The present disclosure includes methods and compositions for improving leaf quality in low-alkaloid tobacco plants, e.g., by combining inducible promoters and non-coding RNAs for suppression of an ornithine decarboxylase (ODC) gene. Also provided are low alkaloid tobacco plants with normal, suppressed, or otherwise altered polyamine levels. Further provided are tobacco plants with altered total alkaloid, nicotine levels, commercially acceptable leaf grade, their development via breeding or transgenic approaches, and production of tobacco products from these tobacco plants.

The invention provides recombinant DNA molecules and constructs, as well as their nucleotide sequences, useful for modulating gene expression in plants. The invention also provides transgenic plants, plant cells, plant parts, and seeds comprising the recombinant DNA molecules operably linked to heterologous transcribable DNA molecules, as are methods of their use.

A method for controlling the building of architecture of gramineous crops and application thereof. The gene CYC U4;1 (Os10g41430) has a specific expression in a rice pulvinus (which is believed to have a specific expression in other gramineous crops), with a CDS sequence as shown in SEQ ID NO: 2, and an encoded amino acid sequence as shown in SEQ ID NO: 3. Also a promoter sequence of the gene, with the sequence as shown in SEQ ID NO: 1. Transgenic lines obtained by cloning a promoter and full-length CDS of CYC U4;1 to pCAMBIA1301 and transferring this into rice Nipponbare are all characterized by having smaller leaf-stem angles than those of wild rice, accordingly, the expression level of the gene CYC U4;1 can be increased or decreased with genetic engineering technology to control the plant architecture development, thereby improving the plant architecture and increasing the density of germplasm.

The present invention is directed to promoter sequences and promoter control elements, polynucleotide constructs comprising the promoters and control elements, and methods of identifying the promoters, control elements, or fragments thereof. The invention further relates to the use of the present promoters or promoter control elements to modulate transcript levels.

This invention relates to genetically modified plants with improved drought tolerance and to genetically modified cells thereof. These plants may have thicker leaves, rounder leaf shape or higher chlorophyll content. The plants may be modified to increase the expression of a plant calmodulin-binding protein IQD22, IQD23 or IQD24. The modified plants are expected to have improved yields under variable field conditions. The invention also relates to a method of genetically modifying a plant to have these characteristics. The invention further relates to isolated nucleic acids and polynucleotide constructs for the genetic engineering of such plants and their use.

The present disclosure includes methods and compositions for improving leaf quality in low-alkaloid tobacco plants, e.g., by combining inducible promoters and non-coding RNAs for suppression of an ornithine decarboxylase (ODC) gene. Also provided are low alkaloid tobacco plants with normal, suppressed, or otherwise altered polyamine levels. Further provided are tobacco plants with altered total alkaloid, nicotine levels, commercially acceptable leaf grade, their development via breeding or transgenic approaches, and production of tobacco products from these tobacco plants.

The invention provides recombinant DNA molecules and constructs, as well as their nucleotide sequences, useful for modulating gene expression in plants. The invention also provides transgenic plants, plant cells, plant parts, and seeds comprising the recombinant DNA molecules operably linked to heterologous transcribable DNA molecules, as are methods of their use.

Vascular sheath tissue-specific expression of phytochrome B or variants thereof in C3 plants increases photosynthesis rate and/or introduces a carbon refixation mechanism. The heritable genetic material of a C.sub.3 plant cell is altered such that one copy of phytochrome B, or active variant or functional fragment thereof is expressed specifically in vascular sheath cells. Whole plants are regenerated from these genetically altered plant cells. Alternatively, a Crispr modification of a native phytochrome locus in a plant cell is used to insert a vascular sheath-specific regulatory element, e.g. promoter or enhancer element, so that phytochrome B is expressed in vascular sheath cells of a regenerated whole plant. Genetically altered whole plants have increased yield-related traits, e.g. increased seed yield, resulting from the enhancement of photosynthesis and/or introduction of a carbon refixation mechanism.

The present disclosure provides approaches for reducing tobacco-specific nitrosamines (TSNAs) in tobacco. Some of these approaches include genetically engineering tobacco plants to increase one or more antioxidants, increase oxygen radicle absorbance capacity (ORAC), or reduce nitrite. Also provided are methods and compositions for producing modified tobacco plants and tobacco products therefrom comprising reduced TSNAs.

The present disclosure provides approaches for reducing tobacco-specific nitrosamines (TSNAs) in tobacco. Some of these approaches include genetically engineering tobacco plants to increase one or more antioxidants, increase oxygen radicle absorbance capacity (ORAC), or reduce nitrite. Also provided are methods and compositions for producing modified tobacco plants and tobacco products therefrom comprising reduced TSNAs.