Process of Bipolaris sorghicola invasion of host cells.

Target leaf spot is a sorghum leaf disease caused by Bipolaris sorghicola, a species of fungus with a global distribution. In this study, we investigated the process by which B. sorghicola invades cells of barley, onion, Arabidopsis thaliana species, and sorghum. The results showed that within 8 h of coming into contact with host cells, the hyphal ends of B. sorghicola expand and form a uniform infective penetration pegbolt-like structure; a primary infection mycelium can be formed inside host cells within 24 h after contact, which can infect closed cells after 48 h. A mycelium can grow within the gap between cells and form infective hyphae. The pathogen infection process was the same in different host cells. B. sorghicola can affect root cells through soil infection, indicating that it may also have characteristics of soil-borne pathogens.

Tobacco serine/threonine protein kinase gene NrSTK enhances black shank resistance.

A serine/threonine protein kinase gene (NrSTK) was cloned from Nicotiana repanda based on the sequence of a previously isolated resistance gene analog (RGA). Expression of RGA was induced by challenge with the pathogen black shank. The NrSTK gene was predicted to encode a protein kinase that contained an ATP binding site at residues 41-69 and a serine/threonine protein kinase activation sequence spanning the region 161-173. Overexpression of NrSTK in the susceptible tobacco variety Honghuadajinyuan significantly enhanced resistance to black shank, indicating that NrSTK plays a role in incompatibility reactions between tobacco and the pathogen. Characterization of NrSTK will help elucidate the molecular mechanisms involved in black shank resistance in N. repanda.

Association between the -607 C > A polymorphism in interleukin-18 gene promoter with gastrointestinal cancer risk: a meta-analysis.

The interleukin-18 (IL-18) gene -607 C/A polymorphism has been reported to be associated with gastrointestinal cancer, but there are conflicting results from previous studies on said topic. Therefore, the aim of this meta-analysis is to derive a more precise estimation of the association between the -607 C/A polymorphism in the IL-18 gene and gastrointestinal cancer risk. Literature searches of PubMed, Google Scholar, and Web of Science databases were carried out in 2015. Five studies were assessed with a total of 1618 cases and 1155 healthy controls. When results from all eligible studies were pooled into the meta-analysis, we found significant association between the IL-18 gene -607 C/A polymorphism and gastrointestinal cancer risk (CC vs AA: OR = 0.93, 95%CI = 0.72- 1.20; CC vs CA: OR = 0.76, 95%CI = 0.62-0.92; dominant model: OR = 1.25, 95%CI = 1.03-1.50; recessive model: OR = 1.09, 95%CI = 0.87-1.37). In the subgroup analysis, significant associations between the -607 C/A polymorphism and gastrointestinal cancer risk were found in esophageal cancer. However, this polymorphism did not appear to have any influence on gastric cancer and colorectal cancer susceptibility. In conclusion, this meta-analysis suggests that the -607 C/A polymorphism in the IL-18 gene may be associated with susceptibility to esophageal cancer. Further studies with large sample sizes are needed to confirm these conclusions.

Expression and clinical significance of miR-122 and miR-29 in hepatitis B virus-related liver disease.

MicroRNA molecules have been increasingly regarded as a diagnostic and prognostic marker of certain diseases. The aim of this study was to investigate the expression and clinical significance of miR-122 and miR-29 in liver disease related to hepatitis B virus infection. The serum levels of miR-122 and miR-29 in 20 patients with hepatocellular carcinoma (HCC), 20 patients with liver cirrhosis (LC), 29 patients with chronic hepatitis B (CHB), 20 cases of hepatitis B virus carriers (ASC), and 20 healthy controls (HC) were determined by a fluorescence real-time quantitative PCR method and then evaluated by clinical correlation analysis. Compared with the serum levels of miR-122 in the HC, LC, and ASC groups, those in patients with HCC and CHB were significantly increased. The serum levels of miR-29 in LC patients were lower than those in the healthy controls (P < 0.01). A positive correlation was observed between the expression of miR-122 and miR-29, and HBV DNA in patients with CHB. A negative correlation was found between miR-29 and α-fetoprotein in patients with HCC. The elevation in miR-122 was correlated with liver damage in CHB patients and with the pathogenesis of liver cancer in HCC patients. The decrease in miR-29 expression was related to the incidence of liver fibrosis. The detection of miR-122 and miR-29 may be useful in evaluating the inflammatory liver injury and fibrosis associated with chronic HBV infection.

Expressed sequence tag-simple sequence repeat-based molecular variance in two Salicornia (Amaranthaceae) populations.

Salicornia spp is one of the most salt-tolerant vascular plants and is native to salt marshes and estuaries. We developed expressed sequence tag derived-simple sequence repeat (EST-SSR) markers for estimating genetic diversity and marker-assisted Salicornia breeding. Six polymorphic EST-SSRs of 40 detected 27 alleles, ranging from three to five alleles per locus. The average number of alleles per locus was 4.33 and 4.17, and the major allele frequency at locus DY529765 was high, being 0.859 and 0.857 in S. bigelovii and S. europea, respectively. Gene diversity, heterozygosity and polymorphism information content were highest at locus DY529950 and similar in these two species. Gene diversity increased with increase in the number of alleles that had a low major allele frequency at a locus. Six polymorphic loci effectively discriminated 46 taxa into three clusters via different analyses. Significant deviation of F(ST) from zero in three suggested populations for six loci indicated population differentiation and limited gene flow among them. A reduced median network established that taxon SB65 is primitive. SMART (simple modular architecture research tool) analysis of peptide sequences of six EST-SSRs showed that loci DY529765, DY529950 and EC906203 contained transmembrane, TLC, AgrB and NTR domains and might be involved in salinity stress tolerance. These EST-SSRs are a valuable resource for marker development and may be useful in marker-assisted Salicornia breeding.

Molecular diversity analysis of eggplant (Solanum melongena) genetic resources.

Eggplant (Solanum melongena), a vegetable that is cultivated worldwide, is of considerable importance to agriculture in China. We analyzed the diversity of this plant using inter-simple sequence repeat (ISSR) and RAPD procedures to subdivide 143 Chinese-cultivated eggplants based on coefficient of parentage, genetic diversity index (GDI) and canonical discriminant analysis. ISSR markers were more effective than RAPD markers for detecting genetic diversity, which ranged from 0.10-0.51, slightly lower than what is known from other crops. Our ISSR/RAPD data provide molecular evidence that coincides with morphological-based classification into three varieties and further subdivision into eight groups, except for two groups. Intensive use of elite parents and extensive crossing within groups have resulted in increased coefficient of parentage and proportional contribution but decreased GDI during the past decades. The mean coefficient of parentage and proportional contribution increased from 0.05 to 0.10% and from 3.22 to 6.46% during 1980-1991 and 1992-2003, respectively. The GDI of landraces was 0.21, higher than the 0.09 and 0.08 calculated for the hybrid cultivars released during the two periods. The recent introduction of alien genotypes into eggplant breeding programs may broaden the genetic base.