Crenate Broomrape Research Articles

Escape and true resistance to crenate broomrape ( Orobanche crenata Forsk.) in grass pea ( Lathyrus sativus L.) germplasm

Grass pea ( Lathyrus sativus L.) is an annual cool season legume widely grown as a pulse crop for human food and animal feed and as forage. Infection by the parasitic weed crenate broomrape ( Orobanche crenata Forsk.) has been identified as major constraint for grass pea cultivation. We studied the response to O. crenata of a germplasm collection of grass pea in field trials over two seasons showing that the level of infection was highly influenced by environmental factors and plant growth cycle. Earlier or very late accessions were less infected. O. crenata infection increased with host plant vigour. O. crenata infection strongly reduced host biomass and grain yield. Even when resistance is scarce and masked by confounding environmental and plant growth cycle factors, calculation of the deviations from the polynomic nonlinear regression provided an improved approximation of the true genetic resistance levels present in the germplasm, here defined as resistance that do not depend on precocity.

Proteomic analysis by two-dimensional differential in gel electrophoresis (2D DIGE) of the early response of Pisum sativum to Orobanche crenata.

Crenate broomrape (Orobanche crenata) is considered to be the major constraint for legume crops in Mediterranean countries. Strategies of control have been developed, but only marginal successes have been achieved. For the efficient control of the parasite, a better understanding of its interaction and associated resistance mechanisms at the molecular level is required. The pea response to this parasitic plant and the molecular basis of the resistance was studied using a proteomic approach based on 2D DIGE and MALDI-MSMS analysis. For this purpose, two genotypes showing different levels of resistance to O. crenata, as well as three time points (21, 25, and 30 d after inoculation) have been compared. Multivariate statistical analysis identified 43 differential protein spots under the experimental conditions (genotypes/treatments), 22 of which were identified using a combination of peptide mass fingerprinting (PMF) and MSMS fragmentation. Most of the proteins identified were metabolic and stress-related proteins and a high percentage of them (86%) matched with specific proteins of legume species. The behaviour pattern of the identified proteins suggests the existence of defence mechanisms operating during the early stages of infection that differed in both genotypes. Among these, several proteins were identified with protease activity which could play an important role in preventing the penetration and connection to the vascular system of the parasite. Our data are discussed and compared with those previously obtained in pea and Medicago truncatula.

Colonisation of field pea roots by arbuscular mycorrhizal fungi reduces Orobanche and Phelipanche species seed germination

Fernández‐Aparicio M, García‐Garrido JM, Ocampo JA & Rubiales D (2010). Colonisation of field pea roots by arbuscular mycorrhizal fungi reduces Orobanche and Phelipanche species seed germination. Weed Research50, 262–268.SummaryPea (Pisum sativum) is an important grain legume crop whose cultivation in the Mediterranean basin and West Asia is severely constrained by infection by the weedy root parasite Orobanche crenata (crenate broomrape). Pea is a false host of other species such as O. minor, O. foetida and Phelipanche aegyptiaca. In the present experiments, we demonstrate that seed germination of the Orobanche and Phelipanche species examined is reduced in the presence of root exudates from pea plants colonised by arbuscular mycorrhizal (AM) fungi, Glomus mosseae and G. intraradices. Reduced germination was due to the effect of the AM fungi and not to the microbial populations potentially present in the soil inoculum. This protective effect of mycorrhizae was noticeable after 35 days of AM colonisation for O. crenata, O. foetida and P. aegyptiaca, but at least 45 days of colonisation were needed to get some reduction of O. minor germination.

Spatial distribution and temporal stability of crenate broomrape ( Orobanche crenata Forsk) in faba bean ( Vicia faba L.): A long-term study at two localities

Long-term field studies were conducted at two locations to describe the spatial distribution and temporal stability of Orobanche crenata infestation in faba bean. Spatial analysis with distance indices (SADIE) was used to provide aggregation indices for the distribution of O. crenata at different times. SADIE spatial association index was used to measure the spatial stability of O. crenata aggregation patterns through time. Crenate broomrape increased its populations until reaching an average of around 23 plants m −2. SADIE shows that spatial distribution in each locality was significantly consistent showing aggregation, with aggregation distribution seeming to become stronger over the years. Spatial distributions between consecutive years were positively associated, indicating patch location stability. If the locations of crenate broomrape population distributions are predictable and stable in the long term, the potential for reducing herbicide input to farmland will be increased, through the wider use of precision application methods.

Disease resistance in pea (Pisum sativum L.) types for autumn sowings in Mediterranean environments - a review

Pea is an important grain legume mainly grown as spring crop in temperate regions. However, in areas with mild winters and dry springs, like Mediterranean type environments, spring pea types are autumn sown. Unfortunately, little efforts have been made so far in pea breeding for constraints typical of these environments, such as crenate broomrape (Orobanche crenata), rust (Uromyces pisi), powdery mildew (Erysiphe pisi) and ascochyta blight (Mycosphaerella pinodes). In this paper we revise the present state of the art in pea breeding against these diseases and we will critically discuss present progress and future perspectives.

First Report of Crenate Broomrape (Orobanche crenata) on White Lupine (Lupinus albus) Growing in Alkaline Soils in Spain and Egypt.

Crenate broomrape (Orobanche crenata Forsk.) is a parasitic weed known to threaten legume crops since antiquity. It is mainly restricted to the Mediterranean Basin, Southern Europe, and the Middle East where it is an important pest in grain and forage legumes and in some apiaceous crops such as carrot and celery (1). White lupines are cultivated in acid soils, which usually are free of O. crenata infestations. However, breeders are attempting to develop white lupine cultivars adapted to alkaline soils (2). We report here findings of O. crenata infection in field trials of this new lupine germplasm in alkaline soils in experimental farms with a known history of faba bean cultivation and heavy infestation of O. crenata in Kafr El-Sheikh, Egypt and Córdoba, Spain in the spring of 2009. Symptoms were typical of O. crenata infection with reduced growth and emergence of typical O. crenata nonbranched spikes close to the lupine plants. Infection was confirmed by digging up the plants to verify the attachment of the broomrape plant to the lupine. O. crenata plants growing on lupines were fully fertile, producing viable seeds. Plant morphology was typical of O. crenata (1). Voucher specimens were deposited at the Herbarium of the Botanic Department of the University of Córdoba. To our knowledge, this is the first report of O. crenata infecting lupine and is relevant because the expected introduction of alkaline-tolerant lupine cultivars will extend its area of cultivation into fields heavily infested with Orobanche. O. crenata is highly polymorphic and could easily adapt to, recognize, and infect this new host. Development of lupine-adapted O. crenata populations should be monitored because it could represent a major constraint on lupine introduction into alkaline soils.

Identification of quantitative trait loci for specific mechanisms of resistance to Orobanche crenata Forsk. in pea (Pisum sativum L.)

Crenate broomrape (Orobanche crenata) is the major constraint for pea cultivation in the Mediterranean Basin and Middle East. Cultivation of resistant varieties would be the most efficient, economical and environmentally friendly way to control this parasite. However, little resistance is available within cultivated pea. Promising sources of resistance have been identified in wild peas but their use in breeding programs is hampered by the polygenic nature of the resistance. The identification of molecular markers linked to the resistance would allow tracking of the underlying genes, facilitating their introgression into pea cultivars. The main objective of this study was the identification of genomic regions associated with resistance to O. crenata. A RIL (Recombinant Inbred Lines) population derived from a cross between a resistant accession of the wild pea Pisum sativum ssp. syriacum, and a susceptible pea variety was screened for resistance to O. crenata under field conditions during two seasons. In addition, resistance reactions at different stages of the O. crenata infection cycle were assessed using a Petri dish method. The approach allowed the identification of four Quantitative Trait Loci (QTL) associated with field resistance, assessed as the number of emerged broomrape shoots per pea plant under field conditions. These identified QTLs explained individually from 10 to 17% of the phenotypic variation. In addition QTLs governing specific mechanisms of resistance, such as low induction of O. crenata seed germination, lower number of established tubercles per host root length unit, and slower development of tubercles were also identified. Identified QTLs explained individually from 8 to 37% of the variation observed depending on the trait. Host plant aerial biomass and root length were also assessed and mapped. Both traits were correlated with the level of O. crenata infection and three out of the four QTLs controlling resistance under field conditions co-localized with QTLs controlling plant aerial biomass or root length. The relationship observed among these traits and resistance is discussed.

Field response of Lathyrus cicera germplasm to crenate broomrape ( Orobanche crenata)

Crenate broomrape ( Orobanche crenata Forks.) is a major constraint for grain and forage legume cultivation in Mediterranean agriculture, to which little resistance is available. We studied the response to O. crenata of a germplasm collection of chickling pea ( Lathyrus cicera L.) in field trials over two seasons showing that resistance although scarce and masked by confounding factors, is available and can be used in breeding. The level of infection was highly influenced by environmental factors and plant growth cycle. Earlier accessions were less infected due to competition of the earlier settled pods with O. crenata tubercles. O. crenata infection strongly reduced host biomass and grain yield. Deviations from the polynomic regression gave an improved approximation of the true genetic resistance levels present in the germplasm.

Characterization of resistance to crenate broomrape (Orobanche crenata) in a new small-seeded line of Tunisian faba beans

Orobanche crenata, crenate broomrape, causes major drawbacks in faba bean production in Mediterranean countries. The development of resistant varieties remains the most efficient way to solve this problem. This study was designed to assess the resistance of the breeding line XBJ90.03-16-1-1-1-1 to crenate broomrape, using cv. Bachaar as a susceptible control. Incidence and severity parameters were evaluated in infested fields to values reaching 95% and 4 (on a 1 to 9 scale), respectively, in 'Bachaar', and reaching only 5% and 1.5, in 'XBJ90.03-16-1-1-1-1'. This selected line displayed, at the most, an average of one emerged crenate broomrape individual per plant at crop maturity, whereas 'Bachaar' plants displayed five emerged broomrape individuals under the same conditions. In addition, the seed yield of 'XBJ90.03-16-1-1-1-1' plants was two-fold higher than that of 'Bachaar'. In pot experiments, number and total dry weight of broomrape individuals per plant were significantly higher for 'Bachaar' than for 'XBJ90.03-16-1-1-1-1'. In root chambers, percent germination of broomrape seeds was five-fold lower in the vicinity of 'XBJ90.03-16-1-1-1-1' roots (3%) than close to 'Bachaar' roots (15%). The direct consequence was a limited number of broomrape tubercles per 'XBJ90.03-16-1-1-1-1' plant. Furthermore, tubercle formation on 'XBJ90.03-16-1-1-1-1' roots was delayed by a week compared with the infection process on 'Bachaar' roots. Finally, some features of 'XBJ90.03-16-1-1-1-1' roots were characterized, such as the low amount of exudation of germination stimulant, which, combined with a deep root system, triggers resistance to the parasite.

First Report of Crenate Broomrape (Orobanche crenata) on Lentil (Lens culinaris) and Common Vetch (Vicia sativa) in Salamanca Province, Spain.

Broomrapes (Orobanche spp.) are obligate parasites that infect roots of dicotyledonous plants. Orobanche species are particularly important in southern and eastern Europe, the Middle East, and North Africa. O. crenata (crenate broomrape) has been known to threaten legume crops since antiquity. This parasitic weed is mainly restricted to the Mediterranean Basin, southern Europe, and the Middle East and is an important pest in grain and forage legumes as well as in some Apiaceous crops such as carrot and celery (2,3). In Spain, O. crenata is a well-known problem on grain legumes in the south (Andalucía and Extremadura regions) and along the entire east coast north to the border with France. However, it has never been reported as a problem in central Spain. Castilla-León is the major pea-, vetch-, and lentil-producing area of Spain and was believed to be free of O. crenata. However, widespread and heavy infections of O. crenata (as many as 20 broomrapes per m2) were identified in the spring of 2007 on lentil and common vetch growing in several fields in Salamanca Province, between La Vellés, Palencia de Negrilla, and Aldeanueva de Figueroa, covering an area of approximately 80 km2. Infection of lentil and vetch plants was confirmed by digging up the plants to verify the attachment of the broomrape plant to the lentil or vetch roots. Morphology was typical of O. crenata (2), i.e., large erect plants with single, nonbranched spikes that may reach a height of up to 1 m, bearing many flowers of diverse pigmentation from yellow through white to pink and violet. The calyx is 13 to 18 mm with segments free and bidentate. The corolla is 18 to 28 mm, glandular pubescent, the lips often with lilac veins, lips divergent, large, and not ciliate. The anthers are brown, glabrous, or subglabrous. The filaments insert 2 to 3 mm above the base of the corolla and are hairy at the base with glandular hair at the apex. Voucher specimens were deposited at the Herbarium of the Botanic Department of the University of Córdoba. The heavy and widespread level of infection observed in several fields is most likely explained by an inadvertent introduction of O. crenata seed mixed with seed of lentil and vetch. To our knowledge, this is the first report of O. crenata infecting lentil and common vetch in Salamanca Province and is relevant because the area was considered free of the plant. Remarkably, a recent modeling study suggested that O. crenata might become a problem in central and northern Spain (1) since climatic conditions are suitable for its establishment. The spread of this infestation should be monitored because it could represent a major constraint on legume production in this region.

Medicago truncatula as a model for nonhost resistance in legume-parasitic plant interactions.

Crenate broomrape (Orobanche crenata) is a root parasitic weed that represents a major constraint for grain legume production in Mediterranean and West Asian countries. Medicago truncatula has emerged as an important model plant species for structural and functional genomics. The close phylogenic relationship of M. truncatula with crop legumes increases its value as a resource for understanding resistance against Orobanche spp. Different cytological methods were used to study the mechanisms of resistance against crenate broomrape of two accessions of M. truncatula, showing early and late acting resistance. In the early resistance accession (SA27774) we found that the parasite died before a tubercle had formed. In the late resistance accession (SA4327) the parasite became attached without apparent problems to the host roots but most of the established tubercles turned dark and died before emergence. The results suggest that there are defensive mechanisms acting in both accessions but with a time gap that is crucial for a higher success avoiding parasite infection.

Mechanisms limiting the geographical range of the parasitic weed Orobanche crenata

Factors and mechanisms limiting the geographical range of the root parasitic plant Orobanche crenata (crenate broomrape) were investigated and the risk of a spread beyond its current distribution area was assessed. Information on distribution and ecophysiology of O. crenata was gathered from literature and laboratory studies. A simulation model of seedbank dynamics served to test hypotheses and identify risk areas. The geographical range of O. crenata is strongly affected by mechanisms acting on the seedbank. Relevant processes include seed conditioning, germination, loss of viability, and dormancy induction and release. These are driven by the dynamics of soil temperature and moisture, and the presence or absence of hosts. Populations of O. crenata can only establish where a distinct precipitation seasonality prevails, with a warm and dry period being followed by warm and wet conditions, and where the presence of conditioned seeds coincides with that of a host. Climatically suitable regions include all Mediterranean climate areas and part of the monsoon, savanna and winter-dry climate regions of Central America, Africa, Australia and South Asia. In humid areas, both temperate and tropical, preponderance of dormancy-inducing wet conditions and lack of a warm-dry period facilitating dormancy release prevent the completion of the O. crenata life cycle and thus establishment of the species.

Some compatible Rhizobium leguminosarum strains in peas decrease infections when parasitised by Orobanche crenata

Summary Orobanche crenata (crenate broomrape) produces serious damage to many legume crops and particularly becomes a limiting factor for pea production in the Mediterranean basin. Nodulation effects on pea–broomrape relationships were studied using the commercial pea cultivar Douce de Provence and different Rhizobium strains using pot and Petri dish experiments. First, the benefit of bacterial inoculation on plant growth and efficiency of N incorporation were demonstrated for two isolates, P.SOM and P.1236. These isolates did not influence parasite germination induced by the artificial stimulant, GR24. In contrast, pea root inoculation with P.SOM and P.1236 isolates led to a reduced root infection by O. crenata, resulting from a lower Orobanche germination rate close to pea roots and a limited capacity of the parasitic seedlings to develop tubercles. Broomrape necrosis was observed both before and after parasite attachment to inoculated pea roots. Concomitantly, reduction in infection was accompanied by enhanced peroxidase activity and constantly high phenylalanine ammonia lyase activity in pea roots. These data suggest the involvement of these enzymes in pea resistance to crenate broomrape induced by the compatible rhizobia. Management of Orobanche via crop selection based on these enzyme systems is a viable option.

Identification by suppression subtractive hybridization and expression analysis of Medicago truncatula putative defence genes in response to Orobanche crenata parasitization

Crenate broomrape ( Orobanche crenata) is the major constraint for pea and faba bean production in the Mediterranean region. In this study, a systematic sequencing of expressed sequence tags (ESTs) was chosen to obtain a first global picture of the assembly of genes involved in defence response. A cDNA-library was established by suppression subtractive hybridization in the model legume Medicago truncatula infected by O. crenata in order to identify a large number of host plant ESTs. Eighty-one presumably up-regulated genes were identified and classified in functional categories. EST-annotations showed homologies to a number of well-characterized genes. Most of the proteins encoded by these genes, are already known in defence in M. truncatula, such as genes related to the JA pathway or involved in cell wall modifications. A notable number of the ESTs, however, were derived from novel genes not matching entries of the large-scale M. truncatula sequences collections. Expression analyses by quantitative RT-PCR of 20 genes corresponding to different functional categories showed high expression levels, supporting their involvement in the defence response.

Assessing Strategies for Orobanche sp. Control Using a Combined Seedbank and Competition Model

Infection with the parasitic weed crenate broomrape (Orobanche crenata Forsk.) causes considerable yield losses in legumes grown in Mediterranean climates. Strategies to control the parasite must include the long‐term containment of its soil seedbank. This requires a better understanding of seedbank and competition dynamics. Hence, we built a model of crenate broomrape seedbank dynamics and combined it with a model of broad bean (Vicia faba L.)–crenate broomrape competition within the simulation framework of the Agricultural Production Systems Simulator (APSIM). Parasite seed production is modeled as a function of parasite dry weight, which is an output of the competition model. Newly produced seeds are progressively added to the top‐most of three vertically organized seed classes and vertically redistributed by tillage. Seed viability loss follows negative exponential functions, with the rate of seed decay depending on soil moisture status. Effects of further external factors, such as temperature, are not yet included. Viable parasite seeds present at sowing of a host crop serve as input to the next run of the competition model. We quantified effects of environment, rotation, tillage, hand‐pulling, and combined strategies on parasite seedbank dynamics and broad bean yield through multiseason simulations. Modeled responses compared well with previously reported field observations. Results suggest that only by combining several management approaches, such as delayed sowing, no‐till, and hand‐pulling, can parasite populations be contained.

Determinate Faba Bean Young Pod Response to Glyphosate and Crenate Broomrape (Orobanche crenata)

ABSTRACT Crenate broomrape is a major constraint for faba bean production in Mediterranean countries. Several control strategies have been approached with relative success. Moderate resistance is available in standard indeterminate field bean cultivars for animal feed, but not in determinate types for horticultural uses. In this paper, we present evidence that a new faba bean cultivar of determinate growth habit for early harvest of young pods for fresh consumption might serve as a profitable catch crop. It escapes broomrape damage due to early harvesting of young pods at the time that broomrape is being established. After this early harvest, the crop is removed, destroying established broom-rapes before flowering, thus reducing the broomrape seed bank in the soil.

Sources of Resistance to Crenate Broomrape Among Species of Vicia.

Crenate broomrape is a parasitic weed that represents a major constraint for pulse and forage legume production in the Mediterranean and West Asia regions. Control strategies have centered around agronomic practices and the use of herbicides, although success has been marginal. Resistance breeding is hampered by scarcity of proper sources of resistance and of a reliable and practical screening procedure. A germ plasm collection of 208 accessions of vetch belonging to 42 Vicia spp. was screened for resistance to crenate broomrape under field conditions. High levels of resistance were found in several species. Resistance of selected accessions was confirmed by a low induction of broomrape seed germination in pot and in vitro experiments. This was followed by a scarce establishment of broomrape radicles in contact with host roots and a limited development of established tubercles. In addition, a hypersensitive-like necrosis occasionally was observed, but at low frequency.

Effect of sowing date and host resistance on the establishment and development of Orobanche crenata in faba bean and common vetch

SummaryThe effect of early and late sowing dates on the establishment of Orobanche crenata Forsk. (crenate broomrape) in resistant and susceptible cultivars of faba bean (Vicia faba L.) and vetch (Vicia sativa L.) were studied over four seasons in southern Spain. Differences in establishment, development and shoot emergence of the parasite were compared. With resistant faba bean and vetch cultivars, there was reduced attachment and shoot emergence of O. crenata with all sowing dates. Susceptible cultivars were more severely affected by the parasite with early sowing. Orobanche crenata development was also delayed in resistant cultivars. Crop yield, estimated by the number of pods per plant, decreased with late sowings. The combined use of resistant cultivars and early sowing is a useful tool as part of an integrated control strategy. Resistant cultivars allow early sowing (with low O. crenata attack), thus avoiding yield losses due to the short crop cycle with late sowing.

A proteomic approach to studying plant response to crenate broomrape (Orobanche crenata) in pea (Pisum sativum)

Crenate broomrape (Orobanche crenata) is a parasitic plant that threatens legume production in Mediterranean areas. Pea (Pisum sativum) is severely affected, and only moderate levels of genetic resistance have so far been identified. In the present work we selected the most resistant accession available (Ps 624) and compared it with a susceptible (Messire) cultivar. Experiments were performed by using pot and Petri dish bioassays, showing little differences in the percentage of broomrape seed germination induced by both genotypes, but a significant hamper in the number of successfully installed tubercles and their developmental stage in the Ps 624 compared to Messire.The protein profile of healthy and infected P. sativum root tissue were analysed by two-dimensional electrophoresis. Approximately 500 individual protein spots could be detected on silver stained gels. At least 22 different protein spots differentiated control, non-infected, Messire and Ps 624 accessions. Some of them were identified by MALDI-TOF mass spectrometry and database searching as cysteine proteinase, β-1,3-glucanase, endochitinase, profucosidase, and ABA-responsive protein. Both qualitative and quantitative differences have been found among infected and non-infected root extracts. Thus, in the infected susceptible Messire genotype 34 spots were decreased, one increased and three newly detected, while in Ps 624, 15 spots were increased, three decreased and one newly detected. In response to the inoculation, proteins that correspond to enzymes of the carbohydrate metabolism (fructokinase, fructose-bisphosphate aldolase), nitrogen metabolism (ferredoxin-NADP reductase) and mitochondrial electronic chain transport (alternative oxidase 2) decreased in the susceptible check, while proteins that correspond to enzymes of the nitrogen assimilation pathway (glutamine synthetase) or typical pathogen defence, PR proteins, including β-1,3-glucanase and peroxidases, increased in Ps 624. Results are discussed in terms of changes in the carbohydrate and nitrogen metabolism an induction of defence proteins in response to broomrape parasitism.

Crenate broomrape control in pea by foliar application of benzothiadiazole (BTH)

Parasitic plants are becoming a severe constraint on major agricultural crops in Mediterranean and tropical countries and the efficacy of available means of control is minimal. The problem is particularly severe in field pea, which is very sensitive to standard glyphosate treatments and in which little resistance has been identified. Systemic Acquired Resistance (SAR) has proven to be effective as a tool for controlling plant pathogens, including fungi, bacteria and viruses, but only recently has this phenomenon started to be evaluated as a control strategy against parasitic weeds. The present studies were conducted to evaluate the potential of SAR activation for broomrape control in pea. The effect of salicylic acid, glutathione and benzothiadiazole (BTH) in three different application methods was studied. Foliar application of 0.6–1.0 mM BTH, in the form of Bion 50 (50% a.i.), reduced broomrape infection under controlled conditions (growth chamber and greenhouse) by limiting the success in attachment and retarding the development of established tubercles.