Droplet Vitrification: A Lifeline for Long-term Conservation of Threatened Species Garcinia indica
Left to right: Vartika Srivastava, ICAR-National Bureau of Plant Genetic Resources (New Delhi, India); Bart Panis, Bioversity International (Leuven, Belgium); Anuradha Agrawal, ICAR (New Delhi, India)
Cryopreservation is becoming an essential method for the long-term ex situ conservation of plant biodiversity, particularly for species unsuitable for seed bank conservation. This study focuses on Garcinia indica, a vulnerable species endemic to the biodiversity hotspot of the Western Ghats in India, which produces recalcitrant seeds and is experiencing rapid population decline. We developed the first successful cryopreservation protocol for G. indica using a modified droplet vitrification technique. Utilizing in vitro-derived shoots, we demonstrated that droplet vitrification is superior to standard vitrification. Our results showed a maximum regeneration rate of 51.76% for apical shoots from 24-week-old explants (IC638183) on Murashige and Skoog (MS) medium with 2.22 μM 6-benzylaminopurine (BAP). This method not only achieved successful regeneration post-cryopreservation but also ensured 85% survival during hardening in a mist chamber, crucial for future restoration efforts. Additionally, this protocol was effective across three other accessions (IC638184, IC638185, and IC638186), with an average post-thaw regeneration rate of 43.7%, demonstrating its potential for conserving G. indica germplasm. Our study provides a robust solution for conserving the genetic diversity of G. indica and sets a precedent for the cryopreservation of other threatened Garcinia species, emphasizing the importance of advanced cryopreservation techniques in protecting biodiversity.
Vartika Srivastava, Bart Panis, and Anuradha Agrawal. Droplet Vitrification: a lifeline for long-term conservation of threatened species Garcinia indica. In Vitro Cellular & Developmental Biology-Plant, 60:318 – 332, 2024.
Establishment of First Protocol of Hypocotyl-based Regeneration and Callus Transformation in Waterhemp (Amaranthus tuberculatus)
Waterhemp (Amaranthus tuberculatus) is a troublesome weed in the Midwest USA. This weed has developed resistance to multiple herbicides due to extensive herbicide use, limiting the options for controlling it. Genome editing tools like CRISPR/Cas9 when coupled with a gene drive have potential in weed science system for sustainable weed management. This study aimed to create a protocol for regenerating waterhemp through callus culture and to optimize an Agrobacterium-mediated transformation method. The regeneration process involved culturing hypocotyl explants on callus induction medium for two weeks, followed by subculture into shoot induction medium for 4 to 6 weeks. Additionally, an efficient Agrobacterium-mediated transformation system was developed using the regeneration protocol. The presence of transgenes was confirmed in the transformed calluses, though transgenic plants were not produced. This marks a significant step in exploring genome editing research in weed science.
Yaiphabi Kuman, Harold N. Trick, Veerendra Sharma, P.V. Vara Prasad, Mithila Jugulam. Establishment of first protocol of hypocotyl-based regeneration and callus transformation in waterhemp (Amaranthus tuberculatus). In Vitro Cellular & Developmental Biology-Plant, 60:283-293. 2024.
Scratching the Surface: The In Vitro Research That Will Be Critical for Conserving Exceptional Plants to Scale
Valerie Pence, Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo & Botanical Garden (Cincinnati, OH)
Emily Bruns, current address: Cyclopure, Inc. (Chicago, IL).
Seed banking is the most efficient method for conserving plant germplasm long-term, as a backup to threatened species in the wild. However, there are predicted to be at least 30,000 species that cannot be conserved in conventional seed banks. Known as exceptional species, most of these will require cryobiotechnologies that rely heavily on in vitro methods for long-term ex situ conservation. This study evaluated the current in vitro plant literature, as represented in Web of Science, to determine its taxonomic overlap with the families and genera of the 775 species currently listed as exceptional. More than 19,000 articles were evaluated. There were only five families with significant overlap between the in vitro literature and exceptional species, Fabaceae, Asteraceae, Orchidaceae, Arecaceae, and Rutaceae, and only three genera Citrus, Coffea, and Quercus. Additional gaps were found, with 14 exceptional families and half of the exceptional genera having no representation in the Web of Science search results. The 20 exceptional species with the most articles were all economically important species, and these had 343 threatened congeners that could benefit from this body of work. A highly important group of exceptional plants that was significantly under-represented in the literature was tropical woody species, which form the backbone of the diversity of the world’s threatened rainforests. Overall, there are areas of strength in the current state of in vitro research that could be leveraged for conservation, but there are also significant gaps where in vitro research needs to be prioritized to broaden its effective use for conserving plant diversity.
Valerie C. Pence, Emily Beckman Bruns. Scratching the surface: The in vitro research that will be critical for conserving exceptional plants to scale. In Vitro Cellular & Developmental Biology-Plant, 60:266-282, 2024.
