水稻白叶枯病菌致病相关基因筛选系统的建立

水稻白叶枯病菌Xanthomonas oryzae pv.oryzae是水稻生产中最严重的细菌性病害之一。本研究采用Tn5转座子随机插入突变的方法构建水稻白叶枯病菌广西菌株K74的突变体库,Southern杂交显示Tn5随机单拷贝插入基因组。通过水稻致病性检测试验,目前获得15个致病力降低50%以上的突变体,为定位Tn5插入突变基因,经质粒拯救、测序、序列分析后发现:4个突变基因为gum基因簇基因,5个为LPS基因簇基因,2个为metB基因,1个为hrpB1基因,2个是与糖合成转移酶相关基因,1个为编码假定蛋白的基因。其中14个突变基因是已知的与致病相关的基因。实验结果表明本研究成功建立了一个筛选水稻白叶枯病菌致病相关基因的系统,为进一步研究水稻白叶枯病致病相关基因,阐明该病的致病机理奠定基础。     

丝瓜布固定化米根霉发酵生产L-乳酸

L-乳酸因其为生产绿色化学材料聚L-乳酸的原料而倍受重视．文中以米根霉As3．6462为菌种,玉米淀粉为原料,研究了用吸附固定米根霉发酵L等L酸．结果表明,相对聚乙烯醇、棉布,丝瓜布有更好的固定化效果．实验条件下,载体边长在8—10mm,载体用量为15mL／50mL种子培养基,玉米淀粉发酵L-乳酸产量为72—83g/L,连续发酵4批后产量基本稳定．丝瓜布固定化米根霉发酵L看L酸有良好的工业的应用前景．     

水稻稻瘟病菌特异性抗病蛋白质的初步鉴定

稻瘟病抗病品种“地优63”的组织蛋白提取液对稻瘟菌株A_(15)的孢子萌发有显著抑制作用,而感病品种“索马里稻V_(41)B”则否,此抑制作用与“地优63”的蛋白质组成有关。IEF电泳显示,在“索马里稻V_(41)B”中有一pI为5.4的蛋白质与孢子吸附后消失。     

稻瘟病菌粗毒素对水稻成熟胚愈伤组织生长和分化的影响及抗性筛选

利用目前稻瘟病不同的优势小种菌株的液体培养提取的粗毒素对水稻成熟胚进行处理,粗毒素液对水稻愈伤组织的生长及分化有严重的抑制作用,与对照相比差异性极显著;不同浓度的粗毒素提取液其作用效果不同,随着毒素浓度的增大或是作用时间的延长,水稻分化受到的抑制作用越强。水稻成熟胚组织培养中进行抗稻瘟病菌突变体筛选的毒素浓度在25%~30%较好;愈伤组织浸泡12~24h可以得到分化出苗。在愈伤组织上直接加上毒素并长时间处理对愈伤组织的生长有很大的破坏作用,每个愈伤组织滴加的毒素应小于2.0ml。不同的水稻品种产生的耐性不同,可以筛选出抗稻瘟病的突变体。     

对鸢尾新鲜根状茎发酵生香的微生物研究

对影响鸢尾新鲜根状茎发酵生香的微生物进行了初步探讨．从已陈化产香的鸢尾根状茎干片中分离到细菌９株，丝状真菌１４株．细菌中能产香的有２株，均属枯草芽孢杆菌（Ｂａｃｉｌ－ｌｕｓｓｕｂｔｉｌｉｓ），真菌中产香的只１株，为米根霉（Ｒｈｉｚｏｐｕｓｏｒｙｚａｅ）．实验证明，某些微生物对新鲜鸢尾根状茎的产香具有良好作用．经ＧＣ／ＭＳ分析表明，微生物发酵产物中含有鸢尾酮     

Enzymatic Modification of Poly （ethylene terephthalate） Fiber with Lipase from Aspergillus oryzae

Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly （ethylene terephthalate） fibers and a possible hydrolytic product mono （2-hydroxyethyl） terephthalate was released. After the iipase modification, there were more carboxyi groups on the treated poly （ethylene terephthalate） fabric surface that resulted in binding with more cationic dyes. Increased hydrophilicity and antistatic ability of poly （ethylene terephthalate） samples were found based on moisture regain, water contact angle and static half decay time.     

稻瘟菌REMI突变体库的构建

以稻瘟病菌菌株P131和Y34为材料，利用REMI技术构建了含有8000个转化体的突变体库．对REMI转化的部分条件进行了优化，比较了不同限制性内切酶(XhoI、ApaI和EcoRV)之间REMI转化效率的差异．结果表明，稻瘟菌分生孢子在摇培32h和Drisdase消化菌丝2h或3h时较适宜REMI转化；XhoI和ApaI之间没有明显差异，而两者的转化率高于EcoRV．     

米曲霉（Aspergillusoryzae）A－9005酸性蛋白酶的初步研究

米曲霉（Ａｓｐｅｒｇｉｌｌｕｓｏｒｙｚａｅ）Ａ－９００５菌株的麸曲培养物，经水浸泡抽提其酸性蛋白酶活力为６０００ｕ／ｇ左右。硫酸铵分段沉淀中，饱和度为７０％，８０％和９０％时沉淀的比活最高，得率在７０％以上，该酸性蛋白酶的最适作用温度为５０℃，最适ｐＨ为３．５～４．７．在ｐＨ３．５～５．５时酶活力稳定，ｐＨ超过６时酶活力迅速丧失。在４０～６０℃下该酶的活力相对稳定，在７０℃下酶活力半衰期仍达７４ｍｉｎ，这一结果表明该酶为一耐热性酶种。Ｍｎ~（２＋）对酶有激活作用，其它多数金属离子如Ｚｎ~（２＋），Ｆｅ~（２＋），Ｋ~＋，Ｍｇ~（２＋），Ｌｉ~＋及Ｃａ~（２＋）等对酶有轻度抑制作用或无影响。     

Genetic and physical mapping of AvrPi7, a novel avirulence gene of Magnaporthe oryzae using physical position-ready markers

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating crop diseases worldwide. The avirulence gene corresponding to rice blast resistance gene Pi7 in field isolate CHL346 was inherited as a single gene, designated AvrPi7, in a segregating population consisting of 189 ascospore progenies derived from a cross between field isolates CHL346 and CHL42. In order to determine the chromosomal location of the AvrPi7 locus, a total of 121 simple sequence repeat (SSR) markers were developed based on the whole-genome sequence of reference isolate 70-15 of M. oryzae. Linkage analysis of the locus with these SSR markers showed that eight SSR markers on chromosome 1 were linked to the locus, among which the closest flanking markers MS1-9 and MS1-15 were 3.2 and 16.4 cM from the locus, respectively. For fine mapping, additional PCR-based makers including eight SSR markers and three candidate avirulence gene (CAG) markers were developed in the region flanking both markers. The AvrPi7 locus was genetically delimited within a 1.6-cM region flanked by markers MS1-21 and MS1-22, and co-segregated with the marker CAG2. To construct a physical map of the AvrPi7 locus, molecular markers linked to the Avr gene were mapped on the supercontigs of the ref-erence isolate 70-15 through bioinformation analysis (BIA). Consequently, the AvrPi7 locus was delim-ited to a 75-kb interval flanked by markers MS1-21 and MS1-22 based on the reference sequence. Merodiploids observed in this study are also discussed.     

稻瘟病抗性基因Pi36的表达分析

为研究稻瘟病抗性基因Pi36的表达模式,利用半定量RT-PCR对抗病亲本Kasalath和感病亲本丽江新团黑谷(LTH)进行了接种前和接种后24 h和48 h的表达分析.结果表明:Pi36无论在接种前还是接种后以及无论在抗病亲本Kasalath还是感病亲本LTH中均有表达,并且各个时间段的表达量没有大的差别.由此说明,Pi36属于组成型而不是诱导型表达的基因.