جستجوی مقالات مرتبط با کلیدواژه « genetic variation » در نشریات گروه « گیاهپزشکی »

A disorder on Satsuma mandarin, Citrus unshiu (Yu.Tanaka ex Swingle) trees with bark scaling of the trunk, ring spot or mosaic pattern symptoms on mature fruits especially around the calyx and extended yellow ring spot on the old leaves observed over the recent years in Mazandaran province. The results of virus mechanical inoculation on Gomphrena globosa indicator plants and indexing on different citrus stock and biological properties of the studied isolates indicated the presence of the type B citrus psorosis virus in samples. Molecular detection of CPsV was done by using RT-PCR and specific designed primers in which a desired amplicon with a size about 600bp amplified in infected samples collected from the orchards and greenhouse. Phylogenetic analysis of the representative isolates on the basis of nucleotide sequences of the CPsV-coat protein, categorized the representative isolates into two distinct groups which the group one further divided into three subgroups. Iranian isolates were clustered in the second subgroup beside the Americans and Japanese isolates and showed the lowest identity with the isolates from Latin American and African countries

Legume diseases characterized by yellowing, stunting and leaf rolling cause heavy losses to legume crops. One of the causal agents of these diseases is Bean leaf roll virus (BLRV) which is widespread in legume species throughout Iran. In the present research, genetic variation of BLRV isolates from different plants and different geographical regions is investigated. Samples of Vicia faba, Pisum sativum, Cicer arietinum, Medicago sativa, Lens culinaris, Trifolium spp., Trigonella foenum-graecum and Phaseolus vulgaris showing symptoms of yellowing, dwarfing and leaf rollingwere collected from the fields of Markazi, Fars, Khuzestan, Kohgiluye-va-Boyerahmad, Golestan, Zanjanand Qazvin provinces in 2016-2017. Total RNA was extracted from symptomatic samples and subjected to RT-PCR using specific primers amplifying a fragment of 389 bp in size from the CP region of the virus which was cloned and sequenced. BLRV was detected in faba bean, alfalfa, lentil, chickpea, bean and clover. Comparison of obtained nucleotide (nt) and amino acid (aa) sequences of Iranian isolates of BLRV with corresponding nt and aa sequences of other BLRV isolates available in GenBank showed a 94-98% and a 96-100% nt and aa similarity, respectively. Phylogenetic analyses indicated that all Iranian BLRV isolates constituted a group district from the group formed by non-Iranian BLRV isolates. These data indicated that the CP region of this virus is relatively conserved among different isolates of BLRV.

Hippodamia variegata is one of the major predators of crop pests which feed an aphids and psyllids. RAPD is a useful genetically marker to determine polymorphism and relationship among LadyBirds species. The aim of this study was to identify and study the genetic diversity of Hippodamia variegata Goeze (Col.:Coccinellidae)in 9 natural populations and 2 commercial breeding populations. To investigate the genetic diversity of 8 primers, 10 randomized nucleotides (C-15, C-16, C-18, C-19, BE-03, BE-09, B-01, B-06) were used. All primers created clear and repeated bands. Of the 147 bands produced, 82 bands, 55.78 percent, were polymorphic. The length of amplified fragments by all primers varied from 225 to 2000 base pairs. The dendrogram was calculated based on the Jaccard similarity coefficient by UPGMA method. The results of cluster analysis indicated that there was a high genetic difference among the populations studied in Lorestan province. Primer BE-09 (28 bands) produced the highest and primer C-16(13 bands) produced the lowest number of bands. Two populations Dorud and Kuhdasht formed the first cluster close to 0.28 Jaccard coefficient of using UPGMA method. Other clusters formed a very low percentage of similarity. This shows that the susceptibility of the ecology and geography of the province despite the small size establishes and maintains the genetic diversity in the province of the ladybirds. The results of cluster analysis indicated high genetic differences between populations studied in the Lorestan province.

Beet necrotic yellow vein virus (BNYVV, Benyvirus) is an economically important soil borne pathogen of sugar beet throughout the world. It is a multipartite virus in which RNA-3 encoded p25 protein controls disease symptoms in sugar beet. Under certain conditions, resistance-breaking variants are generated by amino acid changes at positions 67 and 68 in p25. In the present study p25 protein in three populations of the virus from Moghan, Lorestan and Fars were analyzed in susceptible and resistant sugar beet cultivars. Lorestan and Fars populations were serially passaged through resistant or susceptible sugar beet cultivars for 4 generations and p25 was monitored for possible amino acid changes. No significant amino acid changes were observed when the populations were passaged through susceptible cultivars. However, passage of the populations through resistant cultivars resulted in changes of amino acids at positions 30, 49, 67, 68, 129, 163 and 198. Changes were more frequent in position 67 in the tetrad amino acids. Biotype P of BNYVV which was found in Moghan and Lorestan may have appeared as a result of selection under pressure of resistant cultivars. Information on certain evolutionary parameters and motifs of p25 is included.

In this study population variability of Sclerotinia sclerotiorum, the causal organism of Sclerotinia stem and stalk rot of canola and sunflower, respectively, was determined by mycelial compatibility grouping (MCG). Among 355 isolates tested, 64 MCGs were identified, and single–isolate mycelial compatibility groups, 64% and 36% were obtained from the North and NorthWest of Iran, respectively. The results showed that highly significant differences (P<0.001) were observed in growth, number of sclerotia, weight of sclerotia and aggressiveness among MCG’s of North and Northwest of Iran.

Genetic variation in 75 common bean genotypes from three regions (Markazi province، Lorestan province، CIAT center) was assessed using RAPD markers. PCR analysis was performed on genomic DNA using 6 primer pairs. PCR products were detected agarose gel. The proportion of polymorphism with an average of 58% varied from 38 for OPO3 to 78 for OPBD20. The average of polymorphism information content was 0. 26. OPM9 and OPO10 primers had the highest and lowest value (0. 35 and 0. 17). Nei’s gene diversity and Shannon s information index were 0. 18 and 0. 14. Genetic similarity was estimated using the Nei coefficient، and dendrogram was constructed using the UPGMA method. Generally، results showed the similarity of genetic structure between the three populations of common bean.

Alfalfa (Medicago Sativa) is one of the most important forage plants in Iran. Several pests like aphids cause damage to these plants. One of the important aphids is the spotted alfalfa aphid (Therioaphis trifolii). In order to study the genetic variation of this pest, samples were taken from alfalfa fields of different provinces of Iran (Kerman, Fars, Kohkiloieyeh, Lorestan, Hamadan, Kermanshah, Kurdistan, West Azerbaijan, Markazi and Esfahan provinces) during 2007-2009. Seven RAPD primers were used in PCR test. At the range of 200-400 bp., 68 bands out of 88 had polymorphism. The primers A11 and CO4 had the highest polymorphisms that were 77.78 and 73.68 percent respectively. The related dendrogram showed 3 clusters and the second cluster had two sub clusters. In this research genetic differences were seen between collected samples from various regions, but no relationship was observed between these differences and altitudes, longitude, and position of the sampling locations.

To investigate the genetic diversity of Chilo suppressalis populations in Guilan province، a number of 37 of samples (4-6th larva stages) were collected from 17 different regions of the province. The collected samples were parted into three population groups coming from west، center and east parts of Guilan. Extracted DNAs were polymerized through 12 RAPD markers. RAPD-PCR products were electrophoresed on a 1. 5% agarose gel and photographed through GelDoc. Following bands scoring، analysis of data revealed that the 12 primers produced a total of 112 polymorphic bands. Results indicated that C. suppressalis population differs from the other two populations. Center and east Guilan populations demonstrated more similarities to each other. This could be due to an occurrence of gene-flow between the two populations causing the similarities. The population coming from the center of Guilan demonstrated a highest level of intrapopulation genetic variation due to a wider activity area and as well due to a higher number of the studied samples. These results finally indicated that population’s active in the province lack homogeny and are comprised of two different biotypes. In total، the results could be considered as an explanation for morphological and biochemical differences found among the active biotypes within the studied areas.

One of the most important pathogen attacking pigeonpea root, the nematodeHeterodera cajani Koshy, is causing significant economic losses in India. Knowledge ofgenetic variability present among different geographical populations is important for theselection of suitable control strategies. Molecular diversity among ten populations of H.cajani in India from pigeonpea growing areas is demonstrated by random amplifiedpolymorphic DNA (RAPD). Operon series of decamer primers were used for exploringthe polymorphism. The number of amplified fragments per primer varied from 7 (withOPA 16 and OPD 4) to 24 (with OPB 2) whereas the size varied from 300 bp to 3.1 kb.Out of the 32 primers tested 23 revealed 100% polymorphism (OPA 1, 2, 3, 4, 5, 6, 10,OPB 2, 3, 4, 12, OPC 1, 4, 5, 7, 8, 9, 10, 11, 16, OPD 4 and 10). Overall, 451amplification products were obtained out of which, 434 were polymorphic and 17 weremonomorphic. The Jaccard’s coefficient and cluster analysis showed that the nematodepopulation from Indore was distinct from the other populations of H. cajani in India.Samastipur and Pusa R.S. populations showed high degree of similarity in thisexperiment.