Prediction of retrotransposons and assessment of genetic variability based on developed retrotransposon-based insertion polymorphism (RBIP) markers in Pyrus L.

Interspecific hybridization has been considered the major mode of evolution in Pyrus (pear), and thus, the genetic relationships within this genus have not been well documented. Retrotransposons are ubiquitous components of plant genomes and 42.4 % of the pear genome was reported to be long terminal repeat (LTR) retrotransposons, implying that retrotransposons might be significant in the evolution of Pyrus. In this study, 1,836 putative full-length LTR retrotransposons were isolated and 196 retrotransposon-based insertion polymorphism (RBIP) primers were developed, of which 24 pairs to the Ppcr1 subfamily of copia retrotransposons were used to analyze genetic diversity among 110 Pyrus accessions from Eurasia. Our results showed that Ppcr1 replicated many times in the development of cultivated Asian pears. The genetic structure analysis and the unweighted pair group method with arithmetic mean (UPGMA) dendrogram indicated that all accessions could be divided into Oriental and Occidental groups. In Oriental pears, wild pea pears clustered separately into independent groups in accordance with their morphological classifications. Cultivars of P. ussuriensis Maxim, P. pyrifolia Nakai, and P. pyrifolia Chinese white pear were mingled together, which inferred that hybridization events occurred during the development of the cultivated Asian pears. In Occidental pears, two clades were obtained in the UPGMA dendrogram in accordance with their geographical distribution; one contained the European species and the other included species from North Africa and West Asia. New findings in this study will be important to further understand the phylogeny of Pyrus and origins of cultivated pears.

[Effects of two organic pollutants on biomarker system of fish Lateolabrax japonicus and the pollution assessment].

Responses of a select suite of protective enzymes in Lateolabrax japonicus including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx), reduced glutathione (GSH) glutathione S-transferase (GST), nitric oxide synthase (iNOS) in liver tissue and brain acetylcholinesterase (AChE), which could work as sensitively biochemical biomarkers were analyzed when exposed to different concentrations of sodium dodecylbenzene sulfonate (SDBS) and benzo[a]pyrene (B[a]P) under controlled laboratory conditions. Results showed that: (1) The biochemical biomarkers included in this investigation, different responses occurred in the enzymatic activities when exposed to different pollutants: the activities of SOD, GST, Gpx and GSH content were significantly induced by B[a]P (p < 0.05) while others present little different as compared to the control. Differently, SDBS exposure greatly affected the activities of CAT, Gpx, iNOS and AChE while showed little effect on the other evaluated biomarkers. Gpx was the most sensitive biomarker that sensitively indicated the organic pollution stress. (2) The simultaneous assay on heat shock protein 70 (Hsp70) expression was conducted by flow cytometry (FCM) and result presented that Hsp 70 expression could be effectively induced by SDBS as compared to the control throughout the experiment; however, B[a]P obviously induced Hsp70 during the first 12 d and then decreased to the level of the control. (3) The evaluated method of biomarker system combined with principal component analysis (PCA) could effectively distinguish different pollutants under controlled laboratory conditions and might be a promising and warning method for the early assessment of environmental change exposed to different organic pollutions.