Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 1995
Publication Date: N/A
Interpretive Summary: Invertase is an important enzyme to convert sucrose to simple sugars which are then utilized into multiple metabolic processes in a developing seed. However, very little is known so far about the genes which encode this enzyme. Such knowledge is critical in its genetic manipulation to attain better crop productivity. We describe here the first success in this direction in an important crop plant, corn. We have cloned and sequenced and invertase gene in corn, and have described how similar or dissimilar it is from an invertase gene in tobacco and carrot. In addition, the gene is now mapped to a region on chromosome 5 of the corn genome. Although no direct benefits are envisioned for farmers, such basic research is needful in understanding how sucrose is utilized in the normal development of a seed, the ultimate unit of crop productivity.
Maize cell wall (CW) invertase gene is isolated from a cell suspension cDNA library using a heterologous clone from sorghum, isolated previously. The deduced amino acid sequence of the maize clone has shown sequence identity of 57% and 58% with tobacco and carrot CW invertases, respectively. The cDNA clone is expressed in E coli and the expressed protein cross reacted with antibodies against carrot CW invertase. Northern and Western blot analyses in maize have identified a transcript of approximately. 2.1kb and a polypeptide of approximately 65kDa, respectively. Genomic Southern blot analyses indicate that the gene is in low copy number and maps to chromosome 5.