The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed ...The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed to discover that the entire diversity of inter-gene interactions is presented in four major forms: complementarity, epistasis, polymery, and modifying effect of genes. However, gene interaction mechanism which is reflected on the segregation nature of variously crossed hybrids has not been sufficiently studied. Exclusive of molecular genetics, biochemistry and physiology, a genetic analysis of inheritance of characteristics in gene interaction taken by itself cannot reveal nature of this interaction. Lately, molecular-genetic and physiological studies on A. thaliana mutants have enabled to isolate and sequence a wide range of genes controlling certain links of the signalling chain. At the same time, effect of the plant development regulation signalling system on interaction of these genes in inheritance of characteristics of Arabidopsis root system haven’t been studied so far which was a cause for our studies. Gene interaction problem is closely related to the plant development regulation signalling system. Mechanism involved in gene interaction may be explained based on current idea of molecular principles of biological response. Affected by mutations occurring in various genes that control certain links of the signalling chain, signalling path to the cell nucleus and response are blocked partially or in full which leads to distortion in expression of the characteristic on the plant level in general or its organ level. Such phenomenon is observed in realization of many characteristics in animals and plants, including in A. thaliana. In inheritance of such characteristics, as a rule, both allelic, and non-allelic gene interactions are observed. Results of a study of the plant signalling system interconnection and gene interaction in inheritance of characteristics of Arabidopsis root system are presented. It is established that complementary interaction of genes RHD3 and SAR1 is observed in the second crossing generation for plants of rhd3-1 × sar-1 mutant lines. When gpa1-3 × slr-1 mutant-line plants are crossed, recessive epistasis (slr-1 slr-1 > GPA1_) occurs in F<sub>2</sub> generation. Polymeric interaction of genes SHY2 and MSG1 is observed in F<sub>2</sub> in crossing of shy2-2 × msg1-2 mutant-line plants.展开更多
Arabidopsis thaliana seedlings were cultivated in 0-500 μmol/L of extraneous cerium （Ce） for 7 d to investigate the toxicity, uptake and translocation of rare earth elements （REEs）. The results showed that Ce cou...Arabidopsis thaliana seedlings were cultivated in 0-500 μmol/L of extraneous cerium （Ce） for 7 d to investigate the toxicity, uptake and translocation of rare earth elements （REEs）. The results showed that Ce could be largely absorbed by the roots ofA. thaliana and translocated to the shoots. But the uptake rates of Ce by the roots were much higher than the translocation rates from roots to shoots. Ultrastructural analysis revealed that Ce was mainly distributed on the cell wall. At higher concentration, Ce could also enter cell, destroy the ultrastructure of cells and disturb the intrinsic balance of nutrient elements of A, thaliana, Addition of Ce （50-500 μmol/L） to the culture medium significantly inhibited the elongation of primary roots, decreased chlorophyll content, rosette diameter and fresh mass of plants. The damage increased with the increase of Ce concentration in culture medium, although primary root elongation, chlorophyll content, and rosette diameter were stimulated by relatively low concentration （0.5 μmol/L） of Ce. Thus, it is speculated that REEs may become a new type contamination if we don＇t well control the release of REEs into the environment.展开更多
Pharmacological, laser scanning confocal microscopic (LSCM), real-time PCR and spectrophotographic approaches are used to study the roles of hydrogen sulfide (H2S) and nitric oxide (NO) in signaling transduction of st...Pharmacological, laser scanning confocal microscopic (LSCM), real-time PCR and spectrophotographic approaches are used to study the roles of hydrogen sulfide (H2S) and nitric oxide (NO) in signaling transduction of stomatal movement response to ethylene in Arabidopsis thaliana. In the present study, inhibitors of H2S synthesis were found to block ethylene-induced stomatal closure of Arabidopsis. Treatment with ethylene induced H2S generation and increased L-/D-cysteine desulfhydrase (pyridoxal-phosphate-dependent enzyme) activity in leaves. Quantitative PCR analysis showed AtL-CDes and AtD-CDes transcripts were induced by ethylene. It is suggested that ethylene-induced H2S levels and L-/D-cysteine desulfhydrase activity decreased when NO was compromised. The data clearly show that ethylene was able to induce H2S generation and stomatal closure in Atnoa1 plants, but failed in the Atnia1,nia2 mutant. Inhibitors of H2S synthesis had no effect on ethylene-induced NO accumulation and nitrate reductase (NR) activity in guard cells or leaves of Arabidopsis, whereas ethylene was able to induce NO synthesis. Therefore, we conclude that H2S and NO are involved in the signal transduction pathway of ethylene-induced stomatal closure. In Arabidopsis, H2S may represent a novel downstream indicator of NO during ethylene-induced stomatal movement.展开更多
Abstract: Cis-cinnamic acid (CA) is a naturally occurring compound, presumably converted from trans-CA in higher plants. To investigate the effect of cis-CA on the activity of Arabidopsis phenylalanine ammonia lyase (...Abstract: Cis-cinnamic acid (CA) is a naturally occurring compound, presumably converted from trans-CA in higher plants. To investigate the effect of cis-CA on the activity of Arabidopsis phenylalanine ammonia lyase (PAL), AtPAL1, AtPAL2, and AtPAL4 genes were isolated using reverse transcription poly-merase chain reaction. These genes were fused to a glutathione S-transferase gene and overexpressed in a heterologous prokaryotic system of Escherichia coli. The purified PAL1, PAL2 and PAL4 enzymes were characterized biochemically to determine the effects of cis-CA on the kinetic parameter Km. The results showed that cis-CA is a competitive inhibitor for PAL1, but not PAL2 and PAL4, whereas trans-CA acts as a competitive inhibitor for all three PAL isomers, suggesting that cis- and trans-CA have different effects on the catalytic activity of PAL.展开更多
Primary dormant seeds of Arabidopsis thaliana did not germinate in darkness at temperature higher than 10–15℃.Ethylene improved the germination of dormant wild-type(Col-0)seeds at 25℃ in darkness but seeds of the m...Primary dormant seeds of Arabidopsis thaliana did not germinate in darkness at temperature higher than 10–15℃.Ethylene improved the germination of dormant wild-type(Col-0)seeds at 25℃ in darkness but seeds of the mutant affected in the proteolytic N-degronpathway,proteolysis6(prt6),were insensitive to ethylene suggesting that PRT6 was involved in dormancy release by ethylene.The substrates of the N-degron pathway,the Ethylene Response Factors from group VII(HRE1,HRE2,RAP2.2,RAP2.3,and RAP2.12),were identified to be involved in this insensitivity with an increased germination in prt6 rap2.2 rap2.3 rap2.12 rather than in prt6 hre1 hre2,which also indicated that the three RAPs acted downstream of PRT6,while the two HREs acted upstream of PRT6.Ethylene reduced the expression of the three RAPs in Col-0 seeds but they were maintained or induced by ethylene in prt6 seeds.The promoting effect of ethylene was associated with a down-regulation of dormancy-related genes in gibberellins(GAs)and abscisic acid(ABA)signaling,such as RGA,RGL2,and ABI5,and with a strong decrease in ABA/GA4 ratio in the presence of ethylene.In contrast,we show that the insensitivity of prt6 seeds to ethylene was mainly related to GA signaling disturbance.展开更多
成花素(flowering locus T,FT)是决定植物开花时间的关键信号因子。为研究桑树成花调控机制和FT基因的功能,构建插入桑树FT基因和报告基因GFP的植物双元表达载体p BE2133-FT-GFP,并通过蘸花方法转化拟南芥植株。利用卡那霉素抗性筛选和R...成花素(flowering locus T,FT)是决定植物开花时间的关键信号因子。为研究桑树成花调控机制和FT基因的功能,构建插入桑树FT基因和报告基因GFP的植物双元表达载体p BE2133-FT-GFP,并通过蘸花方法转化拟南芥植株。利用卡那霉素抗性筛选和RT-PCR鉴定获得的转基因拟南芥植株,提取植株总蛋白进行Western blot分析,出现一条符合预期大小的阳性条带,证实桑树FT基因已整合进拟南芥基因组,并成功表达FT蛋白。转基因拟南芥播种25 d,虽然只长出5片幼叶,但却开始抽薹开花,表现出明显的早花性,证明桑树FT基因具有促进早期开花的功能。展开更多
文摘The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed to discover that the entire diversity of inter-gene interactions is presented in four major forms: complementarity, epistasis, polymery, and modifying effect of genes. However, gene interaction mechanism which is reflected on the segregation nature of variously crossed hybrids has not been sufficiently studied. Exclusive of molecular genetics, biochemistry and physiology, a genetic analysis of inheritance of characteristics in gene interaction taken by itself cannot reveal nature of this interaction. Lately, molecular-genetic and physiological studies on A. thaliana mutants have enabled to isolate and sequence a wide range of genes controlling certain links of the signalling chain. At the same time, effect of the plant development regulation signalling system on interaction of these genes in inheritance of characteristics of Arabidopsis root system haven’t been studied so far which was a cause for our studies. Gene interaction problem is closely related to the plant development regulation signalling system. Mechanism involved in gene interaction may be explained based on current idea of molecular principles of biological response. Affected by mutations occurring in various genes that control certain links of the signalling chain, signalling path to the cell nucleus and response are blocked partially or in full which leads to distortion in expression of the characteristic on the plant level in general or its organ level. Such phenomenon is observed in realization of many characteristics in animals and plants, including in A. thaliana. In inheritance of such characteristics, as a rule, both allelic, and non-allelic gene interactions are observed. Results of a study of the plant signalling system interconnection and gene interaction in inheritance of characteristics of Arabidopsis root system are presented. It is established that complementary interaction of genes RHD3 and SAR1 is observed in the second crossing generation for plants of rhd3-1 × sar-1 mutant lines. When gpa1-3 × slr-1 mutant-line plants are crossed, recessive epistasis (slr-1 slr-1 > GPA1_) occurs in F<sub>2</sub> generation. Polymeric interaction of genes SHY2 and MSG1 is observed in F<sub>2</sub> in crossing of shy2-2 × msg1-2 mutant-line plants.
基金National Natural Science Foundation of China(30900071,30671126)
文摘Arabidopsis thaliana seedlings were cultivated in 0-500 μmol/L of extraneous cerium （Ce） for 7 d to investigate the toxicity, uptake and translocation of rare earth elements （REEs）. The results showed that Ce could be largely absorbed by the roots ofA. thaliana and translocated to the shoots. But the uptake rates of Ce by the roots were much higher than the translocation rates from roots to shoots. Ultrastructural analysis revealed that Ce was mainly distributed on the cell wall. At higher concentration, Ce could also enter cell, destroy the ultrastructure of cells and disturb the intrinsic balance of nutrient elements of A, thaliana, Addition of Ce （50-500 μmol/L） to the culture medium significantly inhibited the elongation of primary roots, decreased chlorophyll content, rosette diameter and fresh mass of plants. The damage increased with the increase of Ce concentration in culture medium, although primary root elongation, chlorophyll content, and rosette diameter were stimulated by relatively low concentration （0.5 μmol/L） of Ce. Thus, it is speculated that REEs may become a new type contamination if we don＇t well control the release of REEs into the environment.
基金supported by the National Natural Science Foundation of China (30970288 and 31170237)the Shandong Provincial Natural Science Foundation (ZR2010CM024)the Foundation of State Key Laboratory of Plant Physiology and Biochemistry (SKLPPBKF09001)
文摘Pharmacological, laser scanning confocal microscopic (LSCM), real-time PCR and spectrophotographic approaches are used to study the roles of hydrogen sulfide (H2S) and nitric oxide (NO) in signaling transduction of stomatal movement response to ethylene in Arabidopsis thaliana. In the present study, inhibitors of H2S synthesis were found to block ethylene-induced stomatal closure of Arabidopsis. Treatment with ethylene induced H2S generation and increased L-/D-cysteine desulfhydrase (pyridoxal-phosphate-dependent enzyme) activity in leaves. Quantitative PCR analysis showed AtL-CDes and AtD-CDes transcripts were induced by ethylene. It is suggested that ethylene-induced H2S levels and L-/D-cysteine desulfhydrase activity decreased when NO was compromised. The data clearly show that ethylene was able to induce H2S generation and stomatal closure in Atnoa1 plants, but failed in the Atnia1,nia2 mutant. Inhibitors of H2S synthesis had no effect on ethylene-induced NO accumulation and nitrate reductase (NR) activity in guard cells or leaves of Arabidopsis, whereas ethylene was able to induce NO synthesis. Therefore, we conclude that H2S and NO are involved in the signal transduction pathway of ethylene-induced stomatal closure. In Arabidopsis, H2S may represent a novel downstream indicator of NO during ethylene-induced stomatal movement.
文摘Abstract: Cis-cinnamic acid (CA) is a naturally occurring compound, presumably converted from trans-CA in higher plants. To investigate the effect of cis-CA on the activity of Arabidopsis phenylalanine ammonia lyase (PAL), AtPAL1, AtPAL2, and AtPAL4 genes were isolated using reverse transcription poly-merase chain reaction. These genes were fused to a glutathione S-transferase gene and overexpressed in a heterologous prokaryotic system of Escherichia coli. The purified PAL1, PAL2 and PAL4 enzymes were characterized biochemically to determine the effects of cis-CA on the kinetic parameter Km. The results showed that cis-CA is a competitive inhibitor for PAL1, but not PAL2 and PAL4, whereas trans-CA acts as a competitive inhibitor for all three PAL isomers, suggesting that cis- and trans-CA have different effects on the catalytic activity of PAL.
文摘Primary dormant seeds of Arabidopsis thaliana did not germinate in darkness at temperature higher than 10–15℃.Ethylene improved the germination of dormant wild-type(Col-0)seeds at 25℃ in darkness but seeds of the mutant affected in the proteolytic N-degronpathway,proteolysis6(prt6),were insensitive to ethylene suggesting that PRT6 was involved in dormancy release by ethylene.The substrates of the N-degron pathway,the Ethylene Response Factors from group VII(HRE1,HRE2,RAP2.2,RAP2.3,and RAP2.12),were identified to be involved in this insensitivity with an increased germination in prt6 rap2.2 rap2.3 rap2.12 rather than in prt6 hre1 hre2,which also indicated that the three RAPs acted downstream of PRT6,while the two HREs acted upstream of PRT6.Ethylene reduced the expression of the three RAPs in Col-0 seeds but they were maintained or induced by ethylene in prt6 seeds.The promoting effect of ethylene was associated with a down-regulation of dormancy-related genes in gibberellins(GAs)and abscisic acid(ABA)signaling,such as RGA,RGL2,and ABI5,and with a strong decrease in ABA/GA4 ratio in the presence of ethylene.In contrast,we show that the insensitivity of prt6 seeds to ethylene was mainly related to GA signaling disturbance.
