Circadian Clock Components Offer Targets for Crop Domestication and Improvement

Abstract

During plant domestication and improvement, farmers select for alleles present in wild species that improve performance in new selective environments associated with cultivation and use. The selected alleles become enriched and other alleles depleted in elite cultivars. One important aspect of crop improvement is expansion of the geographic area suitable for cultivation; this frequently includes growth at higher or lower latitudes, requiring the plant to adapt to novel photoperiodic environments. Many crops exhibit photoperiodic control of flowering and altered photoperiodic sensitivity is commonly required for optimal performance at novel latitudes. Alleles of a number of circadian clock genes have been selected for their effects on photoperiodic flowering in multiple crops. The circadian clock coordinates many additional aspects of plant growth, metabolism and physiology, including responses to abiotic and biotic stresses. Many of these clock-regulated processes contribute to plant performance. Examples of selection for altered clock function in tomato demonstrate that with domestication, the phasing of the clock is delayed with respect to the light–dark cycle and the period is lengthened; this modified clock is associated with increased chlorophyll content in long days. These and other data suggest the circadian clock is an attractive target during breeding for crop improvement.

Circadian Rhythms in Legumes: What Do We Know and What Else Should We Explore?

“…The circadian system is a highly intricate network, with extensive crosstalk among output pathways that can be influenced by external conditions. External (or environmental) signals, such as light and temperature, are integrated by the central oscillator that coordinates various physiological processes [ 3 , 11 ]. A proper regular clock function is essential for the coordination of multiple physiological pathways, which include flowering time, growth and metabolism, hormone signaling, and responses to biotic and abiotic stresses ( Figure 2 ).…”

“…More research to understand the molecular mechanisms of circadian rhythmicity in potential underutilized crops is crucial to help ensure the sustainability for future food or protein. All things considered, optimizing circadian function can offer opportunities to enhance the productivity of potential legumes and crops in general, including those grown over broad latitudinal ranges [ 3 ].…”

“…Efficient resource management is especially important for sessile organisms, such as plants, which cannot evade unfavorable conditions [ 2 ]. In general, the circadian rhythms in plants, which are often regulated by multiple feedback loops, have a higher complexity than those in animals, which are governed mostly by a centralized pacemaker [ 1 , 3 ]. Plants have multiple tissue- and organ-specific clocks that allow fine-tuning of physiological adaptations to changing environmental conditions.…”

“…Plant circadian rhythms are key to plant survival in diverse environmental conditions [ 4 ] and hence, have become a major focus in plant research. Understanding plant circadian rhythm and its manipulation may revolutionize modern food crop production and enhance food security [ 3 , 5 ].…”

The Roles of Temperature-Related Post-Transcriptional Regulation in Cereal Floral Development

“…An accurate circadian clock is integral to ensure core biological processes, from photosynthesis to flowering, are timed optimally with the external environment. Clock genes have been identified to influence many agricultural traits, including yield potential and flowering time; thus, understanding the effect of environmental factors on the expression of these genes is vital [23]. The expression of core clock genes enables the formation of interlocking feedback loops and the maintenance of an oscillating day-night cycle across a 24 h period.…”