Facultatea de Biologie și Geoştiinţe / Faculty of Biology and Geosciences

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Author: search.filters.author.Clapco, StelianaSubject: search.filters.subject.orobanche cumana

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    EFFICIENCY OF MICROSATELLITE MARKERS IN GENOTYPING OF OROBANCHE CUMANA POPULATIONS
    (Iasi University of Life Sciences, 2021-10-21) Mutu, Ana; Clapco, Steliana; Duca, Maria
    Microsatellites or simple sequence repeats (SSRs) markers are widely dispersed across the genome, have a codominant and multiallelic nature, high variability and informativeness, and a specific chromosomal location. For this reason, they are playing a significant role in different fundamental and applicable fields, including genetic studies at the individual, population, species levels, and molecular breeding programs. In this study, the utility of 15 microsatellite markers in discrimination of 33 Orobanche cumana (broomrape) populations from different geographical locations was assessed: Republic of Moldova (11 populations), Romania (1), Bulgaria (4), Serbia (7), Turkey (7) and China (3). The PCR amplification products obtained showed differences by number and size depending on the markers used (3 and 16 alleles). A total of 110 alleles with fragment sizes ranged from 76-343 bp were determined. The evaluation of the genetic polymorphism of SSR markers was performed by the effective number of alleles per locus (Ne) with an average of 5.31, Polymorphic Information Content index (PIC) – 0.75, Nei's genetic diversity index (H) – 0.78 and, Resolving Power index (Rp) – 5.79. High values of all indices revealed the significant informative capacity and effectiveness of markers studied. At the same time, most markers showed PIC values higher than 0.5, indicating a high polymorphism in O. cumana populations. Seven microsatellite markers (Ocum-052, Ocum-059, Ocum-074, Ocum-081, Ocum-087, Ocum-196, Ocum-197) were selected based on the analyzed statistical parameters, suggesting that these markers can efficiently measure genetic diversity in broomrape. Based on the Rp index and PIC values of these 15 SSR markers, genetic diversity of Turkish (Rp: 4.774; PIC: 0,722) and Moldavian (Rp: 4.394; PIC: 0,716) Orobanche cumana populations was higher than in other populations. However, the studied microsatellite (SSR) markers system characterized very well the genetic structure of all O. cumana populations included in this study. Selected markers could eventually be useful for breeders and sunflower seed producers to improve their control strategies for this parasitic plant.
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    THE EVOLUTION OF OROBANCHE CUMANA RACES IN SUNFLOWER CROP IN THE REPUBLIC OF MOLDOVA
    (Trakya University Publisher, 2021-09-01) Duca, Maria; Clapco, Steliana
    One of the most critical constraints for sunflower production in the majority of European countries, as well as in the Middle East and Asia is broomrape (Orobanche cumana Wallr.) – non-photosynthetic, obligatory, root parasitic plant. The continuous introduction of new resistant sunflower hybrids exerts a selection pressure on broomrape populations evolution and contribute to the development of new more virulent races that overcome sunflower genetic resistance. Thus, until now, eight races of O. cumana, A through H, have been identified. In this study, the chronology of broomrape races occurrence in sunflower crop in the Republic of Moldova was analysed. In Moldova sunflower broomrape was firstly attested at the end of the 19th century. In 1937 a more virulent race B was identified especially in the regions situated along the border with Romania. Later, at the beginning of 1970s, a new biotype that infested sunflower genotypes carrying genes of resistance to races A and B occurred. This new race was called the Moldovan race or race C and was found preferentially in the central part of the country. In early 2000s the presence of races D, E and F in Moldovan sunflower fields was reported. The most spread were the less virulent races A, B and D, which were found in all part of the country, followed by race E detected in the South and Centre and more virulent race F, which was identified only in the Central part. In few years, the study of racial status demonstrated the presence in the south of the country of a new highly virulent race G, which overcame all known genes of resistance. It has been established that the populations from the northern part of the Republic of Moldova belonged predominantly to race E, those from the central part of the republic – to race F and southern populations were attributed to the race G. Our greenhouse test carried out in 2014 revealed, for the first time, the presence in sunflower fields of the most aggressive race H. This pathotype was found especially in the south and centre and sporadically in the north. A research performed recently (2019-2020) showed the occurrence of new highly aggressive biotypes able to infest even the genotypes considered resistant to the most virulent race H. According to the results, in a short period of time new aggressive races of O. cumana occurred and spread rapidly over all Moldovan sunflower growing regions, the most virulent races G and H becoming dominant.