RESUMEN
In this study, the physio pathological effects of Aspergillus alliaceus (Aa, fungi, biocontrol agent) on Orobanche (parasitic plant) were investigated by hormone and phenolic substance tests. In experimental group, Orobanches were treated with the fungi, considering control group was fungus-free. Based on the hormonal tests, in the experimental group, salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA) and gibberellic acid (GA) levels significantly decreased, and only indole acetic acid (IAA) hormone levels were fairly higher than the control group. According to phenolic substance tests, it was found that only gallic acid, syringic acid and caffeic acid values significantly increased compared with control, and catechin and p-coumaric acid values were significantly lower. Consequently, it was determined that Aa pathogenesis (1) considerably reduces the effects of all defence hormones (JA, ABA, SA), (2) operates an inadequate defence based solely on the IAA hormone and several phenolic substances (gallic acid, syringic acid and caffeic acid), (3) and inevitably the fungi lead the Orobanche to a slow and continuous death. The results were evaluated in detail in the light of similar recent article and current literature in terms of biocontrol and pathology.
Asunto(s)
Aspergillus/fisiología , Agentes de Control Biológico , Orobanche/metabolismo , Helianthus/parasitología , Orobanche/inmunología , Orobanche/microbiología , Fenoles/análisis , Fenoles/metabolismo , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/prevención & control , Reguladores del Crecimiento de las Plantas/análisis , Reguladores del Crecimiento de las Plantas/metabolismo , Metabolismo SecundarioRESUMEN
Broomrapes (Orobanche sp.) are root holoparasitic plants causing severe damage to various families of horticultural crops. A Preliminary survey was carried in tomato fields infested with orobanche in Potohar plateau of Pakistan. Results indicated that each planting bed comprising10-12 tomato plants contained 7-8 parasitic weeds. Overall survey indicated the 65-70% plants suffered partial or complete yield loss. Further, it was estimated that the number of weeds inhabiting plant-1 was ranged from 2-4. Yield loss was estimated at 57.17 tons/ha while in terms of financial loss, it was 2579.87 $/ha. Hence total estimated loss on the total surveyed area of 16 hectares was 41395.85 $. The high potential of tomato cultivation in Pakistan reinforces the urgent protection measures to resolve this emerging issue.
Asunto(s)
Orobanche/fisiología , Solanum lycopersicum/parasitología , Interacciones Huésped-Parásitos , PakistánRESUMEN
BACKGROUND AND AIMS: The broomrapes, Orobanche sensu lato (Orobanchaceae), are common root parasites found across Eurasia, Africa and the Americas. All species native to the western hemisphere, recognized as Orobanche sections Gymnocaulis and Nothaphyllon, form a clade that has a centre of diversity in western North America, but also includes four disjunct species in central and southern South America. The wide ecological distribution coupled with moderate taxonomic diversity make this clade a valuable model system for studying the role, if any, of host-switching in driving the diversification of plant parasites. METHODS: Two spacer regions of ribosomal nuclear DNA (ITS + ETS), three plastid regions and one low-copy nuclear gene were sampled from 163 exemplars of Orobanche from across the native geographic range in order to infer a detailed phylogeny. Together with comprehensive data on the parasites' native host ranges, associations between phylogenetic lineages and host specificity are tested. KEY RESULTS: Within the two currently recognized species of O. sect. Gymnocaulis, seven strongly supported clades were found. While commonly sympatric, members of these clades each had unique host associations. Strong support for cryptic host-specific diversity was also found in sect. Nothaphyllon, while other taxonomic species were well supported. We also find strong evidence for multiple amphitropical dispersals from central North America into South America. CONCLUSIONS: Host-switching is an important driver of diversification in western hemisphere broomrapes, where host specificity has been grossly underestimated. More broadly, host specificity and host-switching probably play fundamental roles in the speciation of parasitic plants.
Asunto(s)
Orobanche/fisiología , Biodiversidad , América Central , ADN de Plantas/genética , ADN Espaciador Ribosómico/genética , Ecología , América del Norte , Orobanche/genética , Filogenia , Plastidios/genética , Alineación de Secuencia , Análisis de Secuencia de ADN , América del SurRESUMEN
Broomrape (Orobanche crenata Forsk.) is a major root-parasite of faba bean (Vicia faba L.), that seriously limits crop cultivation in the whole Mediterranean area. This parasitic weed is difficult to control, difficult to evaluate and the resistance identified so far is of polygenic nature. This study was conducted to identify genetic regions associated with broomrape resistance in recombinant inbred lines (RILs) and to validate their previous location in the original F(2) population derived from the cross between lines Vf6 and Vf136. A progeny consisting of 165 F(6) RILs was evaluated in three environments across two locations in 2003 and 2004. Two hundred seventy seven molecular markers were assigned to 21 linkage groups (9 of them assigned to specific chromosomes) that covered 2,856.7 cM of the V. faba genome. The composite interval mapping on the F(6) map detected more quantitative trait loci (QTL) than in the F(2) analysis. In this sense, four QTLs controlling O. crenata resistance (Oc2-Oc5) were identified in the RI segregant population in three different environments. Only Oc1, previously reported in the F(2) population, was not significant in the advanced lines. Oc2 and Oc3 were found to be associated with O. crenata resistance in at least two of the three environments, while the remaining two, Oc4 and Oc5, were only detected in Córdoba-04 and Mengíbar-04 and seemed to be environment dependent.