Two scab diseases are currently recognized on citrus：citrus scab, caused by Elsino？ fawcettii, and sweet orange scab, caused by E. australis. Although these pathogens are economically important, there is no molecula...Two scab diseases are currently recognized on citrus：citrus scab, caused by Elsino？ fawcettii, and sweet orange scab, caused by E. australis. Although these pathogens are economically important, there is no molecular data on these species in China. Here we use internal transcribed spacer sequence data to report on host-speciifcity and genetic relationships among 46 isolates collected from the main citrus varieties grown across China. All strains isolated were E. fawcettii. Based on pathogenicity testing on 9 different citrus species, isolates were divided into 11 pathotypes （SM, FBHR, SJCR, SPOJCR, SR, SOJG, SPOJC, SRGC, Lemon and two unnamed pathotypes）. SM is a new pathotype, and two isolates did not ift into any of the known pathotypes of E. fawcettii. Inter-simple sequence repeat （ISSR-PCR） assays separated the E. fawcettii isolates into 10 subgroups;the groupings basically corresponded to the pathogenicity test.展开更多
七叶树是七叶树科七叶树属高大乔木,集药用与观赏于一身。七叶树种子是其主要的药用部位,主要有效成分为齐墩果烷型三萜皂苷类化合物七叶皂苷。为了解七叶树三萜化合物生物合成的分子基础,该研究采用Illumina Hi Seq 2000高通量测序获...七叶树是七叶树科七叶树属高大乔木,集药用与观赏于一身。七叶树种子是其主要的药用部位,主要有效成分为齐墩果烷型三萜皂苷类化合物七叶皂苷。为了解七叶树三萜化合物生物合成的分子基础,该研究采用Illumina Hi Seq 2000高通量测序获得七叶树种子与花的转录组数据,并对其代谢途径相关基因进行挖掘;使用Trinity软件实现unigene的de novo拼接;并将转录组的测序结果运用KEGG数据库进行注释,从而预测七叶树三萜代谢的具体途径。结果显示七叶树转录组共有2个三萜代谢途径相关数据集,分别为萜类物质前体代谢途径(途径编号为ko00900)和倍半萜与三萜代谢途径(途径编号为ko00909),对应的基因分别有47,27条。进一步根据催化酶与活性产物的总结比较分析发现萜类物质前体代谢途径相关酶共有8种,三萜代谢途径相关酶有3种。该研究首次在七叶树中解析出5条与三萜环化酶对应的基因,它们可能参与β-香树精合成进而形成七叶皂苷。通过种子与花的转录组表达差异分析显示,ko00900和ko00909途径相关的差异基因有33个;相对于花器官,种子中有17个unigenes表达量上调,16个unigenes表达量下调。该研究运用qRT-PCR实验对SQE(Unigene25806),HMGS(Unigene36710),β-AS(Unigene33291) 3个差异显著的关键酶基因的表达进行了试验验证,实验结果qRT-PCR结果与转录组数据一致。该研究所发现的七叶树的三萜皂苷合成相关候选基因能对七叶树三萜代谢合成与调控方面提供理论依据。展开更多
基金supported by the China Agriculture Research System (CARS-27)the Technology Application Research Program for Public Interest of Zhejiang Province,China
文摘Two scab diseases are currently recognized on citrus：citrus scab, caused by Elsino？ fawcettii, and sweet orange scab, caused by E. australis. Although these pathogens are economically important, there is no molecular data on these species in China. Here we use internal transcribed spacer sequence data to report on host-speciifcity and genetic relationships among 46 isolates collected from the main citrus varieties grown across China. All strains isolated were E. fawcettii. Based on pathogenicity testing on 9 different citrus species, isolates were divided into 11 pathotypes （SM, FBHR, SJCR, SPOJCR, SR, SOJG, SPOJC, SRGC, Lemon and two unnamed pathotypes）. SM is a new pathotype, and two isolates did not ift into any of the known pathotypes of E. fawcettii. Inter-simple sequence repeat （ISSR-PCR） assays separated the E. fawcettii isolates into 10 subgroups;the groupings basically corresponded to the pathogenicity test.
