拮抗北细辛菌核病木霉菌的分离、鉴定及生防效果

[背景] 菌核病是北细辛根部主要病害之一,木霉菌作为目前应用最广泛的生物防治真菌,利用木霉菌防治北细辛菌核病是目前研究的热点。[目的] 通过稀释分离法对健康北细辛植株根际土壤进行菌株分离,以期筛选出有效拮抗北细辛菌核病的生防木霉菌。[方法] 以北细辛菌核病菌为靶标菌,采用平板对峙培养、挥发性与非挥发性物质抑菌的方法对分离得到的木霉菌进行筛选,采用生长速率法对筛选出的木霉菌的发酵液进行抑菌效果测定,并采用硫代巴比妥酸法测定筛选出的木霉对北细辛菌核病菌的丙二醛（Malondialdehyde,MDA）含量、紫外吸收法测定过氧化氢酶（Catalase,CAT）活性、氮蓝四唑法测定超氧化物歧化酶（Superoxide Dismutase,SOD）活性、愈创木酚法测定过氧化物酶（Peroxidase,POD）活性的影响。[结果] 从土壤中分离出木霉菌共14株,通过形态学和ITS-RPB2双基因联合构建系统发育树,鉴定其为哈茨木霉（Trichoderma harzianum）、钩状木霉（Trichoderma hamatum）、拟康氏木霉（Trichoderma koningiopsis）、深绿木霉（Trichoderma atroviride）、短密木霉（Trichoderma brevicompactum）和装絮木霉（Trichoderma tomentosum）。对峙培养试验表明,钩状木霉A26、拟康氏木霉B30、钩状木霉C6、哈茨木霉A17对北细辛菌核病菌抑制率均在90%以上,挥发性物质抑制测定结果显示钩状木霉C6抑制率最高,为53.73%±0.07%,木霉菌的非挥发性物质抑菌作用较强,哈茨木霉A17、钩状木霉A26、钩状木霉C6的非挥发性物质对细辛菌核病菌的抑制率均在75%以上,而拟康氏木霉B30抑制率可达100%。因此,筛选出的哈茨木霉A17、钩状木霉A26、拟康氏木霉B30、钩状木霉C6为拮抗效果较强的生防木霉菌,这4株木霉菌的发酵液对北细辛菌核病菌的抑制率分别为56.33%±0.12%、77.22%±0.06%、82.28%±0.03%、46.20%±0.04%。经这4株木霉菌的非挥发性物质处理7 d后,菌核病菌MDA含量显著增加,钩状木霉A26是对照组的7.7倍,最为显著;菌核病菌抗氧化酶活性均降低,与对照组相比,CAT、SOD、POD活性分别下降了19.67%-75.84%、4.71%-68.71%和3.57%-67.86%。[结论] 从北细辛健康植株根际土壤中分离的木霉菌株哈茨木霉A17、钩状木霉A26、拟康氏木霉B30、钩状木霉C6对北细辛菌核病菌均有较好的抑制效果,可用于北细辛菌核病的生物防治。     

米修链霉菌TF78对香蕉枯萎病的田间防效及根际土壤微生物的影响

【背景】香蕉枯萎病是香蕉生产上的毁灭性病害,生物防治是遏制该病害发生的有效手段。在前期的研究中,从健康香蕉根际土壤中分离获得一株对香蕉枯萎病具有良好盆栽防治效果的生防菌——米修链霉菌(Streptomyces misionensis) TF78,但其对香蕉枯萎病的田间生防潜力和对土壤微生物环境的影响尚不清楚。【目的】评价米修链霉菌TF78对香蕉枯萎病的田间防治效果,明确其对香蕉根际土壤微生物群落的影响。【方法】选取两块发病香蕉园,测定该生防菌株对香蕉枯萎病的防治效果,并利用扩增子测序技术分析施用菌剂组和空白对照组共12份香蕉根际土壤的微生物多样性和丰度。【结果】米修链霉菌TF78对两块香蕉园的田间防效分别达55.30%和45.32%。该生防菌株处理组的物种稀释曲线坡度大于空白对照组,并显著富集了优势种群梳霉门(Kickxellomycota),消减了绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)和苔藓杆菌(Bryobacter)的丰度,对土壤中优势种群变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)及木霉属(Trichoderma)、鞘氨醇单胞菌属(Sphingomonas)、寡养单胞菌属(Stenotrophomonas)和芽孢杆菌属(Bacillus)的相对丰度影响不显著。【结论】米修链霉菌TF78塑造了不利于香蕉枯萎病菌Fusarium oxysporum f.sp.cubense存活的土壤环境,有效降低了田间香蕉枯萎病的发生,同时对土壤中大部分具有重要生态功能和抑菌功能的优势微生物种群影响不显著。该研究结果为米修链霉菌TF78的进一步开发应用奠定了基础。     

新疆野果林木霉分离鉴定、抑菌作用及固态发酵配方优化

[背景] 新疆野苹果病害发生严重,而木霉（Trichoderma spp.）是重要的植物病害生防菌,因此可利用其对新疆野苹果病害进行防治。[目的] 分离鉴定新疆野果林木霉菌株,分析其对新疆野苹果2种病原菌的抑菌能力,为新疆野苹果专用木霉菌肥的制备提供菌种资源。[方法] 利用平板稀释法对新疆野果林4种草本植物根围木霉菌进行分离,通过形态学与分子生物学方法进行菌种鉴定,平板对峙试验检测其抑菌能力并优化木霉菌株的固态发酵配方。[结果] 共分离得到2种木霉菌共42株,分别为34株棘孢木霉（T. asperellum）和8株深绿木霉（T. atroviride）;棘孢木霉TasT01对苹果炭疽病菌（Colletotrichum gloeosporioides,Cgl）和苹果斑点落叶病病原菌（Alternaria alternaria f.sp.mali,Aal）的抑菌率分别为58.60%和57.14%;深绿木霉TatT35对Cgl和Aal的抑菌率分别为43.86%和36.90%。进一步显微镜观察发现,TasT01可通过菌丝缠绕的方式抑制2种病原菌的生长。TatT35菌株固态发酵配方为稻壳90%、麦麸10%、（NH₄）₂SO₄ 0.5%时,孢子浓度达1.0×10⁸个/g。[结论] TasT01和TatT35对新疆野苹果2种病原菌都有很好的抑制效果,固态发酵配方优化后可以提高孢子浓度,该研究结果为新疆野苹果真菌病害的生物防治提供了可借鉴的方法。     

拟康宁木霉T 51菌株对番茄枯萎病的生物防治及其机理研究

尖孢镰刀菌是番茄枯萎病的致病菌,该研究利用拟康宁木霉T 51菌株对尖孢镰刀菌展开对峙培养试验、防治最适温度、酸碱度筛选试验及生物防治效果试验,并测定防治试验中番茄幼苗叶片的生理生化指标和水杨酸、茉莉酸合成和信号途径关键基因表达量,探讨T 51菌株的生物防治机理。结果表明：(1)T 51菌株可显著抑制对峙培养中尖孢镰刀菌生长;随着环境温度和pH的增加,T 51菌株对尖孢镰刀菌的抑制率先升后降,并且在20 ℃、pH 7环境下效果最佳。(2)T 51菌株和尖孢镰刀菌混合孢子液处理番茄幼苗植株无明显的感病症状,植株生长状态与清水对照组无显著差异,枯萎病发病率和病情指数比单施尖孢镰刀菌孢子液处理显著大幅度降低,相对防效为87.5%。(3)与单施尖孢镰刀菌孢子液处理相比,混合孢子液处理番茄幼苗叶片的叶绿素荧光参数最大光化学效率、光化学淬灭系数和表观光合电子传递速率,以及抗氧化酶SOD、POD、CAT活性均显著增加,而非光化学淬灭系数和过氧化氢含量均显著降低。(4)与单施尖孢镰刀菌孢子液处理相比,混合孢子液处理番茄幼苗叶片的内源水杨酸(SA)显著降低,而茉莉酸(JA)含量显著升高,同时SA信号通路上的PR1和TGA2基因表达量均显著下调,JA合成基因LoxD的表达量显著上调。研究认为,拟康宁木霉T 51菌株对尖孢镰刀菌有显著的防治效果,并在20 ℃、pH 7环境下防治效果最佳;T 51菌株可能通过抑制尖孢镰刀菌侵染,增强番茄叶片抗氧化酶活性,提高叶片光合效率,以及调控水杨酸和茉莉酸合成和信号途径关键基因表达,调节内源水杨酸和茉莉酸含量,进而提高番茄植株的枯萎病抗病性。研究结果为番茄抗枯萎病提供了生防途径的理论依据。     

一株西瓜枯萎病生防菌的鉴定与田间防效

【背景】西瓜枯萎病是由尖孢镰孢菌西瓜专化型(Fusarium oxysporum f. sp. niveum)引起的土传病害,是西瓜最为严重的病害之一。利用拮抗微生物抑制病原菌繁殖,降低其危害程度,已成为西瓜枯萎病防控领域的研究热点。【目的】筛选对西瓜枯萎病病原菌具有拮抗作用的菌株,并探究其抑菌作用,为有效防控西瓜枯萎病提供生防资源。【方法】从西瓜的根围土中分离细菌,采取平板对峙及温室生测的方法筛选生防菌,通过形态学及gyr B基因序列同源性分析对生防菌株进行鉴定;采用鉴别性培养基测定生防菌的拮抗因子(纤维素酶、蛋白酶、几丁质酶、β-1,3-葡聚糖酶);测定生防菌发酵液对西瓜枯萎病菌孢子萌发及菌丝生长的影响;于田间条件下检测该菌株防治西瓜枯萎病的效应。【结果】筛选到了一株对西瓜枯萎病具有防治效果的拮抗菌株SFJ11,经鉴定该菌株为解淀粉芽胞杆菌(Bacillusamyloliquefaciens)。该菌株可以分泌蛋白酶和纤维素酶,其20%的发酵液几乎能完全抑制西瓜枯萎病菌菌丝的生长,对孢子萌发的抑制率为95%,田间防治效果最高可达78%。【结论】菌株SFJ11对西瓜枯萎病具有较强的生防效果,有潜在的应用价值。     

生姜共生真菌的分离及其体外抑菌效应初探

为筛选得到优良植物病害生防菌,对广西生姜Zingiber officinale种植区健康生姜根系和叶片中的共生真菌进行了组织分离,以生姜茎腐病菌群结腐霉Pythium myriotylum和香蕉枯萎病菌尖孢镰刀菌古巴专化型4号生理小种Fusarium oxysporum f. sp. cubense race 4为指示菌,通过平板对峙培养法和发酵液菌落直径法试验进行筛选评价,并结合形态学观察及ITS序列分析对筛选出的生防效果最好的共生真菌进行了鉴定。结果表明,从生姜植株共分离得到34株共生真菌,其中根系分离22株,叶片分离12株;对峙培养发现有6株共生真菌对生姜茎腐病菌和香蕉枯萎病菌均有抑制作用;其中菌株SBM-11拮抗作用最强,对生姜茎腐病菌抑制率达到93%,对香蕉枯萎病菌抑制率达到82%;SBM-11的发酵液对生姜茎腐病菌和香蕉枯萎病菌抑制率分别为82%、73%,与其他菌株发酵液抑制效果相比差异明显;结合形态和分子鉴定结果表明SBM-11菌株为绿色木霉Trichoderma viride,极具生防潜力。     

炭团木霉中非核糖体多肽基因NRPS1的功能研究

[目的] 木霉属真菌是应用最为广泛和潜力最大的生防真菌,其产生的典型化合物哌珀霉素（peptaibols）类抗生素在生物防治中发挥重要作用。本研究采用基因组挖掘技术（genome mining）发现炭团木霉（Trichoderma hypoxylon）的潜在哌珀霉素生物合成基因簇及对病原菌的防治作用。[方法] 生物信息学分析预测合成哌珀霉素的基因簇,利用Quick-change技术构建基因骨架敲除盒,通过PEG介导的原生质体转化方法获得敲除突变株,通过平板对峙法和菌丝生长毒力实验验证该基因簇对炭团木霉生物活性的影响。[结果] 基因挖掘鉴定一个非核糖体多肽合成酶（nonribosomal peptide synthetases,NRPS）可能合成哌珀霉素类抗生素,命名为NRPS1,对该基因进行部分敲除,成功获得3株NRPS1缺失突变株。对峙实验表明,突变株对寄生曲霉（Aspergillus parasiticus）、尖孢镰刀菌（Fusarium oxysporum）、黑白轮枝菌（Verticillium alboatrum）等9株植物病原真菌的抑制作用与野生株相比显著下降,且突变株的粗提物的抑菌活性明显弱于野生型。[结论] NRPS1是一个潜在的哌珀霉素合成基因,该基因在宿主与病原真菌对抗过程中起关键作用,该研究为炭团木霉哌珀霉素结构解析及生物防治机理研究奠定了基础。     

耐热木霉菌株筛选及其对热作区香蕉促生效应的研究

【目的】为筛选安全、高效的耐热木霉功能菌株,有效促进热作区香蕉的生产,本研究从热作区土壤分离筛选适温范围较宽的木霉菌株,研制木霉生物有机肥,并研究其对香蕉枯萎病发病率、果实产量及品质的影响。【方法】通过稀释涂布法筛选出木霉菌株,根据菌株在不同温度下的生长情况、拮抗尖孢菌能力及酶活强弱进行菌株复筛;将复筛所得菌株试制成生物有机肥,在田间条件下,研究木霉生物有机肥的施用对香蕉发病率、产量及品质的影响;最后结合菌株ITS及tef1序列分析鉴定所选菌株的分类信息。【结果】从海南土壤中筛选出4株耐热木霉菌株,其在20–40°C能生长,其中菌株JS84在40°C高温下生长速度最快,对尖孢镰刀菌4号生理小种抑制率最高,产酶活力能力最强。田间试验结果表明:施用JS84木霉生物有机肥(JS84)显著降低了香蕉枯萎病发病率;有效改善了香蕉果实品质并提高了土壤养分;该处理产量显著高于不施肥对照、化肥处理、有机肥处理和商品木霉生物有机肥处理(NJAU4742),分别增产32%、18%、8%和6%。ITS结合tef1序列分析结果表明,JS84菌株为桔绿木霉菌(Trichoderma citrinoviride)。【结论】从热作区土壤中成功筛选到一株桔绿木霉JS84,其适宜生长温度宽,研制的木霉生物有机肥对热区香蕉具有显著的抗枯萎病及增产作用。     

4种木霉菌对棉花黄萎病菌抑制作用的测定

以绿色木霉(Trichoderma viride)、康氏木霉(Trichoderma koningii)和二株未知木霉菌株(Trichoderma spp.)为供试木霉菌株,采用对峙培养法测定了不同温度处理下对棉花黄萎病菌(Verticilliam dahliae)的拮抗作用。结果表明,木霉在不同温度下对棉花黄萎病菌的抑制作用不一,其中以30℃和25℃黑暗条件下木霉对棉花黄萎病菌菌丝生长的抑制作用最强,对峙培养5d后,绿色木霉、康氏木霉和二株未知木霉菌在30℃条件下对棉花黄萎病菌的抑制率分别达到67.3%、65.9%、56.8%、65.9%,25℃条件下的抑制率分别为65.9%、72.9%、65.9%、78.8%;20℃下木霉菌株对棉花黄萎病菌的抑制作用次之,10℃、15℃和35℃条件下木霉菌丝扩散速度较慢,且孢子产生量少,不能有效地抑制棉花黄萎病菌菌丝的扩展,表明环境温度过高或过低对木霉菌丝的生长及分生孢子的产生均有较大影响。该研究为筛选棉花黄萎病菌更为有效的生防木霉菌株提供理论依据。     

洞庭湖湿地木霉多样性及生防活性

【目的】了解湖南省洞庭湖湿地木霉种类及分布,丰富我国的木霉种质资源,为功能菌株筛选应用奠定基础。【方法】利用ITS序列比对分析结合形态学特征对分离到的木霉菌株进行种类鉴定,构建系统发育进化树分析其亲缘关系。通过菌丝生长速率法测定菌株的平板抑菌能力,根据水解带大小检测菌株的水解酶活性,利用灰色关联度分析筛选综合生防效果较好的木霉菌株。【结果】从52个土样和18个水样中分离得到114株木霉菌株,经鉴定分属16个木霉种类:哈茨木霉、绿木霉、刺孢木霉、土星孢木霉、钩状木霉、拟康宁木霉、短密木霉、深绿木霉、猥木霉、毛细木霉(中国新记录种)、长枝木霉、卵孢木霉、侧耳木霉、加纳木霉、厚木霉及一个疑似新种;哈茨木霉为洞庭湖湿地中的优势种,占总菌株数量的19.30%;16种木霉在系统发育树中归于7个进化支:Harzianum Clade、Virens Clade、Longibrachiatum Clade、Lutea Clade、Viride Clade、Hamatum Clade、Unknown Clade。灰色关联度分析表明,菌株TW21990、QT22040和QT22094的灰色关联度较高,分别为0.849 5、0.798 6和0.732 6,综合生防性状较好。【结论】洞庭湖湿地木霉具有种类多样性和分布多样性,发现了一个中国新记录种毛细木霉和一个疑似新种,哈茨木霉TW21990、长枝木霉QT22040和卵孢木霉QT22094是潜在的优良生防菌株。     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

甘菊ClHSP70与ClHSP90基因的克隆及表达分析

该研究以甘菊(Chrysanthemum lavandulifolium)为实验材料,通过RT-PCR方法从甘菊转录组数据中分离出热激蛋白合成相关基因,命名为ClHSP70和ClHSP90。序列分析表明,ClHSP70基因ORF全长为2 559bp,编码852个氨基酸,蛋白功能区预测表明含有典型的HSP70蛋白NBD和SBD保守结构域;ClHSP90基因ORF全长为2 094bp,编码697个氨基酸,含有HATPase结构域和HSP90保守结构域。生物信息学分析表明,甘菊ClHSP70与大豆(Glycine max)和烟草(Nicotiana tomentosiformis)HSP70蛋白有较高的一致性,ClHSP90基因编码的氨基酸序列与紫茎泽兰(Ageratina adenophora)HSP90高度相似;实时荧光定量表达分析表明,在42℃处理不同时间,甘菊叶片中ClHSP70和ClHSP90基因表达均在0.5h时显著增加,1h达到最大值,2h后缓慢下降;不同组织表达分析表明,甘菊在42℃处理1h后,ClHSP70在成熟叶中的表达量显著高于嫩叶和根等其他组织;ClHSP90在成熟茎中的表达量最高。研究说明,ClHSP70和ClHSP90基因具有热激蛋白特征,参与了甘菊热胁迫应答过程,该研究结果为以后深入研究其基因功能奠定了基础。     

Presence of Rhizobium Etli bv . Phaseoli and Rhizobium Gallicum bv . Gallicum in Egyptian Soils

Seven bean rhizobial strains EBRI 2, 3, 21, 24, 26, 27 and 29 identified as Rhizobium etli, and EBRI 32 identified as Rhizobium gallicum, isolated from Egyptian soils and which nodulated Phaseolus vulgaris efficiently, were subjected to hybridization with a nifH probe in order to estimate the copy number of this gene. Seven strains (EBRI 2, 3, 21, 24, 26, 27 and 29) which were only able to nodulate Phaseolus vulgaris, contained three copies of the nifH gene, consistent with their identification as Rhizobium etli bv. phaseoli. Only one strain (EBRI 32) which nodulated both Phaseolus vulgaris and Leucaena leucocephala, had one copy of nifH gene. This confirmed the classification of this strain as Rhizobium gallicum bv. gallicum.     

Evaluation of Beauveria bassiana and B. brongniartii strains and four wild-type fungal species against adults of Bactrocera oleae and Ceratitis capitata

The virulence of two isolates of the hyphomycete fungi, Beauveria bassianaand B. brongniartii, and additional fungal species isolated from diseased Bactrocera oleae pupae and Sesamia nonagrioideslarvae were assessed against adults of the olive fruit fly B. oleae and the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae). Contact and oral bioassays revealed that moderate to high mortality rates for the olive fruit fly occurred when the adults were exposed to conidia of Mucor hiemalis, Penicillium aurantiogriseum, P. chrysogenum and B. bassianaisolates. A strain of M. hiemalis isolated from S. nonagrioides larvae was the most toxic resulting in 85.2% mortality to the olive fruit fly adults. B. brongniartiiand B. bassiana were the most pathogenic to the C. capitataadults causing 97.4 and 85.6% mortality. Metabolites collected from the M. hiemalis and P. chrysogenum isolates were toxic to adults of both species.     

转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响

【目的】为探究转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响。【方法】以转Cry1Ac/1Ab基因棉与其亲本常规棉为实验材料,利用取食不同棉花品种叶片的棉铃虫饲喂异色瓢虫幼虫。【结果】与常规亲本棉相比,取食饲喂转基因棉花叶片的初孵棉铃虫幼虫的异色瓢虫幼虫从1龄发育至化蛹期时间延长0.77 d,但差异不显著;除1龄幼虫体重增加(0.0773 mg)外,其余各龄期幼虫体重均有所下降,但差异均不显著;异色瓢虫1、2、3、4龄幼虫对初孵棉铃虫捕食量均随棉铃虫密度的增加而增加,捕食功能反应均符合HollingⅡ圆盘方程。【结论】转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育无显著影响,饲喂取食转Cry1Ac/1Ab基因棉花的棉铃虫对异色瓢虫捕食功能无显著差异。     

Genome Analysis inNeurospora crassa;Cloning of Four Lociarginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) and Associated Chromosome Walking

We have cloned fourNeurospora crassagenes by complementation analysis. Cloned genes include thearginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) loci. Chromosome walks were initiated in ordered cosmid libraries from the cloned loci. A total of about 700 kb of theNeurosporagenome is covered in these walks.