Arrillaga Isabel, Morcillo Marian, Zanón Israel, Lario Francisco, Segura Juan, Sales Ester
ERI BiotecMed, Departamento de Biología Vegetal, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.
TRAGSA, Vivero de Maceda, Carretera Maceda - Baldrei, Ourense, Spain.
Front Plant Sci. 2019 Feb 19;10:138. doi: 10.3389/fpls.2019.00138. eCollection 2019.
Maritime pine ( Aiton) is a coniferous native of the Mediterranean basin. Because of its adaptability to a wide range of environmental conditions, the species have become a model for studies in coniferous forest management and functional genomics. Somatic embryogenesis (SE) has been so far, the preferred biotechnological strategy for maritime pine breeding programs initiated at the middle-end of the 20th century. To overcome the limitations of the induction and maturation phases in maritime pine SE, we analyzed the possible maternal influence on the embryogenic capability of megagametophytes from controlled crosses, as well as the effect of the temperature and water availability during SE process on the production of plants. A strong maternal effect on the embryogenic potential of maritime pine megagametophytes was observed in our experiments using half-sib and full-sib progenies, while paternal effect was almost undetectable. Besides, it seems possible to improve somatic embryo production of maritime pine megagametophytes by adjusting optimal temperature throughout the process: 28°C during induction and proliferation, and 23°C during the maturation phase. Using induction and proliferation media with reduced water availability (6 g/L Gelrite) can also increase embryo production. Since other limitation of maritime pine SE is culture decline of embryogenic masses (EMs), that reduces embryo yield and germination, we assessed the profile of ABA and IAA and the expression of two embryogenesis-related genes ( and ) during maturation of EMs of two morphotypes that differed in their maturation capability. Spiky morphotype (SK), with high maturation capability, had a steady increase in both hormones along the 12 weeks of the maturation, whereas ABA content in smooth morphotype picked at the 4th week and dropped. EMs with this morphotype also had a higher IAA content at the beginning of the maturation. A decrease of and gene expression over the course of embryo development was found to be characteristic of the SK with high maturation capability.
海岸松（Aiton）是地中海盆地的一种针叶原生植物。由于其对广泛环境条件的适应性，该物种已成为针叶林管理和功能基因组学研究的模式植物。体细胞胚胎发生（SE）一直是20世纪中后期启动的海岸松育种计划首选的生物技术策略。为了克服海岸松体细胞胚胎发生诱导和成熟阶段的局限性，我们分析了来自控制杂交的雌配子体胚胎发生能力可能受到的母体影响，以及体细胞胚胎发生过程中温度和水分供应对植株产生的影响。在我们使用半同胞和全同胞后代进行的实验中，观察到母体对海岸松雌配子体的胚胎发生潜力有强烈影响，而父体影响几乎无法检测到。此外，似乎可以通过在整个过程中调整最佳温度来提高海岸松雌配子体的体细胞胚胎产量：诱导和增殖阶段为28°C，成熟阶段为23°C。使用水分供应减少（6 g/L 结冷胶）的诱导和增殖培养基也可以增加胚胎产量。由于海岸松体细胞胚胎发生的另一个限制是胚性愈伤组织（EMs）的培养衰退，这会降低胚胎产量和发芽率，我们评估了两种成熟能力不同的形态型EMs成熟过程中脱落酸（ABA）和吲哚乙酸（IAA）的概况以及两个胚胎发生相关基因（和）的表达。具有高成熟能力的尖刺形态型（SK）在成熟的12周内两种激素均稳步增加，而光滑形态型的ABA含量在第4周达到峰值后下降。这种形态型的EMs在成熟开始时也具有较高的IAA含量。发现高成熟能力的SK在胚胎发育过程中基因表达下降是其特征。
