Two Advanced Cryogenic Procedures for Improving Stevia rebaudiana (Bertoni) Cryopreservation

A droplet vitrification cryopreservation protocol for conservation of hops (Humulus lupulus) genetic resources

Hops (Humulus lupulus L.) is essentially used in the brewing industry as it contributes to flavor, and aroma of beer. However, the genetic diversity of hops is increasingly threatened by diseases, environmental changes, and urbanization. Cryopreservation has emerged as a pivotal strategy for safeguarding and maintaining the genetic diversity of hops. The present work presents a comprehensive study on the cryopreservation of hops, focusing on the development and optimization of a droplet vitrification based cryopreservation protocol. Shoot tips excised from one month old in vitro cultures were precultured on 0.3 M sucrose, dehydrated in a loading solution followed by treatment with PVS2 solution for different durations. Significant effect of PVS2 dehydration was observed on post-thaw survival and regeneration after cryoconservation with maximum 50% post-thaw regeneration observed in shoot tips dehydrated in PVS2 for 30 min. Genetic fidelity of the regenerated plants was confirmed using 30 ISSR markers. Reproducibility of the developed protocol was tested on seven other accessions and post thaw regeneration ranging from 43 to 70% was observed across the accessions. The present study reports a highly efficient protocol for conservation of hops germplasm. The results indicate that droplet vitrification can be used as a reliable and sustainable approach for hop genetic preservation, with high survival rates and minimal genetic alterations observed in cryopreserved samples. To the best of our knowledge, this is the first report on DV based cryopreservation of hops germplasm.

Plant Cryopreservation: A Look at the Present and the Future

Cryopreservation is known as an applied aspect of cryobiology or the study of life at low temperatures [...].

Vitrification Solutions for Plant Cryopreservation: Modification and Properties

Many plants cannot vitrify themselves because they lack glassy state-inducing substances and/or have high water content. Therefore, cryoprotectants are used to induce vitrification. A cryoprotectant must have at least the following primary abilities: high glass-forming property, dehydration strength on a colligative basis to dehydrate plant cells to induce the vitrification state, and must not be toxic for plants. This review introduces the compounds used for vitrification solutions (VSs), their properties indicating a modification of different plant vitrification solutions, their modifications in the compounds, and/or their concentration. An experimental comparison is listed based on the survival or regeneration rate of one particular species after using more than three different VSs or their modifications. A brief overview of various cryopreservation methods using the Plant Vitrification Solution (PVS) is also included. This review can help in alert researchers to newly introduced PVSs for plant vitrification cryoprotocols, their properties, and the choice of their modifications in the compounds and/or their concentration.