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1.
An increasing number ofmonopartite begomoviruses are being identified that a satellite molecule (DNAβ) is required to induce typical symptoms in host plants. DNAβ encodes a single gene (termed βCl) encoded in the complementary-sense. We have produced transgenic Nieotiana benthamiana and N. tabaeum plants expressing the βC1 gene of a DNAβ associated with Tomato yellow leaf curl China virus (TYLCCNV), under the control of the Cauliflower mosaic virus 35S promoter. Transgenic plants expressing 13C1 showed severe developmental abnormalities in both species. Microscopic analysis of sections of both transgenic and non-transgenic N. tabaeum leaves showed abnormal outgrowths of transgenic N. tabaeum to be due to disorganizedcell division (hyperplasia) of spongy and palisade parenchyma. Immuno-gold labeling of sections with a polyclonal antibody against the βC1 protein showed that the 13C 1 protein accumulated in the nuclei of cells. The possible biological function of the βC1 1protein was discussed.  相似文献   

2.
Tomato yellow leaf curl virus (TYLCV), belonging to the genus Begomovirus of the family Geminiviridae, is emerging as the most destructive pathogen of tomato plants. Since the first report of TYLCV in Shanghai, China in 2006, TYLCV has spread rapidly to 13 provinces or autonomous regions of China. In this study, the molecular variability and evolution of TYLCV were monitored in Shanghai from its first upsurge in 2006 until 2010. Full-length genomic sequences of 26 isolates were obtained by rolling circle amplification. Sequence analysis showed that the intergenic region was the most variable, with a mean mutation rate of 4.81×10?3 nucleotide substitutions per site per year. Genetic differentiation was found within isolates obtained from 2006, 2009, and 2010, though a linear increase in genetic diversity over time was not evident. Whilst significant parts of TYLCV genes were under negative selection, the C4 gene embedded entirely within the C1 gene had a tendency to undergo positive selection. Our results indicate that a mechanism of independent evolution of overlapping regions could apply to the natural population of TYLCV in Shanghai, China.  相似文献   

3.
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4.
The ecological effects of plant-virus-vector interactions on invasion of alien plant viral vectors have been rarely investigated. We examined the transmission of Tomato yellow leaf curl China virus (TYLCCNV) by the invasive Q biotype and the indigenous ZHJ2 biotype of the whitefly Bemisia tabaci, a plant viral vector, as well as the influence of TYLCCNV-infection of plants on the performance of the two whitefly biotypes. Both whitefly biotypes were able to acquire viruses from infected plants and retained t...  相似文献   

5.
A field experiment was conducted to study the response of individual leaf spectral reflectance to five levels of nitrogen fertilizer treatments in rice (Oriza sativa L.) plants. Sampling was combined through a rice canopy at upper, medium and low levels for biomass, nitrogen and water content measurements with spectral signals from the leaves. The vertical gradients of leaf biomass, nitrogen and water contents were associated with the nitrogen availability during tillering, panicle formation, initial heading and heading. Rice plants treated with the lowest rate of N could be characterized with the lowest value of gradient in leaf biomass and leaf water content and the highest value of gradient in leaf N concentration. A spectral gradient of single reflectance (R), ratio (RVI) and normalized difference (ND) of two individual reflectances was defined as this yielded a better relationship between the spectral data and leaf nitrogen concentration. The results suggested the spectral gradients may be used as an improved diagnostic tool for nitrogen status. Project (49771056) supported by Natural Science Foundation of China(NSFC).  相似文献   

6.
INTRODUCTION In recent years poinsettia cultivation has blos-somed from a small garden business into a multimil-lion-dollar industry in China. Some fungal diseases, such as Rhizoctonia stem and root rot, Pythium root rot, Fusarium wilt, and Botrytis blight have been reported to cause considerable damage during propagation (Sun et al., 2003). A new bacterial dis-ease characterized by leaf spot appearance was first observed on poinsettia in October 2003, in the Xiaoshan district of Zhej…  相似文献   

7.
In October 2003, a new bacterial disease with symptoms similar to those caused by Xanthomonas axonopodis pv.poinsettiicola was observed on poinsettia leaves at a flower nursery in Zhejiang Province of China. Three Xanthomonas strains were isolated from infected plants and classified as X. axonopodis. They were differentiated from the pathotype strain LMG849 of X. axonopodis pv. poinsettiicola causing bacterial leaf spot of poinsettia by comparison of pathogenicity, substrate utilization and BOX-PCR genomic fingerprints.  相似文献   

8.
The main objective of this work was to compare the applicability of the single leaf (the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio (mSR705 index) and the leaf positional difference in the vegetation index between L1 and L3 (mSR705L1-mSR705L3) in detecting nitrogen (N)-overfertilized rice plants. A field experiment consisting of three rice genotypes and five N fertilization levels (0, 75, 180, 285, and 390 kg N/ha) was conducted at Xiaoshan, Hangzhou, Zhejiang Province, China in 2008. The hyperspectral reflectance (350–2500 nm) and the chlorophyll concentration (ChlC) of L1 and L3 were measured at different stages. The mSR705L1 and mSR705L3 indices appeared not to be highly sensitive to the N rates, especially when the N rate was high (above 180 kg N/ha). The mean mSR705L1-mSR705L3 across the genotypes increased significantly (P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages. Also, use of the difference (mSR705L1-mSR705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with reflectance data. The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR705 index.  相似文献   

9.
ＩＮＴＲＯＤＵＣＴＩＯＮＶｉｓｉｂｌｅａｎｄｎｅａｒｉｎｆｒａｒｅｄｒｅｆｌｅｃｔｉｏｎｓｐｅｃｔｒｏｓ ｃｏｐｙｗａｓｐｒｏｖｅｄｉｎｒｅｃｅｎｔｙｅａｒｓｔｏｏｆｆｅｒｔｈｅｐｏｓ ｓｉｂｉｌｉｔｙｏｆｏｂｔａｉｎｉｎｇａｒａｐｉｄ ,ｎｏｎ ｄｅｓｔｒｕｃｔｉｖｅｅｓｔｉ ｍａｔｉｏｎｏｆｐｌａｎｔｎｉｔｒｏｇｅｎｃｏｎｔｅｎｔｓ(Ｔｈｏｍａｓｅｔａｌ.,1 972 ;Ｈｉｎｚｍａｎｅｔａｌ.,1 986;Ｔａｋｅｂｅｅｔａｌ.,1 990 ;Ｆｉｌｅｌｌａｅｔａｌ.,1 995;Ｂｌａｃｋｍｅｒｅｔａｌ.,1 994 ,1 996;Ｌａｄｈａ…  相似文献   

10.
Genome segments S8 of two Chinese isolates of rice black-streaked dwarf virus (RBSDV), one from Zhejiang Province and another from Hebei Province, were amplified by RT-PCR and sequenced. Both segments consisted of 1936 nts in full length (EMBL accession numbers were AJ297431 and AJ297432, respectively) and contained only one big open reading frame which encoded a polypeptide with molecular weight of 68kD. The two Chinese isolates shared 94.0% and 96.5% identity at nucleotide and amino acid level, respectively. They shared 94.5-94.9% and 92.5-92.9% homology with S8 of RBSDV Japanese isolate at nucleotide and amino acid level, respectively; shared 85.1-87.6% and 91.7-91.9% homology with S7 of Italian MRDV (maize rough dwarf virus).  相似文献   

11.
Microbial diversity of sediments from the northern slope of the South China Sea was studied by constructing bacterial and archaeal 16S rRNA gene clone libraries. Fourteen bacterial phylogenetic groups were detected, including Gammaproteo-bacteria, Deltaproteobacteria, Planctomycetes, Alphaproteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Chloroflexi, Acidobacteria, Betaproteobacteria, Nitrospirae, candidate divisions OP8 and OP11, and an unknown group. Gammaproteobacteria was the predominant group in bacterial libraries with the percentage ranging from 31.8% to 63.2%. However, archaeal libraries had relatively lower diversity, with most clones belonging to marine archaeal group I uncultured Crenarchaeota. In addition, two novel euryarchaeal clones were detected not to match any culture-dependent or -independent isolates. Compared with other gas hydrate-rich ecosystems and different areas of the South China Sea, a distinct microbial community was revealed in this study.  相似文献   

12.
In this study, we investigated the molecular phylogeny of 64 clinical isolates which were identified as Sporothrix schenckii sensu lato by morphological identification. All of the strains were isolates from patients from several provinces in China. The phylogeny was inferred by DNA sequence analyses based on datasets of the ribo- somal internal transcribed spacer （ITS） and a combined ITS and partial 13-tubulin region. Reference sequences were retrieved from GenBank. Results showed that all of the isolates were clustered in a distinct clade with a type of Spo- rothrix globosa. Our analysis showed that S. globosa is the causal agent of the tested sporotrichosis in China, rather than S. schenckii that was generally believed to be the case. The existence of S. schenckii in China remains to be confirmed. This study improved our understanding of the distribution of the species in S. schenckii complex.  相似文献   

13.
Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols.  相似文献   

14.
A rice pse(t) (premature senescence, tentatively) mutant line, was isolated from 4500 independent T-DNA inserted transgenic lines. The symptoms of premature senescence appeared more severely than those of the control plants (Zhonghua 11,japonica) at the last development stage. To characterize the mutant and provide basic information on the candidate genes by mapping to a physical region of 220-kb, experiments were carried out in two phytotrons under controlled temperature of 24 ℃ and28 ℃, respectively. The content of chlorophyll, soluble protein and MDA (malondialdehyde), net photosynthesis, the antioxidant enzyme activities of SOD (superoxide dismuase) (EC 1.15.1.1) and POD (peroxidase) (EC 1.11.1.7) and the peptidase activities of leaves were measured from top to bottom according to the leaf positions at the flowering stage. Compared with the control plant,the mutant showed the following characteristics: (1) Higher net photosynthesis rate (Pn) appeared in the 1 st and 2nd leaves, contents of chlorophyll and soluble protein were also higher in the 1 st leaf; (2) The activities of SOD, POD and peptidase were higher according to the leaf position from top to bottom; (3) The symptom of premature senescence was accelerated in the mutant at 28℃treatment. The MDA content and the SOD and POD activities between the 24 ℃ and 28 ℃ treatment mutants were not significantly different. Content of chlorophyll and soluble protein of leaves mutant decreased rapidly at 28 ℃ treatment. The results show that pse(t) is sensitive to high temperature. The probable function of PSE(T) is discussed.  相似文献   

15.
Rice stripe virus (RSV) is the type member of the genus Tenuivirus. RSV is known to have four segmented, single-stranded RNA molecules and causes rice stripe disease in the rice fields of China, Japan, and Korea. Based on the complete genomic sequences of the determined 6 RSV isolates (from Yunnan, Jiangsu, Zhejiang, and Liaoning Provinces, China) and 27 other RSV isolates (from Yunnan, Jiangsu, Anhui, Henan, and Shandong Provinces of China, also Japan and Korea) downloaded from GenBank, we provided a genotyping profile of RSV field isolates and described the population structure of RSV. All RSV isolates, except isolate CX, could be divided into two subtypes, one including 6 isolates from Yunnan Province, and the other including 26 isolates from different parts of China, Japan, and Korea, which were referred to as subtype II and subtype I, respectively. The amino acid distances between subtypes range from 0.053 to 0.085. RSV isolates in Yunnan Province were genetically differentiated from other parts of China, Japan, and Korea and showed infrequent gene flow. The RSV populations collected from other parts of China, Japan, and Korea were only composed of subtype I and showed very low genetic diversity. We speculated that isolate CX may be the result of recombination of isolates from two subtypes. Two potential recombination events were detected in RNA4 of isolate CX.  相似文献   

16.
Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China,efficiency of chloramines as a coagulant aid in enhancing coagulation was investigated by Jar stirring and pilot-scale tests,using Yellow River water containing high concentration of natural organic matters (NOM) and bromide in winter. The jar tests results showed that,compared with no preoxidation,preformed chloramine apparently decreased the turbidity of settled and filtered water with low dosage (2.0 mg/L),and the aid-coagulation efficiency was further enhanced with the increase of chlorine (Cl2) to Ammonia-N (N) ratio. Pilot-scale studies indicated that,in comparison to the case without pre-oxidation,the turbidity removal efficiency of flotation and filtration effluent water was significantly improved,the particle counts of filtered water were decreased 63.4%,the average rate of filter head loss was reduced 18.2%,and filter run time was prolonged 15.7%. Therefore,chloramine preoxidation may substantially enhance the particle separation efficiency.  相似文献   

17.
Strawberry anthracnose, caused by Colletotrichum spp., is a major disease of cultivated strawberry. This study identifies 31 isolates of Colletotrichum spp. which cause strawberry anthracnose in Zhejiang Province and Shanghai City, China. Eleven isolates were identified as C. acutatum, 10 as C. gloeosporioides and 10 as C. fragariae based on morphological characteristics, phylogenetic and sequence analyses. Species-specific polymerase chain reaction (PCR) and enzyme digestion further confirmed the identific...  相似文献   

18.
以农大108玉米为材料，在苗期进行缺氯处理，结果如下：（1）叶片长度在处理后第5天出现明显差异，处理组叶长低于对照组，仅为对照组的66．67％；（2）对照与处理组间叶绿素含量从第6天开始出现显著差异；（3）处理组叶片蛋白质含量在处理后第5天明显低于对照组；（4）叶片硝酸还原酶活性在处理的第4天明显低于对照组，并始终低于对照组水平．综合利用上述指标可以在出苗后4-6d时间内对缺氮玉米幼苗做出比较准确的诊断．  相似文献   

19.
采用干法灰化处理植物体样品,湿法处理土壤样品.用火焰原子吸收法测定香附子与大香附中Mg、Cr、Mn、Fe、Ni、Cu、Pb等7种微量元素的含量.结果显示：香附中各元素的总体含Mg＞ Fe＞ Ni＞ Mn＞Cu＞ Pb＞Cr,大香附Mg＞Fe＞ Mn＞ Ni＞Cu＞ Pb＞Cr.两种植物对Mg外的6种元素的富集系数都小于1.同种元素在同一植株中不同部位的含量不同.香附中：Mg元素叶＞根＞茎;Fe、Cr、Ni、Pb四种元素含量根＞叶＞茎;Cu、Mn是叶＞茎＞根.大香附中：Mg元素叶＞根＞茎;Cr、Mn、Ni三元素含量根＞茎＞叶;Fe根＞叶＞茎;Cu、Pb的含量茎＞根＞叶.两种草药的Cr、Pb含量均超过2000年的《中国药典（一部）》标准.  相似文献   

20.
For a long time, classification of Demodex mites has been based mainly on their hosts and phenotypic characteristics. A new subspecies of Demodex folliculorum has been proposed, but not confirmed. Here, cox1 partial sequences of nine isolates of three Demodex species from two geographical sources (China and Spain) were studied to conduct molecular identification of D. folliculorum. Sequencing showed that the mitochondrial cox1 fragments of five D. folliculorum isolates from the facial skin of Chinese individuals were 429 bp long and that their sequence identity was 97.4%. The average sequence divergence was 1.24% among the five Chinese isolates, 0.94% between the two geographical isolate groups (China (5) and Spain (1)), and 2.15% between the two facial tissue sources (facial skin (6) and eyelids (1)). The genetic distance and rate of third-position nucleotide transition/transversion were 0.0125, 2.7 (3/1) among the five Chinese isolates, 0.0094, 3.1 (3/1) between the two geographical isolate groups, and 0.0217, 4.4 (3/1) between the two facial tissue sources. Phylogenetic trees showed that D. folliculorum from the two geographical isolate groups did not form sister clades, while those from different facial tissue sources did. According to the molecular characteristics, it appears that subspecies differentiation might not have occurred and that D. folliculorum isolates from the two geographical sources are of the same population. However, population differentiation might be occurring between isolates from facial skin and eyelids.  相似文献   

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