Gene expression during phosphate starvation in tomato
Abstract
Phosphorus (Pi) is one of the least available of all essential nutrients in the soil. Pi deficiency can result in retardation of plant growth and severe reduction in yield. Plants have developed adaptive mechanisms to enhance Pi availability and uptake. In this study, expression of genes induced during early periods of Pi starvation was examined along with that of phosphate transporter genes in tomato. As a part of my research goal of identifying early molecular events during Pi starvation, a phosphate starvation induced gene (TPSI1) was cloned from tomato by mRNA differential display. The TPSI1 transcripts are rapidly induced in roots, leaves and cell cultures during Pi starvation. The induction of TPSI1 gene appears to be a response specific to Pi starvation and it is reversible in the presence of phosphate. In a second part of this study, tissue specific regulation of tomato phosphate transporter genes (LePT1 and LePT2) by Pi was analyzed. Both genes are highly expressed in roots during Pi deficiency. The transcripts of LePT1 and LePT2 genes are primarily localized in root epidermis under phosphate starvation. The study with divided root system indicated that internal signals may be involved in the regulation of genes during Pi starvation. These studies suggest that differential regulation of gene expression may be an important component of the Pi starvation rescue mechanism in plants.
Degree
Ph.D.
Advisors
Raghothama, Purdue University.
Subject Area
Molecular biology|Botany|Genetics
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