Somatic embryogenesis in Abies nebrodensis, an endangered Sicilian fir

Abstract

Somatic embryogenesis, as a promising biotechnological tool for many conifer trees, has never been applied for the Abies nebrodensis species. Although all the encouraging results previously obtained by the EU LIFE (European LIFE program) funded projects in over ten years, the critically endangered Sicilian fir remains alarmingly close to extinction. In this study, we reported the first protocol of somatic embryogenesis obtained from mature zygotic embryos of the Abies nebrodensis. Seeds from Abies adult trees with specific identification numbers (IN) were collected and full seeds were identified by X-ray. Different experiments were carried out for callus initiation, from both zygotic immature and mature embryos, testing different culture media. The immature embryos did not give embryogenic tissue (ET). Embryogenic callus (EC) was successfully induced from mature embryos with variable frequencies (0–40%). Schenk and Hilderbrandt (SH) was the most suitable initiation medium where the obtained callus initiation rate reached up to 40% for IN7 (first experiment). 6-benzylaminopurine (BAP) showed to be essential to induce EC (second experiment). IN8 presented the highest callus initiation rate (40%) among all tested donor trees, whereas IN13 recorded the lowest rate with 4% (third experiment). ET maturation from each singular embryo of IN7, IN8, IN10 and IN21 was successfully achieved in SH medium containing 37,83 µM abscisic acid (ABA), 8% of polyethylene glycol (PEG-4000) and 4% maltose. The encapsulation technology was assessed on the obtained ET and its proliferation was observed after encapsulation.

Under Stress: Searching for Genes Involved in the Response of Abies pinsapo Boiss to Climate Change

“…Given the extended reproductive time required for these coniferous trees, the multiplication of the best-suited genotypes identified by using molecular markers and genomic data can be accelerated through vegetative multiplication via somatic embryogenesis (SE). Protocols for the efficient production of somatic embryos have been developed for several conifer species [58,59], and embryogenic cultures can be cryopreserved for long periods [60]. SE technology, in combination with molecular tools [61] (this work), could yield elite genotypes for the conservation of pinsapo forests.…”

“…developed for several conifer species [58,59], and embryogenic cultures can be cryopreserved for long periods [60]. SE technology, in combination with molecular tools [61] (this work), could yield elite genotypes for the conservation of pinsapo forests.…”

Current status of the cryopreservation of embryogenic material of woody species

“…Since the first reports on SE ( Chalupa, 1985 ; Hakman et al., 1985 ), this propagation method has been mainly developed in species with economical relevance. However, in the last years it has also been developed for endangered species ( Ahn and Choi, 2017 ; Ahn et al., 2019 ; Maruyama and Hosoi, 2019 ; Jouini et al., 2023 ).…”

Effects of plant growth regulators and sucrose on proliferation and quality of embryogenic tissue in Picea pungens

“…The first success of somatic embryogenesis in coniferous species can be dated back to 1985, when Hakman et al 6 used immature zygotic embryos of Norway spruce ( Picea abies ) to induce embryogenic tissue (ET) and then obtained mature somatic embryos (SEs). Several articles have been published since 2000 on optimization of somatic embryogenesis in coniferous species, including: Pinus radiata 7 , Picea abies 8 , Picea glauca 9 , Larix hybrids 10 , Korean pine 11 – 14 , Abies nebrodensis 15 , Abies nordmanniana 16 , Abies alba 17 and blue spruce 1 . The proliferation of ET together with SE maturation are key steps for large-scale propagation and longterm preservation of coniferous germplasm 15 .…”

“…Several articles have been published since 2000 on optimization of somatic embryogenesis in coniferous species, including: Pinus radiata 7 , Picea abies 8 , Picea glauca 9 , Larix hybrids 10 , Korean pine 11 – 14 , Abies nebrodensis 15 , Abies nordmanniana 16 , Abies alba 17 and blue spruce 1 . The proliferation of ET together with SE maturation are key steps for large-scale propagation and longterm preservation of coniferous germplasm 15 . Nielsen et al 16 reported strong clonal effects in most of the traits during the propagation process via SEs in Abies nordmanniana 16 .…”