title: Starch accumulation and activities of key enzymes involved in starch synthesis in the grains of maize inbred lines with different starch contents.
abstract: Amylose, amylopectin and starch dynamic accumulation and key enzymes activities in the grains of 4 maize inbred lines (two high-starch ones and two low-starch ones) were studied. The amounts of amylose, amylopectin and starch in the grains of 4 maize inbred lines increased as sigmoid curves during grain filling period. The changes in amylose, amylopectin and starch accumulation rates followed single-peaked curves, and reached their peaks in the 25-30 days after pollination (DAP). Changes in activities of adenosine diphosphoglucose pyrophosphorylase (ADPG-PPase, EC 2.7.7.27), soluble starch synthase (SSS, EC 2.4.1.21) and starch granule-bound synthase (GBSS, EC 2.4.1.21) in the grains of 4 inbred lines appeared single-peaked curves with the peaks appearing 20-30 DAP. Changes in activities of starch-branching enzyme (Q-enzyme, EC 2.4.1.18) in the grains of high-starch inbred lines appeared single-peaked curves with the peak values at 20 DAP, while the two low-starch inbred lines showed double-peaked curves with the peak values in the 15-20 DAP and 30-35 DAP. There was significant correlation between ADPG-PPase, SSS and GBSS activities. The results indicated that the Q-enzyme had different expression in high- and low-starch maize inbred lines, and verified that ADPG-PPase, SSS and GBSS activities were significantly and positively correlated with amylose, amylopectin and starch accumulation rates.
authors: College of Life Sciences, Sichuan Agricultural University, Ya'an, Sichuan 625014, China.
authors: Jun-Jie
authors: JJ
authors: Zhang
authors: Yu-Feng
authors: YF
authors: Hu
authors: Hui
authors: H
authors: Zhou
authors: Yu-Bi
authors: YB
authors: Huang
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000378:metabolism; D000687:Amylopectin / Q000378:metabolism; D000688:Amylose / Q000378:metabolism; D001947:Breeding; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000378:metabolism; D013213:Starch / Q000378:metabolism*; D013214:Starch Synthase / Q000378:metabolism; D003313:Zea mays / Q000201:enzymology* / Q000378:metabolism*
chemical_list: D013213:Starch; D000688:Amylose; D000687:Amylopectin; D015061:1,4-alpha-Glucan Branching Enzyme; D013214:Starch Synthase; D051599:Glucose-1-Phosphate Adenylyltransferase