The mechanics of oviposition in Rhipicephalus evertsi evertsi Neumann, 1897     

R Gothe  G Nadler 《Berliner und Münchener tier?rztliche Wochenschrift》1987,100(4):109-113

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Use of linear free energy related and other parameters in the study of fungicidal selectivity     

Arie Verloop  Jacobus Tipker 《Pest management science》1976,7(4):379-390

The modulation of fungicidal activity in a congeneric series of compounds is dependent on several processes taking place in the biological object which may be influenced by the different hydrophobic, electronic and steric properties of the members of the series. These possible influences can be studied in a quantitative way with multiple regression analysis using substituent constants for the properties mentioned. The comparative study of the resulting regression equations for the activity on different fungi or on a fungus and another biological subject may contribute to an understanding of fungicidal selectivity. This is illustrated in studies on the fungitoxicity of isophthalonitriles, 2-chlorobenzonitriles, arylsulphonyl- and arylsulphinyl-alkylthio-cyanates, acetylenic sulphones, methyl benzimidazol-2-ylcarbamates and phosphorus compounds derived from 3-amino-1,2,4-triazole. In these studies new steric parameters were used, which have been introduced recently.  相似文献   

Effect of saline irrigation and water deficit on tuber quality   总被引：2，自引：0，他引：2  

A. Nadler  Bruria Heuer 《Potato Research》1995,38(1):119-123

Summary The effect of salinity and water dificit on the quality of tubers for processing was investigated. Total tuber yield was not affected by the treatments, while the percentage of non-marketable tubers was significantly reduced by high salinity (EC_i=6dS m⁻¹) and by water reduction. Accumulation of dry matter in the tubers was increased by all the treatments, that of proline by salinity only and the content of reducing sugars was increased only by water deficit. The colour of the french fries was similar in tubers from the various treatments.  相似文献   

Nucleotide Sequence Variability at the 5′-UTR of Potato PVY Isolates     

Arie Rosner  Ludmila Maslenin 《Potato Research》2006,49(3):217-224

Potato virus Y (PVY) isolates from potato were divided into two major groups – I and II – on the basis of nucleotide sequence variability at the 5′-UTR of the virus genome. In this paper, a consensus sequence for each group was compiled by examining PVY isolates of potato. The consensus sequences of the two groups differed from each other by as much as 31% of nucleotide sequence divergence. However, sequences of most individual members within each group (except for one, the 605 strain) were conserved and varied by less than 1% in group II and up to 6% in group I. These results confirm that the two virus groups are markedly distinct but that the 5′-UTR sequence of individual members within each group is highly conserved. These findings imply that the 5′-UTR can be reliably applied for major grouping of isolates but that its use for discrimination among individual isolates within each group is limited. Isolates of both group I and II included members of the O/N-NTN virus types. Classification of PVY isolates in potato is discussed.  相似文献   

Stolon characteristics and tuber initiation in a wild potato species (Solanum demissum Lindl.)     

Hans Helder  Arie van der Maarl  Dick Vreugdenhil  Paul C. Struik 《Potato Research》1993,36(4):317-326

Summary Solanum demissum Lindl. is a short-day dependent, tuber-bearing species. In vitro propagated genetically identical plants were grown under long-day (16 h) conditions at 20°C day and 15°C night temperatures. Subsequently, from day 0 onwards, plants were exposed to shortday (10 h) conditions and grown in a multi-compartment system that allowed stolon initiation, stolon branching, stolon growth and tuber initiation to be monitored twice weekly. These frequent measurements resulted in detailed life-histories of all 841 stolon tips formed until day 46. Tuber initiation was irregular under these well-defined conditions; at day 46 only 106 stolon tips showed subapical swelling. This irregularity of tuber initiation was also observed within stolons. It is therefore suggested that tuber initiation depends on characteristics of the stolon or stolon branch, and several such characteristics were analyzed to obtain information on their potentially determining role in tuber initiation. No positive correlations were found between subapical swelling and branching order, stolon and stolon-branch age, longitudinal growth rates of stolons and stolon branches, and attachment of the stolon to the main stem.  相似文献   

Involvement of jasmonic acid signalling in bacterial wilt disease resistance induced by biocontrol agent Pythium oligandrum in tomato     

S. Hase  S. Takahashi  S. Takenaka  K. Nakaho  T. Arie  S. Seo  Y. Ohashi  H. Takahashi 《Plant pathology》2008,57(5):870-876

When the biocontrol agent Pythium oligandrum (PO) colonizes the rhizosphere, it suppresses bacterial wilt disease in tomato (Solanum lycopersicum cv. Micro‐Tom) caused by Ralstonia solanacearum, and a homogenate of its mycelia exhibits elicitor activity, inducing an ethylene (ET)‐dependent defence response in Micro‐Tom. Since salicylic acid (SA) and jasmonic acid (JA) play an important role in plant defence responses to pathogens, the involvement of SA‐ and JA‐dependent signal transduction pathways in resistance to R. solanacearum was investigated in tomato roots treated with a mycelial homogenate of PO. Bacterial wilt disease was also suppressed in tomato cv. Moneymaker treated with the PO homogenate. However, the SA‐inducible PR‐1(P6) gene was not up‐regulated in either Micro‐Tom or Moneymaker. SA did not accumulate in homogenate‐treated roots in comparison with distilled water‐treated controls, even 24 h after inoculation. Induced resistance against R. solanacearum was not compromised in SA‐non‐accumulating NahG transgenic plants treated with the PO homogenate. On the other hand, the expression of the JA‐responsive gene for the basic PR‐6 protein was induced in both tomato cultivars treated with the PO homogenate. Furthermore, quantitative disease assays showed that the induced resistance against R. solanacearum was compromized in PO homogenate‐treated jai1‐1 mutant plants defective in JA signalling. These results indicated that the JA‐dependent signalling pathway is required for PO‐induced resistance against R. solanacearum in tomato.  相似文献   

Are herbicide‐resistant crops the answer to controlling Cuscuta?     

Talia Nadler‐Hassar  Dale L Shaner  Scott Nissen  Phill Westra  Baruch Rubin 《Pest management science》2009,65(7):811-816

BACKGROUND: Herbicide‐resistant crop technology could provide new management strategies for the control of parasitic plants. Three herbicide‐resistant oilseed rape (Brassica napus L.) genotypes were used to examine the response of attached Cuscuta campestris Yuncker to glyphosate, imazamox and glufosinate. Cuscata campestris was allowed to establish on all oilseed rape genotypes before herbicides were applied. RESULTS: Unattached seedlings of C. campestris, C. subinclusa Durand & Hilg. and C. gronovii Willd. were resistant to imazamox and glyphosate and sensitive to glufosinate, indicating that resistance initially discovered in C. campestris is universal to all Cuscuta species. Glufosinate applied to C. campestris attached to glufosinate‐resistant oilseed rape had little impact on the parasite, while imazamox completely inhibited C. campestris growth on the imidazolinone‐resistant host. The growth of C. campestris on glyphosate‐resistant host was initially inhibited by glyphosate, but the parasite recovered and resumed growth within 3–4 weeks. CONCLUSION: The ability of C. campestris to recover was related to the quality of interaction between the host and parasite and to the resistance mechanism of the host. The parasite was less likely to recover when it had low compatibility with the host, indicating that parasite‐resistant crops coupled with herbicide resistance could be highly effective in controlling Cuscuta. Published 2009 by John Wiley & Sons, Ltd.  相似文献   

Infection by Magnaporthe oryzae chrysovirus 1 strain A triggers reduced virulence and pathogenic race conversion of its host fungus, <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>     

Mitsuhiro Aihara  Syun-ichi Urayama  Minh Tuong Le  Yu Katoh  Tomoya Higashiura  Toshiyuki Fukuhara  Tsutomu Arie  Tohru Teraoka  Ken Komatsu  Hiromitsu Moriyama 《Journal of General Plant Pathology》2018,84(2):92-103

Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is associated with an impaired growth phenotype of its host fungus, Magnaporthe oryzae. In this report, we assayed the virulence and pathogenicity of MoCV1-A-infected and MoCV1-A-free M. oryzae on rice plants. MoCV1-A infection did not affect virulence-associated fungal traits, such as conidial germination and appressorium formation. However, after punch inoculation of leaves on rice plants, MoCV1-A-infected strain formed smaller lesions than the MoCV1-A-free strain did on all rice varieties tested, showing that MoCV1-A infection resulted in reduced virulence of host fungi in rice plants. In contrast, after spray inoculation of rice seedlings, in some cases, MoCV1-A-infected and MoCV1-A-free strains caused different lesion types (resistance to susceptible, or vice versa) on individual international differential rice varieties. However, we did not find any gain/loss of the fungal avirulence genes by PCR, suggesting that MoCV1-A infection can convert the pathogenicity of the host M. oryzae from avirulence to virulence, or from virulence to avirulence, depending on the rice variety. We also confirmed the correlation of these race conversion events and invasive hyphae growth of the fungi in a leaf sheath inoculation assay. These data suggested that MoCV1-A infection generally confers hypovirulence to the fungal host and could be a driving force to generate physiological diversity, including pathogenic races.  相似文献   

Rapid detection of Magnaporthe oryzae chrysovirus 1-A from fungal colonies on agar plates and lesions of rice blast     

Syun-ichi Urayama  Yu Katoh  Toshiyuki Fukuhara  Tsutomu Arie  Hiromitsu Moriyama  Tohru Teraoka 《Journal of General Plant Pathology》2015,81(2):97-102

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Hairpin-based virus resistance depends on the sequence similarity between challenge virus and discrete,highly accumulating siRNA species     

Victor Gaba  Arie Rosner  Ludmilla Maslenin  Diana Leibman  Sima Singer  Emre Kukurt  Yoel M. Shiboleth  Amit Gal-On 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(2):153-164

Virus resistance can be effectively generated in transgenic plants by using the plant’s silencing machinery. To study the specificity of gene-silencing-based resistance, homozygous tobacco (Nicotiana tabacum L.) plants containing a 597-nt hairpin RNA construct of the Potato Virus Y (PVY) replicase sequence were challenged with a variety of PVY strains. The transgene-carrying tobacco line was immune to five potato PVY strains with high sequence similarity (88.3–99.5%) to the transgene. Infection with more distant tomato and pepper PVY field strains (86–86.8% sequence similarity) caused delayed symptom appearance in the transgenic tobacco. Transgene production of small interfering (si) RNA was detected by northern blot and measured using a custom-designed microarray for the detection of small RNAs. siRNA accumulation peaks were observed throughout the inverted-repeat transgene. In the resistance-breaking tomato and pepper strains there were nucleotide differences in the sequences correlated to siRNA transgene accumulation, indicating the role of siRNA specificity in resistance breaking. The log of transgene siRNA signal intensity increased with probe GC content, indicating that the accumulating siRNA molecules were GC-rich. Sequence similarity of highly accumulating siRNAs with the target virus strain appears to be important for both resistance and resistance-breaking characteristics.  相似文献