الگوي متيله شدن DNA در ريشه و ساقه جو تحت تنش شوري

DNA methylation Pattern in shoot and root of barley under salinity stress

ﺷﻮري ﻳﻜﻲ از ﻋﻮاﻣﻞ اﺻﻠﻲ ﻣﺤﺪود ﻛﻨﻨﺪه ﺗﻮﻟﻴﺪ ﻣﺤﺼﻮﻻت ﻛﺸﺎورزي ﻣﺤﺴﻮب ﻣﻲﺷﻮد. ﻣﻄﺎﻟﻌﺎت ﻣﺨﺘﻠﻒ ﻧﺸﺎن دﻫﻨﺪه ﺗﻐﻴﻴﺮ ﺑﻴﺎن ژنﻫﺎ در ﻧﺘﻴﺠﻪ ﺗﻐﻴﻴﺮات ﻓﺮاژﻧﺘﻴﻜﻲ ﺗﺤﺖ ﺗﻨﺶﻫﺎي ﻏﻴﺮ زﻳﺴﺘﻲ اﺳﺖ. در اﻳﻦ ﻣﻄﺎﻟﻌﻪ، از ﺗﻜﻨﻴﻚ CRED-RA ﺑﺮاي ﺑﺮرﺳﻲ ﺗﻐﻴﻴﺮات اﻟﮕﻮي ﻣﺘﻴﻠﻪ ﺷﺪن ﺗﻮاﻟﻲﻫﺎي CCGG در ﺳﺎﻗﻪ و رﻳﺸﻪ درﻗﻢ ﺟﻮ Sahara3771 )ﻣﺘﺤﻤﻞ ﺑﻪ ﺗﻨﺶ ﺷﻮري( و Clipper )ﺣﺴﺎس ﺑﻪ ﺗﻨﺶ ﺷﻮري( ﺗﺤﺖ دو ﺗﻴﻤﺎر ﺻﻔﺮ و 100 ﻣﻴﻠﻲ ﻣﻮﻻر NaCl اﺳﺘﻔﺎده ﺷﺪ. ﻧﻤﻮﻧﻪﻫﺎي ﺑﺮگ و رﻳﺸﻪ ﺟﻬﺖ اﺳﺘﺨﺮاجDNA ، 24 ﺳﺎﻋﺖ، ﺳﻪ ﻫﻔﺘﻪ و ﭘﻨﺞ ﻫﻔﺘﻪ ﭘﺲ از اﻋﻤﺎل ﺷﻮري ﺑﺮداﺷﺖ ﺷﺪ. ﺗﺤﺖ ﺗﻴﻤﺎر ﺷﻮري در ﺑﺨﺶ ﻫﻮاﻳﻲ Sahara3771 در ﻣﻘﺎﻳﺴﻪ ﺑﺎ ﺗﻴﻤﺎر ﺷﺎﻫﺪ، 26/2 ﺟﺎﻳﮕﺎهﻫﺎ ﻣﺘﻴﻠﻪ و 15/86 آنﻫﺎ ﻣﺘﻴﻞزداﻳﻲ ﺷﺪﻧﺪ. در رﻳﺸﻪ آن ﻧﻴﺰ 7/74 و 9/38 از ﺟﺎﻳﮕﺎهﻫﺎ ﺑﻪ ﺗﺮﺗﻴﺐ اﻓﺰاﻳﺶ و ﻛﺎﻫﺶ ﺳﻄﺢ ﻣﺘﻴﻠﻪ ﺷﺪن ﺗﺤﺖ ﺗﻴﻤﺎر ﺷﻮري در ﻣﻘﺎﻳﺴﻪ ﺑﺎ ﺷﺎﻫﺪ داﺷﺘﻨﺪ. در ﺑﺨﺶ ﻫﻮاﻳﻲ Clipper 17/02% و 11/74% ﺟﺎﻳﮕﺎهﻫﺎ ﺗﺤﺖ ﺗﻴﻤﺎر ﺷﻮري ﺑﻪ ﺗﺮﺗﻴﺐ اﻓﺰاﻳﺶ و ﻛﺎﻫﺶ ﺳﻄﺢ ﻣﺘﻴﻠﻪ ﺷﺪن در ﻣﻘﺎﻳﺴﻪ ﺑﺎ ﺗﻴﻤﺎر ﺷﺎﻫﺪ داﺷﺘﻨﺪ. در رﻳﺸﻪ اﻳﻦ ژﻧﻮﺗﻴﭗ ﻧﻴﺰ ﻣﻘﺎدﻳﺮ اﻓﺰاﻳﺶ و ﻛﺎﻫﺶ ﺳﻄﺢ ﻣﺘﻴﻠﻪ ﺷﺪن ﺗﺤﺖ ﺗﻴﻤﺎر ﺷﻮري ﺑﻪ ﺗﺮﺗﻴﺐ 10/67 ﺑﻮد. در ﻣﺠﻤﻮع ﺗﻌﺪاد ﺟﺎﻳﮕﺎهﻫﺎي ﺑﺪون ﺗﻐﻴﻴﺮ در ﺑﺨﺶ ﻫﻮاﻳﻲ ﺑﻴﺸﺘﺮ از رﻳﺸﻪ ﺑﻮد. ﻫﻤﭽﻨﻴﻦ ﺗﻌﺪاد ﺟﺎﻳﮕﺎه ﺑﺪون ﺗﻐﻴﻴﺮ در ﺑﺨﺶ ﻫﻮاﻳﻲ Clipper ﺑﻴﺸﺘﺮ از Sahara3771 ﺑﻮد. ﻧﺘﺎﻳﺞ ﻧﺸﺎن دادﻧﺪ ﻛﻪ ﺗﻐﻴﻴﺮات اﻟﮕﻮي ﻣﺘﻴﻠﻪ ﺷﺪن ﻣﻲﺗﻮاﻧﺪ ﻳﻜﻲ از ﻓﺎﻛﺘﻮرﻫﺎي ﻛﻠﻴﺪي دﺧﻴﻞ در ﺗﺤﻤﻞ ﺑﻴﺸﺘﺮ ﺑﻪ ﺷﻮري در ﺟﻮ ﺑﺎﺷﺪ.

Salinity is one of the most crucial factors, which inhibits crop production. A large number of evidence reveal that epigenetic mechanisms modulate the gene expression in plants under abiotic stresses. Obviously, by understanding epigenetic regulation of plant growth and response to stresses, a heritable variation could be develop for crop breeding. In this study the DNA methylation alteration under salt stress analyzed in two barley cultivars differing in salt tolerance, namely Sahara3771 and Clipper. Coupled Restriction Enzyme Digestion-Random Amplification (CRED-RA) was utilized to detect CCGG sequence methylation alternation in shoot and root of the plants growing under o and 100 mM NaCl treatment. Leaf and root samples for DNA extraction were harvested 24 hours, 3 weeks, and 5 weeks after salt treatment. The results revealed that under salinity stress in shoot of Sahara3771 26.20% and 15.86% of sites were hypermethylated and demethylated respectively compared to control. Average number of hyper and demethylated sites in root of Sahara3771 were 74.7% and 38.9% respectively. In shoot of Clipper 17.02% of sites was hypermethylated and 11.74% of them demethylated. Average number of hyper and demethylated sites in root of Clipper were 67.10% and 5.7% respectively. Totally, number of methyl-changed sites in shoots was higher than roots in both genotype. In addition, number of methyl-unchanged sites in shoot of Sahara3771 was higher than Clipper. These results revealed that alteration of DNA methylation in plants could be a key factor in adaptation and toleration of plants to salinity.