G-protein β subunit AGB1 positively regulates salt stress tolerance in Arabidopsis

The heterotrimeric G‐protein β subunit, AGB1, plays multiple roles in the Arabidopsis salinity response

“…; Ma et al . ). Interestingly, different from the sos mutants, which were originally identified based upon hypersensitivity to salt‐induced inhibition of root growth (Supporting Information http://onlinelibrary.wiley.com/doi/10.1111/pce.12542/suppinfo) (Wu et al .…”

“…Ma et al . () showed that the expression level of known Na + transporters HKT1 and NHX1 in the wild type is much higher than the expression in agb1 following salt treatment. However, we investigated the transcript levels of HKT1 , NHX1 and NHX7/SOS1 but did not see significant differences between wild‐type and agb1‐2 plants treated hydroponically with 100 m m NaCl for 3 and 27 h (Supporting Information http://onlinelibrary.wiley.com/doi/10.1111/pce.12542/suppinfo), suggesting that, at least under our conditions, AGB1 does not regulate Na + transporter activity at the level of transcription.…”

“…Ma et al . () reported that agb1 had significantly lower Na + and K + content after 12 d of 100 and 150 m m NaCl treatment on agar plates, although the Na + /K + ratio was higher. However, Ma et al .…”

“…Ma et al . () also reported that after 100 or 150 m m NaCl treatment on agar plates for 12 d, the agb1 mutant has shorter primary roots, less Na + and K + , and lower antioxidant enzyme activity, and that the mutant accumulates less proline upon 200 m m NaCl treatment. The agb1 mutation also impairs germination under saline conditions (Ma et al .…”

“…; Ma et al . ). Mutants of the sole Arabidopsis G‐protein β subunit, AGB1, have been found to be hypersensitive to salt stress at both the seedling stage when grown on agar plates and at the mature stage when grown in soil, showing a shoot bleaching phenotype and a lower survival rate as compared to wild type (Colaneri et al .…”