Search for: All records

Carpels in maize undergo programmed cell death in half of the flowers initiated in ears and in all flowers in tassels. The HD-ZIP I transcription factor gene GRASSY TILLERS1 ( GT1 ) is one of only a few genes known to regulate this process. To identify additional regulators of carpel suppression, we performed a gt1 enhancer screen and found a genetic interaction between gt1 and ramosa3 ( ra3 ). RA3 is a classic inflorescence meristem determinacy gene that encodes a trehalose-6-phosphate (T6P) phosphatase (TPP). Dissection of floral development revealed that ra3 single mutants have partially derepressed carpels, whereas gt1 ; ra3 double mutants have completely derepressed carpels. Surprisingly, gt1 suppresses ra3 inflorescence branching, revealing a role for gt1 in meristem determinacy. Supporting these genetic interactions, GT1 and RA3 proteins colocalize to carpel nuclei in developing flowers. Global expression profiling revealed common genes misregulated in single and double mutant flowers, as well as in derepressed gt1 axillary meristems. Indeed, we found that ra3 enhances gt1 vegetative branching, similar to the roles for the trehalose pathway and GT1 homologs in the eudicots. This functional conservation over ∼160 million years of evolution reveals ancient roles for GT1 -like genes and the trehalose pathway in regulating axillary meristem suppression, later recruited to mediate carpel suppression. Our findings expose hidden pleiotropy of classic maize genes and show how an ancient developmental program was redeployed to sculpt floral form. 

Most plant roots have multiple cortex layers that make up the bulk of the organ and play key roles in physiology, such as flood tolerance and symbiosis. However, little is known about the formation of cortical layers outside of the highly reduced anatomy of Arabidopsis . Here, we used single-cell RNA sequencing to rapidly generate a cell-resolution map of the maize root, revealing an alternative configuration of the tissue formative transcription factor SHORT-ROOT (SHR) adjacent to an expanded cortex. We show that maize SHR protein is hypermobile, moving at least eight cell layers into the cortex. Higher-order SHR mutants in both maize and Setaria have reduced numbers of cortical layers, showing that the SHR pathway controls expansion of cortical tissue to elaborate anatomical complexity. 

The localization of a protein provides important information about its biological functions. The visualization of proteins by immunofluorescence has become an essential approach in cell biology. Here, we describe an easy‐to‐follow immunofluorescence protocol to localize proteins in whole‐mount tissues of maize (Zea mays) and Arabidopsis. We present the whole‐mount immunofluorescence procedure using maize ear primordia and Arabidopsis inflorescence apices as examples, followed by tips and suggestions for each step. In addition, we provide a supporting protocol to describe the use of an ImageJ plug‐in to analyze colocalization. This protocol has been optimized to observe proteins in 2‐5 mm maize ear primordia or in developing Arabidopsis inflorescence apices; however, it can be used as a reference to perform whole‐mount immunofluorescence in other plant tissues and species. © 2021 Wiley Periodicals LLC.

Basic Protocol: Whole‐mount immunofluorescence for maize and Arabidopsis shoot apices

Support Protocol: Measure colocalization by JACoP plugin in ImageJ