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Small RNAs in Phytophthora infestans and cross-talk with potato

Jahan, Sultana Nilufar (2015). Small RNAs in Phytophthora infestans and cross-talk with potato. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2015:113
ISBN 978-91-576-8424-0
eISBN 978-91-576-8425-7
[Doctoral thesis]

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Small RNAs (sRNAs) are small non-coding RNAs usually ranging in size 20-30 nt. They are playing important roles in plant-pathogen interactions. This thesis aimed at studying the sRNA populations in potato and Phytophthora infestans and their role in the potato-P. infestans interaction. An attempt was also made to implement such knowledge to improve resistance in potato against P. infestans.

P. infestans is an oomycete that causes severe damage to potato and tomato, and is well known for its ability to evolve rapidly to overcome resistance. It possesses active RNA silencing pathways and sRNAs are playing important roles to control the large numbers of transposable elements (TE) present in its genome and effector genes. Through deep sequencing of sRNAs from two isolates of P. infestans differing in pathogenicity, three clear size classes (21, 25/26 and 32 nt) of sRNAs were identified. RxLR and Crinkler (CRN) effector gene-derived sRNAs were present in both isolates, but exhibited marked differences in abundance. Some effector genes, such as PiAvr3a and PiAvrblb2, to which sRNAs were found, also exhibited differences in transcript accumulation between the two isolates. Majority of sRNAs also mapped to TEs. An additional group of sRNAs, the tRNA-derived RNA fragments (tRFs) ranging in size from 19-40 nt was identified in P. infestansm as well. Some tRFs accumulated differentially during infection.

A host-induced gene-silencing (HIGS) approach was proven to be successful in the potato-P. infestans pathosystem. Four different endogenous genes in P. infestans were targeted in my study by HIGS constructs and choice of target gene was shown crucial for a successful outcome. HIGS has the potential to be adopted in new resistance breeding to improve resistance in potato against P. infestans.

One late blight resistant potato cultivar was sequenced upon infection with compatible isolate of P. infestans. In order to decipher the molecular events underlying its resistance breakdown, analysis of transcript change and the possible role of sRNAs on transcript regulation during infection are ongoing. In infected potato, resistance genes are targeted by its own miRNAs leading to suppression. Additional components are most likely involved in this process and near future analysis will help to enhance our understanding of how P. infestans uses sRNAs to evade plant immune responses.

Authors/Creators:Jahan, Sultana Nilufar
Title:Small RNAs in Phytophthora infestans and cross-talk with potato
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :December 2015
Depositing date:10 December 2015
Number of Pages:62
IVetukuri RR, Åsman AKM, Tellgren-Roth C, Jahan SN, Reimegård J, Savenkov E, Söderbom F, Avrova AO, Whisson SC, Dixelius C. 2012. Evidence for small RNAs homologous to effector-encoding genes and transposable elements in the oomycete, Phytophthora infestans. PLoS One 7:e51399.
IIÅsman AKM, Vetukuri RR, Jahan SN, Fogelqvist J, Corcoran P, Avrova AO, Whisson SC, Dixelius C. 2014. Fragmentation of tRNA in Phytophthora infestans asexual life cycle stages and during host plant infection. BMC Microbiol. 14:308.
IIIJahan SN, Åsman AKM, Corcoran P, Fogelqvist J, Vetukuri RR, Dixelius C. 2015. Plant-mediated gene silencing restricts growth of the potato late blight pathogen Phytophthora infestans. J. Exp. Bot. 66:2785-2794.
IVJahan SN, Åsman AKM, Fogelqvist J, Dixelius C. Can Phytophthora infestans modulate host miRNA to evade defense responses? (manuscript).
Place of Publication:Uppsala
Publisher:Department of Plant Biology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8424-0
ISBN for electronic version:978-91-576-8425-7
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F30 Plant genetics and breeding
H Protection of plants and stored products > H20 Plant diseases
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Plant Biotechnology
Agrovoc terms:solanum tuberosum, phytophthora infestans, oomycetes, pathogens, genes, rna, effectors, gene expression
Keywords:Phytophthora infesters, potato, sRNA, miRNA, HIGS, effector
Permanent URL:
ID Code:12905
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Plant Biology (from 140101)
External funders:FORMAS and Jordbruksverket / Swedish Board of Agriculture and Stiftelsen Lantbruksforskning and Swedish Research Council
Deposited By: Sultana Nilufar Jahan
Deposited On:11 Dec 2015 09:22
Metadata Last Modified:10 Sep 2020 13:41

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