IPPS SYMPOSIUM ON PARASITIC WEEDS
We are pleased to announce that the next IPPS Symposium will take place in Durban (South Africa) on June 24-25, 2004, in collaboration with the International Weed Science Congress (IWSC).
The Symposium will include three workshops:
1. Striga management in various cropping systems.
2. Genetic variation in parasitic weeds.
3. Physiological and molecular aspects of parasitic plant development.
IPPS members are also invited to attend the Parasitic Weeds Sessions of the 4th International Weed Science Congress, scheduled on Thursday 24 June. The IPPS Symposia and the IWSC parasitic weeds sessions are complementary, so that all participants will have the opportunity to discuss parasitic weeds within the wider scope of weed biology and control.
Thursday 24 June 2004
IWSC Plenary lecture - The parasitic weed problem and its fate in the 21st century.
IWSC session - Progress in parasitic weed research, with invited lectures on:
1. Understanding key developmental processes in parasitic weeds (Gebisa Ejeta).
2. New methodologies for the management of parasitic weeds (Joel Ransom).
3. Mechanisms of resistance and their application in susceptible crops (Andre Fer).
4. Demography of parasitic weeds and its impact on management (Paula Westerman).
IPPS Workshop - Striga management in various cropping systems.
Poster session on parasitic weeds, including discussion of selected contributions.
Friday 25 June 2004
IPPS Workshop - Genetic variation in parasitic weeds.
IPPS Workshop - Physiological and molecular aspects of parasitic plant development.
Registration is organized by the IWSC. Please fill in the form that is found at: https://secure.turners.co.za/iwsc2004/form.asp#Payment
Thursday-Friday IWSC sessions and parasitic weed symposium (for those not attending the IWSC):
IPPS members US$ 120
IPPS students US$ 50
Non-members US$ 180
Non-member students US$ 50
Friday IPPS symposium for those registered for the IWSC
IPPS members Free
Non-members US$ 50
Call for papers:
Papers are invited for the three Workshops of the IPPS Symposium. Authors are requested to submit a short summary of their intended contribution in the form of an abstract as described for the IWSC conference at: (http://www.iwsc2004.org.za/Abstracts.htm). The only modification necessary is to include the words, “IPPS Symposium:” in front of the abstract title. The summary should be of not more than 250 words. It should include a clear definition of the objective and approach, present sufficient details regarding results, pointing out material that is new. The authors are asked to indicate whether they wish to contribute a poster or an oral presentation. The Scientific Committee reserves the right to request authors to present a poster after submission of summary for oral presentation. Contributions will be refereed. All accepted contributions will be published on the IPPS website.
The deadline for abstract submission is February 20, 2004.
Scientific Organizing Committee:
H. Bouwmeester (the Netherlands)
P. Delavault (France)
G. Ejeta (USA)
D.M. Joel (Israel)
F. Kanampiu (Kenya)
M. Press (UK)
B. Roman (Spain)
M.P. Timko (USA)
J.A.C Verkleij (the Netherlands)
J.H. Westwood (USA)
K. Yoneyama (Japan)
W.J. Zou (China)
Danny Joel, IPPS Secretary
THE 4TH INTERNATIONAL WEED SCIENCE CONGRESS
We also encourage IPPS members who are interested in parasitic weed control to attend the 4th International Weed Science Congress, on 20-24 June in the same place, where many aspects of weed science will be discussed in detail. More information on the Congress can be found at: http://www.iwsc2004.org.za/
We are looking forward to meeting all parasitic plant researchers and sharing results and views and for fruitful discussions and for the promotion of parasitic plant research.
Useful internet addresses:
Congress venue (ICC) in Durban: www.icc.co.za
Accommodations in South Africa: www.portfoliocollection.co.za
Kingdom of the Zulu: www.zulu.org.za
Kwazulu-Natal Parks: www.kznwildlife.com
City of Durban: www.kwazulu-natal.co.za/DBN
South African National Parks Board: www.parks-sa.co.za
First report of Aeginetia pedunculata causing sugarcane wilt in India
Barring one short mention that Aeginetia pedunculata (Roxb.) Wall. (as Orobanche acaulis Roxb.) grows on China sugarcane (Saccharum sinense Roxb.) in the Botanic Garden at Kolkata (erstwhile, Calcutta) (Roxburgh, 1832), this Aeginetia species has not been reported as a parasite on sugarcane (Saccharum officinarum L.) in India, although A. indica has been (Parker and Riches, 1993). Now, during a survey in 2000 and around Plassey Sugar Mill area in Nadia district of West Bengal, India, the first author observed that nearly 100 ha of sugarcane crop was infected with A. pedunculata as identified by Botanical Survey of India, Kolkata. The parasite, 10 to 15 cm tall, appears at the base of sugarcane clumps during July, one month after the onset of the southwest monsoon. Emergence of new inflorescence and flowering continues till harvest of the crop in December-January. The first flowers produce seeds in capsules in September. The seeds are minute (0.3mm x 0.2 mm) and numerous (8-18,000 per capsule). They float on water and can readily spread to other places. Flowers are very attractive bearing ca > 50 mm purple limbs with a yellow lip. Morphological variations in respect of plant height, shape and colour are also common. A. pedunculata plants which grow on wild grass hosts are smaller than on sugarcane, dark red in colour, appear during August to October and bear only a few flowers and capsules, whereas plants growing on sugarcane produce luxuriant growth, abundant large flowers with varied shades of colour and many capsules. The parasite can survive during mild winter months only under the dense canopy of sugarcane plants. The loss caused due to the parasite is only visible when the infected canes began to wilt and dry at the time of harvest in December-January. Periodic sampling of infected and healthy canes from different varieties and from plant and ratoon crops showed that on an average the infected cane juice contains Brix 7.8 % and sucrose 2 % in compared to healthy plant which contains Brix 19.6 % and sucrose 16.3 %. The loss is 100 % in completely dried up patches in infected fields. For management of the parasite, weeding with manual labour and spraying herbicides like 2,4-D and glyphosate are practiced but resurgence of the parasitic plant is very quick, needing repeated applications albeit without satisfactory management. Development of resistant varieties may be the sustainable solution of the problem. Work has been initiated in this direction at Sugarcane Research Station, Bethuadahari, Nadia, West Bengal, India since 2000-01. We are also attempting to develop an appropriate IPM. A. pedunculata is a rare and threatened plant species which is also a medicinal plant, implying the need for adequate steps in conservation under protection and isolation away from its economic hosts.
A photograph of A. pedunculata can be seen at http://www.odu.edu/webroot/instr/sci/plant.nsf
Hedayetullah, S. and Saha, J.C.. 1942. Current Science 11: 109-110.
Parker, C. and Riches, C.R. 1993. Parasitic Weeds of the World. Wallingford, UK: CABI.
Roxburgh, W. 1832. Flora Indica. Vol 3. p 28.
Bikash Ranjan Ray,
Sugarcane Research Station, Bethuadahari 741126, Nadia, West Bengal, India, firstname.lastname@example.org
and MrinaiKanti Dasgupta,
Institiute of Agriculture, Sriniketan, Birbhum, West Bengal, India.
PARASITIC SCROPHS – NO SUCH THING?
It seems that the problem from serious parasitic weeds of the Scrophulariaceae has at last been eliminated – on paper at least. The editors of Haustorium regret that an important reference – a landmark even – was overlooked two years ago. Olmstead et al.’s paper ‘Disintegration of the Scrophulariaceae’ (American Journal of Botany 2001, 88: 348-361) proposes that all the parasitic genera previously included in the Scrophulariaceae should be transferred to Orobanchaceae. It had previously been pointed out (e.g. by U. Molau in ‘Parasitic Plants’ by Press and Graves, 1995) that the Orobanchaceae were closely allied with the Rhinanthoideae and should be lumped, or integrated with Scrophulariaceae. We now have a re-splitting, or dis-integration, on new lines which appears to be soundly based on the latest molecular phylogenetic techniques. Dan Nickrent has been adopting the new alignment on his ‘Parasitic Plant Connection’ web-site and it is apparently accepted by many others of our parasitic plant colleagues. A survey of web-site data-bases, however, suggests that it has not yet gained full recognition. On the USDA GRIN site, the family for Striga is given as ‘Scrophulariaceae. Also placed in Orobanchaceae’, but other sites such as USDA PLANTS, Missouri Botanic Garden, Flora Europaea/Royal Botanic Garden Edinburgh, IPNI and ITIS all continue to place Striga etc in Scrophulariaceae. It seems there will be an inevitable long lag before this change is fully adopted. Haustorium will be happy to hear from any who have views or comments.
Under this European Union programme, a meeting was recently held in Athens, Greece. See under Proceedings of Meetings below for a list of the papers presented. Further meetings are planned for 2004 including two in February, the first on Genetic Diversity of Parasitic Plants, in Cordoba, Spain, the second on Biological Control, in Rome, Italy.
Symposium on non-weedy hemiparasitic Scrophulariaceae
A two-day symposium on the biology of the non-weedy hemiparasitic Scrophulariaceae (Orobanchaceae) will be held in Wageningen (Netherlands) on 15 and 16 April 2004. A broad range of subjects concerning the biology of this group will be covered by a number of specialists, including Matthies (Ecology), Press (Ecophysiology), Kwak & Bekker (Endangered species), DePamphilis (Evolution), and others. Further information is available on the internet (www.hemiparasites.nl), or can be requested by sending an email to Siny ter Borg (email@example.com).
Denneal Sarah Jamison-McClung (PhD, Department of Vegetable Crops and Weed Science, University of California, Davis, September 2003) Haustorium Development in the Parasitic Plant, Triphysaria (Orobanchaceae): A Genetic and Molecular Analysis.
In the Orobanchaceae, a single origin of root parasitism followed by multiple losses of photosynthetic capacity characterize the evolution of parasitic plants. Increasing heterotrophy or reliance on host nutrients is accompanied by loss of genetic material from the chloroplast, gain of parasite-specific traits, and increasing host specificity via recognition of common plant secondary metabolites.
Triphysaria, a hemiparasitic plant belonging to the Orobanchaceae, was used as a model to investigate the genetic and molecular mechanisms governing haustorium development. Haustoria are the “organs of parasitism” and form at the root tips of parasitic Orobanchaceae in response to host-derived haustorium inducing factors (HIF’s). Variation in natural populations of Triphysaria was observed for haustorium development in response to the HIF, 2, 6-dimethoxy-p-benzoquinone (DMBQ). DMBQ responsiveness was shown to be heritable and influenced by maternal effects.
Development of autohaustoria, haustoria that form in the absence of host-derived factors, was monitored in Triphysaria pusilla. Triphysaria rarely form haustoria when grown alone or with conspecific plants, suggestive of a mechanism for self-recognition and avoidance of self-parasitism. Propensity to form autohaustoria showed a strong positive correlation with degree of anthocyanin pigmentation. GA3 pre-treatment of seeds obtained from high and low anthocyanin parents leads to a significant and unexpected increase in autohaustoria formation for both groups. Results suggest that high anthocyanin plants may be self-inducing via exuded flavonoids and that plant hormones, particularly auxin and gibberellin, may be involved in regulating self-recognition and autohaustorium development in root parasitic plants.
Transcript accumulation of three genes was assayed in variant Triphysaria populations. Two genes, TvQR1 and TvQR2, encode putative quinone oxidoreductases and one, TvPirin, encodes a nuclear transcription factor involved in cell cycle regulation. TvQR1 performs a one-electron reduction of quinone to semiquinone, and was positively correlated to haustorium development. TvQR2 performs a two-electron reduction of quinone to phenolic acid and was correlated to DMBQ induction, though not haustorium development. TvPirin was also correlated to DMBQ induction, but not haustorium development. Results support the proposed redox cycling model of semiquinone-induced haustorium development in the Orobanchaceae.
Cinzia Costantino (PhD Università degli Studi, Genova, July 2003) Experiments with in vitro growth of Scurrula pulverulenta G. Don (plant parasite of woody-plant species widely distributed in sub-tropical areas). (in Italian)
The study involved in vitro culture of the hemi-parasitic plant Scurrula pulverulenta G.Don (Loranthaceae), grown from in vitro germinated seeds, without any growth regulators (exogenous hormones), and followed the development of shoots, leaves and haustorial strands. In the optimum medium numerous new shoots grew close to the chlorophyllous hypocotylar region. These were excised in the second year taking particular care to preserve some of the undifferentiated callus. Cultures involving different hosts revealed that the haustorium penetrated the host by cellular lysis, allowing the haustorium to penetrate further by mechanical means into the inner tissues. The host Genista monosperma Lam. responded to the penetration by producing a pink callus but still allowed penetration to the central stele and suffered damage. In the case of the host Citrus auriantum L. there was also progressive sub-cortical growth of the haustorium in the stem.
S. pulverulenta grown on a nutrient medium with cellulose, without a host, but with the addition of a Viscum album extract, showed abundant development of self-regenerating chlorophyllous callus originating from the site of cotylar fusion in the embryo. Furthermore, this callus and the hypoctyl callus also showed consolidated callus leading to the development of pseudo-xylem tissue, lignin-like material, lining the culture tubes. Addition of the Viscum extract was conducive to more vigorous growth, including development of the epidermis and most noticeably, of the powdery surface responsible for the specific name ‘pulverulenta’. After 3 years in in vitro culture, S. pulverulenta is observed to produce a thin web of viscin and to show full vegetative vigour. Electron microscope study of the epidermis in field-grown plants revealed the presence of Lactobacillus sp. inside pedunculate hairs in the form of a three-pointed star.
S. pulverulenta spreads freely in its native habitats in sub-tropical regions, while in the Mediterranean area it only spreads as a result of the sporadic activity of birds or deliberate transfer by researchers. It is suggested that S. pulverulenta may be a useful indicator of climate change since the amount of fruiting is noted to be closely correlated to temperature and rainfall.
It is also suggested that improved techniques for in vitro culture could be welcome as the cyto-toxic effects from extracts of this species on tumour cells (Ascites-test Yoshida) compare favourably with the standard extract (Hiscia Iscador ®) prepared from Viscum album L.. Other comparisons by Drs Urech and Schaller of leaf and pseudo-berry extracts of S. pulverulenta with the standard extract (Hiscia Iscador ®) obtained from V. album also suggest similar anti-tumour activity.
Finally, chromatographic studies of extracts from S. pulverulenta show differences depending on the host plant, confirming interaction between host and hemi-parasite resulting in differences of biochemical compounds in the extracts.
Anat Reizelman-Lucassen (PhD, University of Nijmegen, 4 November, 2003) Synthesis and function of germination stimulants for seeds of the parasitic weeds Striga and Orobanche spp. (Supervision: Professor Binne Zwanenburg)
This thesis reviews the synthetic methods used in the synthesis of strigol and other strigolactones. All 8 stereoisomers of strigol were prepared and their activity compared. ‘Natural’ strigol was by far the most active, by a factor of at least 100 compared with most others.
An efficient synthesis of (+/-) orobanchol is reported; also new improved methods for GR7, GR24 and Nijmegen-1, based on a palladium-catalyzed asymmetric coupling
The remainder of the thesis is devoted to studies aimed at the isolation and identification of the strigolactone receptor with the help of a biotin-labelled strigolactone analogue (amino-GR-24), affinity chromatography, immobilized avidin or streptavidin, and fluorescence correlation spectroscopy. The presence of a strigolactone specific binding protein (SPLB) in the insoluble membrane fractions of Striga seeds was shown by a dot-blot analysis. Preliminary results with SDS-PAGE showed an enrichment of a 60kDa protein, isolated from these fractions by purification.
Christina Vieira Dos Santos (PhD, University of Nantes, France). Molecular aspects of the Arabidopsis thaliana response infected by the obligate root parasite Orobanche ramosa. (Supervision: Philippe Delavault and Patrick Thalouarn, Groupe de Physiologie et Pathologie Végétales) (in French)
The infection of Arabidopsis thaliana roots with the holoparasite Orobanche ramosa represents a useful model for a molecular study of the host plant response to a parasitic plant attack. Thus, we developed an in vitro co-culture system, allowing us an investigation by PCR amplification methods of the expression of some host genes already known to be involved in plant/pathogen interactions: ethylene, isoprenoid, phenylpropanoid, and jasmonate pathways, oxidative stress responses and PR proteins. A non-targeted study based on a suppression subtractive hybridization strategy was also used to identify genes that were induced two hours after placing O. ramosa seeds near A. thaliana roots. Infestation will not start before the seventh day. The kinetic gene expression was assayed from 1h to 7 days after O. ramosa germinations were placed. Proteins encoded by these genes are also involved in A. thaliana defence pathways: signal transduction, pectin methylesterase inhibition, detoxification of reactive oxygen species, jasmonate-dependent pathway and cell wall reinforcement. From these studies, no salicylic acid-dependent defence has been detected whereas jasmonate- and ethylene-dependent pathways were induced.
Related papers :
Vieira Dos Santos C., Letousey P., Delavault P. and Thalouarn P., 2003. Defence gene expression analysis of Arabidopsis thaliana parasitized by Orobanche ramosa. Phytopathology, 93:451-457
And Santos et al. 2003 – in Literature section below.
Aurélie Rousset (PhD, University of Nantes, France) Contribution to the chemical control of the parasitic and mannitol-producing plants. Identification and characterization of in vitro inhibitors of mannose 6-phosphate reductase and study of their activity on simplified biological models (protoplasts and calli). (Supervision: Philippe Delavault and Patrick Thalouarn, Groupe de Physiologie et Pathologie Végétales) (in French)
The strategy based on the inhibition of mannose 6-phosphate reductase (M6PR), the key enzyme of mannitol production, could be efficient against Striga and Orobanche. Some aromatic and phosphorylated compounds inhibit competitively M6PR in vitro and protoplasts and callus culture were obtained from Striga leaves to estimate their activity on simple models. Protoplasts and calli kept mannitol synthesis as a major pathway, as shown by the analysis of their carbon fluxes, carbohydrate patterns and M6PR activities. In a similar proportion as in leaves, a significant part of the photosynthetically fixed 14C is incorporated into mannitol in protoplasts. Calli were much less active in photosynthesis but synthesized mannitol from exogenous sucrose or mannose. In presence of M6PR inhibitor, carbon fluxes towards soluble carbohydrates, notably mannitol, were reduced in treated protoplasts and calli.
Related paper :
Rousset et al. 2002. in Literature section below.
PROCEEDINGS OF MEETINGS
7th EWRS (European Weed Research Society) Mediterranean Symposium, Adana, Turkey, 2003. The Proceedings of this meeting are not yet published but should be available from the EWRS web site (www.ewrs.org) bookshop before long. The following are selected titles relating to parasitic plants, which will be published in the form of 2-page abstracts.
Manschadi A.M.et al. - Development of a systems approach for ecological management of parasitic weeds in legume-based Mediterranean cropping systems.
Grenz J. et al. - Identification of optimum sowing strategies for faba bean infested with the parasitic weed Orobanche crenata in the Cukurova region, Turkey. Predictions from simulation studies.
Nemli Y. et al. - Problems caused by broomrape (Orobanche spp.) and some control methods. Review and results.
Goran, M. et al. - Weed and broomrape (Orobanche cernua) control in Clearfield sunflower.
Orel-Aksoy E. and Uygur F.N. - Distribution of Orobanche spp. in the East Mediterranean region of Turkey.
Demirci M. et al. - Effect of soil temperature on Orobanche cernua Loeffl. growing stages and control strategies.
COST Action 849 Meeting: Biology and control of broomrape. October 30-November 2, Athens, Greece. Abstracts of this meeting are available on the COST web-site (see below). Titles were as follows:
Sauerborn, J. - Parasitic flowering plants – from botanical curiosity to antibiosis.
Cubero, J.I. - Phylogeny of the genus Orobanche inferred from cpDNA sequence variation.
Fer, A. - Experimental data strongly suggest the existence of several pathovars in Orobanche ramosa L.
Verkleij, J.A.C. et al. - Assessing genetic variability in Striga hermonthica and S. aspera by RAPD and SCAR analysis.
Delavault, P. et al. - Defense gene expression in host roots infected by Orobanche species.
Press, M.C. - Biology and control of parasitic weeds: Striga and Orobanche.
Bouwmeester, H. et al. - Germination of broomrape seeds.
Wegmann, K. - Recent experience in Orobanche control by suicide germination.
Matusova, R. et al. Changes in the sensitivity of parasitic weed seeds to germination stimulants.
Joel, D.M. - Sanitation and quarantine policies need to be adopted in Europe.
Murdoch, A.J. - Evaluating integrated management strategies for Orobanche and Striga.
Slavov, S. et al. - Chlorsulfuron resistant transgenic tobacco as a tool for broomrape control.
Kotoula-Syka, E. - Orobanche ramosa control in tomato.
Montemurro, P. and Lasorella, C. - Control of Orobanche ramosa by glyphosate in tomato.
Cagán, L. and Tóth, P. - Impact of Orobanche ramosa to the yield of tomato fruits in the southwest of Slovakia.
Vouzounis, N. - Control of Orobanche sp. in melon and watermelon crops in Cyprus.
Nadal, S. et al. Control of broomrape (Orobanche crenata Forsk.) in narbon bean (Vicia narbonensis L) by glyphosate.
Pacureanu-Joiþa, M. and Procopovici, E. - Broomrape control in Romania.
Rubiales, D. et al. - Integrated control of crenate broomrape in pea.
Vurro, M. - Toxins from pathogens of parasitic plants.
Gressel, J. - So what if transgenic hypervirulence changes host range of a biocontrol agent? We need not jump to conclusions.
Dor, E. - The efficacy of a mixture of fungi to control Egyptian and sunflower broomrape.
Zermane1, N. et al. - Natural antagonists of Orobanche spp. in Tunisia with potential as biocontrol agents
Tóth, P. and Cagán, L. - Natural enemies of dodders (Cuscuta spp.) in Slovakia.