Dynamic transcriptome landscape of maize pericarp development

Abstract

SUMMARYAs a maternal tissue, the pericarp supports and protects for other components of seed, such as embryo and endosperm. Despite the importance of maize pericarp in seed, the genome‐wide transcriptome pattern throughout maize pericarp development has not been well characterized. Here, we developed RNA‐seq transcriptome atlas of B73 maize pericarp development based on 21 samples from 5 days before fertilization (DBP5) to 32 days after fertilization (DAP32). A total of 25 346 genes were detected in programming pericarp development, including 1887 transcription factors (TFs). Together with pericarp morphological changes, the global clustering of gene expression revealed four developmental stages: undeveloped, thickening, expansion and strengthening. Coexpression analysis provided further insights on key regulators in functional transition of four developmental stages. Combined with non‐seed, embryo, endosperm, and nucellus transcriptome data, we identified 598 pericarp‐specific genes, including 75 TFs, which could elucidate key mechanisms and regulatory networks of pericarp development. Cell wall related genes were identified that reflected their crucial role in the maize pericarp structure building. In addition, key maternal proteases or TFs related with programmed cell death (PCD) were proposed, suggesting PCD in the maize pericarp was mediated by vacuolar processing enzymes (VPE), and jasmonic acid (JA) and ethylene‐related pathways. The dynamic transcriptome atlas provides a valuable resource for unraveling the genetic control of maize pericarp development.

Genetic Analysis and QTL Mapping for Pericarp Thickness in Maize (Zea mays L.)

“…Notably, there was an observable trend of initial increase followed by decrease in pericarp thickness across different maize varieties. The trend of pericarp thickness was similar to that of Zhang et al [14]. Furthermore, by analyzing the changes in pericarp thickness and disparities in pericarp cell structure, maize pericarp development has been classi ed into four stages: growth, formation, autophagy, and maturation.…”

“…Zhang et al used the hierarchical clustering and PCA analysis of high temporal resolution transcriptome to classify maize pericarp development into four stages: undeveloped, thickening, expansion, and strengthening [14]. Xiong et al performed dynamic measurements of pericarp thickness using M03 and M08 as materials.…”