Scientia Agricultura Sinica

Establishment of an efficient RNA interference system in rice and the application on the functional analysis of receptor-like kinase genes

Scientia Agricultura Sinica. 2006, 39(9): 1729-1735 .

Abstract ( 1108 )

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RNA interference (RNAi) technology can be used to specifically suppress the expression of target gene in eukaryotes. In this research, RNAi-inducing vector pCADS1341 was constructed for rice transformtion. In order to examine its effectiveness, RNAi vector targeting GUS gene was constructed using pCADS1341 and introduced into transgenic rice calli stably expressing GUS gene using gene-gun transformation method. GUS staining results indicated that transient expression of the RNAi apparatus could significantly suppress the expression of GUS gene. In order to investigate factors that affect RNAi efficiency, detailed analyses were carried out on rice RNAi plants targeting a given rice receptor-like kinase gene. T-DNA insertion copy number and expression level of target gene in each T0 RNAi plant were detected using Southern blot and Northern blot, respectively. A line with single-copy T-DNA insertion and well-suppressed target gene expression was selected out for semi-quantitative RT-PCR assay on its T1 offspring. The results indicated that RNAi effect could be inherited to the next generation of trangenic rice plants, but the RNAi efficiencies in different individuals were variable. Expression level of RNAi apparatus might determine RNAi efficiency. Our high efficiency RNAi system would play an important role in rice functional genomics research. We have successfully made more than six　RNAi constructs for rice receptor-like kinase genes and systematic functional analysis of those genes are underway.

Isolation of cDNA fragments and genes related to wheat salt-tolerance via cDNA-AFLP

Scientia Agricultura Sinica. 2006, 39(9): 1736-1742 .

Abstract ( 1048 )

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98-160 is a wheat line with excellent salt-tolerance which is controlled by major genes. The expression profile of 98-160 under salt stress for different times was studied using cDNA-AFLP. One hundred and twelve fragments were cloned and sequenced. The tBlastx analysis showed that 62.5% of the sequenced fragments had similarity with known genes in the database, in which 18 cDNA were tightly related to wheat salt tolerance, most of them were transcription factor, transportation related protein, signal transduction related protein and proteins related to other stresses. Some fragments encoded proteins involved in protein-protein interaction.Several full length cDNAs have been obtained based on the above fragments, expression analysis by RT-PCR indicated that they might play important roles in reaction to wheat salt stress.

Sequence analysis of α/β-gliadin genesfrom Sichuanwheat landrace AS1643

Scientia Agricultura Sinica. 2006, 39(9): 1743-1750 .

Abstract ( 1550 )

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Using PCR amplification method, the full coding regions (open reading frame, ORF) of three α/β-gliadin genes Gli-AS1643-1 (GenBank No.DQ166376), Gli-AS1643-2 (GenBank No.DQ166377) and Gli-AS1643-3 (GenBank No.DQ166378), were isolated form the genomic DNA of Sichuan wheat landrace AS1643. Among which, Gli-AS1643-1 and Gli-AS1643-2 were 873 bp and 852 bp, and could encode two mature proteins with 270 and 263 amino acid residues, respectively. Due to one stop codon in its coding region, Gli-AS1643-3 was a pseudogene. Multiple sequence alignment analysis suggested that Gli-AS1643-1, Gli-AS1643-2 and Gli-AS1643-3 have the higher similarity in their structure with the known α/β-gliadin genes in GenBank. N-terminal amino acid sequences of the three cloned genes were basically consistent with other α-, β-, γ- and α/β-gliadins, whereas it was clearly different with ω-gliadins and LMW-GS. N-terminal amino acid sequence was dodecapeptide tandem repeat with five more closely proline boxes and two polyglutamine domains encoded by microsatellite-like sequences. Sequence active in celiac disease and adenovirus type twelve infection sequences were presented in N-domain and in C-domain of Gli-AS1643-2, respectively. The six conserved cysteine residues would form three intramolecular disulfide bonds in Gli-AS1643-1, Gli-AS1643-2 and Gli-AS1643-3, respectively.

Detection and Identification of Natural Variation of Sterility in Soybean

Scientia Agricultura Sinica. 2006, 39(9): 1756-1764 .

Abstract ( 1331 )

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Sterile plants were screened from 8327 soybean landraces and 414 hybrid populations during 1998-2003, and eleven and six sterile lines were identified and evaluated respectively. Ten of the eleven sterile lines obtained from different landraces might be natural mutants according to their morphological and agronomical performances similar to their corresponding parents. Among the 17 sterile lines, 13 lines performed completely male sterile and four lines were male partially sterile, and the female fertility of these lines could also be divided into fertile, partially sterile and completely sterile according to the results of parallel crossing and natural outcrossing rate of sterile lines, therefore, all the sterile lines were grouped into six male and female performance types. Among them, seven lines belonged to the male-sterile and female-fertile (MS-FF) type (including NJS-3H, NJS-4H, NJS-8H with good outcrossing ability); two lines (NJS-2H, NJS-12H) were male sterile, female partially sterile (MS-FPS); two lines(NJS-9, NJS-11H) were male partially sterile, female fertile(MPS-FF); three lines NJS-18H, NJS-7H, NJS-10H were male-sterile and female-sterile (MS-FS), both male and female partially sterile(MPS-FPS), and male partially sterile and female sterile(MPS-FS) types, respectively; and other three lines(NJS-17H、NJS-20H、NJS-22H) were male sterile but female fertility uncertain yet. The results of genetic analyses showed that the sterility of 17 lines was controlled by nuclear gene(s). Some sterile lines, including NJS-8H (MS-FF type controlled by one dominant gene), NJS-2H and NJS-12 (MS-FPS new type by one recessive gene), NJS-9 (MPS-FF type by two recessive genes), NJS-7H (MPS-FPS type by two recessive genes), and NJS-10H (MPS-FS type with abnormal flower structure and leaf shape), were new sterility types in soybean, and other lines appeared one recessive gene inheritance. The mutation rate of sterility was estimated as 0~1.87×10-4 from five cultivars with large population size. The present study indicates that there exists certain amount of natural variation and mutants in sterility which are feasible to be obtained through natural variation selection and could be used as elite sources for further research on developmental and reproductive biology as well as in breeding programs of soybeans.

Correlation analysis of agro-meteorology and rice yield components over middle and lower reaches of the Yangtze River

Scientia Agricultura Sinica. 2006, 39(9): 1765-1771 .

Abstract ( 1150 )

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The relationship between weather data and early and middle rice yield components over middle and lower reaches of Yangtze River from 1981 to 2003 is analyzed .Percentage of undeveloped grain of early rice increase as mean precipitation rise and as mean maximum temperature decrease at the stage of flowering , premilk and late milk; the relation is clear between Percentage of undeveloped grain of middle rice and agro-meteorology at flowering stage: it goes up as mean precipitation and mean maximum temperature rise. Percentage of partially grain of early and middle rice has the increasing trend with the rise of mean precipitation and fall of mean maximum temperature at late milk stage. Thousand grain weight of early rice goes up with the increase of mean maximum temperature and the decrease of mean precipitation at the stage of premilk and late milk; that of middle rice has the increasing trend with increase of mean maximum temperature and the decrease of mean precipitation at the stage of late milk.

Studies on the Root Vigor and Grain-filling Characteristics in Super Hybrid Rice and Their Parental Lines

Scientia Agricultura Sinica. 2006, 39(9): 1772-1779 .

Abstract ( 1143 )

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In the present paper , the relationship between root vigor and grain-filling characteristics were studied, in which three two-line super hybrid rice，Yue-za 122,Yue-za 889,and Yue-za 922, as well as their restorer lines R122, W889,W922 and P/TGMS line GD-1S were used. The results showed that, a) The maximum root bleeding intensity was achieved at different grain-filling stage for the rice hybrids and their parental lines. It occurred at heading for Yue-za 889 and Yue-za 922 and the restorer line R122, and at 5 days after heading(DAH) for Yue-za 122 and W922, but 10 DAH for W889 and GD-1S. The root bleeding intensity consequently declined for all the hybrids and their parental lines except for GD-1S, and its sharp-down point occurred at 15 DAH. b) The fertilized grain-root activity of hybrids was positively and significantly correlated with their parental lines. It suggested that hybrids with high fertilized grain-root activity can be developed by using parental lines with high fertilized grain-root activity. c) The super hybrid rice and their restorer lines had two-period grain-filling phenomenon to some extent, and the maximum grain-filling rate was at about 15 DAH for the superior grains, but at about 30-35 DAH for the inferior grains. d) The grain filling rate of superior grains was significantly correlated with three root vigor indices, ie. root bleeding intensity, spikelet-root activity, and fertilized spikelet-root activity, respectively, only at 15 DAH. The grain-filling rate of inferior grains was significantly correlated with the three root vigor indices at 10, 15 and 20 DAH. Developing super rice hybrid with strong root vigor and maintaining and enhancing its root vigor at the grain-filling period through cultivation measures, could be helpful in solving the problems of two-period grain-filling phenomenon and poor grain filling of super hybrid rice.

Effect of silicon on photosynthesis and its related physiological parameters in two winter wheat cultivars under freezing stress

Scientia Agricultura Sinica. 2006, 39(9): 1780-1788 .

Abstract ( 1363 )

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Two winter wheat (Tritium aestivum L.) cultivars, Linmai No.2 (resistant) and Yangmai No.5 (susceptible), were grown hydroponically to investigate the effects of exogenous silicon (Si) on photosynthetic and physiological parameters of the seedlings grown under cold stress. Wheat seedlings grown in nutrient solutions were treated with 0, 0.1or 1.0 mmol / L Si, and then were subjected to freezing stress. The results showed that the photosynthesis and photosynthetic efficiency of the seedlings were significantly inhibited under freezing stress, but significantly enhanced by added Si. In comparison with the control, freezing stress induced a decline in net photosynthetic rate (Pn), stomatal conductance (Cs), transpiration rate (Tr), stomatal limitation value (Ls) and water utiliy efficiency (WUE) in seedlings. However, exogenous Si significantly increased the Pn, Cs and Tr. The transpiration rate was decreased under freezing stress and even lower in Si-supplied cold treatment than in Si-deprived one. The content of chlorophyll, the value of chl a/chl b and the content of soluble sugar were decreased under freezing stress. Exogenous Si decreased the content of soluble sugar significantly in both cultivars, whereas it did not significantly increase the contents of chlorophyll or the value of chl a/chl b.

THE APPLICABILITY RESEARCH 0F WCSODS GROWTH MODEL IN HENAN PROVINCE

Scientia Agricultura Sinica. 2006, 39(9): 1789-1795 .

Abstract ( 1072 )

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Based on WCSODS, the experiments of sowing date and nitrogenous fertilizer were carried out successively, and the parameters adjusted and have the wheat mode-WCSODS checked in Henan province. The results showed that:1)It was high precision for phenophase and yield between simulated data and observed, compared with the observed data, the error was 1～2 days for whole stage ,and was 4～6 days for elongation stage and 2～5 days for holding stage, for the yield, the error between simulated and observed was 4.5～20 kg/667m2;2)Based on distribution index of green leaf and dry matter above, wheat leaf area index were simulated by WCSODS, the error was avoided caused by calculation green leave area, simultaneously it also thought over the limit of leaf area index increasing for tiller number and included the wheat variety of different tiller ability ,so it had good application. The results showed that the correlation coefficient between observed and simulated data of the leaf area index、tiller number and dry matter weight was 0.9877～0.9995;3)The problem for the model-WCSODS is disregarded the effects of nitrogen intimidation on the growth of wheat.

Heredity Correlation Analysis bewteen Leaf Water Use Efficiency and Related Physiological Traits in Wheat

Scientia Agricultura Sinica. 2006, 39(9): 1796-1803 .

Abstract ( 1145 )

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In order to understand the correlation between water use efficiency （WUE）and related physiological traits, and offer some information for genetics and breeding of wheat WUE, the 4×4 complete dialed cross was set up with 4 drought resistant and high-yield wheat varieties. The results of the phenotype and heredity correlation analysis among parents and offsprings show as follows, during filling prophase and metaphase as well anaphase,there was a significant positive correlation or very significant positive correlation between the leaf WUE and the photosynthetic rate(Pn); very significant negative correlation between leaf WUE and interstellar CO2 concentration(Ci) and transpiration rate(Tr); the relation between leaf WUE and leaf temperature(Tl) was the negative correlation, and that reached the very significant negative correlation during filling anaphase; the relation between leaf WUE and stomatal conductance(Cond) show quadratic curve tendency. There are stable correlation between leaf WUE and other related traits druing filling satge, these results could be used in physiology and genetic improving of WUE in wheat.

The research of Sporisorium reiliana’s infection efficiency and spread course in maize based on PCR assays

Scientia Agricultura Sinica. 2006, 39(9): 1804-1809 .

Abstract ( 1428 )

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Abstract: Head smut of maize substantially reduces grain yield. Two varieties of maize were used in our experiments: huangzao4 which is susceptible to maize head smut and Mo17 which has resistance. The DNA of the leaves, root, stem and male ear from Sporisorium reiliana of the infected and noninfected young and mature maize plants is detected with the existence of specific DNA only appearing in the pathogen S. reiliana’s genome by PCR based assays. Through the PCR amplification, we can distinguish the young plant which has been invaded by the S. reiliana from the healthy plant at the early invaded Stage. So it provides a sensitive and reliable tool to make an objective appraisal of the S. reiliana’s infection. The study of the course of the S. reiliana’s spread in the maize indicates that the resistance of the maize to the head smut majority represents in the stage of infection and spread. And the result shows that it couldn't present evidently resistance during the growth of the male ears. Key words: Maize (Zea mays L.); Head smut; PCR; infection; spread

Sensitivity of the different developing stages in the life cycle of Pseudoperonospora.cubensis to enostrobilurin

Scientia Agricultura Sinica. 2006, 39(9): 1810-1816 .

Abstract ( 1076 )

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Abstract: The effects of enostrobilurin to the different development stages in the life cycle of P. cubensis was studied. The results showed that enostrobilurin had no effect on cystospore germination, but prevented the zoospore dischargement, zoospore motility, germ tube elongation, hypha growth , sporangiophore emergency from stomata and sporangial formation. The EC50 of enostrobilurin to zoospore dischargement and germ tube elongation were 0.0239μg/ml, 0.0037μg/ml, respectively. enostrobilurin made zoospore cleaned up at 0.05µg/ml and inhibited hypha, growth sporangiophore emergency from stomata and sporangial formation obviously at 5μg/ml.

The special expression and comparison of c-kit protein in spermatogenesis of four species of locusts of Arcypteridae

Scientia Agricultura Sinica. 2006, 39(9): 1817-1822 .

Abstract ( 1534 )

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In order to elucidate the regulation of c-kit protein in spermatogenesis of locust, immunohistochemistry and biological statistics were used to investigate the expression of c-kit protein in four representative phases of spermatogenesis of three dominant species of locusts of Arcypteridae (Orthoptera:Acridoidea) which are Omocestus viridulus (Linnaeus), Euchorthippus unicolor (Ikonn.) and Euchorthippus vittatus Zheng and so on in Siping area of Jilin province,China. The results were as follows: (1)there were weak positive expression of c-kit protein in spermatogonia and positive granule was thinner;(2)there were a strong positive expression of c-kit protein in primary spermatocyte and positive granule became biggest than all developmental stages;(3)c-kit protein positive expression became stronger in secondary spermatocyte while positive granule became thinner;(4)there were strong positive expression of c-kit and thinner positive granule in mature sperm, which distributed on head and tail;(5)there were strong c-kit positive protein granule massing at the end of spermary;(6) the intensity of c-kit protein positive expression of three species of locusts in spermatogenesis were compared and analyzed. Results showed that there were significant differences among different kinds of locusts. The data suggested that c-kit might play a crucial role in spermatogenesis as well as keep the physiological action of sperms and fertilization, and even regulate developmental speed in spermatogenesis and maintain species isolation etc.

EFFECT OF BENSULFURON METHYL ON GROWTH OF CHLORELLA PYRENOIDOSA

Scientia Agricultura Sinica. 2006, 39(9): 1823-1827 .

Abstract ( 1284 )

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The growth effects of bensulfuron methyl of different concentrations on Chlorella pyrenoidosa were studied through 96h acute toxicity tests in this paper. The results showed that bensulfuron methyl accelerated the growth of algae at lower concentration （<1mg/L） with content increase of chlorophyll or protein, and inhibited the growth of algae at higher concentration (>5mg/L). The content of chlorophyll or protein in algae cells reduced with the increasing concentration of bensulfuron methyl, exhabiting the good concentration-effect relationship. The 96h-EC50 of bensulfuron methyl upon the algae was 15.7mg/L.

The Heterogeneity of soil nutrients and their influencing factors in peak-cluster depression areas of karst region

Scientia Agricultura Sinica. 2006, 39(9): 1828-1835 .

Abstract ( 1218 )

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Selecting a typical karst peak cluster-depression system in northwest Guangxi Autonomous region, we have evaluated the effects of land-uses and topographic factors on soil nutrients. The results indicated that: with a long-term of tillage, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN) and available potassium (AK) in depression are significantly lower than slope land. Yet the available phosphorus (AP) is significantly higher than that of slope land，and it may be implied that fertilizer input was very important for AP in soil; SOC, TN, TP, TK, AN and AP were highly affected by Land-uses in slope-line scale. Topographic factors have a significant effect on SOC, TN, TP, AN, AP, AK and PH, but its variance ratio is lesser than land-use type; In the depression, different cropping systems have a significant effect on SOC, TP, TK and AK, though its variance ratio is low, it reflected the difference of fertilization and crop character among cropping systems; In research area, SOC, TN and AN decrease significantly with land-use intensity increases. Nature field and abandoned field have a higher accumulation of SOC, and it’s SOC contents is 3.35 times and 1.91 times of the tillage field. As a result of erosion and leaching, witch are induced by cultivation (or past cultivation), tillage field have a lower accumulation of SOC, TN and AN. SOC, TN, TK, AN and AK is significantly higher in rehabilitated field than in tillage field on research area scale, converting cropland to forest-land has a positive effect on soil organic matter accumulation. But on slope-line scale, SOC, TN, TP, AN and AK in rehabilitated field is significantly lower than in Nature field and abandoned field, suggesting that physical and chemical property changes within the degradation soil may take a longer periods to the nature level.

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