Assem Shireen K, Basry Mahmoud A, Taha Taha A, El-Aziz M H Abd, Alwa Taher, Fouad Walid M
Department of Plant Molecular Biology, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt.
Genetics Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt.
J Genet Eng Biotechnol. 2023 May 15;21(1):58. doi: 10.1186/s43141-023-00517-6.
Sudangrass (Sorghum sudanense) is a major biomass producer for livestock feed and biofuel in many countries. It has a wide range of adaptations for growing on marginal lands under biotic and abiotic stresses. The immature inflorescence is an explant with high embryogenic competence and is frequently used to regenerate different sorghum cultivars. Caffeic acid O-methyl transferase (COMT) is a key enzyme in the lignin biosynthesis pathway, which limits ruminant digestion of forage cell walls and is a crucial barrier in the conversion of plant biomass to bioethanol. Genome editing by CRISPR/Cas9-mediated mutagenesis without a transgenic footprint will accelerate the improvement and facilitate regulatory approval and commercialization of biotech crops.
We report the overcome of the recalcitrance in sudangrass transformation and regeneration in order to use genome editing technique. Hence, an efficient regeneration system has been established to induce somatic embryogenesis from the immature inflorescence of two sudangrass cultivars on four MS-based media supplemented with different components. Our results indicate an interaction between genotype and medium composition. The combination of Giza-1 cultivar and M4 medium produces the maximum frequency of embryogenic calli of 80% and subsequent regeneration efficiency of 22.6%. Precise mutagenesis of the COMT gene is executed using the CRISPR/Cas9 system with the potential to reduce lignin content and enhance forage and biomass quality in sudangrass.
A reliable regeneration and transformation system has been established for sudangrass using immature inflorescence, and the CRISPR/Cas9 system has demonstrated a promising technology for genome editing. The outcomes of this research will pave the road for further improvement of various sorghum genotypes to meet the global demand for food, feed, and biofuels, achieving sustainable development goals (SDGs).
苏丹草（高粱属苏丹草种）是许多国家用于生产牲畜饲料和生物燃料的主要生物质来源。它对生物和非生物胁迫下的边际土地具有广泛的适应性。未成熟花序是一种具有高胚性能力的外植体，常用于再生不同的高粱品种。咖啡酸 O - 甲基转移酶（COMT）是木质素生物合成途径中的关键酶，它限制了反刍动物对饲料细胞壁的消化，并且是植物生物质转化为生物乙醇的关键障碍。通过 CRISPR/Cas9 介导的诱变进行基因组编辑且无转基因痕迹，将加速生物技术作物的改良，并促进其监管审批和商业化。
为了利用基因组编辑技术，我们报道了克服苏丹草转化和再生难的问题。因此，已经建立了一种高效的再生系统，以在添加不同成分的四种基于 MS 的培养基上，从两个苏丹草品种的未成熟花序诱导体细胞胚胎发生。我们的结果表明基因型和培养基成分之间存在相互作用。吉萨 - 1 品种与 M4 培养基的组合产生的胚性愈伤组织最大频率为 80%，随后的再生效率为 22.6%。使用 CRISPR/Cas9 系统对 COMT 基因进行精确诱变，有可能降低苏丹草中的木质素含量并提高饲料和生物质质量。
利用未成熟花序为苏丹草建立了可靠的再生和转化系统，并且 CRISPR/Cas9 系统已证明是一种有前景的基因组编辑技术。本研究结果将为进一步改良各种高粱基因型铺平道路，以满足全球对食品、饲料和生物燃料的需求，实现可持续发展目标（SDGs）。
