Yield Increase in Plants Overexpressing the SHSRP Genes

Abstract

A transgenic crop plant transformed by a Serine Hydroxymethyltransferase-Like Stress-Related Polypeptide (SHSRP) coding nucleic acid, wherein expression of the nucleic acid sequence in the crop plant results in the plant's increased root growth, and / or increased yield, and / or increased tolerance to environmental stress as compared to a wild type variety of the plant Also provided are agricultural products, including seeds, produced by the transgenic crop plants. Also provided are isolated novel SHSRPs, and isolated novel nucleic acids encoding SHSRPs, and vectors and transgenic plant containing the same.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the priority benefit of U.S. Provisional Application Ser. No. 60 / 700,267 filed Jul. 18, 2005, the entire content of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates generally to nucleic acid sequences encoding polypeptides that are associated with root development, which contribute to plant growth and, ultimately affect plant production (i.e. yield) under abiotic stress or non-stress conditions. In particular, this invention relates to isolated nucleic acid sequences encoding polypeptides that confer upon the plant increased root growth, increased yield, and / or increased drought, cold, and / or salt tolerance, and the use of such isolated nucleic acids.[0004]2. Background Art[0005]The yield of crop plants is central to the well being of humans and is directly affected by the growth of plants under physical environment. Abiotic environment...

AI Technical Summary

Benefits of technology

[0029]In yet another embodiment, the invention concerns a seed produced by a transgenic crop plant transformed by an SHSRP coding nucleic acid, wherein the plant is true breeding for increased root growth, and / or increased yield, and / or increased tolerance to environmental stress as compared to a wild type variety of the plant.

[0032]In another embodiment, the invention concerns a method of increasing root growth and / or yield, and / or increasing stress tolerance to an environmental stress of a crop plant under normal or stress condition as compared to a wild type variety of the plant, wherein the method comprises obtaining the aforesaid transgenic crop plant and growing the plant under a condition that the isolated nucleic acid is expressed.

[0033]In yet another embodiment, the invention concerns a method of producing the aforesaid transgenic crop plant, wherein the method comprises (a) transforming a plant cell with an expression vector comprising an SHSRP coding nucleic acid, and (b) generating from the plant cell the transgenic crop plant that expresses the encoded polypeptide. Preferably, the polynucleotide is operably linked to one or more regulatory sequences, and the expression of the polynucleotide in the plant results in increased root growth, and / or increased yield, and / or increased tolerance to environmental stress under normal or stress conditions as compared to a wild type variety of the plant. Preferably, the one or more regulatory sequences include a promoter. More preferably, the promoter is a tissue specific or developmental regulated promoter.

[0050]In a further embodiment, the invention concerns a transgenic plant comprising such recombinant vector. Preferably, the expression of the SHSRP coding nucleic acid in the plant results in increased root growth, and / or increased yield, and / or increased tolerance to environmental stress as compared to a wild type variety of the plant.

Problems solved by technology

Abiotic environmental stresses, such as drought stress, salinity stress, heat stress, and cold stress, are major limiting factors of plant growth and productivity.

Crop losses and crop yield losses of major crops such as soybean, rice, maize (corn), cotton, and wheat caused by these stresses represent a significant economic and political factor and contribute to food shortages in many underdeveloped countries.

However, artificial limitations on yield due to poor pollination due to the absence of wind or insects, or insufficient space for mature root or canopy growth, can restrict the use of these controlled environments for testing yield differences.

However, if the severity and duration of the drought conditions are too great, the effects on development, growth, plant size, and yield of most crop plants are profound.

Continuous exposure to drought conditions causes major alterations in the plant metabolism which ultimately lead to cell death and consequently yield losses.

However, traditional plant breeding strategies to develop new lines of plants that exhibit resistance and / or tolerance to these types of stresses are relatively slow and require specific resistant lines for crossing with the desired line.

Limited germplasm resources for stress tolerance and incompatibility in crosses between distantly related plant species represent significant problems encountered in conventional breeding.

Additionally, the cellular processes leading to drought, cold, and salt tolerance in model drought-, cold-, and / or salt-tolerant plants are complex in nature and involve multiple mechanisms of cellular adaptation and numerous metabolic pathways.

This multi-component nature of stress tolerance has not only made breeding for tolerance largely unsuccessful, but has also limited the ability to genetically engineer stress tolerant plants using biotechnological methods.

Root architecture is an area that has remained largely unexplored through classical breeding because of difficulties with assessing this trait in the field.

Because of its importance in primary metabolism, plants are not able to perform oxygenic photosynthesis without SHMT, and reductions in SHMT activity leads to deleterious growth defects.

Although some genes that are involved in stress responses in plants have been characterized, the characterization and cloning of plant genes that confer stress tolerance remains largely incomplete and fragmented.

Although it is generally assumed that stress-induced proteins have a role in tolerance, direct evidence is still lacking, and the functions of many stress-responsive genes are unknown.

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