Dynamic Development of Aphelenchoides besseyi on Rice Plant by Artificial Inoculation in the Greenhouse

A study was done on the relationship between Aphelenchoides besseyi and the symptoms of small grains and erect panicles. This is an important rice disease in Jiangsu Province, China. A. besseyi was extracted from small grains and erect panicles and cultured artificially, and then inoculated into bud and leaf sheaths of seedlings of two Oryza sativa cultivars, namely Zhendao 2 and Wuyunjing 7 in a greenhouse. The effect on rice growth, in particular the small grains and erect panicles, was revealed by the extent of the disease, seed expansion stages, nematode load, and nematode mortality. In contrast to healthy seedlings, the height, length, and the numbers of spikelets of unhealthy panicles of Zhendao 2 were decreased by 6.7, 16.4, and 13.5%, respectively. Before anthesis, nematodes were attracted to the leaf sheath and apical meristem, nematode load increased by 40%; after anthesis, nematodes occurred in spikelets principally and the number increased by 90.8%. The percentages of infected seeds and nematode load were highest in plump seeds and lowest in empty seeds. Nematode mortality on grain with normal endosperm was lower than seeds with abnormal endosperm. Results indicated that A. besseyi was the pathogen in rice with the symptoms of small grains and erect panicles. Wuyunjing 7 manifests only the small grains and erect panicles symptoms and not the symptoms of leaf white-tip. These symptoms of small grains and erect panicles are new symptom records for the disease caused by A. besseyi on rice.

Protection and Utilization of Special Biological Resources and Biodiversity in Pu＇er City

In the paper, the animal and plant diversity and its main characteristics in Pu'er City were summarized, and reviewedthe development and utilization of main special biological industry. The policies and research institutions on protection and utilization of biodiversity in Pu'er City were introduced. At the last, we analyzed the deficiencies in the conservation and utilization of biodiversity in Pu'er City and proposed the relevant measures to strengthen protection and utilization of biological diversity in the future.

Toxic and Antifeedant Effects of Different Pesticidal Plant Extracts against Beet Armyworm (Spodoptera exigua)

The beet armyworm(BAW),Spodoptera exigua(Lepidoptera:Noctuidae)is a highly destructive pest of vegetables and field crops.Management of beet armyworm primarily relies on synthetic pesticides,which is threatening the beneficial community and environment.Most importantly,the BAW developed resistance to synthetic pesticides with making it difficult to manage.Therefore,alternative and environment-friendly pest management tactics are urgently required.The use of pesticidal plant extracts provides an effective way for a sustainable pest management program.To evaluate the use of pesticidal plant extracts against BAW,we selected six plant species(Lantana camara,Aloe vera,Azadirachta indica,Cymbopogon citratus,Nicotiana tabacum,and Ocimum basilicum)for initial screening experiment.Four out of six plant species such as A.indica,N.tabacum,C.citratus and O.basilicum showed promising mortality of more than 50%.Therefore,we selected these four plant extracts for the subsequent experiments.Through contact bioassay,A.indica showed high mortality 66.63%,followed by the N.tabacum 53.33%,at 10%w/v concentration.Similarly,N.tabacum showed the highest mortality rate,66%at 10%w/v concentration,followed by the A.indica 46%through feeding bioassay.Furthermore,the feeding deterrence assay showed that C.citratus had a high antifeedant index(−50)followed by A.indica(−39),and N.tabacum(−28).In living plant assay,the N.tabacum extract showed a low mean damage score 3.6 on living cotton plant followed by C.citratus 4.5 and A.indica 5.5.Hence,extracts of three plant species provided promising results against the BAW,which can minimize the use of synthetic chemicals,particularly for small landholding farmers.Further studies are also required to evaluate the effects of these plant extract against BAW on cotton plants under field conditions to optimize the further use.

AcWRKY28 mediated activation of AcCPK genes confers salt tolerance in pineapple(Ananas comosus)

Unfavorable environmental cues severely affect crop productivity resulting in significant economic losses to farmers. In plants, multiple regulatory genes, such as the WRKY transcription factor (TF) family, modulate the expression of defense genes. However, the role of the pineapple WRKY genes is poorly understood. Here, we studied the pineapple WRKY gene, AcWRKY28, by generating AcWRKY28 over-expressing transgenic pineapple plants. Overexpression of AcWRKY28 enhanced the salt stress resistance in transgenic pineapple lines. Comparative transcriptome analysis of transgenic and wild-type pineapple plants showed that “plant-pathogen interaction” pathway genes, including 9calcium-dependent protein kinases (CPKs), were up-regulated in AcWRKY28 over-expressing plants. Furthermore, chromatin immunoprecipitation and yeast one-hybrid assays revealed AcCPK12, AcCPK3, AcCPK8, AcCPK1, and AcCPK15 as direct targets of AcWRKY28. Consistently, the study of AcCPK12 over-expressing Arabidopsis lines showed that AcCPK12 enhances salt, drought, and disease resistance. This study shows that AcWRKY28 plays a crucial role in promoting salt stress resistance by activating the expression of AcCPK genes.

Influence of Long-Term Fixed Fertilization on Diversity of Arbuscular Mycorrhizal Fungi

Diversity of arbuscular mycorrhizal fungi(AMF) was investigated in a field that had received long-term fixed ferti-lization(LFF) for 26 years.There were a total of 12 treatments in triplicates with different amounts of manure,urea,calcium phosphate,and potassium chloride.Rhizosphere soil samples of maize and wheat grown in the experimental field in Shandong Province,China,were collected in September 2003 and May 2004,respectively.Arbuscular mycorrhizal fungal spores were isolated and identified using morphological characters.Mycorrhizal colonization percentage,spore density(SD),species richness(SR),relative abundance(RA),and Shannon-Weiner index(SWI) were determined.Nineteen recognized species of AMF belonging to 5 genera were identified.Long-term fixed fertilization significantly influenced colonization percentage,SR,SD,and species diversity of AMF.The adaptability of AMF to soil fertility was different among species.Species richness and SD of AMF in maize and wheat rhizosphere soils were the highest in the nonferti-lization treatment(control) and lowest in the high manure + high nitrogen treatment(M2N2).The SWI decreased as the fertilization level increased except in the low manure treatment(M1) on maize.Compared with the other treatments,Treatment M2N2 significantly reduced SD of Glomus,and the high manure + low nitrogen treatment(M2N1) significantly retarded sporulation of Scutellospora.Manure treatments stimulated sporulation of Glomus mosseae.Spore density of G.mosseae was higher in the high nitrogen + phosphorus + potassium treatment(N2PK) than in the high nitrogen + phosphorus treatment(N2P) and the high nitrogen + potassium treatment(N2K).The SD of S.pellucida was higher in Treatment N2K than Treatments N2PK and N2P.In conclusion,long-term fixed fertilization,especially with high levels of manure and N,decreased SR,SD,and colonization and changed the species composition of AMF.

Degradation of chlorpyrifos alone and in combination with chlorothalonil and their effects on soil microbial populations

In practice, pesticides are usually applied simultaneously or one after another for crop protection, and this type of pesticide application often leads to a combined contamination of pesticide residues in the soil environment. A laboratory study was conducted to investigate the influence of chlorothalonil on chlorpyrifos degradation and its effects on soil bacterial, fungal, and actinomycete populations. Under the experimental conditions here, the half-lives of chlorpyrifos alone, and in combination with chlorothalonil, at the recommended and double dosages, were measured to be 3.24, 2.77, and 2.63 d, respectively. Chlorpyrifos degradation was not significantly altered by its combination with chlorothalonil. However, the inhibitory effect of chlorpyrifos on soil microorganisms was increased by its combination with chlorothalonil, and the increase was related to the levels of chlorothalonil added. Compared to those in the controls, the populations of bacteria, fungi, and actinomycetes were significantly reduced by 44.1%, 61.1%, and 72.8%, respectively, on the first day after treatment （DAT） by chlorpyrifos alone. With the addition of chlorothalonil, the inhibition was increased to 55.2%, 79.3%, and 85,8% at the recommended dosage, and 86.0%, 94.1%, and 90.8% at the double dosage, at one DAT, respectively. The results suggested that combined effects should be taken into account to assess the actual impacts of pesticide applications.

Effects of Temperature,Humidity and Different Rice Growth Stages on Vertical Migration of Aphelenchoides besseyi

The vertical migration of Aphelenchoides besseyi under different temperatures and humidities and at different rice growth stages was investigated. It was found that the optimum temperature for the development and reproduction of A. besseyiwas 25-30℃. At the same temperature, the rate of vertical migration increased with rising relative humidity. Artificial inoculation tests showed that at the elongation stage, nematodes survived mainly on the upper and middle parts of rice culms and the number of nematodes decreased by 50% at 20 days after inoculation compared with that at 5 days after inoculation. Whereas at the booting stage, nematodes accumulated in young panicles and reproduced quickly,, and the average number of nematodes at 20 days after inoculation increased to 164.5, three times of that at 5 days after inoculation.

First report of Athelia bombacina causing postharvest fruit rot on pear

Pear is an important fruit crop in the world. An uncharacterized disease has been observed on pear fruits during cold storage ir~ Suning, Shenzhou, Xinji and other locations in Hebei Province, China. The incidence rate of the disease has reached 10%, and sometimes up to 20%. A particular fungus was consistently isolated from the infected pear fruit and cultured. Based on its morphology, molecular characteristics, pathogenicity and ITS sequence, the fungus was identified as Athelia bombacina. To our knowledge, this is the first report of Athelia bombacina causing postharvest fruit rot on pear.

Description of Aphelenchoides besseyi from Abnormal Rice with ‘Small Grains and Erect Panicles’ Symptom in China

The abnormal rice with small grains and erect panicles were found on a large scale in China, which showed shortend rice panicle and decreased number of grains in comparison with normal rice, and the grain was small and black-brown, and some of them were distorted, while the flag leaf was normal. A kind of nematode of Aphelenchoides was isolated from the grains of rice variety Wuyujing 3 which performed ＇small grains and erect panicles＇ symptom. There were 2014 nematodes in one hundred grains infected, and up to 74 in single grain, 92 percent of the grains tested had nematodes in the infested panicles. The diagnosis characters of nematode include lateral fields about one-fourth as wide as body, with 4 incisures. The terminus bears 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 arrange in 2-4 rows. The male spicules have a moderately developed rostrum. Morphological measurements showed it to be conspecific with Aphelenchoides besseyi Christie, 1942.

Effects of Pesticide Applications on the Biochemical Properties of Transgenic cry 2A Rice and the Life History Parameters of Nilaparvata lugens Stl (Homptera: Delphacidae)

Effects of transgenic Bt rice on non-target pests following pesticide applications plays an important role in evaluating the ecological safety of transgenic rice. Changes of the life history parameters of laboratory population of Nilaparvata lugens feeding on transgenic Bt rice T2A-1 and its parental line cv. MH63 as the control, and the contents of oxalic acid and soluble sugar following three pesticides （triazophos, jinggangmycin and chlorantraniliprole） treatments were investigated in this paper. Results showed that the population parameters of N. lugens and the physiological and biochemical parameters of rice did not differ significantly between T2A-1 and MH63 without pesticide application. But, the emergence rate （ER）, the nymphal number of next generation （NN）, and the index of population trend （IP） on T2A-1 treated with 10 mg L^-1 of triazophos were significantly higher than those on MH63, respectively, while the hatchability （HB） on T2A-1 treated with the three pesticides were obviously lower than those on MH 63. Furthermore, the content of oxalic acid in MH63 treated with 20 mg L-1 triazophos and, 40 and 80 mg L-1 chlorantraniliprole was significantly higher than that in T2A-1, while the content of soluble sugar in T2A-1 treated with 400 mg L-1 jinggangmycin was significantly higher than that in MH63. The results above indicated that triazophos in a low dose could cause a more favor of T2A-1 to population growth of N. lugens compared with MH 63.

Degradation of chlorpyrifos in laboratory soil and its impact on soil microbial functional diversity

Degradation of chlorpyrifos at different concentrations in soil and its impact on soil microbial functional diversity were investigated under laboratory condition. The degradation half-live of chlorpyrifos at levels of 4, 8, and 12 mg/kg in soil were calculated to be 14.3, 16.7, and 18.0 d, respectively. The Biolog study showed that the average well color development （AWCD） in soils was significantly （P 〈 0.05） inhibited by chlorpyrifos within the first two weeks and thereafter recovered to a similar level as the control. A similar variation in the diversity indices （Simpson index lID and McIntosh index U） was observed, but no significant difference among the values of the Shannon-Wiener index H＇ was found in chlorpyrifos-treated soils. With an increasing chlorpyrifos concentration, the half-life of chlorpyrifos was significantly （P ≤ 0.05） extended and its inhibitory effect on soil microorganisms was aggravated. It is concluded that chlorpyrifos residues in soil had a temporary or short-term inhibitory effect on soil microbial functional diversity.

Screening of antagonistic Trichoderma strains and their application for controlling stalk rot in maize

Maize is one of the major crops in China, but maize stalk rot occurs nationwide and has become one of the major challenges in maize production in China. In order to find an environment-friendly and feasible technology to control this disease, a Trichoderma-based biocontrol agent was selected. Forty-eight strains with various inhibition activities to Fusarium graminearum, and Fusarium verticillioides were tested. A group of Trichoderma strains(DLY31, SG3403, DLY1303 and GDFS1009) were found to provide an inhibition rate to pathogen growth in vitro of over 70%. These strains also prevented pathogen infection over 65% and promoted the maize seedling growth for the main root in vivo by over 50%. Due to its advantage in antifungal activity against pathogens and promotion activity to maize, Trichoderma asperellum GDSF1009 was selected as the most promising strain of the biocontrol agent in the Trichoderma spectrum. Pot experiments showed that the Trichoderma agent at 2–3 g/pot could achieve the best control of seedling stalk rot and promotion of maize seedling growth. In the field experiments, 8–10 g/hole was able to achieve over 65% control to stalk rot, and yield increased by 2–11%. In the case of natural morbidity, the control efficiency ranged from 27.23 to 48.84%, and the rate of yield increase reached 11.70%, with a dosage of Trichoderma granules at 75 kg ha^-1. Based on these results, we concluded that the Trichoderma agent is a promising biocontrol approach to stalk rot in maize.

Effect of chlorpyrifos on soil microbial populations and enzyme activities

Chlorpyrifos is an organophosphate pesticide that acts as an insecticide-acaricide by ingestion, contact, and inhalation, and is now widely used in greenhouse for the control of pests. The dissipation of chlorpyrifos in crops such as orange fruit （Martinez-Vidal et al., 1998）, tomatoes（Aysal et al., 1999）, soil and its effects on soil microbial characteristics （Singh et al., 2002） has been reported frequently. However, little information is available to describe impacts of chlorpyrifos on soil microbial population and enzyme activity in greenhouse. In this study, the effect of chlorpyrifos on soil bacteria, fungi, actinomycetes, and soil enzyme activity was investigated.

Residual dynamics of thiacloprid in medical herbs marjoram,thyme,and camomile in soil

Thiacloprid is a new insecticide of the chloronicotinyl family. To assess its risk after application, residual characteristics of thiacloprid in marjoram, thyme, and camomile and in soil were studied under field conditions. The active ingredient was extracted from the plant material using a mixture of acetone-water. After filtration, the extract was concentrated to the aqueous phase, diluted with water, and portioned against ethyl acetate on a matrix solid phase dispersion column. Thiacloprid was extracted from soil using a mixture of methanol-water, filtered, and re.extracted （clean up） with dichloromethane. The residues were quantified using HPLC-MS-MS. The methods were validated by recovery experiments. Thiacloprid residues in marjoram, thyme, and camomile and in soil persisted beyond 10, 14, 14, and 21 d but no residues were detected after 14, 21, 21, and 28 d, respectively. The data obtained in this study indicated that the biexponential model is more suitable than the first-order function to describe the decline of thiacloprid in fresh marjoram, fresh thyme, and dried camomile flowers with half-life （t1/2） of 1.1, 0.7, and 1.2 d, respectively. However, both the first-order function and biexponential model were found to be applicable for dissipation of thiacloprid in soil with almost the same t1/2 values of 3.5 and 3.6 d. The results indicated that thiacloprid dissipates rapidly and does not accumulate in the tested herbs and in soil.

Generation and Analysis of Pathogenicity-related Gene Mutants of Colletotrichum gloeosporioides Using a Novel Promoter Trapping System

Agrobactedum tumefac/ens-mediated transformation （ATMT） is an efficient tool for insertional mutagenesis and is used in a wide variety of plants. This paper reports a promoter trapping method to generate mutants in the filamentous fungus, Colletotrichum gloeosporioides, by ATMT insertion of a trapping vector （pCAHPH） that carries a promoterless hygromycin phosphotransferase （hph） gone. Transformants were selected on the media containing 200 ~mL hy^omycin B, and screened for pathogenicity-related gene mdtants. Their pathogenicity-related mutants T-DNA flanking sequences were then cloned and analyzed. Hph genes were amplified from mutant genomic DNA but not from wild-type DNA, indicating that the phenotypic alternations of these mutants were the results of T-DNA inser- tion. T-DNA flanking sequences were obtained using modified themud asymmetric interlaced PCR. Two right-sided flanking sequences were highly homologous to proteins from other species.

Molecular Cloning and cDNA Sequence Analysis of Two New Lepidopteran OR83b Orthologue Chemoreceptors

The aim of this study was to isolate the full-length cDNA sequences of an unusually highly conserved olfactory receptor （orthologue to the Drosophila melanogaster DOR83b） from the antennae of Spodoptera exigua and S. litura by using reverse transcription-polymerase chain reaction （RT-PCR） and rapid amplification of cDNA ends （RACE） methods. Bioinformatics methods were used to further analyze the cDNA sequences and putative amino acid sequences. The two full-length cDNA sequences from olfactory receptor （OR） of male S. exigua and S. litura were named as SexiOR2 and SlitOR2, respectively. SexiOR2 and SlitOR2 consisted of nucleotide sequence of 1 906 and 2 483 bp, respectively, and both with deduced amino acid sequences of 473 residues. The sequence analysis indicated that the deduced amino acid sequences of the cDNA shared the high homologies with OR83b orthologue chemoreceptor sequences from previously reported moths, implying that the cDNA sequences were of OR83b orthologue chemoreceptor genes.

Identification and analysis of AP2/ERF gene family in tomato underabiotic stress

AP2/ERE-type transcription factors,as a type of plant-specific transcription factors,play a key role in plant biotic and abiotic stress.Meanwhile,they have been studied in many plants,but rarely in tomatoes.In this study,we performed a genome-wide analysis of the SlAP2/ERF gene family of tomato,and finally identified 29 SlAP2/ERF genes and divided them into different subfamilies.At the same time,its basic physical and chemical properties were analyzed.We also constructed phylogenetic trees with 30 Arabidopsis AP2/ERF proteins and 28 potatoes AP2/ERF proteins to ensure conservative homology between them.In addition,we mapped 29 SlAP2/ERF transcription factors on 10 different chromosomes,and identified 43 responsive plant hormones,responsive light signals,tissue-specific expression and stress response elements from 2000bp upstream of the promoter region,and we analyzed conserved motifs and gene structures of SlAP2/ERF.The tertiary structure of SlAP2/ERF protein was constructed by homology modeling,and the protein-protein interaction network was constructed based on Arabidopsis Thaliana.Finally,the expression pattern of tomato in different tissues was studied by using gene expression database,and the expression level of tomato under abiotic stress was detected by q-RT-PCR.These results provide comprehensive information for further study of the function of the SlAP2/ERF gene family.

茚虫威和六伏隆对小菜蛾卵、幼虫和成虫的药效(英文)

化学防治是世界各地防治小菜蛾Plutella xylostella(L.)的主要方法。选择对小菜蛾各发育阶段高效的杀虫剂有助于很好地控制这一害虫。本研究用浸叶法测定了茚虫威和六伏隆对小菜蛾卵、幼虫和成虫的毒性。茚虫威和六伏隆对小菜蛾卵的LC50值分别为201.40和37.32mg/L。茚虫威和六伏隆对3龄幼虫也有很好的毒性(茚虫威的LC50为4.82mg/L;六伏隆的LC50为1.48mg/L)。对成虫的毒性结果表明,这两种杀虫剂对成虫均没有理想的毒性(茚虫威的LC50为845.20mg/L;六伏隆的LC50为3438mg/L)。根据计算的LC50值,六伏隆对小菜蛾卵和幼虫的毒性比茚虫威高,但是茚虫威对成虫的毒性更高。

Identification and characterization of cDNA sequences encoding the HIS3 and LEU2 genes of the fungus Alternaria tenuissima

Alternaria tenuissima is a fungus widely present in the environment and could cause diseases in plants and humans. In this study, through a yeast genetic approach, cDNA sequences were isolated and characterized for the AtHIS3 and AtLEU2 genes. AtHIS3 cDNA encodes a protein of 238 amino acids, while AtLEU2 cDNA encodes a protein of 363 amino acids. Based on the phylogenetic analysis of amino acid sequences of AtHis3p and AtLeu2p, A. tenuissima is closely related to the plant pathogenic fungus Phaeosphaeria nodorum. This study provides two genetic markers for studies of functions of genes regulating development, morphology, and virulence of A. tenuissima.

Physiological and Molecular Analysis of Applied Nitrogen in Rice Genotypes

Ten genotypes of rice （Oryza sativa L.） were grown for 30 d in complete nutrient solution with 1 mmol/L （N-insufficient）,4 mmol/L （N-moderate） and 10 mmol/L （N-high） nitrogen levels,and nitrogen efficiency （NE） was analyzed.Growth performance,measured in terms of fresh weight,dry weight and lengths of root and shoot,was higher in N-efficient than in N-inefficient rice genotypes at low N level.Of these 10 genotypes,Suraksha was identified as the most N-efficient,while Vivek Dhan the most N-inefficient.To find out the physiological basis of this difference,the nitrate uptake rate of root and the activities of nitrate assimilatory enzymes in leaves of N-efficient and N-inefficient rice genotypes were studied.Uptake experiments revealed the presence of two separate nitrate transporter systems mediating high-and low-affinity nitrate uptake.Interestingly,the nitrate uptake by the roots of Suraksha is mediated by both high-and low-affinity nitrate transporter systems,while that of Vivek Dhan by only low-affinity nitrate transporter system.Study of the activities and expression levels of nitrate assimilatory enzymes in N-efficient and N-inefficient rice genotypes showed that nitrate reductase （NR） and glutamine synthetase （GS） play important roles in N assimilation under low-nitrogen conditions.