Publications by authors named "Wesley Bruce"

Background: Thermography is a popular tool to assess plant water-use behavior, as plant temperature is influenced by transpiration rate, and is commonly used in field experiments to detect plant water deficit. Its application in indoor automated phenotyping platforms is still limited and mainly focuses on differences in plant temperature between genotypes or treatments, instead of estimating stomatal conductance or transpiration rate. In this study, the transferability of commonly used thermography analysis protocols from the field to greenhouse phenotyping platforms was evaluated.

View Article and Find Full Text PDF

Drought at flowering and grain filling greatly reduces maize (Zea mays) yield. Climate change is causing earlier and longer-lasting periods of drought, which affect the growth of multiple maize organs throughout development. To study how long periods of water deficit impact the dynamic nature of growth, and to determine how these relate to reproductive drought, we employed a high-throughput phenotyping platform featuring precise irrigation, imaging systems, and image-based biomass estimations.

View Article and Find Full Text PDF

Hyperspectral imaging is a promising tool for non-destructive phenotyping of plant physiological traits, which has been transferred from remote to proximal sensing applications, and from manual laboratory setups to automated plant phenotyping platforms. Due to the higher resolution in proximal sensing, illumination variation and plant geometry result in increased non-biological variation in plant spectra that may mask subtle biological differences. Here, a better understanding of spectral measurements for proximal sensing and their application to study drought, developmental and diurnal responses was acquired in a drought case study of maize grown in a greenhouse phenotyping platform with a hyperspectral imaging setup.

View Article and Find Full Text PDF

Root hairs are tubular extensions of the epidermis. Root hairs of the monogenic recessive maize mutant roothairless 6 (rth6) are arrested after bulge formation during the transition to tip growth and display a rough cell surface. BSR-Seq in combination with Seq-walking and subsequent analyses of four independently generated mutant alleles established that rth6 encodes CSLD5 a plasma membrane localized 129 kD D-type cellulose synthase with eight transmembrane domains.

View Article and Find Full Text PDF

Root hairs are instrumental for nutrient uptake in monocot cereals. The maize (Zea mays L.) roothairless5 (rth5) mutant displays defects in root hair initiation and elongation manifested by a reduced density and length of root hairs.

View Article and Find Full Text PDF

The rth3 (roothairless 3) mutant is specifically affected in root hair elongation. We report here the cloning of the rth3 gene via a PCR-based strategy (amplification of insertion mutagenized sites) and demonstrate that it encodes a COBRA-like protein that displays all the structural features of a glycosylphosphatidylinositol anchor. Genes of the COBRA family are involved in various types of cell expansion and cell wall biosynthesis.

View Article and Find Full Text PDF

The SCARECROW (SCR) gene in Arabidopsis is required for asymmetric cell divisions responsible for ground tissue formation in the root and shoot. Previously, we reported that Zea mays SCARECROW (ZmSCR) is the likely maize ortholog of SCR. Here we describe conserved and divergent aspects of ZmSCR.

View Article and Find Full Text PDF

The roothairless1 (rth1) mutant is impaired in root hair elongation and exhibits other growth abnormalities. Unicellular root hairs elongate via localized tip growth, a process mediated by polar exocytosis of secretory vesicles. We report here the cloning of the rth1 gene that encodes a sec3 homolog.

View Article and Find Full Text PDF

Microarray technology has become increasingly useful in measuring expression levels of a large number of genes and part of a repertoire of functional genomic tools. We describe the methods of cDNA microarray preparation, the use, data collection, and initial data processing. The cDNA fragments are first prepared by polymerase chain reaction (PCR), and then attached to a solid substrate, such as a chemically treated glass slide.

View Article and Find Full Text PDF

Matrix attachment regions (MARs) are binding sites for nuclear scaffold proteins in vitro, and are proposed to mediate the attachment of chromatin to the nuclear scaffold in vivo. Previous reports suggest that MAR elements may stabilize transgene expression. Here, we tested the effects of two maize MAR elements (P-MAR from the P1-rr gene, and Adh1-MAR from the adh1 gene) on the expression of a gusA reporter gene driven by three different promoters: the maize p1 gene promoter, a wheat peroxidase (WP) gene promoter, or a synthetic promoter (Rsyn7).

View Article and Find Full Text PDF

Matrix attachment regions (MARs) are DNA sequences that bind an internal nuclear network of nonhistone proteins called the nuclear matrix. Thus, they may define discrete gene-containing chromatin loops in vivo. We have studied the effects of flanking transgenes with MARs on transgene expression levels in maize callus and in transformed maize plants.

View Article and Find Full Text PDF

Average maize yields have increased steadily over the years in the USA and yet the variations in harvestable yield have also markedly increased. Much of the increase in yield variability can be attributed to (1) varying environmental stress conditions; (2) improved nitrogen inputs and better weed control; and (3) continuing sensitivity of different maize lines to the variation in input supply, especially rainfall. Drought stress alone can account for a significant percentage of average yield losses.

View Article and Find Full Text PDF