Her Majesty the Queen in Right of Canada, As Represented by the Minister

Her Majesty the Queen in Right of Canada, As Represented by the Minister of Agriculture and Agri-food

Her Majesty the Queen in Right of Canada As Represented by Agriculture

Agri-food Canada

Jas Singh

Theresa C White

Laurian Sylvio Robert

John A Simmonds

Th&eacute;r&egrave;se Ouellet

Titus Tao

Anne M Johnson-Flanagan

Chao Jiang

Janice Carole Morissette

The invention can be summarized as follows. Several silk-specific genes were isolated from corn silk. The specificity of their expression was determined by Northern analysis. A regulatory region was obtained from the silk gene, C3, and found to direct silk, and pistil, expression in transient assays and transgenic plants, in both monocot and dicot plants. The regulatory region of a silk gene may be used to drive the expression of a gene of interest within pistil or silk-tissues for a range of utilities including pathogen resistance or female sterility.

Corn silk gene and regulatory region

A 1.2 kb fragment of the 5' regulatory region (from bp -1107 to +100) was fused to the GUS (.beta.-glucuronidase) reporter gene and BN115-promoted GUS expression was observed in green tissues of transgenic Brassica napus plants only after incubation at 2.degree. C. No expression was observed after incubation at 22.degree. C., either in the presence or absence of abscisic acid. Microprojectile bombardment of winter B. napus leaves with a BN115 promoter/GUS construct yielded similar results and was used to analyze a series of deletions from the 5' end of the promoter. Results obtained from transient expression studies showed that the low temperature regulation of BN115 expression involves a possible enhancer region between bp -1107 and -606 and a second positive regulatory region located between bp -302 and -274. Deletion analyses and results from replacement with a truncated CaMV (cauliflower mosaic virus) 35S promoter suggest that the minimal size required for any maintenance of low temperature GUS expression is a -300 bp fragment. Within this fragment are two 8 bp elements with the sequence TGGCCGAC, which are identical to those present in the positive regulatory region of the promoter of the homologous Arabidopsis cor15a gene and to a 5 bp core sequence in the low temperature- and dehydration-responsive elements (LTREs and DREs) identified in the promoter regions of several cold-responsive Arabidopsis thaliana genes. Mutation of either one or both of the GGCAC core sequence of the putative LTRE's to AATTC resulted in loss of cold-inducible gene expression, providing for the first time, direct evidence that CCGAC is required for low temperature expression. Furthermore, replacement of an enhancer region (-605 to -1107) of the promoter with a more active enhancer from the 35S constitutive cauliflower mosaic virus (CaMV) promoter resulted in a 'hybrid' promoter with increased low temperature induced activity several fold over that of the native promoter.

Cold induced promoter from winter Brassica napus

The initial steps in photosynthesis are the conversion of light energy into chemical energy. This conversion is performed by the multisubunit protein-pigment complexes of the thylakoid membranes. Oxygen-evolving photosystems contain photosystem I (PSI) and photosystem II (PSII), which act in tandem. In PSII, the majority of light-adsorbing chlorophylls are attached to LHCII, the light harvesting complex associated with this photosystem. LHCII is the most abundant member of the family of chlorophyll a/b binding (CAB) proteins. A gene encoding a type I chlorophyll a/b binding protein of LHCII (ICABPSII) has been cloned from Brassica napus L. An anti-sense RNA of this gene has been used to reduce the amount of chlorophyll a/b binding protein and thus reduce the amount of chlorophyll in the resulting transgenic plants. By using 'site' specific promoters the reduction of chlorophyll can be targeted to specific organelles in the transgenic plant and thus can be used to reduce the green color at these sites. Thus it is possible to use the anti-sense RNA of a chlorophyll a/b binding protein as a means for degreening, for example fruits, seeds or floral parts in transgenic plants.

Anti-sense RNA for CAB transcript to reduce chlorophyll content in plants

Growing community of inventors

Nepean, Canada

Jas Singh