Expression analysis of transcription-factor genes related to endoplasmic reticulum stress signaling pathway in alfalfa (Medicago sativa L.)

Identification of genes playing a role in stress tolerance has great importance in the elucidation of biotic and abiotic plant stress pathways. In this study, comparative analysis was carried out for genes (bZIP60 and bZIP28) activated during ER stress response in plant root and leaf tissues. The relative water content (RWC) of the plant leaves grown under stress factors, di-thio-threitol (DTT) and polyethylene glycol (PEG) were measured at critical periods. Expression analysis of bZIP60 and bZIP28 genes involved at ER stress pathways was evaluated through RT-PCR assay at determined intervals of time, (in Nimet cultivar of alfalfa) under the artificial ER stress implemented by DTT and drought stress by PEG. According to the results, it was determined that DTT reduced the functionality of these two genes involved in ER stress pathways. The most critical time for plants in drought (PEG) tolerance was 8th h after treatment, in which the expression of bZIP60 in leaves was increased compared to other applications (about 42 times). Furthermore, according to the findings, the two studied gene regions, bZIP60 have a more active role in the stress pathways than bZIP28; and the leaf tissues were more affected than the root tissues under the stress conditions.