A New Opaque Variant of Maize by a Single Dominant RNA-Interference-Inducing Transgene

Corresponding author: Joachim Messing, Rutgers, The State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ 08854-8020., messing{at}mbcl.rutgers.edu (E-mail)

Communicating editor: J. A. BIRCHLER

In maize, -zeins, the main protein components of seed stores, are major determinants of nutritional imbalance when maize is used as the sole food source. Mutations like opaque-2 (o2) are used in breeding varieties with improved nutritional quality. However, o2 works in a recessive fashion by affecting the expression of a subset of 22-kD -zeins, as well as additional endosperm gene functions. Thus, we sought a dominant mutation that could suppress the storage protein genes without interrupting O2 synthesis. We found that maize transformed with RNA interference (RNAi) constructs derived from a 22-kD zein gene could produce a dominant opaque phenotype. This phenotype segregates in a normal Mendelian fashion and eliminates 22-kD zeins without affecting the accumulation of other zein proteins. A system for regulated transgene expression generating antisense RNA also reduced the expression of 22-kD zein genes, but failed to give an opaque phenotype. Therefore, it appears that small interfering RNAs not only may play an important regulatory role during plant development, but also are effective genetic tools for dissecting the function of gene families. Since the dominant phenotype is also correlated with increased lysine content, the new mutant illustrates an approach for creating more nutritious crop plants.

This article has been cited by other articles:

				S. Ufaz and G. Galili Improving the Content of Essential Amino Acids in Crop Plants: Goals and Opportunities Plant Physiology, July 1, 2008; 147(3): 954 - 961. [Full Text] [PDF]

				S. P. Moose and R. H. Mumm Molecular Plant Breeding as the Foundation for 21st Century Crop Improvement Plant Physiology, July 1, 2008; 147(3): 969 - 977. [Full Text] [PDF]

				M. Dafny-Yelin, S.-M. Chung, E. L. Frankman, and T. Tzfira pSAT RNA Interference Vectors: A Modular Series for Multiple Gene Down-Regulation in Plants Plant Physiology, December 1, 2007; 145(4): 1272 - 1281. [Abstract] [Full Text] [PDF]

				M. Hansen, M. Lange, C. Friis, G. Dionisio, P. B. Holm, and E. Vincze Antisense-mediated suppression of C-hordein biosynthesis in the barley grain results in correlated changes in the transcriptome, protein profile, and amino acid composition J. Exp. Bot., November 1, 2007; 58(14): 3987 - 3995. [Abstract] [Full Text] [PDF]

				T. Chung, C. S. Kim, H. N. Nguyen, R. B. Meeley, and B. A. Larkins The Maize Zmsmu2 Gene Encodes a Putative RNA-Splicing Factor That Affects Protein Synthesis and RNA Processing during Endosperm Development Plant Physiology, June 1, 2007; 144(2): 821 - 835. [Abstract] [Full Text] [PDF]

				K. McGinnis, N. Murphy, A. R. Carlson, A. Akula, C. Akula, H. Basinger, M. Carlson, P. Hermanson, N. Kovacevic, M. A. McGill, et al. Assessing the Efficiency of RNA Interference for Maize Functional Genomics Plant Physiology, April 1, 2007; 143(4): 1441 - 1451. [Abstract] [Full Text] [PDF]

				R. Song, G. Segal, and J. Messing Expression of the sorghum 10-member kafirin gene cluster in maize endosperm Nucleic Acids Res., December 29, 2004; 32(22): e189 - e189. [Abstract] [Full Text] [PDF]

				J. Lai, N. Dey, C.-S. Kim, A. K. Bharti, S. Rudd, K. F.X. Mayer, B. A. Larkins, P. Becraft, and J. Messing Characterization of the Maize Endosperm Transcriptome and Its Comparison to the Rice Genome Genome Res., October 1, 2004; 14(10a): 1932 - 1937. [Abstract] [Full Text] [PDF]