Expansins are cell-wall-loosening proteins that have multiple roles during plant development and stress- related processes. In this study, a novel expansin gene PwEXP2 was cloned by rapid amplification of cDNA ends ba...Expansins are cell-wall-loosening proteins that have multiple roles during plant development and stress- related processes. In this study, a novel expansin gene PwEXP2 was cloned by rapid amplification of cDNA ends based on the cDNA library of Picea wilsonii and EST fragment of PwEXP2. It was found that PwEXP2 coded 253 amino acids, and putative signal peptides exist at the N-terminal, followed by 8 cysteines, a HFD （His-Phe-Asp） conserved domain, and 4 tryptophan residues at the C-terminal. PwEXP2 was located in cytoplasm and nucleus when transformed in an onion epidermal cell. Quantitative real-time PCR assays showed that PwEXP2 was expressed in various tissues with a relatively high level in needles and low level in mature pollen. The expression level of PwEXP2 dramatically increased after seed germination. Gene expression profiles in abiotic stresses showed that PwEXP2 was induced by high temperature and osmotic stress but not involved in ABA-dependent signaling path- way. These results display the important roles of the PwEXP2 in plant development and multiple adversity stresses.展开更多
The introduction of reduced height （Rht） genes Rht-Blb and Rht-Dlb led to impressive increases in wheat （Triticum aestivum L.） yields during the Green Revolution. In the present study, the dynamic elongation of pe...The introduction of reduced height （Rht） genes Rht-Blb and Rht-Dlb led to impressive increases in wheat （Triticum aestivum L.） yields during the Green Revolution. In the present study, the dynamic elongation of peduncle in a set ofnear-isogenic lines （NILs） carrying different Rht alleles （Rht-Blb, Rht-Dlb, Rht-Blc, Rht-Dlb＋Rht-Blb, and Rht-Dlb＋Rht-Blc） were investigated. The reduction of the final length of peduncle in NILs was dependent mainly on the elongation rate, which was reduced by Rht genes, during rapid elongation phase. Resin sections showed that Rht genes strongly reduced the cell extension in peduncle. The expression of expansin genes, which mediate cell wall loosening and leading to cell expansion, were analysed by using real- time quantitative PCR （qPCR）. Among the 23 possible wheat expansin genes, 17 were expressed in the peduncle. The spatial distribution of expression was further analysed for five expansins that showed high expression levels in the peduncles of Rht lines. Compared to wild type plants, the incorporation of Rht-Dlb allele decreased about 37 and 80% of the expression levels of ExpA 7 and ExpA3 in elongation zone, respectively. The presence Rht-Blc dwarfing genes, however, produced 53% reduction in the expression level of ExpA7, and seriously decreased about 70% of ExpB9 expression. Although the expression levels of five genes exhibited variability among the lines, an expansin gene, ExpB2, showed its expression level highly associated with the cell elongation rate in peduncle of different Rht lines.展开更多
Fruit ripening is a complex process and is regulated by many factors.Ethylene and polygalacturonase(PG),lipoxygenase(LOX),expansin(EXP) are all critical regulating factors in fruit ripening and softening process.With ...Fruit ripening is a complex process and is regulated by many factors.Ethylene and polygalacturonase(PG),lipoxygenase(LOX),expansin(EXP) are all critical regulating factors in fruit ripening and softening process.With antisense ACS tomato,Nr mutant tomato and cultivated tomato as materials,Northern blot hybridization showed that PG,LeEXP1 and LOX expressed differently in different parts of cultivated tomato fruit during ripening,which was related to fruit ripening.The ripening process of columella and radial pericarp was faster than pericarp.In both Nr mutant and antisense ACS transgenic tomato fruit,expression levels of PG,LeEXP1 and LOX were generally lower than those in cultivated fruit but still related to fruit ripening.The expression levels of PG,LeEXP1 and LOX increased in the mature green tomato fruits after 0.5 h treatment with ethylene(100 μL/L).These results indicate that gene expression of PG,LeEXP1 and LOX were positively regulated by ethylene.The time and cumulative effect of the concentration exists in the expression of PG regulated by ethylene.The regulation of LOX expression mainly depended on the fruit development after great amount of ethylene was produced.PG played a major role in ripening and softening of tomato fruit,and cooperated with the regulation of EXP and LOX.展开更多
基金supported by National Natural Science Foundation(Grant No.31270663)a grant from Agricultural Ministry of China(Grant No.2013ZX08009003-002-004)
文摘Expansins are cell-wall-loosening proteins that have multiple roles during plant development and stress- related processes. In this study, a novel expansin gene PwEXP2 was cloned by rapid amplification of cDNA ends based on the cDNA library of Picea wilsonii and EST fragment of PwEXP2. It was found that PwEXP2 coded 253 amino acids, and putative signal peptides exist at the N-terminal, followed by 8 cysteines, a HFD （His-Phe-Asp） conserved domain, and 4 tryptophan residues at the C-terminal. PwEXP2 was located in cytoplasm and nucleus when transformed in an onion epidermal cell. Quantitative real-time PCR assays showed that PwEXP2 was expressed in various tissues with a relatively high level in needles and low level in mature pollen. The expression level of PwEXP2 dramatically increased after seed germination. Gene expression profiles in abiotic stresses showed that PwEXP2 was induced by high temperature and osmotic stress but not involved in ABA-dependent signaling path- way. These results display the important roles of the PwEXP2 in plant development and multiple adversity stresses.
基金financed by the National High-Tech R&D Program of China (2011AA10A106)the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (KSCX2-EW-N-02)+1 种基金the Promotive Research Fund for Excellent Young and Middle-Aged Scientists of Shandong Province, China (BS2013NY015)the Shandong Spark Program,China (2012XH11008)
文摘The introduction of reduced height （Rht） genes Rht-Blb and Rht-Dlb led to impressive increases in wheat （Triticum aestivum L.） yields during the Green Revolution. In the present study, the dynamic elongation of peduncle in a set ofnear-isogenic lines （NILs） carrying different Rht alleles （Rht-Blb, Rht-Dlb, Rht-Blc, Rht-Dlb＋Rht-Blb, and Rht-Dlb＋Rht-Blc） were investigated. The reduction of the final length of peduncle in NILs was dependent mainly on the elongation rate, which was reduced by Rht genes, during rapid elongation phase. Resin sections showed that Rht genes strongly reduced the cell extension in peduncle. The expression of expansin genes, which mediate cell wall loosening and leading to cell expansion, were analysed by using real- time quantitative PCR （qPCR）. Among the 23 possible wheat expansin genes, 17 were expressed in the peduncle. The spatial distribution of expression was further analysed for five expansins that showed high expression levels in the peduncles of Rht lines. Compared to wild type plants, the incorporation of Rht-Dlb allele decreased about 37 and 80% of the expression levels of ExpA 7 and ExpA3 in elongation zone, respectively. The presence Rht-Blc dwarfing genes, however, produced 53% reduction in the expression level of ExpA7, and seriously decreased about 70% of ExpB9 expression. Although the expression levels of five genes exhibited variability among the lines, an expansin gene, ExpB2, showed its expression level highly associated with the cell elongation rate in peduncle of different Rht lines.
基金Supported by National Project of Scientific and Technical Supporting Programs Funded by Ministry of Science and Technology of China (No.2006BAD22B01)National Natural Science Foundation of China (No.30800767)Postdoctoral Fund of China (No.20080430725)
文摘Fruit ripening is a complex process and is regulated by many factors.Ethylene and polygalacturonase(PG),lipoxygenase(LOX),expansin(EXP) are all critical regulating factors in fruit ripening and softening process.With antisense ACS tomato,Nr mutant tomato and cultivated tomato as materials,Northern blot hybridization showed that PG,LeEXP1 and LOX expressed differently in different parts of cultivated tomato fruit during ripening,which was related to fruit ripening.The ripening process of columella and radial pericarp was faster than pericarp.In both Nr mutant and antisense ACS transgenic tomato fruit,expression levels of PG,LeEXP1 and LOX were generally lower than those in cultivated fruit but still related to fruit ripening.The expression levels of PG,LeEXP1 and LOX increased in the mature green tomato fruits after 0.5 h treatment with ethylene(100 μL/L).These results indicate that gene expression of PG,LeEXP1 and LOX were positively regulated by ethylene.The time and cumulative effect of the concentration exists in the expression of PG regulated by ethylene.The regulation of LOX expression mainly depended on the fruit development after great amount of ethylene was produced.PG played a major role in ripening and softening of tomato fruit,and cooperated with the regulation of EXP and LOX.
