Regulation of storage lipid metabolism in developing and germinating lupin (Lupinus spp.) seeds

Abstract

The main storage compound in lupin seeds is protein, whose content can reach up to 45-50 % of dry matter. However, seeds of some lupin species can also contain quite a large amount of storage lipid. The range of lipid content in lupin seeds is from about 6 to about 20 % of dry matter. Storage lipid in developing seeds is synthesized mainly from sugars delivered by mother plants. During seed germination, one of the main end-products of storage lipid breakdown is also sugars. Thus, the sugar level in tissues is considered an important regulatory agent, during both lipid accumulation and lipid breakdown. Generally, in developing legume seeds, there is a strong negative relation between accumulation of storage protein and storage lipid. Results obtained in developing lupin cotyledons cultured in vitro pointed to the possibility of a positive relation between protein and lipid accumulation. Such a positive effect could be caused by nitrate. During lupin seed germination and seedling development, the utilization of storage lipid is enhanced under sugar deficiency conditions in tissues and is controlled at the gene expression level. However, under sugar starvation conditions, autophagy is significantly enhanced, and it can cause disturbances in storage lipid breakdown. The hypothesis of pexophagy, i.e., autophagic degradation of peroxisomes under sugar starvation conditions during lupin seed germination, has been taken into consideration. The flow of lipid-derived carbon skeletons to amino acids was discovered in germinating lupin seeds, and this process is clearly more intense in sucrose-fed embryo axes. At least four alternative or mutually complementary pathways of carbon flow from storage lipid to amino acids in germinating lupin seeds are postulated. The different strategies of storage compound breakdown during lupin seed germination are also discussed.

Genetic and Genomic Diversity in a Tarwi (Lupinus mutabilis Sweet) Germplasm Collection and Adaptability to Mediterranean Climate Conditions

“…In spite of their high alkaloid content [7,8], tarwi seeds have high nutritional value, containing up to 53% protein and 24% lipids [9]. The nutritional attributes found in tarwi are supposedly better than those in soybeans [10] and for this reason it is called Andean soybean [11]. Tarwi protein is rich in globulins (43%-45%) and albumins (8%-9%) and the oil has high quality and does not require industrial removal of the linolenic acid like in soybean [12,13].…”

Effect of high night temperature on storage lipids and transcriptome changes in developing seeds of oilseed rape

“…They can be degraded into free FAs by a variety of lipases ( Li-Beisson et al , 2013 ). The free FAs are subjected to β-oxidation, a process in which FAs are degraded into acetyl-CoA and the acetyl-CoA is subsequently converted into 4-C compounds via the glyoxylate cycle which takes place partially in the peroxisome and partially in the cytoplasm ( Pracharoenwattana and Smith, 2008 ; Borek et al , 2015 ). These 4-C compounds are then shipped to the mitochondria to synthesize malate, which either is used for respiration or is transported to the cytosol for gluconeogenesis ( Goepfert and Poirier, 2007 ).…”

Completing Autophagy: Formation and Degradation of the Autophagic Body and Metabolite Salvage in Plants

“…Under such conditions, the autophagic bodies were rapidly degraded and they were not observed in the enlarged vacuoles. Nevertheless, asparagine, a central amino acid in the metabolism of germinating protein lupin seeds [140], caused clear inhibition in the degradation of autophagic bodies and their accumulation in highly enlarged vacuoles. Such accumulation of autophagic bodies inside enlarged vacuoles proves that asparagine only inhibits the degradation of autophagic bodies, but does not reduce the intensity of autophagy in general.…”