Plant physiology and biochemistry : PPB 2016
Combined herbicide and saline stress differentially modulates hormonal regulation and antioxidant defense system in Oryza sativa cultivars.
Plants are simultaneously exposed to a combination of biotic and abiotic stresses in field conditions. Crops respond to the combined stress in a unique way which cannot be understood by extrapolating the results of individual stress. In the present study, effects of individual and combined stress of herbicide (2,4-dichlorophenoxyacetic acid) and salinity (NaCl) on two Oryza sativa cultivars (ZJ 88 and XS 134) were investigated. Both herbicide and saline stress affected the plant growth differentially and produced oxidative stress in rice cultivars. Interestingly, the combination of herbicide and salinity showed a significant protection to both rice cultivars by reducing ROS (H2O2, O2(-)) and lipid peroxidation through modulation of enzymatic (SOD, POD, CAT and APX) and non-enzymatic (TSP, sugars, phenolic and proline) antioxidants. In addition, active regulation of transcript levels of genes encoding Na(+) and K(+) (erm' data-tid='825' href='#term-825'>ata-tid='824' href='#term-824'>term' data-tid='823' href='#term-823'>tid='822' href='#term-822'>='term' data-tid='821' href='#term-821'>OsHKT1;5, OsLti6a,b, OsHKT2;1, OsSOS1, OsCNGC1, OsNHX1 and OsAKT1) transporter proteins reduced sodium and enhanced potassium accumulation under combined stress, resulted a better growth and ionic homeostasis in both rice cultivars. The production of ABA and IAA was significantly higher in cultivar XS 134 compared to cultivar ZJ 88 under control conditions. However, combined herbicide and saline stress enhanced the accumulation of phytohormones (IAA and ABA) and transcription of ethylene in cultivar ZJ 88, which might be one of the factors responsible for poor salt tolerance in sensitive cultivar. These findings indicated that herbicide application under saline stress confers tolerance to salinity in rice cultivars, likely by reducing oxidative damage, modulating mineral absorption, upgradation of antioxidant defense and by dynamic regulation of key genes involved in Na(+) and K(+) homeostasis in plants.
|OsHKT1||Os06g0701700||Q0D9S3 A0A0P0X0T3 A0A0N7KMP0|
|<a class||Os01g0307500||Q0JNB6 B9EVS1|
|tid='822||Os06g0701700||Q0D9S3 A0A0P0X0T3 A0A0N7KMP0|
|term'||Os12g0641100||Q0ILJ6 Q5ICN3 A0A0P0YDP3 A0A0P0YCQ9|
|erm' d||Os01g0648000||Q0JKV1 A0A0P0V5X9|
|and IAA was si||Os01g0348900||Q0JMY8 B7E7K3|