ABSTRACT
We measured the morphological index, nutritional composition and the expression analysis of key genes during grain development of Paeonia suffruticosa cv. 'Fengdan' grown at altitudes of 100, 650 and 1010 m in Luo-yang. The aim of this study was to examine differences in grain yield traits and the transformation of soluble sugar, starch, soluble protein and fatty acid contents, as well as the related enzyme activity and differential expression of key genes in oil metabolism. The results showed that grain yield traits increased with altitudes and that the growth period of grain at the higher altitudes was longer than that at low and mid altitudes. The soluble sugar and starch in mature grains increased with altitudes, while soluble protein and crude fat did not change. During grain development, the activities of sucrose synthase (SS) and sucrose phosphate synthase (SPS) first decreased and then increased, with the lowest occurred at 90 d after flowering. The activities of pyruvate dehydrogenase (PDH), glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminease (GOT) increased rapidly during 50-90 d after flowering and peaked at 90 d. The relative expression of acetyl-CoA carboxylase (ACCase) and stearoyl-ACP desaturase (SAD) peaked at 50 d after flowering, and ω-6 fatty acid desaturase 2 (FAD2) peaked at 90 d, in oil tree peony grain at different altitudes. There was a negative correlation of soluble sugar and starch with the accumulation of soluble protein and crude fat. SPS activity was positively correlated with the contents of soluble sugar and starch, and negatively correlated with the contents of soluble protein and crude fat during grain development. Activities of GPT and GOT were negatively associated with the content of soluble sugar and the content of starch, and had a highly significant positive correlation with the contents of soluble protein and crude fat. Activity of PDH was positively correlated with the content of soluble proteins and activities of GPT and GOT, and negatively correlated with the contents of soluble sugar and starch. It suggested that nutrient accumulation in the process of grain development of tree peony was transformed from sugar to crude fat and protein, and that metabolic enzymes, such as SPS, PDH, GPT and GOT, played an important role in this process. Palmitate acid, stearic acid and linoleic acid were negatively correlated with the relative increment of α-linolenic acid, indicating that fatty acid desaturation process in the grain development of tree peony was towards the direction of α-linolenic acid synthesis. The relative expression of ACCase, SAD, and FAD2 was positively correlated with the relative increment of α-linolenic acid accumulation, which played an important role in α-linolenic acid synthesis. The oil quality of tree peony grain was relatively stable at different altitudes, but grain production increased with altitude. Planting oil tree peony at mid to high altitudes could be an important strategy for the efficient use of marginal land in Luoyang.
Subject(s)
Paeonia , Paeonia/genetics , Paeonia/metabolism , Altitude , alpha-Linolenic Acid , Edible Grain/metabolism , Starch/metabolism , SugarsABSTRACT
A protoplast-to-plant system for the methionine resistant variant of Astragalus cicer L. has been developed. The friable calli induced from stem segments of variant plants were used as materials for protoplast isolation through enzyme digestion. The effects of different media and plating densities on protoplast divisions and plant regeneration were studied. Sustained cell divisions and colony formation from the protoplasts of the methionine resistant cell line of Astragalus cicer L. were obtained by a DPD medium containing 2.0 mg/L 2,4- dichlorophenoxyacetic acid (2,4-D), 0.2 mg/L 6 -benzylaminopurine(6-BA), 0.3 mol/L mannitol, 200 mg/L casein hydrolysate and 2% (W/V) sucrose at a plating density of 2x10(5) /ml. The division frequency was 38.3%. At the same time, different dividing types of protoplasts were found. Organogenesis and shoot formation from the protoplast-derived calli were induced on MS medium supplemented with 0.5 mg/L NAA, 10 mg/L KT and 2% (W/V) sucrose. The protoplast-derived calli still expressed resistance to methionine. The protoplast to plant regeneration protocol developed in this study might provide the foundation for the resistant cell line as a parent for somatic hybridization.
