[Research progress in epigenetic pharmacological effects of rhein].

Rhein, which is one of the main active components of Rheum palmatum, has a range of pharmacological activities such as the regulation of the metabolism of glucose and lipids, anti-inflammatory, anti-tumor, anti-fibrosis, etc. Epigenetics refers to the heritable variation of gene expression without altering the DNA sequence. It is involved in the emergence and development of inflammation, renal fibrosis, diabetes, cancer, atherosclerosis, and other diseases, thus becoming a new strategy for the treatment of many di-seases. A series of studies have shown that epigenetic modification may be a common molecular mechanism of various pharmacological effects of rhein. This paper summarized the effects of rhein on the regulation of epigenetic modification and its underlying mechanisms, which involve the regulation of DNA methylation, protein acetylation, and RNA methylation, so as to provide a basis for the development and application of rhein.

Phenotypic and transcriptomic responses of two Nilaparvata lugens populations to the Mudgo rice containing Bph1.

The Bph1 gene was the first reported brown planthopper (BPH, Nilaparvata lugens) resistance gene in Mudgo rice and was widely used as a commercial cultivar for controlling BPH infestations. However, rapid adaptations of BPH on the Mudgo rice resulted in its resistance breakdown and the emergence of virulent BPH populations. Thus, specific BPH populations and rice varieties can serve as good model systems for studying the roles of different bio-compounds and proteins in the insect-plant interactions. Although our understandings have been improved on the complexity of BPH and rice interactions, the underlying molecular mechanisms remain largely unknown. Here we analyzed the feeding performances and the transcriptomic responses of two BPH populations (Mugdo-BPH and TN1-BPH) during compatible (Mudog-BPH feeding on Mudgo rice) and incompatible (TN1-BPH feeding on Mudgo rice) interactions. The electrical penetration graph (EPG) results indicated that the BPH feeding and performances during the incompatible interaction are significantly affected in terms of decreased honeydew, loss of weight, decreased phloem sap ingestion (N4 waveform), but increased non-penetration (NP waveform) phase. Abundance of glucose and trehalose was reduced in BPH during the incompatible interaction. Transcriptomic surveys of insects in both interactions revealed that genes involved in cuticle formation, detoxification, metabolite transport, digestion, RNA processing, lipid or fatty acid metabolism, and proteolysis were significantly down-regulated during the incompatible interaction, whereas genes involved in insulin signaling were significantly upregulated. Knockdown of four genes, including the sugar transporter NlST45, the serine and arginine-rich protein NlSRp54, the cytochrome P450 gene NlCYP6AY1, and the cuticle protein NlCPR70 through RNA-interference revealed thess genes are important for BPH survival. Overall, the results of this study will be helpful for the future researches on BPH virulence shifts.

Isolation of expressed sequences from a specific chromosome of Thinopyrum intermedium infected by BYDV.

To map important ESTs to specific chromosomes and (or) chromosomal regions is difficult in hexaploid wheat because of its large genome size and serious interference of homoeologous sequences. Large-scale EST sequencing and subsequent chromosome localization are both laborious and time-consuming. The wheat alien addition line TAi-27 contains a pair of chromosomes of Thinopyrum intermedium (Host) Barkworth & D.R. Dewey that carry the resistance gene against barley yellow dwarf virus. In this research, we developed a modified technique based on chromosome microdissection and hybridization-specific amplification to isolate expressed sequences from the alien chromosome of TAi-27 by hybridization between the DNA of the microdissected alien chromosome and cDNA of Th. intermedium infected by barley yellow dwarf virus. Twelve clones were selected, sequenced, and analyzed. Three of them were unknown genes without any hit in the GenBank database and the other nine were highly homologous with ESTs of wheat, barley, and (or) other plants in Gramineae induced by abiotic or biotic stress. The method used in this research to isolate expressed sequences from a specific chromosome has the following advantages: (i) the obtained expressed sequences are larger in size and have 3' end information and (ii) the operation is less complicated. It would be an efficient improved method for genomics and functional genomics research of polyploid plants, especially for EST development and mapping. The obtained expressed sequence data are also informative in understanding the resistance genes on the alien chromosome of TAi-27.

Rapid EST isolation from chromosome 1R of rye.

BACKGROUND: To obtain important expressed sequence tags (ESTs) located on specific chromosomes is currently difficult. Construction of single-chromosome EST library could be an efficient strategy to isolate important ESTs located on specific chromosomes. In this research we developed a method to rapidly isolate ESTs from chromosome 1R of rye by combining the techniques of chromosome microdissection with hybrid specific amplification (HSA). RESULTS: Chromosome 1R was isolated by a glass needle and digested with proteinase K (PK). The DNA of chromosome 1R was amplified by two rounds of PCR using a degenerated oligonucleotide 6-MW sequence with a Sau3AI digestion site as the primer. The PCR product was digested with Sau3AI and linked with adaptor HSA1, then hybridized with the Sau3AI digested cDNA with adaptor HSA2 of rye leaves with and without salicylic acid (SA) treatment, respectively. The hybridized DNA fragments were recovered by the HSA method and cloned into pMD18-T vector. The cloned inserts were released by PCR using the partial sequences in HSA1 and HSA2 as the primers and then sequenced. Of the 94 ESTs obtained and analyzed, 6 were known sequences located on rye chromosome 1R or on homologous group 1 chromosomes of wheat; all of them were highly homologous with ESTs of wheat, barley and/or other plants in Gramineae, some of which were induced by abiotic or biotic stresses. Isolated in this research were 22 ESTs with unknown functions, probably representing some new genes on rye chromosome 1R. CONCLUSION: We developed a new method to rapidly clone chromosome-specific ESTs from chromosome 1R of rye. The information reported here should be useful for cloning and investigating the new genes found on chromosome 1R.

The development of chromosome microdissection and microcloning technique and its applications in genomic research.

The technique of chromosome microdissection and microcloning has been developed for more than 20 years. As a bridge between cytogenetics and molecular genetics, it leads to a number of applications: chromosome painting probe isolation, genetic linkage map and physical map construction, and expressed sequence tags generation. During those 20 years, this technique has not only been benefited from other technological advances but also cross-fertilized with other techniques. Today, it becomes a practicality with extensive uses. The purpose of this article is to review the development of this technique and its application in the field of genomic research. Moreover, a new method of generating ESTs of specific chromosomes developed by our lab is introduced. By using this method, the technique of chromosome microdissection and microcloning would be more valuable in the advancement of genomic research.