HTS-Based Monitoring of the Efficiency of Somatic Embryogenesis and Meristem Cultures Used for Virus Elimination in Grapevine

Abstract

Meristem culture and somatic embryogenesis are effective tools for virus elimination of vegetatively propagated crops including grapevine (Vitis vinifera L.). While both have been shown to be useful to eliminate the main grapevine viruses, their efficiency differs depending on the virus and grapevine variety. In our work, we investigated the efficiency of these two virus elimination methods using small RNA high-throughput sequencing (HTS) and RT-PCR as virus diagnostics. Field grown mother plants of four clones representing three cultivars, infected with different viruses and viroids, were selected for elimination via somatic embryogenesis (SE) and meristem culture (ME). Our results show for the first time that using SE, elimination in mother plants was effective for all viruses, i.e., grapevine rupestris vein feathering virus (GRVFV), grapevine Syrah virus 1 (GSyV-1), Grapevine virus T (GVT) and grapevine Pinot gris virus (GPGV). This study also confirms previous studies showing that SE is a possible strategy for the elimination of GFkV, GRSPaV, HSVd, and GYSVd-1. Our results demonstrate that the efficacy of virus elimination via SE is relatively high while the purging of viroids is lower. Our work provides evidence that the efficiency of SE is comparable to that of the technically difficult ME technique, and that SE will offer a more effective strategy for the production of virus-free grapevine in the future.

Virome Status of Preclonal Candidates of Grapevine Varieties (Vitis vinifera L.) From the Slovenian Wine-Growing Region Primorska as Determined by High-Throughput Sequencing

“…In library 007 ("Rebula" variety) all eight samples were infected, while in library 014 ("Malvazija" variety) only two samples were infected. In Hungary, using sRNA-seq approach, the same contradictory results were reported by three independent studies (Czotter et al, 2018;Demian et al, 2020;Turcsan et al, 2020). The authors indicated that this could be due to technical issues, the possibility that concentrations were under detection threshold due to the bulk sequencing strategy or deeper biological aspects, as a possible long coexistence between grapevine and GRSPaV resulted in mutual adaptation (Gambino et al, 2012), and potentially the plant immune response was not activated.…”

Effects of shoot tip size on in vitro regeneration and virus elimination of grapevine cv. superior seedless

“…Smerea et al (2010) reported that the healthy status of grapevine also affected the meristem regeneration capacity. Turcsan et al (2020) concluded that the meristem culture was a difficult technique as the regeneration capacity of the shoot tips bigger than 0.5 mm is higher but extra length also increase the virus level.…”

Variable Populations of Grapevine Virus T Are Present in Vineyards of Hungary

“…Meristem culture-based elimination could not 100% eliminate GRSPaV or GVT, which could explain their almost even distribution in the infected cultivars. However, chemotherapy and somatic embryogenesis-based methods gave better results for GRSPaV and for both viruses, which could be optimized in the future if new regulations target foveaviruses [16,18].…”