Abstract
Complete differentiation of the spikes guarantees the final wheat (Triticum aestivum L.) grain yield. A unique wheat mutant that prematurely terminated spike differentiation (ptsd1) was obtained from cultivar Guomai 301 treated with ethyl methane sulfonate (EMS). The molecular mechanism study on ptsd1 showed that the senescence-associated genes (SAGs) were highly expressed, and spike differentiation related homeotic genes were depressed. Cytokinin signal transduction was weakened and ethylene signal transduction was enhanced. The enhanced expression of Ca2+ signal transduction related genes and the accumulation of reactive oxygen species (ROS) caused the upper spikelet cell death. Many genes in the WRKY, NAC and ethylene response factor (ERF) transcription factor (TF) families were highly expressed. Senescence related metabolisms, including macromolecule degradation, nutrient recycling, as well as anthocyanin and lignin biosynthesis, were activated. A conserved tae-miR164 and a novel-miR49 and their target genes were extensively involved in the senescence related biological processes in ptsd1. Overall, the abnormal phytohormone homeostasis, enhanced Ca2+ signaling and activated senescence related metabolisms led to the spikelet primordia absent their typical meristem characteristics, and ultimately resulted in the phenotype of ptsd1.
Highlights
Wheat spike differentiation is a key developmental stage as a transition from vegetative growth to reproductive growth in wheat (Triticum aestivum L.) [1]
Many genes involved in metabolism, degradation and regulator processes have been identified from a wheat premature leaf senescence mutant m68 [19]
Our results suggested that senescence-associated genes (SAGs) were highly expressed, programmed cell death (PCD) was enhanced, ethylene signal transduction related genes and the degradation related genes of cytokinins were highly expressed in ptsd1
Summary
Wheat spike differentiation is a key developmental stage as a transition from vegetative growth to reproductive growth in wheat (Triticum aestivum L.) [1]. A few genes related to spike differentiation have been reported in wheat, the gene regulatory network remains largely unknown. Many genes involved in metabolism, degradation and regulator processes have been identified from a wheat premature leaf senescence mutant m68 [19]. The feed-forward signaling cascade involving ETHYLENE-INSENSITIVE2 (EIN2), EIN3, miR164, and ORE1 plays an important role in the processes of leaf senescence in Arabidopsis [24,25]. We have obtained several stable hereditary prematurely terminated spike differentiation (ptsd) mutants from the EMS treated wheat cultivar “Guomai 301” and “Shengnong 1” [26,27]. Global analysis of the metabolism related differentially expressed genes (DEGs) and measurement of the metabolism indicators revealed that the degradation of macromolecules and the biosynthesis pathway of phenylpropanoids were enhanced in mutant ptsd
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
