Whole genome transcriptome profiling of Thellungiella salsuginea guard cells under saline growth conditions

The overall objective was to document transcriptomic changes in the guard cells of Thellungiella salsuginea under short (1x) - and long-term (3x) saline growth conditions. For that. microarray analysis was performed using a 60-mer oligonucleotide probe array from Agilent (44 K, design number 031554, Santa Clara, CA, USA). It was clearly observed that salt salinity alters the transcriptomic landscape of Thellungiella guard cells. However, changes in gene expression were evident under 3x saline growth conditions compared to non-saline conditions. Similarly, more GO terms were significantly enriched in differentially expressed guard cell genes of 3x salt than 1x salt treated plants. Salt induced gene expression studies in the guard cells of Thellungiella salsuginea was conducted. For that, guard cells enriched samples were collected from light adapted plants grown under provided saline growth conditions. Two different salt treatment protocols, a short- and long-term, were applied to 7 weeks old Thellungiella plants by soaking the soil pots in salt solutions each time for two hours. In the long-term salt stress experiment plants were treated three times : (i) On day 1 and 2 (75 mM NaCl), (ii) on day 7 and 8 (150 mM NaCl), and (iii) on day 13 and 14 (200 mM NaCl) named as 3x salt. In the short-term salt stress experiment plants were treated with 200mM NaCl on day 13 and 14 (named as 1x salt) while the control group faced tap water (named as (-) salt). All samples were collected at the end of the salt experiments on day 15 to ensure that plants have the same plant age and developmental stage. Four guard cells enriched samples were collected from each group to conduct gene expression studies.