Molekularna tipizacija tuniskih klonova vrste Myzus persicae (Hemiptera: Aphididae) pomoću mikrosatelitskih biljega

In order to assess the genetic differentiation among Tunisian clones belonging to the Myzus persicae complex (M. persicae (Sulzer), M. antirrhinii (Macchiati) and M. nicotianea Blackman), the molecular technique of microsatellites was used in this study. These markers offer sensitivity and are useful in population genetic studies of parthenogenetic organisms. Here, nine polymorphic microsatellite loci were amplified to distinguish between six parthenogenetic clones belonging to M. persicae complex collected from two different Tunisian areas. Interestingly, this technique allowed discrimination between five different genotypic classes among the six clones. Furthermore, analysis of genetic relatedness between the genotypic classes revealed that two Tunisian clones did not cluster either in M. persicae or in M. antirrhinii taxa, whereas, the four other Tunisian clones clustered into the M. persicae Sulzer taxa.U cilju utvrđivanja genetičkih razlika između tuniskih klonova kompleksa Myzus persicae (Sulzer), M. antirrhinii (Macchiati) i M. nicotianea (Blackman) upotrijebljena je molekularna mikrosatelitska tehnika. Ovi su biljezi vrlo osjetljivi i korisni u takvim istraživanjima partenogenetskih organizama. Umnoženo je devet polimorfnih lokusa mikrosatelita kako bi se razlikovalo šest partenogenetskih klonova kompleksa M. persicae sabranih u dva različita područja u Tunisu. Zanimljivo je da je ova tehnika omogućila razlikovanje između pet različitih genotipskih razreda tih šest klonova. Nadalje, analize genetičke srodnosti između genotipskih razreda pokazale su da dva tuniska klona nisu u istoj grupi niti s M. persicae, niti s M. antirrhinii, dok se četiri tuniska klona nalaze unutar vrste M. persicae Sulzer

Incidence of potato viruses and characterisation of Potato virus Y variability in late season planted potato crops in Northern Tunisia

International audienceSurveys were conducted of symptomatic potato plants in late season crops, from the major potato production regions in Northern Tunisia, for infection with six common potato viruses. The presence of Potato leafroll virus (PLRV), Potato virus Y (PVY), Potato virus X (PVX), Potato virus A (PVA), Potato virus S (PVS) and Potato virus M (PVM) was confirmed serologically with virus infection levels up to 5.4, 90.2, 4.3, 3.8, 7.1 and 4.8%, respectively. As PVY was prevalent in all seven surveyed regions, further biological, serological and molecular typing of 32 PVY isolates was undertaken. Only one isolate was shown to induce PVYO-type symptoms following transmission to tobacco and to react only against anti-PVYO-C antibodies. Typical vein necrosis symptoms were obtained from 31 samples, six of which reacted against both anti-PVYN and anti-PVYO-C antibodies showing they contained mixed isolates, while 25 of them reacted only with anti-PVYN antibodies. An immunocapture RT-PCR molecular test using a PVYNTN specific primer pair set in the 5’NTR/P1 genomic region and examination of recombinant points in three genomic regions (HC-Pro/P3, CI/NIa and CP/3’NTR) showed that all 25 serotype-N PVY isolates were PVYNTN variants with similar recombinations to the standard PVYNTN-H isolate. This is the first report of the occurrence of the PVYNTN variant and its high incidence in late season potatoes in Tunisia

Topical application of Escherichia coli-encapsulated dsRNA induces resistance in Nicotiana benthamiana to potato viruses and involves RDR6 and combined activities of DCL2 and DCL4

16 p.-7 fig.Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants represents an attractive alternative to transgene-based silencing approaches. However, improvement of dsRNA stability in natural conditions is required in order to provide long-term protection against the targeted virus. Here, we tested the protective effect of topical application of Escherichia coli-encapsulated dsRNA compared to naked dsRNA against single and dual infection by Potato virus X expressing the green fluorescent protein (PVX-GFP) and Potato virus Y (PVY) in Nicotiana benthamiana. We found that, in our conditions, the effectiveness of E. coli-encapsulated dsRNA in providing RNAi-mediated protection did not differ from that of naked dsRNA. dsRNA vaccination was partly effective against a dual infection by PVX-GFP and PVY, manifested by a delay in the expression of the synergistic symptoms at early times after inoculation. Using PVX-GFP as a reporter virus together with a suite of RNAi knockdown transgenic lines, we have also shown that RNA-directed RNA polymerase 6 and the combined activities of DICER-like 2 (DCL2) and DCL4 act to promote efficient resistance to virus infection conferred by topical application of dsRNA in N. benthamiana. Our results provide evidence that exogenous dsRNA molecules are processed by the RNA silencing pathways commonly used by the host in response to virus infection.This research was funded by the Ministry of Science and Innovation of Spain, grant number PID2019-109304RB-I00, and Consejo Superior de Investigaciones Científicas (CSIC), grant number COOPA20465 (AEI/FEDER, UE) (T.C. and F.T.). K.N., M.M. and E.S.-G. were supported by funding of the Ministry of Higher Education and Scientific Research of Tunisia, grant numbers 2019-BALT-1077 and 2019-BALT-1079, and Introduction to Research from the State Agency CSIC, grant number JAEINT_20_02094, respectively.Peer reviewe

Incidence and Characterization of Potato Virus Y in Seed Potatoes in Tunisia (vol 53, pg 151, 2010)

International audienceIncidence and Characterization of Potato Virus Y in Seed Potatoes in Tunisia (vol 53, pg 151, 2010