Regulation by sucrose of storage compounds breakdown in germinating seeds of yellow lupine (Lupinus luteus L.), white lupine (Lupinus albus L.) and Andean lupine (Lupinus mutabilis Sweet): I. Mobilization of storage protein

Abstract

Research of the regulatory function of sucrose in storage protein breakdown was conducted on isolated embryo axes, excised cotyledons and whole seedlings of three lupine species grown in vitro on medium with 60 mM sucrose or without the sugar. Sucrose stimulated growth of yellow, white and Andean lupine isolated embryo axes and cotyledons but growth of seedlings was inhibited. Dry matter content was higher in sucrose-fed isolated organs and in seedling organs. Ultrastructure research revealed that lack of sucrose in the medium caused enhancement in storage protein breakdown. Protein deposits in cotyledons were smaller as well as soluble portion content in all studied organs was lower when there was no sucrose in the medium. In the same conditions, the activity of glutamate dehydrogenase was significantly higher. Increase in vacuolization of cells of white lupine root meristematic zone cells was observed and induction of autophagy in young carbohydrate-starved embryo axes is discussed.

Plant Responses to Sugar Starvation

“…al. 2003, Borek et al 2006, Borek and Nuc 2011, 2012a, 2012b, Arabidopsis thaliana (Rose et al 2006). Metabolic changes caused by sugar starvation are usually analysed in cell cultures, callus tissue cultures, and in isolated plant organs cultured in vitro.…”

Diverse regulation by sucrose of enzymes involved in storage lipid breakdown in germinating lupin seeds

“…It is highly possible that in seeds of this lupin species, there also exists carbon flow from lipid into amino acids. This conclusion is based on the following: (1) Andean lupin seeds contain much more storage lipid than yellow lupin seeds (Borek et al 2009(Borek et al , 2012a) and more carbon skeletons might be used for amino acid synthesis; (2) disruption in asparagine synthesis caused a significant increase in fatty acid utilization ; (3) the changes caused by sucrose in aconitase activity (Fig. 5) were very similar to those observed in aconitase activity in yellow lupin seeds (Borek and Nuc 2011); and (4) the changes caused by sucrose in aconitase activity (Fig.…”

“…Lipid content in seeds of this species is about 6 %. White lupin seeds (Lupinus albus L.) contain 7-14 % (Borek et al 2009(Borek et al , 2012a. Regarding storage lipid content, Andean lupin seeds are similar to soybean seeds, which contain 12-26 % of storage lipid (Zhou et al 2006).…”

“…It is well documented that decreased sucrose or glucose levels in tissues enhance, for example, lipid (Dieuaide et al 1992;Yu 1999;To et al 2002;Borek et al 2006Borek et al , 2012a, protein (Brouquisse et al 1991;Yu 1999;Borek and Ratajczak 2002;Borek et al 2012b), and starch (Thomas and Rodriquez 1994;Borek et al 2006Borek et al , 2013 breakdown. In such conditions, photosynthesis is enhanced (Yu 1999) and autophagy may occur as well (Aubert et al 1996;Yu 1999;Inoue and Moriyasu 2006;Bassham 2007).…”

“…Lack of sucrose in the medium causes a considerable decrease in sugar content in tissues, especially in isolated embryo axes (Borek et al 2006). Experiments were conducted both on embryo axes and cotyledons because embryo axes contain less storage lipid than cotyledons (Borek et al 2012a). In this study, the activities of lipase, acyl-CoA oxidase, catalase, cytosolic and mitochondrial aconitase, and phosphoenolpyruvate carboxykinase were assayed.…”