ZmbZIP27 regulates nitrogen-mediated leaf angle by modulating lignin deposition in maize

In grain crops such as maize(Zea mays),leaf angle(LA)is a key agronomic trait affecting light interception and thus planting density and yield.Nitrogen(N)affects LA in plants,but we lack a good understanding of how N regulates LA.Here,we report that N deficiency enhanced lignin deposition in the ligular region of maize seedlings.In situ hybridization showed that the bZIP transcription factor gene ZmbZIP27 is mainly expressed in the phloem of maize vascular bundles.Under N-sufficient conditions,transgenic maize overexpressing ZmbZIP27 showed significantly smaller LA compared with wild type(WT).By contrast,zmbzip27_(ems)mutant showed larger LA under both N-deficient and N-sufficient conditions compared with WT.Overexpression of ZmbZIP27 enhanced lignin deposition in the ligular region of maize in the field.We further demonstrated that ZmbZIP27 could directly bind the promoters of the microRNA genes ZmMIR528a and ZmMIR528b and negatively regulate the expression levels of ZmmiR528.ZmmiR528 knockdown transgenic maize displayed erect architecture in the field by increasing lignin content in the ligular region of maize.Taken together,these results indicate that ZmbZIP27 regulates N-mediated LA size by regulating the expression of ZmmiR528 and modulating lignin deposition in maize.

Non-conventional peptides in plants:From gene regulation to crop improvement

Conventional peptides(CPs)and non-conventional peptides(NCPs)are generated from small open reading frames,but most CPs are derived from large precursors.NCPs,which are derived from sequences other than conventional open reading frames or annotated coding sequences regions,function in plant development and adaptation to stresses.Ribosome profiling,a technique for studying translational regulation,can be used to identify NCPs.Another new technique,peptidogenomics,which integrates mass spectrometry and genomics,is becoming more widely used for identifying plant NCPs.In recent years,numerous studies have investigated the roles in monocots and dicots of miRNA-derived peptides and upstream open reading frames,which have potential for improving agronomic traits.Investigating the biological functions of NCPs will advance molecular plant breeding by identifying regulators of plant growth and development.We present an overview of NCP identification methods and recent findings about NCP biological functions.

The m^(6)A reader SiYTH1 enhances drought tolerance by affecting the messenger RNA stability of genes related to stomatal closure and reactive oxygen species scavenging in Setaria italica

Foxtail millet(Setaria italica),a vital drought-resistant crop,plays a significant role in ensuring food and nutritional security.However,its drought resistance mechanism is not fully understood.N6-methyladenosine(m^(6)A)modification of RNA,a prevalent epi-transcriptomic modification in eukaryotes,provides a binding site for m^(6)A readers and affects plant growth and stress responses by regulating RNA metabolism.In this study,we unveiled that the YT521-B homology(YTH)family gene SiYTH1 positively regulated the drought tolerance of foxtail millet.Notably,the siyth1 mutant exhibited reduced stomatal closure and augmented accumulation of excessive H_(2)O_(2)under drought stress.Further investigations demonstrated that SiYTH1 positively regulated the transcripts harboring m^(6)A modification related to stomatal closure and reactive oxygen species(ROS)scavenging under drought stress.SiYTH1 was uniformly distributed in the cytoplasm of SiYTH1-GFP transgenic foxtail millet.It formed dynamic liquid-like SiYTH1 cytosol condensates in response to drought stress.Moreover,the cytoplasmic protein SiYTH1 was identified as a distinct m^(6)A reader,facilitating the stabilization of its directly bound SiARDP and ROS scavenging-related transcripts under drought stress.Furthermore,natural variation analysis revealed SiYTH1AGTG as the dominant allele responsible for drought tolerance in foxtail millet.Collectively,this study provides novel insights into the intricate mechanism of m^(6)A reader-mediated drought tolerance and presents a valuable genetic resource for improving drought tolerance in foxtail millet breeding.