Tissue-specific transcriptomics reveal functional differences in floral development

Area of Science:

• Plant biology
• Developmental genetics
• Agricultural science

Background:

• Grass flowers (florets) develop within spikelets, with varying numbers and fates.
• In maize (Zea mays), spikelets contain two florets; the lower floret typically aborts despite initial similar development to the upper floret.

Purpose of the Study:

• To investigate the molecular and physiological differences between upper and lower floral meristems in maize.
• To understand the mechanisms underlying lower floret abortion in maize spikelets.

Main Methods:

• Laser capture microdissection coupled with RNA-sequencing (RNA-seq) to analyze gene expression.
• Comparative analysis of gene expression profiles in upper and lower floral meristems.

Main Results:

• Identified differentially expressed genes related to hormone regulation, cell wall dynamics, and energy homeostasis.
• Observed differences in cell wall modifications and sugar accumulation between upper and lower florets.
• Discovered a boundary domain between florets, potentially regulating floral meristem activity.

Conclusions:

• Propose a model where suppressed growth in the lower maize floret is mediated by limited sugar availability and activated growth repression genes.
• This growth repression module may influence floret fertility in other grasses and offers a target for engineering improved cereal crops.