Comparative Analysis of the Endosperm Proteins Separated by 2-D Electrophoresis for Two Cultivars of Hybrid Rice （Oryza sativa L,）

Liangyoupeijiu is a two-parental-line, and Shanyou63 is a three-parental-line hybrid rice （Oryza sativa L.）. Although both belong to the indica subspecies, they have obvious differences with respect to morphology, physiology and grain quality. Variations in endosperm protein compositions were studied by comparing the 2-D electrophoresis （2-DE） maps for these two cultivars of hybrid rice. After matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF/MS） analysis, a 21-kDa precursor of 19- kDa globulin was identified as the major storage protein for both cultivars. Some isoforms of peroxiredoxin and seed maturation protein were found to only exist in Shanyou63, whereas aldose reductase and starch granule-bound starch synthase were only detected in Liangyoupeijiu. These data might provide a foundation for further comparative studies of these two cultivars of hybrid rice.

Purification and Characterization of a New Heme-Binding （HBP59） from the Mutant Strain DJ35 of Azotobacter vinelandii

A new protein, an approximately 59-kDa monomer containing iron atoms, was first isolated from the mutant strain DJ35 of Azotobacter vinelandii Llpmann. After analysis by matrix-assisted laser desorptlon ionization time-of-flight mass spectrometry, the protein was Identified as the product of a predicted gene. Thus, the protein was tentatively called HBP59. Its absorption spectra （ABS） In the reduced state exhibited three peaks at 421,517, and 556 nm and the maximal peak was shifted from 421 to 413 nm after exposure of HBP59 to air. The Soret circular dichrolsm （CD） spectrum of HBP59 In the reduced state displayed four positive peaks at 364, 382, 406, and 418 nm and two negative peaks at 398 and 433 nm; the △ε （CD extinction coefficient） values of these peaks were found to be 0.92, 0.58, 0.87, 0.72, -0.65 and -1.12 L/mol per cm, respectively. Titration with heme showed that the protein has 0.1 heme molecules/protein molecule. After HBP59 had fully Interacted with heme, Its maximal ABS value and Soret CD Intensity were increased by approximately 10-fold compared with values before Interaction. Therefore, It seems that one molecule of HBP59 can be interacted with only one heme. These results indicate that HBP59 contains heme with low spin and may be Involved In heme utilization or adhesion.

RNA Interference-mediated Silencing of Phytochelatin Synthase Gene Reduce Cadmium Accumulation in Rice Seeds

Phytochelatins （PCs） play an important role in heavy metal resistance and accumulation. To reduce the accumulation of cadmium （Cd） in rice seeds, the expression of phytochelatin synthase （PCS） gene OsPCS1 was suppressed by RNA interference （RNAi）. A hairpin construct of a PCS fragment was designed in the pRNAi-OsPCS1 under the control of ZMM1, a seed-specific promoter from maize. The construct was introduced into rice （japonica） through Agrobacterium tumefaciens. The RNAi rice plantlets were selected and cultivated in pots exposured to 10 mg/kg Cd. The transcriptional level of OsPCS1 declined in seeds of some RNAi rice compared to the wild type. As a result Cd accumulation was reduced by about half in the seeds of RNAi rice. As expected, no apparent difference of growth appeared between RNAi and wild-type plants. The results suggest that this new approach can be used to control heavy metal accumulation in crops.

From Acta Botanica Sinica to JIPB:Connecting Chinese Plant Science with the International Community for 60 Years

In 1952, when botany was still regarded as a ＂new science＂ in China, a quarterly journal named Acta Botanica Sinica （ABS） was established by the Botanical Society of China. Dr. Shih- Wei Loo received his Ph.D. from the California Institute of Technology （CIT） in 1945, and was appointed as the journal＇s first Editor-in-Chief for his achievements in plant biology （Tang and Loo 1940; Loo and Wang 1943）. Since then, the journal has continuously nourished the growth of many Chinese botanists, except for a 5-year hiatus during the arduous Cultural Revolu- tion period between 1967 and 1972. By 1989, the journal began publishing monthly.

Decrease of Photosystem Ⅱ Photochemistry in Arabidopsis ppt1 Mutant Is Dependent on Leaf Age

In the present study, we compared the effect of leaf age at one development stage on the photosynthetic behavior of a T-DNA-tagged allele of the pptl mutant. Chlorophyll fluorescence （Fv/Fm, where Fm is the maximum fluorescence yield and Fv is variable fluorescence） and fluorescence decay kinetics of the pptl mutant were different in leaves of different ages. The steady state levels of thylakoid membrane proteins in 40-day-old leaves were decreased compared with those in 20-day-old leaves and changes in photosystem （PS） II proteins were correlated with those of the F,/Fm ratio in the pptl mutant. Increased accumulation of leaf sugars was accompanied by decreased photosynthetic gene transcripts and protein content in 40- day-old leaves of the mutant. Thus, the results of the present study provide evidence for the phosphate translocator in maintaining normal photosynthesis at a late leaf age.

The Plant Exocyst

The exocyst is an octameric vesicle tethering complex that functions upstream of SNARE mediated exocytotic vesicle fusion with the plasma membrane. All proteins in the complex have been conserved during evolution, and genes that encode the exocyst subunits are present in the genomes of all plants investigated to date. Although the plant exocyst has not been studied in great detail, it is likely that the basic function of the exocyst in vesicle tethering is conserved. Nevertheless, genomic and genetic studies suggest that the exocyst complex in plants may have more diversified roles than that in budding yeast. In this review, we compare the knowledge about the exocyst in plant cells to the well-studied exocyst in budding yeast, in order to explore similarities and differences in expression and function between these organisms, both of which have walled cells.

Tree Rings and Ecology The 7th International Conference on Dendrochronology

Tree rings have long been recognized as a useful indicator of past environmental changes. Besides traditional applications in studies of climate change and archaeology, the technique of dendrochronology has been widely used in answering ecological questions. This has been partly reflected by the broad topics on tree rings and ecology presented at the 7th International Conference on Dendrochronology （ICD）, which was held in Beijing, June 11-17 2006. At this conference, Dr Henri Grissono-Mayer, the plenary speaker for the theme, defined dendroecology as the science that uses tree rings, dated to their exact year of formation, to analyze temporal and spatial relationships between living organisms and their environment.

New year,new look,and new goals

Each year, January offers me the opportunity to reflect on what has happened in the past years and to anticipate what is going to happen in coming years. The last few years have without a doubt been an exciting period for JIPB, it has continued to progress, and become a prestigious international journal （Liu 2012）. In 5 years, JIPB＇s subscriptions have grown from 7,853 to over 14,300 libraries worldwide, and the impact factor has increased from 0.859 to 3.75. The number of full- text downloads has increased from 68,851 to 200,000 （Liu 2013）. As we step into 2014, you will notice some important changes, and of course some challenges we will have to face.

TILLING and Associated Technologies

As part of a collaboration between the John Innes Centre （JIC）,Norwich,UK and the Centre for Signal Transduction and Metabolomics （C-STM） at the Institute of Botany （IOB）,