Recovery of virus-free Almond (Prunus dulcis) cultivars by somatic embryogenesis from meristem undergone thermotherapy

Abstract

One of the world's main horticulture problems is the contamination of fruit trees with a variety of plant diseases, especially viral and pseudo-viral diseases. Due to the non-sexual propagation of the trees, these diseases have been transmitted to different parts of the world. The main aim of this study was to obtain a new effective method for virus elimination from almond cultivars, which was performed in two phases. In the first phase, we tested various almond cultivars with ELISA and RT-PCR. The results showed the infection of mother plantlets. So, three types of in vitro thermotherapy treatments were performed on infected plants to make them virus-free. The plantlets obtained from 0.5 mm meristem treated with the first type of thermotherapy (TH1: 8 h at 27 °C and 16 h at 38 °C for 18 days) showed the highest percentage of elimination of ApM, ACLS and TRS viruses. In the second phase, meristems were cultured on MS medium containing 0, 0.5, 1 and 2 mg/L 2,4-D with 1 mg/L TDZ and after two weeks, thermotherapy treatments were performed. The results showed, combining three methods of thermotherapy (TH1), meristem culture and somatic embryogenesis induction from meristem on MS medium supplemented with 0.5 mg/L 2,4-D and 1 mg/L TDZ is the most effective and safe technique for virus eradication without meristem size challenges. The samples that were diagnosed as virus-free were proliferated in temporary immersion bioreactor systems, and rooted to be used for later propagation and establishment of mother healthy orchards.

Micropropagation of Duboisia Species via Shoot Tip Meristem

“…As there are few differences among the basal media used, it is quite difficult to identify the exact nutrient that promotes the growth in MS, but this could be the high level of NH 4 NO 3 present in MS, which is four times higher than that in QL and WPM. In general, MS is the most widely used medium to support tissue culture across a broad range of plant species [39][40][41][42].…”

Eradication of PPV and PNRSV Viruses from Three Peach Cultivars Using Thermotherapy In Vitro, Including Optimization of Microshoots’ Multiplication and Rooting Medium

“…Thermotherapy is the term used to refer to the application of a high temperature that generates unfavorable conditions for virus multiplication in the cells and effectively decreases the virus load in the shoot tips [9][10][11][12]. Among the established thermotherapybased methods typically used for virus elimination, combined in vitro thermotherapy with shoot tip culture, micrografting, electrotherapy, chemotherapy (especially using ribavirin), and shoot tip cryotherapy has been reported to be efficient for the eradication of different viruses from plants [8,[13][14][15][16].…”