TITLE:
Knockdown of GmSOG1 Compromises Drought Tolerance in Transgenic Soybean Lines
AUTHORS:
Samuel Aduse Poku, Peter Nkachukwu Chukwurah, Htut Htet Aung, Ikuo Nakamura
KEYWORDS:
GmSOG1, DNA Damage, Abiotic Stress, Drought Stress
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.12 No.1,
January
20,
2021
ABSTRACT: Plants are regularly exposed to myriads of stress factors
that cause tremendous damage to their genetic make-up. To ensure genome stability
and survival over several generations under harsher environmental conditions, plants
have evolved a unique mechanism for dealing with DNA damage known as the DNA damage
response pathway (DDR). It has been proposed that there may exist a relationship
between the DNA damage response pathway and abiotic stress response in plants. To
further investigate this relationship, we knocked
down the soybean suppressor of gamma response 1 gene (GmSOG1), a master regulatory gene of
the DDR, in soybean plants and subjected the generated transgenic plants to drought
stress analysis. Gene expression analysis of the GmSOG1 gene in drought stressed soybean tissues revealed high levels
of expression in buds and young leaves. The root lengths and root fresh weights
of transgenic soybean plants grown on Murashige and Skoog media supplemented with
Gamborg B5 vitamins (MSB5 media) containing 200 mM mannitol for 10 days were significantly
lesser than those of drought stressed wild-type
plants. Polyethylene glycol (PEG) induced drought stress assay in vivo resulted
in significant damage in transgenic plants compared with wild-type plants. Also,
the relative expressions of known drought responsive
transcription factors such as GmDREB1 and GmLEA as well as antioxidation
related genes like GmAPX and GmCAT were downregulated in transgenic
soybean lines relative to wild-type plants. Moreover, wild-type soybean plants accumulated
more chlorophyll and less malondialdehyde (MDA) than transgenic lines. A confirmatory
experiment in GmSOG1 overexpressing Arabidopsis plants also showed significantly higher survival rates and anti-oxidation enzyme accumulation in drought stressed GmSOG1 overexpressing Arabidopsis lines compared with wild-type plants. These results suggest
that the SOG1 gene may play active roles in plant abiotic stress defense.