Apical stem culturing to enhance cell sap assimilates towards grain sucrose and glutamine metabolism in wheat

Abstract

Apical stem culturing offers an alternative approach of manipulating cell sap for wheat grain carbon and nitrogen metabolism in a near in vivo conditions. Employing this technique, role of sucrose and glutamine in transport stream on sucrose metabolism, ammonia assimilation and aminotransferase activities were assessed towards starch and protein accumulation in two wheat genotypes PBW 343 (low yield) and PBW 621 (high yield). At mid-milky stage, detached tillers were cultured in complete liquid medium containing varied concentration of glutamine and sucrose for seven days during year 2012-13 and 2013-14. Increasing glutamine concentration from 17 to 25 mM in the culture medium having 117 mM sucrose enhanced activities of nitrate reductase, glutamate synthase, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) at 4 days after culturing (DAC) in correspondence with an increase in soluble protein content. However, at 7 DAC content of soluble protein decreased whereas starch accumulation increased showing, thereby a compensatory effect on carbon and nitrogen metabolism. Apparently, activities of sucrose synthase, soluble acid and neutral invertase significantly decreased. Increasing sucrose concentration from 117 to 125 mM led to an increase in transformation of sugars to starch in grain but protein content decreased. PBW 621 showed high protein content due to higher activities of GOT, GPT at 4 DAC which subsequently increased carbon skeleton of proteins towards starch synthesis at 7 DAC. Grain filling processes in terms of soluble sugars/starch were strongly correlated to invertase activities whereas proteins to aminotransferases.Keywords: acid invertase, carbon/nitrogen metabolism, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, sucrose synthase Abbreviations: NR -nitrate reductase, GOGAT -glutamate synthase, GOT -glutamate oxaloacetate transaminase, GPT -glutamate pyruvate transaminase, SS -sucrose synthase, AI -acid invertase, NI -neutral invertase, DAC -days after culturing

Exogenous γ-aminobutyric acid strengthens phenylpropanoid and nitrogen metabolism to enhance the contents of flavonoids, amino acids, and the derivatives in edamame

“…The activity of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) was determined according to the method of Wang et al (2014) . The activity of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was assayed according to Kaur’ s. (2015) method. The activity of glutamate decarboxylase (GAD) and GABA transaminase (GABA-T) was assayed according to Li et al (2016) .…”

Effects of Elevated Root-Zone CO2 on Root Morphology and Nitrogen Metabolism Revealed by Physiological and Transcriptome Analysis in Oriental Melon Seedling Roots

“…The activities of GOGAT and GDH in roots were determined according to the method of Lin and Kao [52]. Kaur's method was used to determine the GOT and GPT activities [53]. All measured indicators were recorded using three biological replicates.…”