Genetic disruption of CRC 12S globulin increases seed oil content and seed yield in Arabidopsis thaliana

Abstract

Oils and proteins represent two major carbon reserves within oil seeds. Attempts to increase seed oil production through the genetic suppression of seed protein, however, have generally been unsuccessful. In those experiments, the total protein content remains stable because of compensation by storage proteins from different gene families. Arabidopsis thaliana may offer a solution to this problem, as only a small number of 12S-globulin and 2S-albumin proteins, which are major seed storage proteins, are found in these seeds. We obtained T-DNA-tagged mutants for the major 12S-globulin genes, CRA1, CRB, and CRC, and found elevated levels of oil in crc seeds. This was associated with the transcriptional upregulation of genes encoding the LEC2 and WRI1 transcription factors, diacylglycerol acyltransferase (DGAT1), and plastidial pyruvate kinase β subunit 1 (PKp-β1), all of which are important for oil production. Furthermore, cra1, crb, and crc single-mutant plants developed substantially more branches, thereby producing more flowers and fruits than did wild-type plants. Thus, cra1, crb and crc mutations resulted in 19%, 22% and 41% increases in seeds and 24%, 25% and 62% increases in oil content per plant, respectively, as compared with wild-type plants. Our results suggest that the perturbation of storage-protein synthesis in developing seeds of Arabidopsis influences the capacity of whole plants for producing sink organs such as shoot branches, flowers and seeds. © 2013 The Japanese Society for Plant Cell and Molecular Biology.