Document Type : Original Article

Authors

• Seyed Hamid Reza Hashemi-Petroudi ¹
• Hamid Reza Ghorbani ²

¹ Department of Genetic Engineering and Biology, Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT), Sari Agricultural Sciences and Natural Resources University (SANRU), Iran

² Assistant Professor, Crop and Horticultural Science Research Department, Mazandaran Agricultural and Natural Resources Research and Education Center, AREEO, Sari, Iran

Abstract

Introduction
Abiotic stress has always affected the plants growth and development through morphological and physiological, biochemical and anatomical alterations, leading to reduce yield and limit the crop area. Development is a completed process that depends on a cell to cell communication to regulate growth and differentiation. In the past, phytohormones were considered the important players of cell signaling. High-throughput techniques have led to finding many new plant peptides over the last years. DEVILS are small peptides that play an important role in plant growth and development and are effective in controlling plant responses to environmental changes caused by stress. These small peptides act in the growth process of plants similar to phytohormones and are called peptide hormones that play a role in plants as molecular messengers. Aeluropus littoralis, belongs to Poaceae that can tolerate NaCl up to 600 mM and grows in marshes, salty and drought lands. Because of C4 photosynthesis system and proper physiological properties, A. littoralis as a halophyte plant could be known as a great source of genes related to salt tolerance.

Materials and methods
In this research, the changes of expression of four genes namaly AlDVL1, AlDVL2, AlDVL3, and AlDVL6 were investigated under salinity stress (600 mM) in Aeluropus littoralis as a halophyte plant at five time-points of 0, 3, 6, 48 and 168 hours post stress (hps). Leaves and roots were sampled and grounded in liquid nitrogen, and total RNA was extracted using Threezol reagent (Riragene). First strand cDNA synthesis and RT-qPCR were performed according to kit instructions. PCR amplification was performed in C1000™ Thermal Cycler (Bio-Rad, USA) according to the company’s suggestions. The 2-ΔΔct method was applied for the relative expression analysis.

Results and discussion
The results showed that the expression pattern of AlDVL genes was affected by salinity stress and had a significant change in root and leaf tissues. In all of genes except AlDVL6, expression changes in the leaf were higher than the root. The highest value of expression in the leaf and root tissue was observed at 48 hps (12.12) and 168 hps (14.83) for AlDVL2, respectively. Expression pattern of AlDVL genes was tissue-specific, and different pattern was observed in root and leaf tissues, while in each tissue, all genes had similar pattern. For example, in all of the studied genes in leaf tissue, the amount of expression of genes was first reduced in the initial time-point, and then the expression increased to 48 hours after the stress and eventually decreased over 168 hps. This trend of change was observed among different genes with a slight difference in leaf tissue. In the root tissue, the trend of gene expression was similar except for the AlDVL3 gene. From the first hours to 48 hps, gene expression value was declined, but was peaked at 168 hps. According to the results, it can be stated that the genes act specifically in each tissue. The results of correlation analysis in different tissues showed that AlDVL6 and AlDVL3 expression correlation in both leaf and root tissues had a negative and significant relation (-0.6) with inverse effects.

Conclusions
Halophyte plants by regulating their gene expression can respond to different various abiotic stresses. Expression pattern of phytohormones -related genes in leaf and root tissue can be taken as an indication of their functional relevance at different time-points of salt stress.

Keywords

• Aeluropus littoralis
• DEVI
• Halophytes
• Phytohormone
• Small polypeptides