代培养5代,得到了多株稳定的转化子,对部分转化子进行PCR鉴定,结果进一步...     

根癌农杆菌介导的球毛壳菌遗传转化及T-DNA插入突变体的获得

根癌农杆菌介导的遗传转化系统是植物基因工程常用方法,目前已将这一转化系统应用到酵母、丝状真菌以及人类细胞的转化。利用这一转化系统,成功地实现了丝状真菌球毛壳菌（Chaetomium globosum）的遗传转化,转化率约为60～180个转化子/10.7个孢子 。通过对转化子的PCR检测和Southern 杂交分析表明,TDNA已整合进毛壳菌基因组中,而且在所检测的转化子中都是以单拷贝的形式整合,转化子都能够稳定遗传。根癌农杆菌介导的遗传转化具有转化率高、低拷贝、遗传稳定、操作简便等优点,因此有可能成为丝状真菌遗传转化和功能基因组研究的有力工具。     

根癌农杆菌介导的哈茨木霉菌遗传转化的研究

利用根癌农杆菌EHA105进行了哈茨木霉Th-33的转化,在优化的转化条件下,EHA105对木霉菌的转化效率约45-100个转化子/106个孢子。本实验室利用该方法已建立了含4000多个转化子的木霉T-DNA插入突变体库。随机挑选24个转化子进行遗传稳定性分析,结果显示转化子经过5代无选择压力连续转接后都能在选择平板上正常生长;潮霉素抗性基因的PCR扩增和Southern blot杂交分析表明,木霉转化子含有该基因,Southern blot杂交进一步表明转化子多为单拷贝随机插入。该转化体系的改进将有利于木霉菌生防功能基因的克隆和作用机制的研究。     

农杆菌介导转化黑曲霉分生孢子及产孢缺陷突变子T-DNA插入位点分析

【目的】利用农杆菌(Agrobacterium tumefaciens)T-DNA系统,建立转化黑曲霉(Aspergillus niger)分生孢子的方法,构建T-DNA插入突变子文库,为黑曲霉基因组功能注释研究打下基础。【方法】采用携带二元质粒载体pCAMBIA1301的农杆菌EHA105,诱导转化黑曲霉分生孢子,筛选具有潮霉素抗性的突变子。分析抗性稳定突变子菌株的表型,采用反向PCR方法分析T-DNA插入位点相邻位置的序列,并推测突变基因可能具有的功能。【结果】实验获得具有稳定潮霉素抗性转化子193株,转化率为5.6×102转化子/108分生孢子。部分转化子表型出现较为明显改变,其中一株不能产孢,对其T-DNA插入位点序列分析比对结果显示,突变基因属于超级转运家族(major facilitator superfamily,MFS)。【结论】本研究建立的农杆菌转化黑曲霉分生孢子平台,结合T-DNA插入突变位点分析,可以为黑曲霉基因组功能注释研究提供一种简便有效的途径。     

High frequency of single-copy T-DNA transformants produced by floral dip in CRE-expressing Arabidopsis plants

For genetic transformation of plants, floral dip with Agrobacterium often results in integration of multiple T-DNA copies at a single locus and frequently in low and unstable transgene expression. To obtain efficient single-copy T-DNA transformants, two CRE/ loxP recombinase-based simplifying strategies for complex T-DNA loci were compared. A T-DNA vector with oppositely oriented loxP sites was transformed into CRE -expressing and wild-type control Arabidopsis thaliana plants. Of the primary CRE -expressing transformants, 55% harboured a single copy of the introduced T-DNA, but only 15% in the wild-type plants. However, 73% of the single-copy transformants in the CRE background showed continuous somatic inversion of the DNA segment between the two loxP sites. To avoid inversion of the loxP -flanked T-DNA segment, two T-DNA vectors harbouring only one loxP site were investigated for their suitability for CRE/ loxP recombinase-mediated resolution upon floral-dip transformation into CRE -expressing plants. On average, 70% of the transformants in the CRE background were single-copy transformants, whereas the single-copy T-DNA frequency was only 11% for both vectors in the wild-type background. Both resolution strategies yielded mostly Cre transformants in which the 35S-driven transgene expression was stable and uniform in the progeny and remarkably, also in Cre transformants with multiple T-DNA copies. Therefore, a role is proposed for the CRE recombinase in preventing inverted T-DNA repeat formation or modifying the locus chromatin structure, resulting in a reduced sensitivity for silencing.     

Transformation of Metarhizium anisopliae mediated by Agrobacterium tumefaciens

A simple, highly efficient, and reliable Agrobacterium tumefaciens-mediated transformation method was developed for the insect pathogenic fungus Metarhizium anisopliae. Expression of the green fluorescent protein gene, egfp, and the benomyl resistance gene, benA3, were used as markers in transformed M. anisopliae. Transformation efficiencies were dependent on the strain of A. tumefaciens used. With strain AGL-1, 17.0 +/- 1.4 transformants per plate could be obtained using conidial concentrations of 10(6) conidia/mL and a 2 day co-cultivation in the presence of 200 micromol/L acetosyringone. On the other hand, transformations using strain LBA4404 were unsuccessful. Ten transformants were tested by Southern analysis and found to contain a single copy T-DNA. Twenty transformants were subcultured for five generations on nonselective media, and 95% of the transformants were mitotically stable. Agrobacterium tumefaciens-mediated transformation of M. anisopliae can serve as a useful tool to investigate genes involved in insect pathogenicity.     

The T-DNA integration pattern in Arabidopsis transformants is highly determined by the transformed target cell

Transgenic loci obtained after Agrobacterium tumefaciens -mediated transformation can be simple, but fairly often they contain multiple T-DNA copies integrated into the plant genome. To understand the origin of complex T-DNA loci, floral-dip and root transformation experiments were carried out in Arabidopsis thaliana with mixtures of A. tumefaciens strains, each harboring one or two different T-DNA vectors. Upon floral-dip transformation, 6–30% of the transformants were co-transformed by multiple T-DNAs originating from different bacteria and 20–36% by different T-DNAs from one strain. However, these co-transformation frequencies were too low to explain the presence of on average 4–6 T-DNA copies in these transformants, suggesting that, upon floral-dip transformation, T-DNA replication frequently occurs before or during integration after the transfer of single T-DNA copies. Upon root transformation, the co-transformation frequencies of T-DNAs originating from different bacteria were similar or slightly higher (between 10 and 60%) than those obtained after floral-dip transformation, whereas the co-transformation frequencies of different T-DNAs from one strain were comparable (24–31%). Root transformants generally harbor only one to three T-DNA copies, and thus co-transformation of different T-DNAs can explain the T-DNA copy number in many transformants, but T-DNA replication is postulated to occur in most multicopy root transformants. In conclusion, the comparable co-transformation frequencies and differences in complexity of the T-DNA loci after floral-dip and root transformations indicate that the T-DNA copy number is highly determined by the transformation-competent target cells.