To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedl...To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedling roots treated with submergence (ST) was used as tester and what from untreated roots (UT) as driver. Products of the secondary PCR from the forward subtraction were cloned into T/A vector and transferred into Escherichia coli strain JM10B by electroporation. Four hundred and eight randomly chosen transformants carrying cDNA fragments were screened with PCR-Select Deferential Screening Kit. One hundred and eighty-four cDNA clones were identified as, submergence specifically induced or highly expressed. After sequencing and removing redundant cDNAs, we got 95 submergence-induced cDNA clones. Of the 95 cDNA clones, 68 contain the regions with 60%-90% identity to their homolog in GenBank, 21 are expected to be novel genes, only 6 correspond to the published maize sequences.展开更多
Abiotlc stress is the main factor negatively affecting crop growth and productivity worldwide. The advances In physiology, genetics, and molecular biology have greatly Improved our understanding of plant responses to ...Abiotlc stress is the main factor negatively affecting crop growth and productivity worldwide. The advances In physiology, genetics, and molecular biology have greatly Improved our understanding of plant responses to stresses. Rice plants are sensitive to various ablotlc stresses, in this short review, we present recent progresses In adaptation of rice to salinity, water deficit and submergence. Many studies show that salt tolerance Is tightly associated with the ability to maintain Ion homeostasis under salinity. Na^＋ transporter SKC1 unloads Na^＋from xylem, plasma membrane Na^＋/H^＋ antlporter SOS1 excludes sodium out of cytosol and tonoplast Na^＋/H^＋ antlporter NHX1 sequesters Na^＋ Into the vacuole. Silicon deposition in exodermls and endodermis of rice root reduces sodium transport through the apoplastlc pathway. A number of transcription factors regulate stress-Inducible gene ex- presslon that leads to Initiating stress responses and establishing plant stress tolerance. Overexpresslon of some transcription factors, Including DREB/CBF and NAC, enhances salt, drought, and cold tolerance In rice. A variant of one of ERF family genes, SublA-1, confers Immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain ablotic stresses.展开更多
The effects of fertilization on activity and composition of soil microbial community depend on nutrient and water availability;however,the combination of these factors on the response of microorganisms was seldom stud...The effects of fertilization on activity and composition of soil microbial community depend on nutrient and water availability;however,the combination of these factors on the response of microorganisms was seldom studied.This study investigated the responses of soil microbial community and enzyme activities to changes in moisture along a gradient of soil fertility formed within a long-term(24 years)field experiment.Soils(0–20 cm)were sampled from the plots under four fertilizer treatments:i)unfertilized control(CK),ii)organic manure(M),iii)nitrogen,phosphorus,and potassium fertilizers(NPK),and iv)NPK plus M(NPK+M).The soils were incubated at three moisture levels:constant submergence,five submerging-draining cycles(S-D cycles),and constant moisture content at 40%water-holding capacity(low moisture).Compared with CK,fertilization increased soil organic carbon(SOC) by 30.1%–36.3%,total N by 27.3%–38.4%,available N by 35.9%–56.4%,available P by 61.4%–440.9%,and total P by 28.6%–102.9%.Soil fertility buffered the negative effects of moisture on enzyme activities and microbial community composition.Enzyme activities decreased in response to submergence and S-D cycles versus low moisture.Compared with low moisture,S-D cycles increased total phospholipid fatty acids(PLFAs)and actinomycete,fungal,and bacterial PLFAs.The increased level of PLFAs in the unfertilized soil after five S-D cycles was greater than that in the fertilized soil.Variations in soil microbial properties responding to moisture separated CK from the long-term fertilization treatments.The coefficients of variation of microbial properties were negatively correlated with SOC,total P,and available N.Soils with higher fertility maintained the original microbial properties more stable in response to changes in moisture compared to low-fertility soil.展开更多
文摘To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedling roots treated with submergence (ST) was used as tester and what from untreated roots (UT) as driver. Products of the secondary PCR from the forward subtraction were cloned into T/A vector and transferred into Escherichia coli strain JM10B by electroporation. Four hundred and eight randomly chosen transformants carrying cDNA fragments were screened with PCR-Select Deferential Screening Kit. One hundred and eighty-four cDNA clones were identified as, submergence specifically induced or highly expressed. After sequencing and removing redundant cDNAs, we got 95 submergence-induced cDNA clones. Of the 95 cDNA clones, 68 contain the regions with 60%-90% identity to their homolog in GenBank, 21 are expected to be novel genes, only 6 correspond to the published maize sequences.
基金Supported by the State Key Basic Research and Development Plan of China （2006CB100100）, the Knowledge innovation Program of the Chinese Academy of Sciences （KSCX2-YW-N-011）, the Shanghai Key Basic Research Foundation and Program of Shanghai Subject Chief Scientist （05DJ14008 and 06XD14023）.Publication of this paper is supported by the National Natural Science Foundation of China （30624808）.Acknowledgements We thank Dr Ying Zhu （Cornell University, USA） for valuable comments and discussion.
文摘Abiotlc stress is the main factor negatively affecting crop growth and productivity worldwide. The advances In physiology, genetics, and molecular biology have greatly Improved our understanding of plant responses to stresses. Rice plants are sensitive to various ablotlc stresses, in this short review, we present recent progresses In adaptation of rice to salinity, water deficit and submergence. Many studies show that salt tolerance Is tightly associated with the ability to maintain Ion homeostasis under salinity. Na^＋ transporter SKC1 unloads Na^＋from xylem, plasma membrane Na^＋/H^＋ antlporter SOS1 excludes sodium out of cytosol and tonoplast Na^＋/H^＋ antlporter NHX1 sequesters Na^＋ Into the vacuole. Silicon deposition in exodermls and endodermis of rice root reduces sodium transport through the apoplastlc pathway. A number of transcription factors regulate stress-Inducible gene ex- presslon that leads to Initiating stress responses and establishing plant stress tolerance. Overexpresslon of some transcription factors, Including DREB/CBF and NAC, enhances salt, drought, and cold tolerance In rice. A variant of one of ERF family genes, SublA-1, confers Immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain ablotic stresses.
文摘The effects of fertilization on activity and composition of soil microbial community depend on nutrient and water availability;however,the combination of these factors on the response of microorganisms was seldom studied.This study investigated the responses of soil microbial community and enzyme activities to changes in moisture along a gradient of soil fertility formed within a long-term(24 years)field experiment.Soils(0–20 cm)were sampled from the plots under four fertilizer treatments:i)unfertilized control(CK),ii)organic manure(M),iii)nitrogen,phosphorus,and potassium fertilizers(NPK),and iv)NPK plus M(NPK+M).The soils were incubated at three moisture levels:constant submergence,five submerging-draining cycles(S-D cycles),and constant moisture content at 40%water-holding capacity(low moisture).Compared with CK,fertilization increased soil organic carbon(SOC) by 30.1%–36.3%,total N by 27.3%–38.4%,available N by 35.9%–56.4%,available P by 61.4%–440.9%,and total P by 28.6%–102.9%.Soil fertility buffered the negative effects of moisture on enzyme activities and microbial community composition.Enzyme activities decreased in response to submergence and S-D cycles versus low moisture.Compared with low moisture,S-D cycles increased total phospholipid fatty acids(PLFAs)and actinomycete,fungal,and bacterial PLFAs.The increased level of PLFAs in the unfertilized soil after five S-D cycles was greater than that in the fertilized soil.Variations in soil microbial properties responding to moisture separated CK from the long-term fertilization treatments.The coefficients of variation of microbial properties were negatively correlated with SOC,total P,and available N.Soils with higher fertility maintained the original microbial properties more stable in response to changes in moisture compared to low-fertility soil.
