REPORT Maize seedlings produced from dry seeds exposed to liquid nitrogen display altered levels of shikimate pathway compounds Rosmery Pereira 1 & Melissa Arguedas 1 & Julia Martínez 1 & Lázaro Hernández 1 & Byron Enrique Zevallos 2 & Marcos Edel Martínez-Montero 1 & Lourdes Yabor 1 & Sershen 3 & José Carlos Lorenzo 1 Received: 23 April 2019 /Accepted: 26 June 2019 / Editor: Yong Eui Choi # The Society for In Vitro Biology 2019 Abstract In light of climate change and risks of food insecurity, it is becoming increasingly important to preserve plant germplasm in genebanks. Storage of seeds, particularly via cryopreservation, is one of the most proficient methods for ex situ plant germplasm conservation. Whilst seed cryo-banking can have little, to no, or even beneficial effects on subsequent seedling vigor in some species, it can lead to a number of plant abnormalities (morphological and physiological). This study investigated the effects of maize seed cryopreservation on seedling growth (until 14 d) and levels of selected amino acids produced in the shikimate pathway, a major link between primary and secondary metabolism. Seed cryopreservation reduced FW in recovered seedlings, reduced caffeic acid (2.5-fold decrease), and increased levels of all other shikimate pathway–related compounds assessed: phenylalanine (2.9-fold increase), tyrosine (2.6-fold increase), and shikimic (2.1-fold increase) and protocathecuic (3.1-fold increase) acids in cotyledons. Our results suggest that maize seed cryopreservation results in seedlings that exhibit signs of an ‘overly’ efficient and caffeic acid–deficient shikimate pathway, possibly related to their reduced growth during a highly vulner- able growth stage. However, these metabolic abnormalities manifested most severely in the maternal (cotyledonary), as opposed to vegetative (roots, stems, and leaves), tissues and hence are likely to disappear when the seedlings shed the cotyledons and become completely autotrophic. Keywords Biochemical . Cryopreservation . Liquid nitrogen . Shikimic acid pathway . Phenolics . Zea mays L Introduction The challenges that climate change poses to agricultural pro- ductivity and biodiversity conservation have motivated global attempts to preserve plant germplasm in genebanks (Berjak and Pammenter 2014; Gonzalez-Arnao et al. 2014; Mira et al. 2015). These efforts have shown that seed storage, more specifically seed cryopreservation (i.e., storage at cryogenic temperatures, most often in liquid nitrogen (LN)), is one of the most proficient methods of ex situ plant germplasm conserva- tion (Pérez-Rodríguez et al. 2017). Most cryobanks prioritize the storage of crop and vegetable seeds such as maize (Zea mays L.) which is stored in numerous cryobanks globally (Gonzalez-Arnao et al. 2014). This is largely because this species is the second most important agricultural crop world- wide, after rice (CIMMYT 2016). Given its prioritization in cryobanks, some studies have looked at the effects of maize seed cryopreservation on sub- sequent germination, seedling growth and vigor, seedling bio- chemistry, and field performance (Arguedas et al. 2018a, b). These papers reported the effects of LN on various parameters at the early germination stages of maize seeds (0, 7, and 14 d). These included the germination percentage, fresh weight (FW) of different seedling parts, levels of chlorophyll pig- ments (a, b), carotenoids, malondialdehyde, other aldehydes, phenolics (cell wall–linked, free), and proteins. Maize seeds * José Carlos Lorenzo jclorenzo@bioplantas.cu 1 Laboratory for Plant Breeding and Conservation of Genetic Resources, Bioplant Center, University of Ciego de Avila, 69450 Ciego de Ávila, Cuba 2 Escuela Superior Politécnica Agropecuaria de Manabí Manuel Félix López (ESPAMMFL), Campus Politécnico El Limón, Carrera de Ingeniería Agrícola, Calceta, Manabí, Ecuador 3 School of Life Sciences, University of KwaZulu-Natal, Durban 4001, South Africa In Vitro Cellular & Developmental Biology - Plant https://doi.org/10.1007/s11627-019-09995-1