Influence of Sulfur Nutrition on Developmental Patterns of Some Major Pea Seed Proteins and Their mRNAs

Publisher Website
Google Scholar
Abstract
In addition to the marked reduction in legumin synthesis and legumin mRNA levels reported earlier pulse labeling of S-deficient P. sativum L. seeds showed that a high relative level of total vicilin (vicilin plus convicilin) synthesis was maintained throughout the entire phase of protein accumulation, whereas in nondeficient seeds vicilin synthesis is largely confined to the 1st half of this phase. Fractionation of pulse-labeled proteins on sodium-dodecyl sulfate-polyacrylamide gels showed that the synthesis of the MW 50,000 family of vicilin polypeptides was increased and greatly extended in S-deficient seeds whereas that of convicilin was slightly reduced. Other changes apparent from pulse-labeling experiments include a depression, to different degrees, in the synthesis of 3 major albumin polypeptides. The level of the mRNA for 7 major seed proteins was followed throughout development of control and S-deficient seeds. In all cases, the changes in each mRNA closely reflected the pattern of synthesis of its corresponding polypeptide seen by pulse labeling. S-deficient seeds showed an elevated level of MW 50,000 vicilin mRNA which remained high throughout seed formation, whereas legumin mRNA levels were greatly reduced at all stages of development. When S-deficient plants were given an adequate supply of sulfate midway through seed development, there was a shift toward the protein synthesis profile characteristic of healthy plants. The synthesis of legumin and 2 albumins rapidly increased, and the synthesis of MW 50,000 vicilin declined more slowly. Similar responses were seen in detached, S-deficient seeds supplied directly with adequate sulfate.