Comparative physiological and molecular responses of a common aromatic indica rice cultivar to high salinity with non-aromatic indica rice cultivars

Abstract

In an attempt to understand the molecular basis of salt-stress response in the aromatic rice Gobindobhog, a comprehensive analysis encompassing physiological or biochemical assays and gene expression studies under high salt (200 mM NaCl) supply regimes were initiated and compared with a salt-sensitive (M-1-48) and salt-tolerant (Nonabokra) rice. The detrimental effects of salinity stress were the most pronounced in Gobindobhog, as reflected by the maximally increased root to shoot ratio, the highest chlorophyll degeneration, the highest foliar concentration of Na(+) ions and peroxide content, with their maximum increment after salt treatment. The amplification of oxidative damages was further stimulated by the accumulation of putrescine and lipid peroxidation-derived toxic degradation products (increased malondialdehyde and lipoxygenase activity), which were comparable in M-1-48 and Gobindobhog. Antioxidants like anthocyanin and particularly cysteine and the osmolytes like reducing sugar, proline and polyamines (spermidine and spermine) showed the highest level in Nonabokra. While the inhibition of catalase activity occurred in all the varieties following salt-stress, the maximum induction in guaiacol peroxidase activity, elevated cysteine and proline levels in Gobindobhog probably constituted the detoxification mechanism obligatory for its survival. Intensification of the aroma content with salt treatment was markedly noted in Gobindobhog. A very low abundance of Rab16A/SamDC transcript and the corresponding proteins were observed both in M-1-48 and Gobindobhog, induced only after salt-stress, whereas they were constitutively expressed in Nonabokra. Thus, our data reflect Gobindobhog as a salt-sensitive cultivar, susceptible to high-stress-induced growth-inhibition, ion imbalances, membrane/oxidative damages with lower expression of stress-tolerant genes.

Response of Rice under Salinity Stress: A Review Update

“…The identification of the metabolic sites affected by salt stress and, conversely, the mechanisms utilized by plants to survive salinity stress has also been well understood. Molecular screening for salt tolerance in rice accounts for the recent approaches for understanding the response of rice under salt stress and thereby mines useful alleles responsible for salt tolerance [91,107,[127][128][129]. The identification of saltol QTL in 2010 by Thomson et al has widened the horizon for further work and development as far as genetic approach is being concerned [130][131][132][133][134][135].…”

Effects of Salt Stress after Late Booting Stage on Yield and Antioxidant Capacity in Pigmented Rice Grains and Alleviation of the Salt-Induced Yield Reduction by Exogenous Spermidine

“…It is considered the most serious threat to agriculture and to the environment in many parts of the world (Parida and Das, 2005). Salinity stress causes a low soil water potential, accumulation of toxic sodium ions, nutritional imbalance and subsequently leads to an over-accumulation of reactive oxygen species (ROS) (Roychoudhury et al, 2008). Salinity results in growth reduction during the vegetative growth stage and yield reduction during the reproductive stage.…”

Crescimento De Mudas De Tamarindo Sob Distintas Doses De Nitrogenio E Irrigaçao Com Aguas Salinas

“…Os efeitos negativos podem ser observados diretamente na planta, durante o crescimento, na redução do rendimento e em casos extremos, pode haver morte das plantas (ROYCHOUDHURY et al, 2008).…”