Yangyang Liu, Lili Zhang, Anting Zhu, Liping Shen, Jiaqi Zhang, Jun Chen, Guowei Chang, Changbin Yin, Ziying Wang, Zhiwen Sun, Kuocheng Shen, Xiaowan Xu, Mengjing Sun, Mingming Xin, Jianhui Wu, Zefu Lu, Yiping Tong, Zhonghu He, Fei Lu, Yuanfeng Hao, Wei Chen, Zifeng Guo <<<

Abstract Wheat (Triticum aestivum L.) spike development is tightly regulated by genetic and metabolic programs that drive organ growth and morphological changes. However, the dynamic interplay between metabolic shifts, gene expression patterns, and their regulatory roles during spike development, remains poorly characterized. To address this knowledge gap, we performed integrated metabolomic and transcriptomic profiling across 12 stages of wheat spike organ development. Our analysis detected 1,105 metabolites in 233 spike, spikelet, and floret samples, uncovering an uneven distribution of phytohormone-related metabolites. The exogenous phytohormone treatments validated the regulatory roles of phytohormones in spike morphogenesis. High-resolution spatiotemporal data from carpel organs enabled the reconstruction of a regulatory network, identifying key genes (including 12-oxo-phytodienoic acid reductase3 (TaOPR3), Grain Length1 (GL1), and Grain Length2 (GL2)) as critical determinants of grain size. Genomic analyses revealed geographical differentiation in gene haplotypes and their selective retention during breeding, with superior alleles associated with increased grain size. This comprehensive dataset provides a valuable resource for understanding the molecular basis of wheat grain yield and offers potential targets for crop improvement. <<<

Abstract Inflorescence branching in the grasses controls the number of florets and hence the number of seeds. Recent data on the underlying genetics come primarily from rice and maize, although new data are accumulating in other systems as well. This review focuses on a window in developmental time from the production of primary branches by the inflorescence meristem through to the production of glumes, which indicate the transition to producing a spikelet. Several major developmental regulatory modules appear to be conserved among most or all grasses. Placement and development of primary branches are controlled by conserved auxin regulatory genes. Subtending bracts are repressed by a network including TASSELSHEATH4, and axillary branch meristems are regulated largely by signaling centers that are adjacent to but not within the meristems themselves. Gradients of SQUAMOSA-PROMOTER BINDING-like and APETALA2-like proteins and their microRNA regulators extend along the inflorescence axis and the branches, governing the transition from production of branches to production of spikelets. The relative speed of this transition determines the extent of secondary and higher order branching. This inflorescence regulatory network is modified within individual species, particularly as regards formation of secondary branches. Differences between species are caused both by modifications of gene expression and regulators and by presence or absence of critical genes. The unified networks described here may provide tools for investigating orphan crops and grasses other than the well-studied maize and rice. <<<