Abstract

Mulberry mosaic dwarf (MMD) disease was first recorded in 1957 and has long been endemic in China. A new viroid-like RNA was detected from mulberry trees affected by MMD and its full nucleotide sequence was determined (1). This mulberry small circular RNA (mscRNA), consisting of 356 nt, does not share significant sequence homology with other viroids and viroid-like satellite RNAs. Here we show that (+) strand of mcRNA contains a hammerhead ribozyme, while the (-) strand contains a hairpin ribozyme, resembling viroid-like satellite RNAs of nepoviruses. mscRNA transcripts of (+) and (-) strands self-cleaved in vitro as predicted by the hammerhead and hairpin structures, respectively, generating fragments with the expected 5' terminus. Circular forms of mscRNA, purified from plant extracts, and dimeric transcripts of both polarities, generated in vitro, were slash-inoculated in mulberry, hop, tomato and cucumber seedlings. Northern-blot hybridization did not detect mscRNA in the inoculated plants so far, suggesting that this circular RNA is not endowed of autonomous replication. These data, taking also into consideration that a nepovirus has been recently reported in mulberry in China (2), strongly suggest that mscRNA could be a novel viroid-like satellite RNA of a nepovirus. This hypothesis is supported by the identification, by next generation sequencing, of both mscRNA and a nepovirus in the same mulberry host. Moreover, a close association of mscRNA with MMD disease was excluded on the bases of a field survey carried out on mulberry trees affected or not affected by the disease. This data are in agreement with our recent results showing that MMD is closely associated with a new geminivirus (3).

Autore Pugliese

• Navarro Ramirez Beatriz , Di Serio Francesco

Tutti gli autori

• Li S.; Lu; Q.; Sagawa K.; Navarro B.; Di Serio F.; Sano T.; Tsushima T.; Kuai Y.; Wang W.; Wu Z.; Xie L.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2015

ISSN

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ISBN

978-3-95758-006-1

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Settori ERC

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Codici ASJC

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