Pez J, Araya-Valverde E, Carro G, Abdelnour-Esquivel A
Centro de Investigacien Biotecnolog, Instituto Tecnolico de Costa Rica, Cartago, Costa Rica.
Escuela de Biolog, Instituto Tecnolico de Costa Rica, Cartago; Centro Nacional de Innovaciones Biotecnolicas (CENIBiot-CENAT), San Jose, Costa Rica.
Cryo Letters. 2017 Nov/Dec;38(6):445-454.
Maize breeding programs focus on the development of hybrid varieties and the cultivation of landrace materials is discouraged; however, they are a valuable source of genes and their conservation is advisable.
Analyzing some stress indicators during cryopreservation of maize landrace seeds.
Seeds of 35 accessions of landrace maize were collected in two regions of Costa Rica and cryopreserved by direct immersion in liquid nitrogen (LN). Membrane integrity, germination of seeds and DNA methylation in tissues were analyzed 5, 7 and 9 days after rewarming.
Germination of landrace maize seeds was near 100 % for most accessions. No statistically significant differences in germination were observed between non-cryopreserved controls and seeds stored in LN for 1 h or 1 year. Membrane integrity, number of leaves and root and shoot length of plantlets were similar after cryostorage of seeds for 1 h and 1 year. A short delay in growth of cryostored seed compared to non-frozen controls was observed. Changes in the proportion of DNA methylation were noted from 0 to day 9 in the organs studied depending on the germination stage and cryopreservation treatment.
It may be inferred that many of the methylated genes were related to growth and development. In addition, a cryobank of maize landraces from two regions of Costa Rica was established.
玉米育种计划专注于杂交品种的培育，不鼓励种植地方品种材料；然而，它们是宝贵的基因来源，建议加以保存。
分析玉米地方品种种子冷冻保存期间的一些胁迫指标。
在哥斯达黎加的两个地区收集了35份地方品种玉米的种子，并通过直接浸入液氮（LN）进行冷冻保存。在解冻后5、7和9天分析膜完整性、种子发芽率和组织中的DNA甲基化情况。
大多数地方品种玉米种子的发芽率接近100%。未观察到未冷冻保存的对照种子与在液氮中保存1小时或1年的种子在发芽率上有统计学显著差异。种子冷冻保存1小时和1年后，幼苗的膜完整性、叶片数量以及根和芽的长度相似。与未冷冻的对照相比，观察到冷冻保存的种子生长略有延迟。根据发芽阶段和冷冻保存处理，在所研究的器官中，从第0天到第9天观察到DNA甲基化比例的变化。
可以推断，许多甲基化基因与生长和发育有关。此外，还建立了来自哥斯达黎加两个地区的玉米地方品种种子库。
