Caeiro André, Caeiro Sandra, Correia Sandra, Canhoto Jorge
Center for Functional Ecology, Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
Plants (Basel). 2022 May 19;11(10):1347. doi: 10.3390/plants11101347.
Somatic embryogenesis (SE) is a complex biological process regulated by several factors, such as the action of plant growth regulators, namely auxins, of which the most physiologically relevant is indole-3-acetic acid (IAA). In tamarillo, an optimized system for induction of SE creates, after an induction process, embryogenic (EC) and non-embryogenic (NEC). In this work the endogenous levels of auxin along the induction phase and in the samples were investigated using chemical quantifications by colorimetric reactions and HPLC as well as immunohistochemistry approaches. Differential gene expression and ) analysis during the induction phase was also carried out. The results showed that the endogenous IAA content is considerably higher in embryogenic than in non-embryogenic , with a tendency to increase as the dedifferentiation of the original explant (leaf segments) evolves. Furthermore, the degradation rates of IAA seem to be related to these levels, as non-embryogenic tissue presents a higher degradation rate. The immunohistochemical results support the quantifications made, with higher observable labeling on embryogenic tissue that tends to increase along the induction phase. Differential gene expression also suggests a distinct molecular response between EC and NEC.
体细胞胚胎发生（SE）是一个受多种因素调控的复杂生物学过程，这些因素包括植物生长调节剂的作用，即生长素，其中生理相关性最强的是吲哚 - 3 - 乙酸（IAA）。在番茄树中，一个优化的体细胞胚胎发生诱导系统在诱导过程后会产生胚性愈伤组织（EC）和非胚性愈伤组织（NEC）。在这项研究中，通过比色反应和高效液相色谱法进行化学定量以及采用免疫组织化学方法，对诱导阶段及样品中生长素的内源水平进行了研究。同时还对诱导阶段的差异基因表达进行了分析。结果表明，胚性愈伤组织中的内源IAA含量显著高于非胚性愈伤组织，并且随着原始外植体（叶片切段）的去分化进程有增加的趋势。此外，IAA的降解速率似乎与这些水平相关，因为非胚性组织呈现出更高的降解速率。免疫组织化学结果支持了所做的定量分析，在胚性组织上观察到更高的标记信号，且该信号在诱导阶段有增加的趋势。差异基因表达也表明胚性愈伤组织和非胚性愈伤组织之间存在明显的分子反应。
