Turning heads: The biology of solar tracking in sunflower

Vandenbrink, Joshua P.; Brown, Evan; Harmer, Stacey L.; Blackman, Benjamin K.

doi:10.1016/j.plantsci.2014.04.006

Cited by 83 publications

(61 citation statements)

References 50 publications

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“…a, b Ultradian, longdistance-propagated SAPs, c, d Ultradian, long-distance-propagated SAPs and series of local SAPs. Examples of a local series of SAPs are marked by asterisks which moves its stem apex to follow the relative position of the sun (Vandenbrink et al 2014) and shows an ultradian, daily and circadian rhythm of CN and CN disturbance after illumination and darkening (Buda et al 2003;Charzewska and Zawadzki 2006;Stolarz et al 2008). There are reports that AP is a light/dark-guided signal in plants (Król et al 2010).…”

Section: Sap-associated Light/dark Sensingmentioning

confidence: 99%

Spontaneous action potentials and circumnutation in Helianthus annuus

Stolarz

Dziubińska

2017

Acta Physiol Plant

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Action potentials (APs) in plants are involved in fast leaf or trap closure as well as elongation, respiration, photosynthesis, and fertilization regulation. Here, spontaneous APs (SAPs) in relation to endogenous stem movement named circumnutation (CN) have been investigated in Helianthus annuus in different light conditions in freely circumnutating and immobilized plants. Extracellular electrical measurements and time-lapse photography were carried out simultaneously. The parameters of CN (trajectory length, period, and direction) and the number and transmission direction of SAPs were analysed. In continuous light (25-40 lmol m -2 s -1), all plants circumnutating vigorously in a regular elliptical manner and no SAPs were observed. In light/dark conditions, the plants circumnutated in a daily pattern, most SAPs were observed in the dark and freely circumnutated sunflowers had two times more SAPs (10 SAPs/24 h/plant) than the immobilized plants (5 SAPs/24 h/plant). In continuous very low light (5 lmol m -2 s -1 ), the plants circumnutated weakly and irregularly and SAPs appeared without the circadian pattern. 3-5 SAPs/24/plant occurred in the freely circumnutating and immobilized plants. In light/dark and continuous very low light conditions, an ultradian rhythm of SAPs was observed and the mean spacing between SAPs was approx. 121-271 min in the freely circumnutating and immobilized plants. Under all light conditions, more SAPs were transmitted basipetally than acropetally. One-hour lasting series of 3-4 min spaced SAPs locally propagated were observed as well in very low light. Basipetal and acropetal SAPs passing along the stem motor region accompany irregularity, changes in the CN trajectory direction, and stem torsion. These results demonstrate that APs and CN changes play a role in plant adaptation to light conditions and that there is an ultradian rhythm of SAPs beside ultradian CN rhythm.

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Section: Sap-associated Light/dark Sensingmentioning

confidence: 99%

Spontaneous action potentials and circumnutation in Helianthus annuus

Stolarz

Dziubińska

2017

Acta Physiol Plant

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“…In evolutionary biology, the Helianthus genus is a long-time model for hybrid speciation and adaptive introgression 10 . In plant science, the sunflower is a model for understanding solar tracking 11 and inflorescence development 12 .…”

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confidence: 99%

The sunflower genome provides insights into oil metabolism, flowering and Asterid evolution

Badouin¹,

Gouzy²,

Grassa³

et al. 2017

Nature

637

705

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The domesticated sunflower, Helianthus annuus L., is a global oil crop that has promise for climate change adaptation, because it can maintain stable yields across a wide variety of environmental conditions, including drought 1 . Even greater resilience is achievable through the mining of resistance alleles from compatible wild sunflower relatives 2,3 , including numerous extremophile species 4 . Here we report a high-quality reference for the sunflower genome (3.6 gigabases), together with extensive transcriptomic data from vegetative and floral organs. The genome mostly consists of highly similar, related sequences 5 and required single-molecule realtime sequencing technologies for successful assembly. Genome analyses enabled the reconstruction of the evolutionary history of the Asterids, further establishing the existence of a whole-genome triplication at the base of the Asterids II clade 6 and a sunflowerspecific whole-genome duplication around 29 million years ago 7 . An integrative approach combining quantitative genetics, expression and diversity data permitted development of comprehensive gene networks for two major breeding traits, flowering time and oil metabolism, and revealed new candidate genes in these networks. We found that the genomic architecture of flowering time has been shaped by the most recent whole-genome duplication, which suggests that ancient paralogues can remain in the same regulatory networks for dozens of millions of years. This genome represents a cornerstone for future research programs aiming to exploit genetic diversity to improve biotic and abiotic stress resistance and oil production, while also considering agricultural constraints and human nutritional needs 8,9 .As the only major crop domesticated in North America, with its sunlike inflorescence that inspired artists, the sunflower is both a social icon and a major research focus for scientists. In evolutionary biology, the Helianthus genus is a long-time model for hybrid speciation and adaptive introgression 10 . In plant science, the sunflower is a model for understanding solar tracking 11 and inflorescence development 12 .Despite this large interest, assembling its genome has been extremely difficult as it mainly consists of long and highly similar repeats. This complexity has challenged leading-edge assembly protocols for close to a decade 13 .To finally overcome this challenge, we generated a 102× sequencing coverage of the genome of the inbred line XRQ using 407 singlemolecule real-time (SMRT) cells on the PacBio RS II platform. Production of 32 million very long reads allowed us to generate a genome assembly that captures 3 gigabases (Gb) (80% of the estimated genome size) in 13,957 sequence contigs. Four high-density genetic maps were combined with a sequence-based physical map to build the sequences of the 17 pseudo-chromosomes that anchor 97% of the gene content (Fig.

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“…Heliotropic plants follow the direction of the sun throughout the day. Plants exhibiting heliotropic capabilities are not only stimulated by the sun, but physically track the sun's motion across the sky from east to west [6]. The first question tends to focus on how heliotropic plants can move without muscles.…”

Section: Observation: the Plant's Ability To Maintain Optimal Sunlightmentioning

confidence: 99%

“…Therefore, a number of components and questions need to be addressed in order to fully comprehend this complex everyday process. First, heliotropism is defined as the directional motion of plant parts in response to the direction of the sun [6]. There are several questions that automatically arise when you contemplate the dynamics of a flower tracking and moving in response to the sun.…”

Section: Introductionmentioning

confidence: 99%