Modulation of endogenous levels of some key organic metabolites by exogenous application of glycine betaine in drought stressed plants of sunflower (Helianthus annuus L.)

Abstract

The present study was conducted to examine the changes in some key metabolites in drought-stressed sunflower plants supplied with glycine betaine externally. Imposition of drought stress at the vegetative or reproductive growth stages decreased the plant dry matter production and increased the accumulation of organic solutes (glycine betaine, proline, soluble proteins, free amino acids and soluble sugars) in two sunflower lines, i.e., Glushan-98 and Suncross. In general, decrease in dry matter production and increase in the endogenous levels of organic solutes, were more pronounced when drought stress applied at the vegetative stage than at the reproductive stage. Glycine betaine applied as a pre-sowing seed treatment was not found to be effective in reducing the negative effects of drought stress in sunflower plants. Foliar application of GB further enhanced the leaf endogenous levels of GB, soluble proteins and total soluble sugars in drought stressed plants without exerting any negative effects on other osmotica. However, this GB-induced increase in endogenous levels of organic solutes was found to be not associated with plant dry matter production under stress conditions.

Effect of exogenously applied kinetin and glycinebetaine on metabolic and yield attributes of rice (Oryza sativa L.) under drought stress

“…In monocots increase in proline has already been reported with exogenous GB application (Farooq et al, 2008(Farooq et al, , 2010Lin Xin et al, 2009). Exogenous GB application at reproductive stage was found to be more effective for proline accumulation as compared to vegetative stage of water stressed sunflower (Iqbal et al, 2011). Similarly, increase in metabolites, particularly amino acids (proline, γaminobutyric acid, alanine, and glycine) and carbohydrates was reported in creeping bent grass with increase in endogenous KIN (Merewitz et al, 2012).…”

Metabolic responses to drought stress in the tissues of drought-tolerant and drought-sensitive wheat genotype seedlings

“…The results implied that a high level of energy and sugar content is crucial for shoots to develop drought stress tolerance, and active synthesis metabolism is a basic response for shoots to tolerate drought stress ( Santos and Pimentel 2009 ; Loutfy et al 2012 ). The active synthesis metabolism of nutrients, including sugars, proline and organic acids, were dramatically enhanced in shoots, which improved the ROS detoxification capacity, osmotic adjustment, membrane stability and drought tolerance ( Iqbal et al 2011 ; Loutfy et al 2012 ; Marcin′ska et al 2013 ). On the basis of the comparison of metabolic profiles and the SPAD value between the two genotypes under control and drought stress, we may conclude that JD17 contains higher compatible solutes, exhibits a more active metabolite synthesis and shows a more rapid growth than JD8 under drought stress.…”

Plant-growth-promoting rhizobacteria: drought stress alleviators to ameliorate crop production in drylands

“…Elevated levels of amino acids, which are considered to be an indication of drought tolerance (Zhu 2002), have been reported in sorghum, pepper and wheat (Yadav et al 2005). Accumulation of amino acids is due to hydrolysis of proteins, which occurs in response to changes contributing to osmotic adjustments (Iqbal et al 2011;Krasensky and Jonak 2012). Proline synthesis results in osmotic adjustment, free radical scavenging and stabilization of subcellular structures in plant cells to overcome the detrimental effects of drought (Hare et al 1998).…”