Overcoming the trade-off between early flowering and high yield in
wheat: Light regimens, developmental dynamics, and transcriptome
landscapes
Abstract
Early flowering is a survival strategy in wheat ( Triticum
aestivum L.) that sacrifices grain yield under long photoperiod
conditions, and this contradiction is greatly affected by floral growth
and development. However, little is known about the regulatory
mechanisms that remove the barrier between “early flowering” and
“high yielding” during floret development. Here, we showed
high-resolution analyses of the number and morphology of floret
primordia and the transcriptomes of wheat spikes in three light
regimens. The development of all floret primordia in a spike could be
divided into four distinct stages: differentiation (Stage I),
differentiation and morphology development concurrently (Stage II),
morphology development (Stage III), and polarization (Stage IV).
Compared to the controls, the long photoperiod supplemented with red
light treatment shortened the time required to complete Stage I-II, then
improved assimilates in the spike and promoted anther development,
thereby increasing fertile floret primordia during Stage III, and
maintained fertile floret primordia development during Stage IV until
they became fertile florets (grains) via a dynamic gene network centered
on ubiquitin, calcium signaling, aldehyde dehydrogenase, zinc finger
proteins, and heat shock proteins. Our findings proposed a light
regimen, critical stages, and candidate regulators that promoted early
flowering and high yield in wheat.