A Plum Marbling Conundrum : Identification of a New Viroid Associated with Marbling and Corky Flesh in Japanese Plums

Over the past 2 decades, fruit symptoms resembling a marbling pattern on the fruit skin or corking of the fruit flesh were observed on Japanese plums in South Africa, resulting in unmarketable fruit. The ability of high-throughput sequencing (HTS) to detect known and unknown pathogens was exploited by assaying affected and unaffected fruit tree accessions to identify the potential aetiological agent of marbling and/or corky flesh disease. In this study, it is shown that the disease is associated with a previously undescribed small RNA with typical viroid structural features. The potential viroid was the only pathological agent consistently detected in all symptomatic trees by HTS, and the association with the symptoms was confirmed in field surveys over two seasons. To date, this RNA was not detectable by RT-PCR in seedlings raised from seeds collected from infected trees. Although the autonomous replication of this viroid-like RNA was not proven, it was shown to be transmissible by grafting and associated with a range of symptoms that include marbling on the fruit skin, corky flesh, reduced fruit size, irregular shape, and uneven fruit surface depending on the cultivar. Moreover, the circular RNA genome, consisting of 317 nucleotides, strongly supports that this viroid-like RNA is most likely a viroid for which the name plum viroid I (PVd-I) is proposed. The primary structure of this viroid showed a less than 90% nucleotide sequence identity to viroids of the genus Apscaviroid, with which it has close phylogenetic relationships and shares conserved structural motifs.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:110

Enthalten in:

Phytopathology - 110(2020), 8 vom: 07. Aug., Seite 1476-1482

Sprache:

Englisch

Beteiligte Personen:

Bester, Rachelle [VerfasserIn]
Malan, Sophia S [VerfasserIn]
Maree, Hans J [VerfasserIn]

Links:

Volltext

Themen:

Apscaviroid
Journal Article
Plum viroid I
Pospiviroidae
RNA, Viral

Anmerkungen:

Date Completed 04.08.2020

Date Revised 04.08.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1094/PHYTO-12-19-0474-R

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM308500172