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10 July 2005, Volume 19 Issue 4 Previous Issue    Next Issue
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研究报告
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avr/pth13 Gene of Xanthomonas oryzae pv. oryzicola, a Novel Virulence Member of avrBs3/PthA Family, Strengthening Virulence of Xanthomonas oryzae pv. oryzae on Rice CHEN Gong-you ,ZOU Li-fang ,WU Xiao-Min ,LI Yu-rong ,WANG Jin-sheng 2005, 19(4): 291-296 .  Abstract ( )   PDF (183KB) ( )   An EcoRⅠ-BamHⅠ DNA, corresponding to the coding region NLS (nuclear localization signal) and AD (acidic transcriptional activation domain) of AvrXa3 of Xanthomonas oryzae pv. oryzae (Xoo), was used as a probe to screen the genomic library of Xanthomonas oryzae pv. oryzicola(Xooc). One avrBs3/PthA gene clone was obtained after positive clones of the library were digested by EcoRⅠ endoenzyme and proved by Southern blot. Sequencing subclone, pPth13, indicated that it contained a gene belonging to the avrBs3/PthA family of Xanthomonas pathogenic bacteria, and was nominated as avr/pth13 gene. As other AvrBs3/PthA, the putative protein of avr/pth13 gene possesses the same 5’- and 3’- terminals, one leucine zipper (LZ), three NLSs and one AD. However, the difference of the gene with other avrBs3/PthA family members was the repeat numbers of 34 amino acid unit coded by 102 bp repeat. The 102 bp unit was repeated 5.5 times in avr/pth13 gene. Blasting the sequence in GenBank database showed that avr/pth13 gene was the smallest in avrBs3/PthA family. (Alignment) of 12-13th residues in 34 amino acid unit of Avr/Pth13 with those of other AvrBs3/PthA proteins demonstrated that at least three HD(His and Asp) residues in 12-13th position of 34 amino acid unit might be necessary for avirulence or/and virulence. Pathogenicity tests of strain PXO99A containing avr/pth13gene on near isogenic lines (NILs) of rice showed that avr/pth13 gene strengthened the virulence of Xoo on the tested NILs. All the above confirmed that avrBs3/PthA gene(s) existed in Xooc as that in Xoo, determining virulence in bacterial streak and blight diseases of rice.

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Minimum Number of SSR Alleles Needed for Genetic Structure Analysis of Oryza rufipogon Populations YANG Qing-wen ,CHEN Cheng-bin ,ZHANG Wan-xia ,SHI Jin-xia ,REN Jun-fang 2005, 19(4): 297-302 .  Abstract ( )   PDF (112KB) ( )   One original population of Oryza rufipogen with 113 individuals (P) and three derivative populations (P1, P2, P3) randomly sampled from the original population were applied by the methods of Mantel correlation test and NTSYS clustering. For each population, the similarity matrix of the total alleles (277) and those of different numbers of alleles from 260 to 60 with the difference of 20 alleles were compared. The correlations of the matrices decreased with the reduction of alleles. When the numbers of alleles were about 200, the correlation coefficients of all the four populations were about 99.5%, meaning the best fit. If the difference of alleles was lessened to 10, the numbers of alleles were 180, 190, 210 and 200 while the correlation coefficients of the four populations (P, P1, P2, P3) all reached 99.5%. When the numbers of alleles continuously reduced to 60, the correlation coefficients of all the four populations were about 95.0%, also meaning good fit. The clustering dendrograms of the four populations with the correlation coefficient of 99.5% were almost the same as those of the toual alleles. However, those dendrograms with the correlation coefficient of 95.0% were obviously different from those of the total alleles. Therefore, the minimum number of SSR alleles needed for genetic structure analysis of O. rufipogon is between 190 and 210. Considering the mean number of alleles per SSR locus in O. rufipogon populations is about 4, fifty pairs of SSR primers could be enough to reveal genetic relationship among the individuals within O. rufipogon populations.

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Analysis of SSR Polymorphism by Genome-Scale Comparing Between Varieties in Rice CHEN Zhong-zhong ,WANG Xu-sheng ,ZHU Jun 2005, 19(4): 303-307 .  Abstract ( )   PDF (112KB) ( )   One thousand four hundred and fifty three loci were identified the same as in two rice varieties, indica rice 93-11 and japonica rice Nipponbare, by using bioinformatics tools based on 6655 sequences released by Monsanto enterprise which consisted of perfect repeats flanked by 100 bp on either side of the simple sequence repeat (SSR). Among those sequence hits, 1449 and 1451 SSRs were detected in 93-11 and Nipponbare, respectively. Among those, 371 SSRs had the same repeat units and the same repeat count, while 804 SSRs had the same special motifs with different repeat counts. In addition, in the same repeat units with different repeat counts SSR class,di-nucleotide SSRs were the most abundant, occupying 62.94% identified, while penta- and hexa-nucleotide SSRs were the least frequent. Polymorphism of SSR between two varieties in the collinear region were identified, revealing that new SSR markers could be developed for the further research of the genetic variation and genome analysis of the two varieties.

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Existence of Ca2+/H+ Antiporter and Its Properties in the Plasma Membranes of Rice Roots SHEN Guo-ming 2005, 19(4): 308-314 .  Abstract ( )   PDF (165KB) ( )   The peptide-sepcific antipobies of the Ca2+/H+ antiporter clearly reacted with a 44.5 kD protein from rice root plasma membrane by immunoblotting. Ca2+ transport activities of rice root plasma membrane by the filtration method using 45Ca2+, indicated that there was a Ca2+/H+ antiporter(OsCAX2) depended on transmembrane proton gradient in the rice root plasma membrane, and manganese ion could restrain Ca2+ transport activities of OsCAX2 partially. Kinetics analysis showed that the Vmax of OsCAX2 was 34.72 nmol/(min·mg), the Km was 3.83 μmol/L and the optimum pH value was 7.2.

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Effect of Rolled Leaf Rl(t) Gene on Grain Quality in Hybrid Rice (Oryza sativa) CHEN Zong-xiang ,CHEN Hong-qi ,SHAO Yuan-jian ,ZHANG Ya-fang ,PAN Xue-biao 2005, 19(4): 315-318 .  Abstract ( )   PDF (89KB) ( )   Grain quality characters of hybrid rice with or without rolled leaf Rl(t) gene were analyzed by using three pairs of rolled leaf near-isogenic lines under two fertilization treatments. Under normal fertilization level (e.g. 450 kg urea per ha), milled rice recovery and head rice rates of rolled leaf hybrids were significantly higher than those of corresponding non-rolled crosses, while the chalky rice rate and chalkiness degree were lower. Of the RVA profiles, the peak viscosity, the hot paste viscosity and the breakdown viscosity of the rolled leaf hybrids were all higher than those of the corresponding non-rolled ones at various degrees. Increasing fertilizer application for panicle development promoted the brown, milled and head rice rates except for (Shanyou) 63, while the RNA parameters metioned above all decreased to different levels. Increasing fertilizer application for panicle development, milled rice recovery and head rice rates of rolled leaf combinations were higher than those of corresponding ones. There existed significant difference in head rice rates between Rl(t) Shanyou 559 and Shanyou 559; indicating that Rl(t) could improve rice quality under a certain condition.

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Analysis on QTLs with Main, Epistasis and Genotype-Environmental Interaction Effects for Cooked Rice Elongation SHEN Sheng-Quan ,ZHUANG Jie-yun ,WANG Shu-zhen ,SHU Qing-yao ,BAO Jin-Song ,XIA Ying-wu 2005, 19(4): 319-322 .  Abstract ( )   PDF (107KB) ( )   The recombinant inbred line population derived from Xieqingzao B/Milyang 46 and its genetic linkage map were used to map the QTLs controlling cooked rice elongation in two environments, Hainan and Hangzhou. The phenotypic performance and distribution were very similar in the two environments, but the correlation coefgicient was small between the two environments. Only one QTL was detected for cooked rice elongation, qCRE 6, with a positive additive effect 3.99% from the male parent and explaining 5.30% of the total phenotypic variations. No genotype-environmental interaction effect was detected for this QTL. Another two pairs of epistasis QTLs were detected, i.e. qCRE 2 vs qCRE 5-1 and qCRE 5-2 vs qCRE 7, the former one showed significant genotype-environmental interaction which increased cooked rice elongation in Hangzhou.

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Ratooning Properties of Axillary Buds in Hybrid Rice ZHANG Gui-lian ,TU Nai-mei ,ZHANG Shun-tang 2005, 19(4): 323-327 .  Abstract ( )   PDF (107KB) ( )   A two-line hybrid rice combination Peiliangyou 500 and a three-line hybrid rice Shanyou 63 were used to study their ratooning characters of axillary buds.Compared to Shanyou 63, Peiliangyou 500 had higher ratooning ability of axillary buds and living bud rate,showing significant heterosis in dry matter accumulation and nonstructural carbohydrate content at late stage of the main crop. There were significant relationship between living bud rate and the dry matter weight of different stem nodes, soluble carbohydrate content and starch content, respectively. The activities of SOD and POX were increased 20 days after full heading of the main crop and reached the highest at maturity stage, leading to raise the ability of eliminating free radicals and active oxygen and improve the sprouting of axillary buds. It would be favorable to enhance ratooning ability of axillary buds with larger area of root absorption and specific surface area at late stage of the main crop.

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Physiological Characteristics of High-Yielding Rice under Different Irrigation Methods LIN Xian-qing ,ZHU De-feng ,LI Chun-shou ,RUAN Guan-hai ,ZHANG Yu-ping ,CHEN Hui-zhe 2005, 19(4): 328-332 .  Abstract ( )   PDF (141KB) ( )   A field experiment was conducted to study the physiological characteristics of high-yielding rice under aerobic irrigation. The results showed that the water level in the paddy field under aerobic irrigation was lower than that under the traditional irrigation throughout the whole growing season, resulting in the increases of oxidation-reduction potential and number of early tillers, and the productive panicles and grain yield were increased by 7.1% to 18.3% and 8.6% to 10.8% over the traditional irrigation, respectively. Under aerobic irrigation, the light transmittance of rice canopy was increased while the leaf area per hill was decreased insignificantly, the root exudates at the booting and flowering stages and net photosynthetic rate, stomatal conductance and specific leaf weight of leaf after flowering were increased as compared with those under traditional irrigation.

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Exogenous Nitric Oxide Alleviates Salt Stress-induced Membrane Lipid Peroxidation in Rice Seedling Roots LIU Kai-li ,HAN Hang-ru ,XU Ying-jie ,LING Teng-Fang ,LIU Zhi-bing ,SUN Yong-gang ,HUA Rong ,SHEN Wen-biao 2005, 19(4): 333-337 .  Abstract ( )   PDF (115KB) ( )   Exogenous application of 10 μmol/L sodium nitroprusside (SNP), a nitric oxide (NO) donor, obviously counteracted the accumulation of malondialdehyde (MDA), a lipid peroxidation product in roots of rice seedling under salt stress, and significantly increased soluble protein content in roots of rice seedling. Meanwhile, the activities of ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) were induced in roots of rice seedling by 10 μmol/L SNP treatment under salt stress. However, the opposite effects of higher concentration of 50 μmol/L SNP were found. All these above indicated that exogenous lower concentration of NO could effectively attenuate the oxidative damage caused by salt stress, which was mainly achieved by means of enhancing anti-oxidative capability in roots of rice seedling.

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Effects of Cadmium Stress on Photosynthesis, Chlorophyll Fluorescence Characteristics and Excitation Energy Distribution in Leaves of Rice XU Hong-xia ,WENG Xiao-yan ,MAO Wei-hua ,YANG Yong 2005, 19(4): 338-342 .  Abstract ( )   PDF (115KB) ( )   Photosynthesis, chlorophyll fluorescence characteristics and excitation energy distribution in leaves of rice variety Zhenong 952 were investigated under different cadmium concentration stresses. Under the low Cd concentration (0.1 mmol/L), Pn, Fv/Fm, ΦPSⅡ and qN had a slight increase while qP remained unchanged, indicating that rice under 0.1 mmol/L Cd stress had triggered excitation energy dissipation to protect photosynthetic apparatus from the damage by excess excitation energy. Pn, Fv/Fm and ΦPSⅡ were significantly decreased as well as qP and qN at the high Cd concentration (1.0 mmol/L). In the aspect of excitation energy distribution, both D and Ex increased while P declined significantly. It suggested that under 1.0 mmol/L Cd stress, PSⅡ was injured, and some pathway of excitation energy dissipation was blocked, and excitation energy couldn′t be dissipated efficiently and triggered the overproduction of reactive oxygen species (ROS) which induced the increase of activities of antioxidant enzymes, and led to the aggravation of membrane lipid peroxidation and the chlorophyll structure damage.

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Effect of Indigenous Nitrogen Supply of Soil on the Grain Yield and Fertilizer-N Use Efficiency in Rice LIU Li-jun ,XU Wei ,Tang Cheng ,WANG Zhi-qin ,YANG Jian-chang 2005, 19(4): 343-349 .  Abstract ( )   PDF (128KB) ( )   The effect of applying N-fertilizer or not in wheat on soil fertility and grain yield and fertilizer-N use efficiency (FNUE) of rice in the wheat-rice cropping system were studied. N-fertilizer application in wheat significantly increased total N, ammonium-N and nitrate-N contents in paddy field, resulting in high indigenous N supply of soil (INS). Compared with low INS, the effect of N rate on the grain yield of rice was reduced significantly, and FNUE was also decreased to different extent under high INS. These results indicated that high INS was one of the main reasons for low FNUE in rice. Under high INS, rice grain quality tended to be worse.

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Effects of Elevated pCO2 on Nutrient Uptake by Rice and Nutrient Contents in Rice Grain PANG Jing ,ZHU Jian-guo ,XIE Zu-bin ,CHEN Gai-ping ,LIU Gang ,ZHANG Ya-li 2005, 19(4): 350-354 .  Abstract ( )   PDF (323KB) ( )   Nutrient uptake and distribution in different tissues of rice (Oryza sativa L.) and nutrient contents in grain at low N (14 mg/L) and normal N (28 mg/L) were studied under ambient air and elevated atmospheric pCO2 (Ambient+200 μmol/mol) by the China FACE (Free-Air Carbon-Dioxide Enrichment). Supplied with available forms of nutrients at current normal level, rice uptook more K, Ca, Fe under elevated pCO2 treatment. N, P, Mg, Mn but not K, Ca, Cu, Zn, Fe distribution in panicle increased due to elevated pCO2 treatment. P, Ca, Mg, Cu, Zn, Fe, Mn contnets in rice grain remained unaffected while N, K contents declined significantly under elevated pCO2 treatment. Effect of elevated pCO2 on the possible “hidden hunger” in rice grain was also discussed.

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Effects of Supplied P Levels on Plant Growth and Uptake of P and Zn in Different P-Efficiency Rice GUO Zai-hua ,HE Li-yuan ,XU Cai-Guo 2005, 19(4): 355-360 .  Abstract ( )   PDF (177KB) ( )   Four low-P tolerant rice genotypes and two low-P sensitive rice genotypes were used in a pot culture experiment with four supplied P levels (P30, 30 mg/kg P; P50, 50 mg/kg P; P100, 100 mg/kg P; P200, 200 mg/kg P).Rice genotypes with different P-efficiency had varietal difference in uptake and use ability of P and Zn. Low-P tolerant rice genotypes 580 and 99011 absorbed more P than the others, and 580 had better uptake ability especially at low-P level such as P50 and P30. Rice genotype 508 could absorb considerable amounts of P, and had the lowest P percentage in shoot, indicating it had good performance in P use efficiency. So these three rice genotypes had larger biomass and less response to changed P level than 99112, 99056 and 99012. Rice genotype 99112 showed low-P tolerance mainly by sacrificing biomass production to keep high relative grain yield. 99056 had the lowest P uptake efficiency, and 99012 had the lowest P use efficiency. Zn contents in shoots of P200, P100 and P50 were similar, but increased significantly at P30. Zn content in shoot of 99112, 99056 and 99012 were higher than those of 508, 99011 and 580, especially at tillering stage and booting stage. As for total Zn in shoot, low-P tolerant rice genotype 580 had the largest amount followed by 99011 and 508, low-P tolerant rice genotype 99012 had the lowest at the three sampling stages followed by 99056. Furthermore, P/Zn in shoot of 99012 was the highest, but that of 99056 was the lowest at the same P level.

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Description of Aphelenchoides besseyi from Abnormal Rice with Small Grains and Erect Panicles in China LIN Mao-song ,DING Xiao-fan ,WANG Zi-ming ,ZHOU Feng-ming ,LIN Na 2005, 19(4): 361-365 .  Abstract ( )   PDF (489KB) ( )   The abnormal rice with small grains and erect panicles were found on a large scale in Jiangsu, China, which showed that the length of rice panicle was shortened and number of grains was decreased in comparison with normal rice, and grains were small and black-brown, moreover, some of them were unfilled, while flag leaf was normal. A kind of nematode of Aphelenchoides was isolated from the rice variety Wuyujing 3 with small grains and erect panicles. There were 2014 nematodes in one hundred grains infected, and up to 74 in a single grain, 92 percent of the grains tested had nematodes in the infested panicles. The diagnosis characters of nematode included that lateral fields was about one-fourth as wide as body, with four incisures. The terminus bore a mucro of diverse shape with 3-4 pointed processes. The female post-vulval uterine sac extends less than 50% of distance from vulva to anus, no sperm in it. Oocytes usually arranged in 2-4 rows. The male spicules has a middle rostrum. Morphological character and measurements showed that it might be conspecific with Aphelenchoides besseyi Christie, 1942.

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Geostatistical Analysis on the Temporal Patterns of the Yellow Rice Borer, Tryporyza incertulas YUAN Zhe-ming ,ZHANG Zhong-fei ,HU Xiang-yue 2005, 19(4): 366-370 .  Abstract ( )   PDF (114KB) ( )   In order to comprehend temporal pattern of the larvae population of the yellow rice borer, Tryporyza incertulas, and provide valuable information for its forecast, the data series of the population for each generation and the over-(wintering) larvae from 1960 to 1990 in Dingcheng District, Changde City, Hunan Province, were analyzed by geostatistics. The data series of total number, the 1st generation, the 3rd generation and the over-wintering larvae year to year displayed rather better autocorrelation and prediction. The data series of generation to generation, the 2nd generation and the 4th (generation) year to year, however, demonstrated poor autocorrelation, especially for the 4th generation, with degree of (autocorrelation) being zero. The population dynamics of the yellow rice borer was obviously intermittent. A remarkable cycle of four generations in one year was observed in the population of generation to generation. Omitting the certain generation or (interposing) the over-wintering larvae in analysis of population dynamics only resulted in a less or slight change in (autocorrelation) of the whole data series of generation to generation. Crop system, food, climate and nature enemies, therefore, played more important roles in regulating the population dynamics than base number of the larvae. The basic (techniques) of geostatistics applied in analyzing temporal population dynamics were outlined.

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Compound Basis of Bensulfuron-Methyl and Quinclorac and Prospect of Its Application in Direct-Seeded Paddy LU Yong-liang ,ZHOU Yong-jun ,ZHAO Hang ,YU Liu-qing 2005, 19(4): 371-376 .  Abstract ( )   PDF (109KB) ( )   The bio-activity of barnyardgrass, co-toxicity coefficient, compound basis, rice safety, and the effect of weed control in direct-seeded rice field treated with the compound of bensulfuron-methyl and quinclorac were studied. The compounds of bensulfuron-methyl and quinclorac for weed control were more effective compared with bensulfuron-methyl or quindorac individually, especially when the compound rate was 2 percent of bensulfuron-methyl and 34 percent of quinclorac. The six different rates of compounds had no influence on rice plant height, number of tillers or plant fresh weight. When the bensulfuron-methyl and quinclorac were used at the rates of (18+150) g/hm2 (in the active ingredient) to (24+198) g/hm2, they had a marked effect on controlling the weed density and plant fresh weight for 4 kinds of weeds. The compound of 36% wettable powder applied at 2- to 3- leaf stage in direct-seeded rice field, with the dosages of 162-270 g/hm2 was safe to rice. The dosages of 216-432 g/hm2 had a remarkable effect on 5 kinds of weeds. When the compound was applied in the direct-seeded paddy, the kinds of weeds controlled were increased and the control effect was improved.

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Effects of Temperature During Grain Filling Period on Activities of Key Enzymes for Starch Synthesis and Rice Grain Quality JIN Zheng-xun ,YANG Jing ,QIAN Chun-rong ,LIU Hai-ying ,JIN Xue-yong ,QIU Tai-quan 2005, 19(4): 377-380 .  Abstract ( )   PDF (109KB) ( )   Three japonica rice varieties with different eating and cooking quality were investigated under high temperature conditions in greenhouse and natural conditions to reveal the effects of temperature during the grain filling on the activities of the key enzymes for starch synthesis and quality of eating and cooking of rice. Under the conditions of higher temperatures(mean temperature 24.5℃) during grain filling, protein content in rice grain increased and amylose content and taste meter value decreased. Inferior quality varieties were higher in degree of increasing protein or decreasing amylose than supperior quality ones. Reaction in RVA properties to temperature during grain filling varied with rice varieties and RVA indexes. Activities of ADPG pyrophosphorylase, soluble starch synthase and starch branching enzymes increased first and then fell down. Different varieties had different enzyme activities at the same filling stage and differed in the time when enzyme activity reached a peak value. Activities of ADPG pyrophosphorylase and soluble starch synthase responsed dully to the temperature but starch branching enzyme was more sensitive to the temperature and its activity declined when temperature was too high or too low. High temperature is propitious to enhancing the activities of ADPG pyrophosphorylase and soluble starch synthetic enzyme.

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Effects of Chilling Stress on Photosynthetic Rate and the Parameters of Chlorophyll Fluorescence in Two Rice Varieties Differing in Sensitivity WANG Guo-li ,GUO Zhen-fei 2005, 19(4): 381-383 .  Abstract ( )   PDF (103KB) ( )   A chilling-tolerant variety, Xiangnuo 1, and a chilling-susceptible variety, IR50, were used to study the influences of chilling on the photosynthesis rate and chlorophyll fluorescence parameters in rice seedlings. The photosynthetic rate of the seedlings of the two rice varieties decreased dramatically during chilling. Photosynthetic rate decreased by 48.7% and 67.5% in Xiangnuo 1 and IR50, respectively, after they were subject to chilling stress for 2 days. Chlorophyll fluorescence measurements showed that less accumulation of redundant excitation energy in the reaction centers did less harm to the centers and the antenna systems in Xiangnuo 1 under chilling stress. Accordingly, higher qP and qN in Xiangnuo 1 were used to dissipate the redundant excitation energy and protect the reaction centers from chilling injury. However, in chilling-susceptible variety, IR50, qP and qN declined rapidly, while Ex increased as the chilling stress persisted. It indicated that the reaction centers and antenna systems in IR50 were damaged severely under chilling stress, which led to the lower photosynthetic rate.

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Preliminary Studies on Rice Blast Control by Defence-Inoculation with Barnyardgrass (Echinochloa spp.) Pathogenic Fungi Huang Shi-wen ,LU Ji-ying ,ZHAO Hang ,DUAN Gui-fang ,TAN Zhou-jin ,LUO Kuan 2005, 19(4): 384-386 .  Abstract ( )   PDF (90KB) ( )   In artificial intelligentized incubator, rice seedlings of Yuanfengzao, the susceptible cultivar to rice blast (Magnaporthe grisea), were defensively inoculated with 106-108/m2 conidia suspension dosage of barnyardgrass (Echinochloa spp.) pathogens Alternaria alternata, Curvularia lunata, Helminthosporium gramineum sp. Echinochloae and Exserohilum monoceras. Challenge inoculations with strong pathogenic races Zhong A1 and Zhong B1 of Magnaporthe grisea were carried out at intervals of 1, 2, 3, 5 and 7 days after defence-inoculation. The lesions on rice leaves of defence-inoculation plants were decreased, and the control efficacy to rice blast was significantly increased compared to the control treatment of spraying 002% Tween 20. Reduced rate of lesions ranged from 35.59% to 80.00%, and the control efficacy ranged from 53.08% to 81.56%. No negative effect on rice seedlings was observed after defence-inoculation with barnyardgrass pathogenic fungi.