The Chinese garden of genetics——celebrating 40~(th) anniversary of Genetics Society of China

正In 2018,we will celebrate the 40~(th) anniversary of Genetics Society of China(GSC),which was founded in Nanjing,China in October,1978,soon after China adopted an open door policy for reform.One major mission of GSC during its inception was to publish a genetics journal,aiming to provide a window for Chinese geneticists to showcase their new discoveries.In fact,a genetics journal named Acta Genetica Sinica(AGS)had been published since June of 1974(Fig.1).This journal pub-     

Simultaneous targeting of pea glutathione reductase and of a bacterial fusion protein to chloroplasts and mitochondria in transgenic tobacco

N-terminal presequences from cDNAs encoding mitochondrion- or chloroplast-specific proteins are able, with variable efficiencies, to target preproteins to their respective organelles. In the few cases studied in which a nuclear-encoded protein is found in both these organelles, each compartment-specific isoform is encoded by a separate gene. Glutathione reductase (GR) from peas is encoded by a single nuclear gene and yet GR is distributed between chloroplasts, mitochondria and the cytosol. Previous sequence analysis of a full-length GR cDNA revealed the presence of a putative plastid transit peptide. However, expression of this cDNA in transgenic tobacco resulted in substantially elevated GR activities in both chloroplasts and mitochondria in four independent lines examined. There was no effect on expression of the endogenous tobacco GR genes. Replacement of the GR presequence with presequences from pea rbcS (chloroplast) and Nicotiana plumbaginifolia Mn-SOD (mitochondrion) resulted in targeting of GR only into the appropriate organelle. Expression of a fusion protein between the amino terminal region of GR and phosphinothricin acetyl transferase resulted in targeting of the foreign protein to chloroplasts and mitochondria. Thus, the pea GR presequence is capable of co-targeting this enzyme or a foreign protein to chloroplasts and mitochondria in vivo . This is the first example of co-targeting by a higher plant preprotein.     

The presence of a side population and its marker ABCG2 in human deciduous dental pulp cells

Stem cells have been identified using the DNA-binding dye Hoechst 33342 and flow cytometry (FCM) in various tissues known as the side population (SP). The present study shows, for the first time, the presence of side population cells in human deciduous dental pulp cells (DPCs). Flow cytometric identification revealed that 2% of human deciduous DPCs were SP cells and that this SP profile disappeared in the presence of verapamil. The SP marker ABCG2 protein was localized to DPCs in the cell membrane by immunofluorescence staining, and flow cytometric analysis demonstrated that 3.6% of DPCs were ABCG2-positive. Furthermore, quantitative real-time PCR proved that ABCG2 mRNA expression in DPCs isolated from human exfoliated deciduous teeth was higher than in DPCs from permanent teeth. Our findings demonstrate that DPCs from human exfoliated deciduous teeth contain a higher proportion of the SP phenotype than permanent teeth and that they may constitute a stem cell population.     

A putative lipase gene EXTRA GLUME1 regulates both empty-glume fate and spikelet development in rice

Recent studies have shown that molecular control of inner floral organ identity appears to be largely conserved between monocots and dicots, but little is known regarding the molecular mechanism underlying development of the monocot outer floral organ, a unique floral structure in grasses. In this study, we report the cloning of the rice EXTRA GLUME1 ( EG1 ) gene, a putative lipase gene that specifies empty-glume fate and floral meristem determinacy. In addition to affecting the identity and number of empty glumes, mutations in EG1 caused ectopic floral organs to be formed at each organ whorl or in extra ectopic whorls. Iterative glume-like structures or new floral organ primordia were formed in the presumptive region of the carpel, resulting in an indeterminate floral meristem. EG1 is expressed strongly in inflorescence primordia and weakly in developing floral primordia. We also found that the floral meristem and organ identity gene OsLHS1 showed altered expression with respect to both pattern and levels in the eg1 mutant, and is probably responsible for the pleiotropic floral defects in eg1 . As a putative class III lipase that functionally differs from any known plant lipase, EG1 reveals a novel pathway that regulates rice empty-glume fate and spikelet development.     

Genetic features of a pollen-part mutation suggest an inhibitory role for the <Emphasis Type="Italic">Antirrhinum</Emphasis> pollen self-incompatibility determinant

Self-incompatibility (SI), an important barrier to inbreeding in flowering plants, is controlled in many species by a single polymorphic S-locus. In the Solanaceae, two tightly linked S-locus genes, S-RNase and SLF (S-locus F-box)/SFB (S-haplotype-specific F-box), control SI expression in pistil and pollen, respectively. The pollen S-determinant appears to function to inhibit all but self S-RNase in the Solanaceae, but its genetic function in the closely-related Plantaginaceae remains equivocal. We have employed transposon mutagenesis in a member of the Plantaginaceae (Antirrhinum) to generate a pollen-part SI-breakdown mutant Pma1 (Pollen-part mutation in Antirrhinum1). Molecular genetic analyses showed that an extra telocentric chromosome containing AhSLF-S ₁ is present in its self-compatible but not in its SI progeny. Furthermore, analysis of the effects of selection revealed positive selection acting on both SLFs and SFBs, but with a stronger purifying selection on SLFs. Taken together, our results suggest an inhibitor role of the pollen S in the Plantaginaceae (as represented by Antirrhinum), similar to that found in the Solanaceae. The implication of these findings is discussed in the context of S-locus evolution in flowering plants. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Yongbiao Xue, Yijing Zhang, and Qiuying Yang contributed equally to this work.     

Molecular analysis of rice plants harboring a multi-functional T-DNA tagging system

About 25,000 rice T-DNA insertional mutant lines were generated using the vector pCAS04 which has both promoter-trapping and activation-tagging function. Southern blot analysis revealed that about 40% of these mutants were single copy integration and the average T-DNA insertion number was 2.28. By extensive phenotyping in the field, quite a number of agronomically important mutants were obtained. Histochemical GUS assay with 4,310 primary mutants revealed that the GUS-staining frequency was higher than that of the previous reports in various tissues and especially high in flowers. The T-DNA flanking sequences of some mutants were isolated and the T-DNA insertion sites were mapped to the rice genome. The flanking sequence analysis demonstrated the different integration pattern of the right border and left border into rice genome. Compared with Arabidopsis and poplar, it is much varied in the T-DNA border junctions in rice.     

华南丘陵区农林复合生态系统稻田二氧化碳排放及其影响因素

采用静态箱-气相色谱法对稻田CO2排放进行田间原位测定,探讨农林复合生态系统稻田温室气体CO2的排放规律。结果表明,在生长季节中,有植株参与稻田CO2排放速率的日变化形式均为白天出现排放高值,夜间出现排放低值。有植株参与稻田CO2昼夜排放速率平均值都显著高于无植株参与稻田。温度(气温、地表温度、地下5 cm温度)是有植株参与稻田在植株生长期间稻田CO2排放速率昼夜变化的主要影响因素。水稻作物对CO2的排放影响较大,早稻有、无植株参与稻田CO2季节平均排放速率分别为316.29±23.74和101.88±16.83 mg.m-2.h-1。晚稻有、无植株参与稻田CO2季节平均排放速率分为622.40±57.67和179.41±19.51 mg.m-2.h-1。早、晚稻有植株参与稻田的CO2季节平均排放量分别比无植株参与稻田增加了310%和347%。     

Effects of root diameter and root nitrogen concentration on in situ root respiration among different seasons and tree species

Knowledge of root respiration is a prerequisite for a better understanding of ecosystem carbon budget and carbon allocation. However, there are not many relevant data in the literature on direct measurements of in situ root respiration by root chamber method. Furthermore, few studies have been focused on the effects of root diameter (D _r) and root nitrogen concentration (N _r) on in situ root respiration among different seasons and tree species. To address these goals, we used a simplified root-chamber system to measure in situ root respiration rates of Acacia crassicarpa and Eucalyptus urophylla in subtropical plantations of south China. We found that the species and season variation in root respiration were affected by D _r and N _r. Also, the root respiration per unit dry mass (R _r, nmol CO₂ g⁻¹ s⁻¹) and root respiration per unit N (R _n, nmol CO₂ g N⁻¹ s⁻¹) were affected by D _r and N _r. The R _r, R _n, N _r and soil temperature sensitivity (Q ₁₀) of R _r for the two species significantly decreased with an increase of D _r. The R _r of the two species showed significant an inter-seasonal and diurnal pattern, and this trend decreased with increasing D _r. Both the R _r and Q ₁₀ of the two species increased with increasing N _r. The D _r and N _r explained 54 and 52% of the observed variation in R _r for A. crassicarpa, and 65 and 70% for E. urophylla. The R _r, N _r, and Q ₁₀ of A. crassicarpa were significantly higher than those of E. urophylla. Our results indicated that root respiration was dependent on D _r and N _r, and this dependence varied with season and plant species.