作者机构：
[Chen Li-yun; Xiao Ying-hui; Lei Dong-yang] Hunan Agr Univ, Rice Res Inst, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Chen, LY ] ;Hunan Agr Univ, Rice Res Inst, Changsha 410128, Hunan, Peoples R China.
关键词：
rice;photoperiod/thermo-sensitive genic male sterility;mechanism of;sterility;breeding strategy
摘要：
To understand the male sterility mechanism of photoperiod/thermo-sensitive genic male sterile [P（T）GMS] lines in rice, the research progress on genetics of photoperiod and/or temperature sensitive genic male sterility in rice was reviewed. A new idea was proposed to explain the sterility mechanism of P（T）GMS rice. The fertility transition from sterile to fertile is the result of cooperative regulation of major-effect sterile genes with photoperiod and/or temperature sensitive genes, but not the so-called pgms gene in P（T）GMS rice. The minor-effect genes, which exhibit accumulative effect on sterility, are the important factors for the critical temperature of sterility transition. The more minor-effect genes the sterile line holds, the lower the critical temperature of sterility transition is. The critical temperature of sterility transition will be invariable if all the minor-effect genes are homozygous. The strategies for breeding P（T）GMS rice were also proposed. The selective indices of critical photoperiod and temperature for sterility transition should be set according to varietal type and ecological region. Imposing selection pressure is a key technology for breeding P（T）GMS rice with lower critical temperature for sterility, and improving the comprehensive performance of the whole traits and combining ability is vital for breeding P（T）GMS rice lines.
摘要：
SUMMARY Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is the most devastating disease of rice and severely affects crop stability and sustainability worldwide. This disease has advanced to become one of the premier model fungal pathosystems for host—pathogen interactions because of the depth of comprehensive studies in both species using modern genetic, genomic, proteomic and bioinformatic approaches. Many fungal genes involved in pathogenicity and rice genes involved in effector recognition and defence responses have been identified over the past decade. Specifically, the cloning of a total of nine avirulence (Avr) genes in M. oryzae, 13 rice resistance (R) genes and two rice blast quantitative trait loci (QTLs) has provided new insights into the molecular basis of fungal and plant interactions. In this article, we consider the new findings on the structure and function of the recently cloned R and Avr genes, and provide perspectives for future research directions towards a better understanding of the molecular underpinnings of the rice–M. oryzae interaction.
期刊：
African Journal of Biotechnology,2009年8(7):1273-1279 ISSN：1684-5315
通讯作者：
Guan Chun-yun
作者机构：
[Guan Chun-yun; Zhang Zhen-qian] Hunan Agr Univ, Oilseed Res Inst, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Guan Chun-yun] H;Hunan Agr Univ, Oilseed Res Inst, Changsha 410128, Hunan, Peoples R China.
关键词：
This paper reports a comprehensive study of screening rapeseed soil sample inVictoria blue solution solid medium;with olive oil as sole carbon source. The lipaseof Enterobacter agglomerans which has the highest activity was identified. Underthe optimum conditions determined;the enzyme activity of this strain reached 39.09 U/mL. The optimal conditions were found to be: initial pH 7.0;agitating at 30°C for 48 h;with 2.0% (w/v) lactose as carbon source;1.5% (w/v) beef extract and 1.0% (w/v) yeast extract as nitrogen source;and 0.1% (w/v) MgSO4·7H2O. Olive oil;sesame oil and tea oil as raw materials can be catalyzed to biodiesel by the lipase of this strain at 30°C and 180 rpm. And the yield reached 54.51% with sesame oil as raw material;even when they contained 92.4% (w/v) water in the starting materials. This strain will potentially serve as a promising alternative lipase for biodiesel production with raw materials containing water.
摘要：
This paper reports a comprehensive study of screening rapeseed soil sample in Victoria blue solution solid medium, with olive oil as sole carbon source. The lipase of Enterobacter agglomerans which has the highest activity was identified. Under the optimum conditions determined, the enzyme activity of this strain reached 39.09 U/mL. The optimal conditions were found to be: initial pH 7.0, agitating at 30 degrees C for 48 h, with 2.0% (w/v) lactose as carbon source, 1.5% (w/v) beef extract and 1.0% (w/v) yeast extract as nitrogen source, and 0.1% (w/v) MgSO4 center dot 7H(2)O. Olive oil, sesame oil and tea oil as raw materials can be catalyzed to biodiesel by the lipase of this strain at 30 degrees C and 180 rpm. And the yield reached 54.51% with sesame oil as raw material, even when they contained 92.4% (w/v) water in the starting materials. This strain will potentially serve as a promising alternative lipase for biodiesel production with raw materials containing water.
关键词：
Biotic and abiotic stresses;Crop improvement;Crop management;Grain yield;Rice research;Stress tolerance
摘要：
Rice production in China has more than tripled in the past five decades mainly due to increased grain yield rather than increased planting area. This increase has come from the development of high-yielding varieties and improved crop management practices such as nitrogen fertilization and irrigation. However, yield stagnation of rice has been observed in the past ten years in China. As its population rises, China will need to produce about 20% more rice by 2030 in order to meet its domestic needs if rice consumption per capita stays at the current level. This is not an easy task because several trends and problems in the Chinese rice production system constrain the sustainable increase in total rice production. Key trends include a decline in arable land, increasing water scarcity, global climate change, labor shortages, and increasing consumer demand for high-quality rice (which often comes from low-yielding varieties). The major problems confronting rice production in China are narrow genetic background, overuse of fertilizers and pesticides, breakdown of irrigation infrastructure, oversimplified crop management, and a weak extension system. Despite these challenges, good research strategies can drive increased rice production in China. These include the development of new rice varieties with high yield potential, improvement of resistances to major diseases and insects, and to major abiotic stresses such as drought and heat, and the establishment of integrated crop management. We believe that a sustainable increase in rice production is achievable in China with the development of new technology through rice research.
摘要：
Weak organic acids including tartaric and citric acids were applied to a typical paddy soil in southern China to test their effects on rice in the field for three years. Their effects were also compared with top dressings of the two acids, basal application of diammonium acid phosphate, calcium carbonate, and the control. The results showed that rice grain yield of the citric acid treatment was significantly higher than that of the control and the same difference was also observed for the filled spikelets per panicle. There were no significant difference among all the treatments and the control on the accumulation of above ground dry matter. However the root dry matter, length, peroxidase activity, and white root number of citric acid treatment were significantly higher than that of the control, while no significant differences among other treatments were observed. Basal application of citric acid played a positive role on this soil.
摘要：
[ Objective ] The aim of this experiment is to explore the role of ethylene in sexual determination in ramie. [ Method ] The ethylene release rates in ramie stem apex of different sexes at different times, bud of the same node in female and hermaphrodite ramie in second crop and single inflorescence of different sexes in hermaphrodite ramie were measured by gas chromatography. Effects of two ethylene inhibitors on sex expression in ramie were investigated. [ Result ] The ethylene release rate of stem apex was higher in the second crop or female ramie than that in the third crop or hermaphrodite ramie during growth. Although ethylene release rates between lower nodes and higher nodes were little different, it was lower in the middle nodes in hermaphrodite ramie. The ethylene release rates were higher in the higher nodes of female ramie in the second crop. In third crop, the ethylene release rates were higher in lower nodes, lower in middle nodes and then highest in higher nodes in female ramie. However, an opposite ethylene release pattern was observed in hermaphrodite ramie. The ethylene release rate was higher in female flower than male flower and mixed inflorescence in hermaphrodite ramie. The male flower could be distinctly induced by AVG. The node of the first male flower, percentage of female flowers and ratio of female flowers to male in ramie were evidently depressed by AVG in contrast to water. The percentage of mixed male and female flowers was also increased and the percentage of female flower decreased by spraying AgNO3. [Conclusion]There was close relationship between sexual differentiation and ethylene release rate in ramie. The female ramie could be induced by high ethylene release rate. The female flower could be inhibited by AVG and AgNO3. AVG at a concentration of 300 mg·L^-1 was the most effective.
摘要：
SummaryImprovement of drought tolerance in plants depends upon understanding their molecular responses to dehydration stress. The drought resistance of 14 varieties of tall fescue (Festuca arundinacea Schreb.) was analysed by measuring various physiological traits under high temperature and drought conditions. A dehydration-responsive element-binding-2 (DREB2) homologue cDNA from the cultivar ‘Plantation’, with high drought tolerance, designated FapDREB2, was isolated and sequenced. The FapDREB2 cDNA was predicted to encode a protein of 262 amino acid residues, with a molecular mass of 41.3 kDa and a pI of 5.28. Its deduced protein sequence, with a conserved AP2 DNA-binding domain, shared characteristics with the DREB2 gene family based on sequence homology, structure and phylogenetic analysis. Expression of the FapDREB2 gene in different plant organs indicated that its transcripts were abundant in leaves and leaf sheaths, and scarce in roots. In addition, FapDREB2 gene expression under drought and high temperature conditions was stronger than without such treatments in the laboratory. FapDREB2 mRNA accumulated in response to various abiotic stresses, confirming that its expression was induced more prominently by drought or salt treatment than by cold stress, and did not respond to abscisic acid (ABA) treatment. FapDREB2 gene expression in seedlings grown in a study plot varied irregularly under drought and high temperature conditions, in contrast to seedlings grown with drought treatment in the laboratory. This suggests that expression of the DREB2 transcription factor would be complex during plant responses to different stresses. We concluded that the FapDREB2 gene is involved in plant responses to drought or salt stress through an ABA-independent pathway, which may lead to a better understanding of the regulatory mechanism of the DREB2 transcription factor in tall fescue.
摘要：
Rice diseases caused by fungi, bacteria and viruses are one of the major constraints for sustainable rice (Oryza sativa L.) production worldwide. The use of resistant cultivars is considered the most economical and effective method to control rice diseases. In the last decade, a dozen resistance genes against the fungal pathogen Magnaporthe grisea and the bacterial pathogen Xanthomonas oryzae pv. oryzae have been cloned. Approximately half of them encode nuclear binding site (NBS) and leucine rich repeat (LRR)-containing proteins, the most common type of cloned plant resistance genes. Interestingly, four of them encode novel proteins which have not been identified in other plant species, suggesting that unique mechanisms might be involved in rice defense responses. This review summarizes the recent advances in cloning and characterization of disease resistance genes in rice and presents future perspectives for in-depth molecular analysis of the function and evolution of rice resistance genes and their interaction with avirulence genes in pathogens.
