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Full-Text Articles in Life Sciences

An Automated Method For Rapid Identification Of Putative Gene Family Members In Plants, Ronald L. Frank, Ajay Mane, Fikret Erçal Sep 2006

An Automated Method For Rapid Identification Of Putative Gene Family Members In Plants, Ronald L. Frank, Ajay Mane, Fikret Erçal

Biological Sciences Faculty Research & Creative Works

Background: Gene duplication events have played a significant role in genome evolution, particularly in plants. Exhaustive searches for all members of a known gene family as well as the identification of new gene families has become increasingly important. Subfunctionalization via changes in regulatory sequences following duplication (adaptive selection) appears to be a common mechanism of evolution in plants and can be accompanied by purifying selection on the coding region. Such negative selection can be detected by a bias toward synonymous over nonsynonymous substitutions. However, the process of identifying this bias requires many steps usually employing several different software programs. We …


A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber Jul 2006

A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber

Dartmouth Scholarship

The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of …


Expression Profiling And Local Adaptation Of Boechera Holboellii Populations For Water Use Efficiency Across A Naturally Occurring Water Stress Gradient, Charles A. Knight, Heiko Vogel, Juergen Kroymann, Alice Shumate, Hanneke Witsenboer, Thomas Mitchell-Olds Apr 2006

Expression Profiling And Local Adaptation Of Boechera Holboellii Populations For Water Use Efficiency Across A Naturally Occurring Water Stress Gradient, Charles A. Knight, Heiko Vogel, Juergen Kroymann, Alice Shumate, Hanneke Witsenboer, Thomas Mitchell-Olds

Biological Sciences

We studied the physiological basis of local adaptation to drought in Boechera holboellii, a perennial relative of Arabidopsis thaliana, and used cDNA–AFLPs to identify candidate genes showing differential expression in these populations. We compared two populations of B. holboellii from contrasting water environments in a reciprocal transplant experiment, as well as in a laboratory dry-down experiment. We continuously measured the water content of soils using time domain reflectometery (TDR). We compared populations for their water use efficiency (WUE), root/shoot ratios (R:S) and leaf mass per unit area (LMA) in the field and in the laboratory, and identified candidate …


Establishment Of Polarity During Organization Of The Acentrosomal Plant Cortical Microtubule Array, Ram Dixit, Eric Chang, Richard Cyr Jan 2006

Establishment Of Polarity During Organization Of The Acentrosomal Plant Cortical Microtubule Array, Ram Dixit, Eric Chang, Richard Cyr

Biology Faculty Publications & Presentations

The plant cortical microtubule array is a unique acentrosomal array that is essential for plant morphogenesis. To understand how this array is organized, we exploited the microtubule (+)-end tracking activity of two Arabidopsis EB1 proteins in combination with FRAP (fluorescence recovery after photobleaching) experiments of GFP-tubulin to examine the relationship between cortical microtubule array organization and polarity. Significantly, our observations show that the majority of cortical microtubules in ordered arrays, within a particular cell, face the same direction in both Arabidopsis plants and cultured tobacco cells. We determined that this polar microtubule coalignment is at least partially due to a …