Ming-Feng Yang

Abscisic acid pretreatment enhances salt tolerance of rice seedlings: proteomic evidence.

Enhanced salt tolerance of rice seedlings by abscisic acid (ABA) pretreatment was observed from phenotypic and physiological analyses. Total proteins from rice roots treated with ABA plus subsequent salt stress were analyzed by using proteomics method. Results showed that, 40 protein spots were uniquely upregulated in the seedlings under the condition of ABA pretreatment plus subsequent salt stress, whereas only 16 under the condition of salt treatment. About 78% (31 spots) of the 40 protein spots were only upregulated in the presence of the subsequent salt stress, indicating that plants might have an economical strategy to prevent energy loss under a false alarm. The results also showed that more enzymes involved in energy metabolism, defense, primary metabolism, etc. were upregulated uniquely in ABA-pretreated rice seedlings, suggesting more abundant energy supply, more active anabolism (nitrogen, nucleotide acid, carbohydrate, etc), and more comprehensive defense systems in ABA-pretreated seedlings than in salt stressed ones.

Proteomic Analysis of Oil Mobilization in Seed Germination and Postgermination Development of Jatropha curcas

To understand oil mobilization in germinating seeds, we performed ultrastructural observation and proteomic analysis of endosperm in germinating Jatropha curcas seeds. Results showed that the oil mobilization was initiated during germination, and then the oil was consumed for early seedling development. The significant change in abundance of 50 protein spots during germination indicated that several pathways including beta-oxidation, glyoxylate cycle, glycolysis, citric acid cycle, gluconeogenesis, and pentose phosphate pathway were involved in the oil mobilization.

A comparative proteomic analysis of rice seedlings under various high-temperature stresses

To understand the responses of rice seedlings to different high-temperature stresses, seven-day-old rice seedlings were exposed to different high temperatures for 48 h, and the maximal quantum yield of PS II photochemistry measurements, ascorbate peroxidase activity assays and proteomic analyses in leaf tissue were performed. The results showed that when rice seedlings were exposed to high temperatures at 35 degrees C, 40 degrees C and 45 degrees C, the maximal quantum yield of photosystem II photochemistry, the activity of ascorbate peroxidase and the proteome changed greater at higher temperature. The proteomics analysis showed that proteins such as lignification-related proteins were regulated by high temperature and distinct proteins related to protection were up-regulated at different high temperatures. All the results indicated that different strategies were adopted at different levels of high temperature: the higher the temperature, the more protection machineries were involved. At 35 degrees C, some protective mechanisms were activated to maintain the photosynthetic capability. At 40 degrees C, antioxidative pathways were also active. When rice seedlings encountered high-temperature stress at 45 degrees C, in addition to those induced at 35 degrees C and 40 degrees C, heat shock proteins were effectively induced.

Major Energy Plants and Their Potential for Bioenergy Development in China

China is rich in energy plant resources. In this article, 64 plant species are identified as potential energy plants in China. The energy plant species include 38 oilseed crops, 5 starch-producing crops, 3 sugar-producing crops and 18 species for lignocellulosic biomass. The species were evaluated on the basis of their production capacity and their resistance to salt, drought, and/or low temperature stress. Ten plant species have high production and/or stress resistance and can be potentially developed as the candidate energy plants. Of these, four species could be the primary energy plants in China: Barbados nut (Jatropha curcas L.), Jerusalem artichoke (Helianthus tuberosus L.), sweet sorghum (Sorghum bicolor L.) and Chinese silvergrass (Miscanthus sinensis Anderss.). We discuss the use of biotechnological techniques such as genome sequencing, molecular markers, and genetic transformation to improve energy plants. These techniques are being used to develop new cultivars and to analyze and manipulate genetic variation to improve attributes of energy plants in China.

A Comparative Analysis of Embryo and Endosperm Proteome from Seeds of Jatropha curcas

Jatropha curcas is an important economic plant for biodiesel, which is extracted mainly from the endosperm of its mature seeds. Despite the morphological and functional differences between the embryo and endosperm, proteomic characteristics of the two tissues are not yet known. Similar proteomic profiles were observed in the two-dimensional gel electrophoresis maps from the two tissues. There were 380 and 533 major protein spots in the embryo and endosperm, respectively. Fourteen identical spots, showing a notable change, were selected and identified by tandem mass spectrometry. Among these proteins, dihydrolipoamide acetyltransferase (spot 27) participates in tricarboxylic acid cycle, which is an amphibolic pathway. The two parts both included proteins related to stress (spots 8, 115, 118, 125, 130) and signal transduction (spots 7, 100, 108). According to the volume percentage of proteins in embryo and endosperm, the proteins in endosperm (spots 54, 61, 73) were catabolism-related enzymes and reserves to provide the nutrition for seed germination; the proteins in embryo (spots 27, 62, 122) were inclined to anabolism and utilized the nutrition from the endosperm to generate a new life.

The differential proteome of endosperm and embryo from mature seed of Jatropha curcas.

Jatrpha curcas L., a non-model woody plant belonging to Euphorbiaceae family, is a promising economic plant due to the high oil content in seed and high tolerance to drought and salt stress. The embryo and endosperm of J. curcas seed differ in morphology, function and ploidy. To characterize the protein profiles of these two tissues, we have performed proteomic analysis with the dry mature J. curcas seeds. The data showed that the 2-DE profiles of endosperm and embryo were similar to each other. There are 66 differential proteins between the two seed tissues, in which 28 proteins distributed in 9 distinct functional classes, have been identified successfully in endosperm or embryo. The major groups of differential proteins are associated with metabolism (25%) and disease/defence (18%). Our results demonstrated that in the dry mature J. curcas seeds, the proteins involved in oil mobilization, signal transduction, transcription, protein synthesis, and cell cycle which are essential for the seed germination have occurred in endosperm and embryo, reflecting the fact that proteins required for germination are already present in the dry mature seed.

JcDof1, a Dof transcription factor gene, is associated with the light‐mediated circadian clock in Jatropha curcas

Jatropha curcas is an economically important plant in terms of its seed oil. However, the molecular mechanisms underlying this plant response to light signals are unknown. One group of DNA-binding with one finger (Dof) transcription factor genes exhibits circadian rhythms and plays a crucial role in the control of flowering time by photoperiod perception in plants. In the present study, a full-length cDNA designated JcDof1, containing a conserved Dof-DNA-binding domain, was isolated from J. curcas seedlings by yeast one hybrid library. Subcellular localization assays and yeast one hybrid systems confirmed that JcDof1 was localized to the onion epidermal cell nucleus, and exhibited DNA-binding and transcriptional activation activities in yeast. The JcDof1 expression was characterized by a circadian-clock oscillation under long day, short day and continuous light conditions, whereas in the etiolated cotyledons under continuous dark conditions, JcDof1 expression remained at relatively basal levels. Red and blue light downregulated the JcDof1 expression, but this effect was not observed under far-red light. Taken together, these results suggested that JcDof1 was a circadian clock-Dof transcription factor gene responding to light signals.

A putative flowering-time-related Dof transcription factor gene, JcDof3, is controlled by the circadian clock in Jatropha curcas.

Plant-specific DNA-binding transcription factors with one finger (Dof) perform important roles in several biological processes. A yeast one-hybrid cDNA library of Jatropha curcas was used to identify Dof-type transcription factors. JcDof3, isolated from the library as a full-length cDNA, encoded a protein of 518 amino acids and contained a highly conserved Dof domain. Yeast one-hybrid systems and subcellular localization assays confirmed that JcDof3 was a typical transcription factor. In contrast to arrhythmic expression at basal level in etiolated cotyledons under continuous dark conditions, the circadian oscillations of JcDof3 transcripts were observed under long day, short day or continuous light regimes. A phylogenetic analysis showed that JcDof3 was clustered into the same clade with CYCLING DOF FACTOR (CDF), which interacts with F-box protein to regulate photoperiodic flowering. Moreover, a yeast two-hybrid assay showed that JcDof3 also interacted with F-box proteins. Our results suggest that JcDof3 is a circadian clock regulated gene, and might be involved in the flowering time regulation of J. curcas.

Organ-specific responses of vacuolar H+-ATPase in the shoots and roots of C3 halophyte Suaeda salsa to NaCl.

Suaeda salsa L. is a halophytic species that is well adapted to high salinity. In order to understand its salt tolerance mechanism, we examined the growth and vacuolar H(+)-ATPase (V-ATPase) response to NaCl within the shoots and roots. The growth of shoots, but not roots, was dramatically stimulated by NaCl. Cl(-) and Na(+) were mainly accumulated in shoots. V-ATPase activity was significantly increased by NaCl in roots and especially in shoots. Interestingly, antisera ATP95 and ATP88b detected three V(1) subunits (66, 55 and 36 KDa) of V-ATPase only in shoots, while an 18 kDa V(0) subunit of V-ATPase was detected by both antisera in shoots and roots. It suggested that the tissue-specific characteristics of V-ATPase were related to the different patterns of growth and ion accumulation in shoots and roots of S. salsa.

RNA interference-based suppression of phosphoenolpyruvate carboxylase results in susceptibility of rapeseed to osmotic stress.

The diverse functions of phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.31) in C(3) plants are not as well understood as in C(4) plants. To investigate the functions of PEPCase in C(3) plants, rapeseed (Brassica napus L.) PEPCase gene (referred to as BNPE15) was silenced by the RNA interference (RNAi) technique. Under normal growth conditions, no significant difference in lipid content and fatty acid composition were found between wild-type (WT) and transgenic rapeseed plants. However, when these plants were subjected to osmotic stress induced by osmoticum polyethylene glycol (PEG-6000), membrane permeability and membrane lipid peroxidization in roots and leaves of transgenic plants were higher than those of WT plants. It suggested that transgenic plants are more susceptible to osmotic stress than WT plants. Taken together, the results showed that the suppression of PEPCase by RNAi leads to susceptibility to osmotic stress in rapeseed, and PEPCase is involved in the response of C(3) plants to environmental stress.