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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED FOOD QUALITY IN DRY BEANS USING GENETIC AND MOLECULAR APPROACHES

Location: Sugarbeet and Bean Research

Title: Characterization and expression analysis of a dehydrin gene in Phaseolus vulgaris

Authors
item Astudillo, Carolina -
item Cichy, Karen

Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Other
Publication Acceptance Date: March 10, 2011
Publication Date: June 1, 2011
Citation: Astudillo, C., Cichy, K.A. 2011. Characterization and expression analysis of a dehydrin gene in Phaseolus vulgaris. Bean Improvement Cooperative Annual Report. 54:16-17.

Interpretive Summary: Humans require zinc in their diet but its availability is often limited and therefore human zinc deficiency is widespread. Increasing the zinc density in staple crops such as dry bean is a strategy to address human zinc deficiency. Characterization of genes involved in zinc movement to the seed is a useful step to effectively increase seed zinc content. Recent molecular studies have identified a number of gene families involved in metal transport within the plant. One gene family named dehydrins were recently shown to play a role in transporting micronutrients throughout the plant. The objective of this research was to characterize a dehydrin gene in dry bean and determine its role in zinc accumulation in bean seeds. The dehydrin gene was found to be highly expressed in bean pod tissue, indicating that it may be involved in zinc transport to the seed. In addition the gene is expressed differently in the pods of the two navy bean varieties with known differences in zinc levels such that the variety with the higher seed zinc levels has higher dehydrin gene expression.

Technical Abstract: Humans require zinc in their diet but its availability is often limited and therefore human zinc deficiency is widespread. Increasing the zinc density in staple crops such as dry bean is a strategy to address human zinc deficiency. Characterization of genes involved in zinc transport and remobilization to the seed is a useful step to effectively increase seed zinc content. Recent molecular studies have identified a number of gene families involved in metal transport and homeostasis within the plant. One such gene family is dehydrins, which were recently shown to facilitate phloem-mediated long distance transport of micronutrients. The objective of this research was to characterize a dehydrin gene in Phaseolus vulgaris and determine its expression level in two navy bean lines with contrasting seed zinc concentration, Voyager (high seed Zn) and Albion (low seed Zn). .The sequence for the P. vulgaris dehydrin gene was previously identified as an EST-SSR and was named Pvm073 and mapped to linkage group B9. Based on sequence alignment with the soybean genome, this gene is composed of one intron and two exons. The primers of the EST-SSR Pvm 073 were screened on two navy bean lines, Voyager and Albion and found to be polymorphic. The level of expression of the dehydrin gene in Voyager and Albion pods was determined using the Pvm073 primers which the span exon-exon junction of the gene. The analysis revealed that the dehydrin gene is highly expressed in pod tissue. There were differences in expression between Albion and Voyager, where Voyager (high seed zinc) showed 1.5 fold higher expressing than Albion (low zinc).

Last Modified: 9/10/2014
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