September 2011 issue

Effect of different concentrations of kinetin on regeneration of ten weeks (Matthiola incana)

Afshin Ahmadi Hesar, Behzad Kaviani, Alireza Tarang and Sahar Bohlooli Zanjani

Abstract

We present a simple and reliable strategy for micro-propagation of Matthiola incana, an ornamental plant, in the presence of the single growth regulator, kinetin, which enables the production of stock plants. In vitro single nodes of Matthiola incana were cultured in MS basal medium with different concentrations of kinetin to produce shoots and roots. Multiple shoots containing roots simultaneously obtained on MS medium only with supplementation of 0.5-2 mg/L kinetin. The best shoot length (11.72 mm) and the most number of nodes (4.64) were obtained when we used 2 mg/L of kinetin. The largest number (3.40) and the longest length of roots (54.0 mm) were achieved using 1 mg/L kinetin. Data analysis showed that the effect of kinetin was significant on the length of shoot and root, and the number of node and root.

Pages 236-238 | Full Text PDF

Comparative analysis of the genomic regions flanking Xa21 locus in indica and japonica ssp of rice (Oryza sativa L.)

Anirudh Kumar, Waikhom Bimolata, Gouri Sankar Laha_, R. Meenakshi Sundaram, Irfan Ahmad Ghazi
Abstract

Comparative analysis of a 100 kb region flanking the major bacterial blight resistance gene Xa21 (3.57 kb) in the two subspecies of rice Oryza sativa L. ssp. japonica cv. Nipponbare and Oryza sativa L. ssp. indica cv. 93-11 was performed to understand the evolution and divergence of Xa21 locus between the two subspecies. A total of 12 genes in japonica and 14 genes in indica were predicted and annotated in this region. Functional annotation revealed the presence of 4 genes and 8 genes in japonica and indica, respectively which could be putatively associated with disease resistance in the 100 kb region of Xa21 locus. The study also revealed that 50% of japonica genes and 42.8% of indica genes in the genomic region of interest were transposable elements protein coding genes. Analysis of each predicted gene in this region revealed more or less similar GC content in both the subspecies. A total of 109 SSRs have been identified in the region of interest in both indica and japonica. The numbers of repeated motifs were observed to decrease with the increased number of nucleotides. Interestingly, most of the leucine rich repeat (LRR) gene products were predicted to be localized in the plasma membrane and the transposable element related protein coding genes were localized in the nucleus. Phylogenetic tree analysis revealed that the majority of predicted genes with similar functions of both the subspecies were grouped together.

Pages 239-249 | Full Text PDF | Supplementary data

Identification of membrane proteins in maize leaves, altered in expression under drought stress through polyethylene glycol treatment

F. J. Tai, Z. L. Yuan, X. L. Wu, P. F. Zhao, X. L. Hu, W. Wang
Abstract

Membrane proteins are involved in many functions due to their cellular locations. Although the effect of drought on plants has been extensively studied, little is known about the changes of membrane proteome in plants under drought conditions. We used gel-based proteomics to study the effect of drought on membrane protein expression in maize (Zea mays L.) plants. Moderate drought stress was applied by 16% (w/v) polyethylene glycol (PEG) treatment of maize seedlings for 8 h. Membrane proteins were extracted from membrane fraction of leaf tissues and separated by two-dimensional electrophoresis followed by matrix-assisted laser-desorption ionization time of flight mass spectrometry. Seventeen protein spots were up-regulated and 18 were down-regulated in response to PEG stress. Hydropathicity (gravy) analysis indicated that 8 spots were hydrophobic and 26 spots were hydrophilic. The identification of proteins indicated that these PEG responsive proteins played diverse functions. Furthermore, the prediction of subcellular localization suggested that 25 spots located in chloroplast, 2 in cytoplasm, while others had other location. Therefore, PEG-responsive membrane proteins are mainly from chloroplasts, which are very sensitive in response to drought stress. Besides, the suitability of the present extraction method for membrane proteins was discussed in the text.

Pages 250-256 | Full Text PDF

Improved protein identification using a species-specific protein/peptide database derived
from expressed sequence tags

Jinhui Chen, Jisen Shi, Dagang Tian, Liming Yang, Yuming Luo, Denghua Yin, Xiangyang Hu
Abstract

The use of peptide mass fingerprinting data obtained by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry in conjunction with protein database searching is a fast, high-throughput method that is widely used to identify proteins in a proteome. The success of a search is limited, however, by the number of proteins represented in the database. When the fully sequenced genome of an organism is not available, cross-species databases are usually used, which can compromise the reliability of the results. Databases containing expressed sequence tag sequences are available and are potentially invaluable resources for proteomic studies. For the study reported herein, we developed a proteomic approach that incorporates a species-specific protein/peptide database constructed from expressed sequence tag sequences, and we validated this approach by accurately retrieving proteins from this database that matched, on the basis of the masses of their in silico-generated tryptic peptides, experimentally isolated proteins derived from a wheat stem proteome. We also compared the results obtained using the wheat database with those obtained using the same peptide mass fingerprints and a cross-species protein database search. Given the reliability of the results and the improved scoring obtained with the wheat database study in comparison with the cross-species database study, species-specific databases derived from expressed sequence tags may replace cross-species databases for proteomic studies involving organisms for which a completely sequenced genome is unavailable.

Pages 257-263 | Full Text PDF | Supplementary data

Analysis of elicitor inducible cytochrome P450 induction in Astragalus chrysochlorus cells

Neslihan Turgut-Kara, Sule Ari
Abstract

In this study, elicitor-inducible cytochrome P450 biosynthesis in Astragalus chrysochlorus was investigated for further analysis on phenylpropanoid metabolism. In order to analyse cytochrome P450s under yeast extract elicited conditions, we used non-radioactive P450 targeted differential display method. The P450 targeted differential display of mRNA technique was performed with upstream primers based on the conserved heme-binding region [PFG] of P450s, as a result 56 clearly differential bands were revealed; 37 of the bands were correctly analysed, and one of the PCR products was contained the P450 fingerprint. This sequence has been confirmed to be up-regulated and subsequently cloned and sequenced. Homology analysis of the 400 bp long sequence revealed that 81 % similarity with cinnamate 4-hydroxylase in the manner of amino acid. Quantitative real-time-PCR analysis showed that putative C4H gene was up-regulated 13,24-fold by 6h yeast extract treatment unlike untreated control. 1338 bp long cDNA fragment (Accession no: GQ844863) of A. chrysochlorus C4H (AcC4H) has been obtained by PCR with degenerate primers. Bioinformatics analyses revealed that putative AcC4H (1338 bp) was highly similar (95 %) to trans-cinnamate 4-monooxygenase (EC 1.14.13.11). As a result, we have isolated a putative C4H fragment from A. chrysochlorus suspension cells under yeast extract elicited conditions. This knowledge will use for obtaining whole C4H sequence, and to manupulate phenylpropanoid metabolic pathway of this medicinal plant.

Pages 264-269 | Full Text PDF

Defense proteins are induced in wheat spikes exposed to Fusarium graminearum

Kwang-Hyun Shin, Abu Hena Mostafa Kamal, Kun Cho, Jong-Soon Choi, Yu-Jin, Nam-Chon Paek, Yin Won Lee, Jong Kwan Lee, Jong-Chul Park, Heung-Tae Kim, Hwa-Young Heo, and Sun Hee Woo
Abstract

Fusarium head blight (FHB), caused by Fusarium graminearum, infects wheat and barley and diminishes both grain yield and quality. Triticum spp. ecotypes differ in their susceptibility to this disease. Using a proteomics approach, we isolated and identified the proteins associated with FHB resistance in a popular Korean wheat genotype with moderate resistance. At 5 days post-anthesis, the floral spikes were point-inoculated with a macroconidial suspension of F. graminearum. After 48 h, we detected 31 of 100 acidic protein spots, and determined that these differentially expressed protein (DEP) spots were the result of FHB exposure. In all, 17 DEPs were up-regulated, 5 were down-regulated, and 2 were unevenly changed. Following tryptic digestion, we used MALDI-TOF/TOF mass spectrometry to identify 14 unique proteins in those 24 DEPs, including those related to carbon metabolism and photosynthesis. After inoculation, Rubisco small and large subunits, isoflavone reductase, a chloride carrier/channel, and (1,3;1,4) b-glucanase were markedly up-regulated, whereas wall-associated kinase 4 was down-regulated. In addition, a (1,3;1,4) b-glucanase protein (PR-2) was up-regulated in FHB-infected spikes, a finding that is in agreement with previous proteomics and transcriptomics analyses of other crops. Interestingly, most of these proteins were unevenly regulated over the course of infection, although their levels of protein expression were not lower than those untreated samples.

Pages 270-277 | Full Text PDF