Differential inductions of phenylalanine ammonia-lyase and chalcone synthase during wounding, salicylic acid treatment, and salinity stress in safflower,Carthamus tinctorius

Abstract

Safflower (Carthamus tinctorius L.) serves as a reference dicot for investigation of defence mechanisms in Asteraceae due to abundant secondary metabolites and high resistance/tolerance to environmental stresses. In plants, phenylpropanoid and flavonoid pathways are considered as two central defence signalling cascades in stress conditions. Here, we describe the isolation of two major genes in these pathways, CtPAL (phenylalanine ammonia-lyase) and CtCHS (chalcone synthase) in safflower along with monitoring their expression profiles in different stress circumstances. The aa (amino acid) sequence of isolated region of CtPAL possesses the maximum identity up to 96% to its orthologue in Cynara scolymus, while that of CtCHS retains the highest identity to its orthologue in Callistephus chinensis up to 96%. Experiments for gene expression profiling of CtPAL and CtCHS were performed after the treatment of seedlings with 0.1 and 1 mM SA (salicylic acid), wounding and salinity stress. The results of semi-quantitative RT–PCR revealed that both CtPAL and CtCHS genes are further responsive to higher concentration of SA with dissimilar patterns. Regarding wounding stress, CtPAL gets slightly induced upon injury at 3 hat (hours after treatment) (hat), whereas CtCHS gets greatly induced at 3 hat and levels off gradually afterward. Upon salinity stress, CtPAL displays a similar expression pattern by getting slightly induced at 3 hat, but CtCHS exhibits a biphasic expression profile with two prominent peaks at 3 and 24 hat. These results substantiate the involvement of phenylpropanoid and particularly flavonoid pathways in safflower during wounding and especially salinity stress.

Cooperative interaction of antimicrobial peptides with the interrelated immune pathways in plants

“…The plant must also scavenge ROS to prevent cell damage, e.g. by the synthesis of antioxidants, such as glutathione and ascorbate, and enzymes that detoxify ROS, such as superoxide dismutases and catalases (Dehghan et al, 2014;Sadeghi et al, 2013). AMPs can also help to regulate directly the cellular redox status.…”

Overexpression of snapdragon Delila (Del) gene in tobacco enhances anthocyanin accumulation and abiotic stress tolerance

“…Potato plants overexpressing transcription factor IbMYB1 exhibited enhanced anthocyanin production and improved salinity tolerance [17]. Anthocyanin biosynthetic genes PAL and CHS are proposed as candidates for molecular breeding to increase crop resistance to wounding and salt stress [18]. Finally, Fini et al [19] and Nakabayashi et al [20] showed that improved abiotic stress tolerance under enhanced flavonoid accumulation is linked to greater ROS scavenging ability.…”

Overexpression of RsMYB1 enhances heavy metal stress tolerance in transgenic petunia by elevating the transcript levels of stress tolerant and antioxidant genes

“…In addition, the roles of GSH and PCs in the detoxification of heavy metals and ROS scavenging have also been documented (Millar et al, 2003; Freeman et al, 2004; Hirata et al, 2005; Foyer and Noctor, 2005; Shao et al, 2008). The enhancement of antioxidant activities and stress tolerances in anthocyanin-enriched plants has been reported for various plant species (Winkel-Shirley, 2002; Dixon et al, 2005; Dehghan et al, 2014; Agati et al, 2011). Recently, overexpression of MYB TFs in various species has been shown to enhance anthocyanin accumulation and abiotic stress tolerance (Cheng et al, 2013; Meng et al, 2014; Qi et al, 2015; Yuan et al, 2015).…”

“…Under the same conditions, the higher expression of the genes in the RsMYB1-overexpressing plants than in the WT plants could be explained by the presence of anthocyanin, which is regulated by RsMYB1. High anthocyanin accumulation is linked to high antioxidant activities (Naing et al, 2017; Winkel-Shirley, 2002, Dixon et al, 2005, Dehghan et al, 2014; Agati et al, 2011). Therefore, this result supports the hypothesis that the higher stress tolerance in RsMYB1-overexpressing plants compared to WT plants depends on their antioxidant content.…”

“…In addition, the roles of antioxidants in scavenging ROS and reducing the oxidative stress caused by heavy metals have also been investigated (Hirschi et al, 2000, Tseng et al, 2007). Generally, a higher antioxidant content is found in anthocyanin-enriched plants, and these plants can survive abiotic and biotic stress conditions (Winkel-Shirley, 2002; Dixon et al, 2005; Dehghan et al, 2014; Agati et al, 2011). In addition, it has been suggested that improved abiotic stress tolerance when flavonoid accumulation is enhanced may be linked to increased ROS scavenging abilities (Fini et al, 2011; Nakabayashi et al, 2014).…”