White clover cryptic virus-1 in New Zealand and eastern Australia

Abstract

The distribution and abundance of cryptic viruses (Partitiviridae) in natural and agricultural systems have received little attention. White clover cryptic virus-1 (WCCV-1) was detected infecting white clover plants and seed growing in New Zealand, but was not detected in field collections and in only two of 114 seedlings grown from seed collected in eastern Australia using enzyme-linked immunosorbent assay and RT-PCR. WCCV-1 was detected at high incidences (14-48%) in the cultivars Huia, Kopu II and Tahora and at low incidences (0-7%) in Aran, Haifa, Ladino, Siral and Sustain white clovers. WCCV-1 remained viable in seed stored for 50 years. The results are compared with another group of obligate seed-transmitted pasture microbes: the fungal endophytes of perennial grasses.

Transmission from seed to seedling and elimination of alfalfa viruses

“…The viruses of Partiviridae and Amalgavirdae are unlikely to be transmitted by vectors due to the absence of movement proteins, therefore, their spread among plants mainly relied on pollens or seeds, a means with a relatively high transmission rate ( Nibert et al., 2014 ). For example, white clover cryptic virus-1 (WCCV-1) of Partitiviridae had a transmission rate of 48% ( Guy and Gerard, 2016 ), and southern tomato virus (STV) and blueberry latent virus (BBLV) of Amalgavirdae had the transmission rate of 86% and 100%, respectively ( Fukuhara et al., 2020 ; Martin et al., 2011 ). Unlike Partiviridae and Amalgavirdae viruses, Secoviridae viruses could be transmitted in a variety of ways, by seeds, pollens, and arthropod vectors, with varying transmission rates ( Thompson et al, 2017 ).…”

“…Partitiviridae had a transmission rate of 48% (Guy and Gerard, 2016), and southern tomato virus (STV) and blueberry latent virus (BBLV) of Amalgavirdae had the transmission rate of 86% and 100%, respectively (Fukuhara et al, 2020;Martin et al, 2011). Unlike Partiviridae and Amalgavirdae viruses, Secoviridae viruses could be transmitted in a variety of ways, by seeds, pollens, and arthropod vectors, with varying transmission rates (Thompson et al, 2017).…”

First report of Pittosporum cryptic virus 1 in Pittosporum tobira in Lebanon

“…PiCV1 was first reported on P. tobira in Italy. Although cryptic viruses have no known vectors and are not transmitted mechanically or by grafting, they are vertically transmitted at high rates by ovule or pollen (Guy and Gerard 2016). Therefore, PiCV1 has the potential to spread in other Lebanese regions and neighboring countries.…”

First record of White clover cryptic virus-2 in New Zealand

“…Representatives of two of these genera have been reported from New Zealand (Veerakone et al 2015). Radish yellow edge virus is present, probably as a mixture of Alpha-and Delta-partitiviruses (Li et al 2016), Ryegrass cryptic virus (RGCV, Deltapartitivirus) was detected in one cultivar of ryegrass (Veerakone et al 2015) and White clover cryptic virus-1 (WCCV-1, Alphapartitivirus) occurs at varying incidences (0-48%) across New Zealand (Guy and Gerard 2016). To date there have been no records of Betapartitiviruses.…”