Biological functions of Arabidopsis thaliana MBP-1-like protein encoded by ENO2 in the response to drought and salt stresses.

Arabidopsis thaliana ENO2 (AtENO2) plays an important role in plant growth and development. It encodes two proteins, a full-length AtENO2 and a truncated version, AtMBP-1, alternatively translated from the second start codon of the mRNA. The AtENO2 mutant (eno2- ) exhibited reduced leaf size, shortened siliques, a dwarf phenotype and higher sensitivity to abiotic stress. The objectives of this study were to analyze the regulatory network of the ENO2 gene in plant growth development and understand the function of AtENO2/AtMBP-1 to abiotic stresses. An eno2- /35S:AtENO2-GFP line and an eno2- /35S:AtMBP-1-GFP line of Arabidopsis were obtained. Results of sequencing by 454 GS FLX identified 578 upregulated and 720 downregulated differential expressed genes (DEGs) in a pairwise comparison (WT-VS-eno2- ). All the high-quality reads were annotated using the Gene Ontology (GO) terms. The DEGs with KEGG pathway annotations occurred in 110 pathways. The metabolic pathways and biosynthesis of secondary metabolites contained more DEGs. Moreover, the eno2- /35S:AtENO2-GFP line returned to the wild-type (WT) phenotype and was tolerant to drought and salt stresses. However, the eno2- /35S:AtMBP-1-GFP line was not able to recover the WT phenotype but it has a higher tolerance to drought and salt stresses. Results from this study demonstrate that AtENO2 is critical for the growth and development, and the AtMBP-1 coded by AtENO2 is important in tolerance of Arabidopsis to abiotic stresses.

[The role analysis of APX gene family in the growth and developmental processes and in response to abiotic stresses in Arabidopsis thaliana].

Oxidative stress caused by reactive oxygen species (ROS) is one of the major abiotic stresses in plants. Under adverse growth conditions, the incoordination of various metabolic processes in plant cells can result in increased hydrogen peroxide (H2O2), thus causing a variety of threats and injuries to plant cells. Ascorbate peroxidase (APX) is an important enzyme to remove H2O2 in plants. In Arabidopsis thaliana, there are eight APX gene family members, including APX1?APX6, sAPX and tAPX. In this study, we analyzed the expression patterns of the eight APX genes in the wild-type and apx mutant plants at different developmental stages and under different abiotic stress conditions. Meanwhile, the tolerance of each apx mutant to salt, drought and heat stresses was studied. qRT-PCR analysis showed that during development (from 4 to 8 weeks old), APX1 and APX2 exhibited the highest and lowest expression levels, respectively. In addition, the expression levels of APX4, sAPX and tAPX decreased during development, while the expression of APX6 increased with the maturity of the plants. Moreover, under different abiotic stress conditions, APX1, APX2 and APX6 were significantly induced by heat stress, sAPX actively responded to salt stress, and APX3 and APX5 exhibited obvious responses to salt, drought and heat stresses. Further tolerance analysis showed that the resistance of all apx mutants to salt and drought stresses was lower than that of the wild-type plant at both germination and maturity stages. At germination stage, all apx mutants were more sensitive to drought stress than to salt stress. At maturity stage, the apx1 and apx6 mutants were more sensitive to salt and drought stresses than the wild-type and other apx mutant plants. The physiological indexes indicated that the H2O2 content in all mutants, especially in the apx1, sapx and tapx, was significantly higher than that in the wild type 10 days after drought stress treatment, the malondialdehyde (MDA) content in all mutants was significantly higher than that in the wild type 5 days after salt stress treatment, while heat stress treatment for 2 h resulted in a significant increase in the contents of H2O2 and MDA in apx1, apx2 and apx6, especially in apx2. Taken together, our study revealed that all eight APX members of Arabidopsis participate in the growth and developmental processes and the abiotic stress responses, with some specific APXs playing a major role in a certain process.

[The development of genetics teaching in China in the last four decades and its future prospect].

Chinese genetics educators have carried out a comprehensive and systematic exploration and reform since 1978. With the guidance and help of the Genetics Society of China, they have made significant strides in the fields of genetics teaching system, publication of genetics textbooks, content of genetics teaching, workshop on genetics teaching, experimental teaching, application of advanced techniques, etc. These efforts have made remarkable achievements and promoted the vitality of genetics. The comprehensive development of education and teaching has trained a large number of excellent genetic talents for the development of China's economy and society. Here, we sum up the overall achievements of the teaching reform and propose some suggestions on the future development of genetics teaching in China, hoping that the quality of genetics teaching in China will take a new step in the new era.

[Research progress in the mechanism of translation initiation of eukaryotic mRNAs].

The translation of mRNA is a complicated multi-step process, including initiation, elongation and termination. Among them, the regulation of the initial stage plays the key role. There are many ways to initiate mRNA translation, and the most classical way is the m 7G cap-dependent scanning mechanism that was also the first mechanism identified. When cells encounter adversity and the classical mechanism is inhibited, other types of translation initiation mechanisms will be activated. In this review, we summarize the translation initiation mechanisms of eukaryotic mRNAs, especially some alternative mechanisms. It will provide a reference for further understanding of the expression and regulation of eukaryotic genes at the translation levels.

The molecular mechanisms of plant plasma membrane intrinsic proteins trafficking and stress response.

Plasma membrane intrinsic proteins (PIPs) are plant channel proteins located on the plasma membrane. PIPs transfer water, CO2 and small uncharged solutes through the plasma membrane. PIPs have high selectivity to substrates, suggestive of a central role in maintaining cellular water balance. The expression, activity and localization of PIPs are regulated at the transcriptional and post-translational levels, and also affected by environmental factors. Numerous studies indicate that the expression patterns and localizations of PIPs can change in response to abiotic stresses. In this review, we summarize the mechanisms of PIP trafficking, transcriptional and post-translational regulations, and abiotic stress responses. Moreover, we also discuss the current research trends and future directions on PIPs.

[Expression regulation of plant ascorbate peroxidase and its tolerance to abiotic stresses].

Ascorbate peroxidase (APX), a type I heme peroxidase, catalyzes oxidation of ascorbic acid. It possesses a high degree of specificity to ascorbic acid. APX gene cluster consists of four sub-clusters: the gene clusters of cytosol, chloroplast, mitochondria, and peroxidase. As a key component of hydrogen peroxide detoxification system, the ascorbate-glutathione cycle, APX plays a vital role in the metabolism of H2O2 of plant cells. Studies showed that APX is one of the most important enzymes, which modulate the cellular H2O2 level in redox signaling system. The expression mechanisms of APX isoenzymes are quite complex. Briefly, cytosolic APX is regulated by a variety of signals; two chloroplastic APX isoenzymes are tissue-dependently regulated by alternative splicing. Generated APXs could regulate redox signaling in cells, which further boosts plants tolerance to abiotic stresses. This review focuses on recent advances concerning catalytic prop-erties, physiological function, and gene expressing regulation and abio-stress responding mechanism of APX.

[Study on the longevity related mitochondrial genome variation in Bama elderly population in Guangxi province].

OBJECTIVE: To investigate the human mitochondrial DNA (mtDNA) variations associated with longevity in Bama elderly population from Guangxi. METHODS: Mitochondrial genome of 20 individuals over 96 years of age was sequenced, and seven target single nucleotide polymorphism (SNPs) were observed by comparing with the standard rCRS sequence, and two were tested by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in a larger population including 208 individuals of 90-113 years old, and 586 unrelated control individuals from Guangxi. RESULTS: The 4824G frequency of the mtDNA4824A/G locus increased with age both in the long-lived elderly and in controls. And it was significantly higher in controls than that in long-lived population (P<0.05). CONCLUSION: The mtDNA4824 A/G is not only an age-related locus, its mutation is also negatively correlated with longevity.

[Charles Robert Darwin: the great founder of scientific evolutionism].

Today, we celebrated 200 years since Charles Darwin, one of the world's most creative and influential thinkers, was born. And there happens to be the 150th anniversary of the publication of his famous book, On the Origin of Species. It is verified that On the Origin of Species is an immortal classic book and is still guiding the study of anagenesis in life science as the development of natural science from then on, and even though most of the ideas in the book are well-known at the present age. In the article, we recall the brilliance and predomination life of Darwin, a great sage with rich scientific achievements, review briefly the novel discoveries and theories after him in the field, and then elucidate the focal points and perspectiveas in near future study of evolution.

[Gibberellin signal transduction and cotton fiber molecular development].

Gibberellins (GAs) is a sort of high efficiency plant growth regulator which is very important for cotton fiber initiation and development. Recently, the research of GA signal transduction mostly focuses on Arabidopsis, wheat, barley, maize, rice and so on. Yet we know little about molecular mechanism of GA to cotton fiber initiation and development. In recent years, exciting progress has been made in identifying many important components involved in gibberellin signal transduction pathways, which can help us to understand deeply these pathways and their regulation. This review summarized the recently research process of GA signal transduction and correlation of GA and cotton fiber' molecular development. We hope that the paper can provide some new ideas about the function and mechanism of GA in cotton fiber initiation and development, and for cotton breeding task.

[Progress in the research of genes related to human longevity].

Human longevity is the result of combined actions by many factors including genetics, environment and so on. Although longevity can take its natural course, it can be extended with social and scientific advances. This review presents the recent progress in longevity studies, especially on the research of longevity related genes in model species. It also summarizes the research of longevity related genes in humans in both the nuclear and mitochondrial genome. The prospect and strategy of human longevity research is also discussed.