Understanding the effect of Far red light on shoot and root architecture in Lettuce

Increasing demand necessitates growing crops in high density planting systems. In high dense planting systems, plants receive light reflected from their proximate neighbors that is strongly enriched in the far red (FR) part of the spectrum. Plants detect FR light with phytochrome photoreceptors and respond with so-called shade avoidance responses. These responses include elongated hypocotyl and internodes and a more upward orientation of leaves (hyponasty), but FR enrichment aboveground also has effects belowground where it inhibits lateral root formation primary root elongation. Under experimental conditions, these phenomena can be studied by exposing plants to additional FR light from dedicated LEDs as addition to a standard white light background. We study, as members of the LettuceKnow consortium, how FR enrichment regulates Lettuce (L. sativa) shoot and root growth and architecture. To this end we combine genetic variation screens using different lettuce varieties, RNA sequencing of shoot and root tissues of contrasting lettuce varieties and dedicated physiological and molecular biology approaches. These integrated approaches will provide new insights into our understanding developmental plasticity in lettuce under varying light quality regimes.