OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 20/8/2130    most recent tpc.107.055087v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wu, C.-y. Articles by Pennell, R. I. Search for Related Content PubMed PubMed Citation Articles by Wu, C.-y. Articles by Pennell, R. I. Agricola Articles by Wu, C.-y. Articles by Pennell, R. I.

Brassinosteroids Regulate Grain Filling in Rice^[W],[OA]

^a Ceres Inc., Thousand Oaks, California 91320
^b Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
^c Department of Chemistry, Joetsu University of Education, Joetsu-shi, Niigata 943-8512, Japan
^d Advanced Science Institute, RIKEN (The Institute of Physical and Chemical Research), Wako-shi, Saitama 351-0198, Japan

¹ Address correspondence to rpennell{at}ceres-inc.com.

Genes controlling hormone levels have been used to increase grain yields in wheat (Triticum aestivum) and rice (Oryza sativa). We created transgenic rice plants expressing maize (Zea mays), rice, or Arabidopsis thaliana genes encoding sterol C-22 hydroxylases that control brassinosteroid (BR) hormone levels using a promoter that is active in only the stems, leaves, and roots. The transgenic plants produced more tillers and more seed than wild-type plants. The seed were heavier as well, especially the seed at the bases of the spikes that fill the least. These phenotypic changes brought about 15 to 44% increases in grain yield per plant relative to wild-type plants in greenhouse and field trials. Expression of the Arabidopsis C-22 hydroxylase in the embryos or endosperms themselves had no apparent effect on seed weight. These results suggested that BRs stimulate the flow of assimilate from the source to the sink. Microarray and photosynthesis analysis of transgenic plants revealed evidence of enhanced CO₂ assimilation, enlarged glucose pools in the flag leaves, and increased assimilation of glucose to starch in the seed. These results further suggested that BRs stimulate the flow of assimilate. Plants have not been bred directly for seed filling traits, suggesting that genes that control seed filling could be used to further increase grain yield in crop plants.

This article has been cited by other articles:

				L.-Y. Zhang, M.-Y. Bai, J. Wu, J.-Y. Zhu, H. Wang, Z. Zhang, W. Wang, Y. Sun, J. Zhao, X. Sun, et al. Antagonistic HLH/bHLH Transcription Factors Mediate Brassinosteroid Regulation of Cell Elongation and Plant Development in Rice and Arabidopsis PLANT CELL, December 1, 2009; 21(12): 3767 - 3780. [Abstract] [Full Text] [PDF]

				A. Tanaka, H. Nakagawa, C. Tomita, Z. Shimatani, M. Ohtake, T. Nomura, C.-J. Jiang, J. G. Dubouzet, S. Kikuchi, H. Sekimoto, et al. BRASSINOSTEROID UPREGULATED1, Encoding a Helix-Loop-Helix Protein, Is a Novel Gene Involved in Brassinosteroid Signaling and Controls Bending of the Lamina Joint in Rice Plant Physiology, October 1, 2009; 151(2): 669 - 680. [Abstract] [Full Text] [PDF]