稻瘟病分子生物学研究进展

稻瘟病分子生物学发展迅速 ,已分子标记定位的稻瘟病主效抗性基因 15个 ,微效抗性基因 3个 ;水稻抗稻瘟病基因Pi-ta和Pi-b已成功克隆。稻瘟病菌系谱与致病型关系可分为简单与复杂两种类型。本文对水稻抗稻瘟病基因的定位和克隆 ,稻瘟病菌群体遗传结构、致病性遗传、基因组分析、无毒基因克隆、准性生殖等研究进展进行了评述。

A Preliminary Study on Genetic Variation of g E Gene of an Epidemic Pseudorabies Virus Strain and Its Pathogenicity to Piglets

[Objective] This study aimed to investigate the genetic variation of g E gene of an epidemic pseudorabies virus（PRV） strain and its pathogenicity to piglets. [Method] By serial passage in Vero cells, a PRV strain was isolated from the brain tissues of stillborn fetuses delivered by sows with suspected PRV infection and preliminarily identified by PCR. g E gene of the isolated PRV strain was amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old piglets was evaluated. [Result] A PRV strain was successfully isolated and named PRV N5 B strain, which could proliferate in Vero cells and TCID50 of the 15 thgeneration virus liquid reached 10^7.125/0.1 ml. Specific bands could be amplified by PCR. g E gene in the isolated PRV strain was 1 740 bp in length. A phylogenetic tree was constructed based on full-length g E sequences, which showed that PRV N5 B strain and PRV strains isolated since 2012 were clustered into the same independent category and shared 99.7%-100% homology of nucleotide sequences. Compared with related sequences published previously, there were insertions of three consecutive bases at two loci. Animal experiments showed that intranasal inoculation of 6-week-old piglets with 2 ml of PRV N5 B strain（10^6/0.1 ml） led to a mortality rate of 100%. [Conclusion] In this study,genetic variability of g E gene in PRV N5 B isolate and its pathogenicity to piglets were analyzed, which provided a theoretical basis for the development of new vaccines to prevent and control porcine pseudorabies.

Genetic characteristics and pathogenicity of human hepatitis E virus in Nanjing,China

AIM： To investigate the genetic characteristics and pathogenicity of hepatitis E virus （HEV） and assess the potential risk factors for sporadic hepatitis E.

Functional genomics in the rice blast fungus to unravel the fungal pathogenicity

A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.

Physiological Races of Fusarium oxysporum f. sp. Ciceris in Iraq

Twenty isolates of Fusarium oxysporum f. sp. ciceris were isolated from wilted chickpea plants obtained from different districts of north part of Iraq to assess variability in pathogenicity of the populations. Each isolate was tested on 12 differential chickpea varieties. Isolates showed highly significant variation in wilt severity on the differential varieties. Based on the reaction types that induced on differential varieties, isolates were grouped into four groups, First group included isolates FocSl, FocQ7, FocQ 10, FocFI3, FocH 17 and FocHl8; the second group included isolates FocS2, FocS3, FocS4, FocQ5, FocQ8, FocQ9, FocF11, FocF12, FocFl4 and FocH19; the third group included isolates FocF15, FocHl6, FocH20; where the isolate FocQ6 was placed in the fourth group. Results showed that the percentage of genetic similarity was ranged 42% to 100% and was 42% between the first group and other groups and 72% between the three groups the rest and thus this indicate the presence of four races of the fungus which are O, 4, 5 and 1B/C, this represent the first record of these races in lraq.

Mutations in CCIN cause teratozoospermia and male infertility

Teratozoospermia is usually associated with defective spermiogenesis and is a disorder with considerable genetic heterogeneity. Although previous studies have identified several teratozoospermia-associated genes, the etiology remains unknown for a majority of affected men. Here, we identified a homozygous missense mutation and a compound heterozygous mutation of CCIN in patients suffering from teratozoospermia. CCIN encodes the cytoskeletal protein Calicin that is involved in the formation and maintenance of the highly regular organization of the calyx of mammalian spermatozoa, and has been proposed to play a role in sperm head structure remodeling during the process of spermiogenesis. Our morphological and ultrastructural analyses of the spermatozoa obtained from all three men harboring deleterious CCIN mutants reveal severe head malformation. Further immunofluorescence assays unveil markedly reduced levels of Calicin in spermatozoa. These patient phenotypes are successfully recapitulated in mouse models expressing the disease-associated variants, confirming the role of Calicin in male fertility.Notably, all mutant spermatozoa from mice and human patients fail to adhere to the zona mass, which likely is the major mechanistic reason for CCIN-mutant sperm-derived infertility. Finally, the use of intracytoplasmic sperm injections(ICSI) successfully makes mutated mice and two couples with CCIN variants have healthy offspring. Taken together, our findings identify the role of Calicin in sperm head shaping and male fertility, providing important guidance for genetic counseling and assisted reproduction treatments.