Orobanche species are commonly identified using morphological characteristics. In many cases, the distinction of closely related species is difficult, and a molecular tool is more suitable to differentiate them. In this study, genomic polymorphism between morphologically distinct species was investigated through amplification by polymerase chain reaction (PCR) of intersimple sequence repeat (ISSR) regions. Five primers were used to study genetic variation in the morphologically distinct species O. hederae and O. amethystea, as well as the closely related species O. cernua and O. cumana. For the first two species, all the primers detected genetic polymorphism. Anchored primers allowed the identification of more specific molecular markers than non-anchored tri-and tetranucleotide primers. Genetic polymorphism was investigated among three O. hederae populations using the two types of primer. One non-anchored and two anchored primers detected intraspecific variation, which was not correlated with the geographical location of those populations. The primer (GATA) 4 detected polymorphism between five specimens each of O. cernua and O. cumana species collected from different countries, permitting these two closely related species to be clearly differentiated. This study demonstrated that ISSR markers can be highly reliable for precise identification of Orobanche species.
-In France, the obligate root parasite O. ramosa L. (broomrape) causes significant decreases in yields in several crops such as Brassica napus L., Cannabis sativa L. and Nicotiana tabacum L. Over the past few years, the broad distribution and the continuous expansion of this parasitic plant have been pointed out. The diversity of its host plants and the increase in its locations in France led us to investigate the virulence of some O. ramosa populations against their potential host plants. Significant variation in their aggressiveness was observed. These results are therefore consistent with the existence of at least two O. ramosa pathovars throughout populations scattered in France. A study by PCR of inter-simple sequence repeat (ISSR) of these two populations allowed us to characterize each of them by specific molecular markers.broomrape / hemp / oilseed rape / virulence / pathovar
Using a host differential screening method in pot and in hydroponic co-cultures, four populations of the sunflower root parasite Orobanche cumana Wallr. were studied for their pathogenicity against seven sunflower genotypes that are thought to carry specific resistance genes. These broomrape populations, which belong to three supposed races (D, E, and F), were observed to differ by their virulence. The Spanish supposed-race F population was the most virulent, showing the greatest number of Orobanche fixations and biomass reduction on sunflower genotypes resistant to the other tested populations (Romanian supposed-race D population and both Spanish and Bulgarian supposed-race E populations). However, from the differential screening none of the sunflowers was absolutely immune to all populations of broomrape since at least a few broomrape attachments, which sometimes became necrosed, were observed during some weeks on the most resistant roots. However, typical hypersensitive response was not observed on the host roots, whose exudates stimulate germination of all four O. cumana populations to the same extent, but with some variations depending on the sunflower genotypes. Before attachment, Orobanche seedlings released cell-wall-degrading enzymes such as pectin methylesterase (PME, EC 3.1.1.11) and polygalacturonase (PG, EC 3.2.1.15). These pectinolytic activities were higher in the most virulent and recently discovered "race F".
Among members of the Orobanchaceae, parasitism has led to a drastic reduction in the morphological characters useful in identification. This is especially the case of species belonging to the subsection Minores (section Orobanche), which is a real tangle for agronomists and botanists. In this study, more than 120 specimens collected in the west of France were studied for their morphological characters and molecular markers. Their rbcL plastid gene was analyzed by RFLP and nucleotide sequencing. Because of several substitutions, insertions and deletions in the coding sequence, leading to stop codons and frameshift, this rbcL gene could be considered as a pseudogene. Variations in both 5′ upstream and coding regions allowed us to distinguish among specimens inside the Minores subsection. It was then possible to point out morphological characters, not used in floras, that fit with molecular analysis and confirm the existence of four taxa. Consequently, a new key to species determination using molecular analysis or morphological characters or a combination of both is proposed for O. hederae, O. amethystea, O. minor and O. loricata. Finally, the value of plastid pseudogenes in taxonomy is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.