AUTHOR=Ciacka Katarzyna , Tyminski Marcin , Wal Agnieszka , Gniazdowska Agnieszka , Krasuska Urszula 

TITLE=Nitric oxide–an antidote to seed aging modifies meta-tyrosine content and expression of aging-linked genes in apple embryos

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.929245

DOI=10.3389/fpls.2022.929245

ISSN=1664-462X

ABSTRACT=<p>Short-term (3 h) treatment of embryos isolated from accelerated aged apple seeds (<italic>Malus domestica</italic> Borkh.) with nitric oxide (NO) partially reduced the effects of aging. The study aimed to investigate the impact of the short-term NO treatment of embryos isolated from apple seeds subjected to accelerated aging on the expression of genes potentially linked to the regulation of seed aging. Apple seeds were artificially aged for 7, 14, or 21 days. Then, the embryos were isolated from the seeds, treated with NO, and cultured for 48 h. Progression of seed aging was associated with the decreased transcript levels of most of the analyzed genes (<italic>Lea1</italic>, <italic>Lea2a</italic>, <italic>Lea4</italic>, <italic>Hsp70b</italic>, <italic>Hsp20a</italic>, <italic>Hsp20b</italic>, <italic>ClpB1</italic>, <italic>ClpB4</italic>, <italic>Cpn60a</italic>, <italic>Cpn60b</italic>, <italic>Raptor</italic>, and <italic>Saur</italic>). The role of NO in the mitigation of seed aging depended on the duration of the aging. After 7 and 14 days of seed aging, a decreased expression of genes potentially associated with the promotion of aging (<italic>Tor</italic>, <italic>Raptor</italic>, <italic>Saur</italic>) was noted. NO-dependent regulation of seed aging was associated with the stimulation of the expression of genes encoding chaperones and proteins involved in the repair of damaged proteins. After NO application, the greatest upregulation of <italic>ClpB</italic>, <italic>Pimt</italic> was noted in the embryos isolated from seeds subjected to 7-day long accelerated aging, <italic>Hsp70b</italic>, <italic>Hsp70c</italic>, and <italic>Cpn</italic> in the embryos of seeds aged for 14 days, and <italic>Lea2a</italic> in the embryos of seeds after 21 days of aging. We also demonstrated the increased <italic>meta</italic>-tyrosine concentration depending or in respect the progression of artificial aging, and the NO-induced increased phenylalanine content in seeds artificially aged for 21 days. In the NO-treated embryos of seeds aged for 7 and 21 days, the level of tyrosine was almost doubled compared to the aged tissue. Our data confirmed the usage of <italic>meta</italic>-tyrosine as a marker of seed aging and indicated that the increased <italic>meta</italic>-tyrosine/tyrosine ratio could be related to the loss of seed viability.</p>