Abstract
We quantify the shape of hooked hairs which is a newly observed
phenotype of epidermal cell extensions [1] in the common bean
genotype L88-57 (Phaseolus vulgaris). The hooked hairs emerge
below-ground before the root hairs and have a distinct ‘hooking’
morphology. We generated a dataset capturing their full distribution
under the microscope within 3-5 days of germination. We quantify their
shape by a novel computational pipeline that can automatically phenotype
morphology. Our phenotyping pipeline quantifies traits like length,
curvature, perimeter, area, and ‘hooking.’ Our objective is to quantify
their response to nutrient stress to determine the function of hooked
hairs in common bean during early development. We used the pipeline for
analyzing our dataset of hydroponically grown beans and observed
statistically significant responses compared to the control for length,
curvature, perimeter, and area to nitrogen (p<0.001**) and
phosphorus (p<0.001**) stress treatments. The calculation of
‘hooking’ for our dataset is still ongoing. We are simultaneously
developing a landmark-free method for the two-dimensional shape analysis
of our dataset and believe that our phenotyping efforts will enable the
high-throughput analysis of morphological root hair traits for any plant
species.