Leaf spots caused by Curvularia lunata infection pose a significant threat to global maize production. Although resistance gene breeding faces challenges due to pathogen evolution, the plant microbiome has emerged as a key modulator of disease resistance. However, the mechanisms via which plant genes regulate phyllosphere metabolites to recruit beneficial microbes remain poorly understood. Here, we combined gene mapping, metabolomics, microbiome analyses, cytological analysis, and in vitro and in vivo experiments to investigate the disease resistance mechanism of ZmHPATR1. We first identified that the loss‐of‐function mutation in ZmHPATR1 significantly increased the levels of fumaric acid, folic acid, and tetrahydrofolic acid in the leaves, leading to the enrichment of the genus Sphingomonas. We further demonstrated that the extracellular polysaccharide, welan gum, biosynthesized by Sphingomonas, effectively inhibited C. lunata growth and disrupted its cell structure. These results enable us to comprehensively understand the complicated mechanisms of plant resistance to disease through a four‐level regulatory network that links plant genes, metabolites, microbes, and pathogens. Our findings provide new strategies for targeted microbiome‐based disease‐resistant breeding and the development of novel biopesticides for maize.
Xinhao Luo, Hanchen Shan, Boyan Wang et al.· New Phytologist· 0 citations
The R1R2R3-MYB (3R-MYB) transcription factor subfamily is associated with stress tolerance; however, the underlying mechanisms in crops remain poorly understood. This study investigates the function of maize MYB3R in regulating seedling drought tolerance. We characterised MYB3R overexpression lines and CRISPR-Cas9 loss-of-function mutants in maize and rice using physiological assays and transcriptome profiling. DNA affinity purification sequencing (DAP-seq) and molecular interaction assays were employed to identify direct downstream targets. MYB3R overexpression enhanced drought tolerance by promoting root development, stomatal closure and antioxidant defence, whereas mutants displayed hypersensitivity. MYB3R binds the mitosis-specific activator (MSA) motif to directly transactivate the B-type cyclin gene CYCB1;2, and cycb1;2 mutants phenocopied the myb3r drought defects. These findings establish that the MYB3R-CYCB1;2 module positively regulates maize drought tolerance by coordinating developmental and physiological adaptations. This pathway provides a valuable molecular target for breeding drought-resilient crops.
Kang Guo, Yingli Jiang, Yuxin Guo et al.· The Plant Journal· 0 citations
ABSTRACT The precise enhancement of nutritional quality in silage maize is a core strategy for increasing livestock production efficiency. Through evolutionary analysis of multiple plant species, we identified two functionally synergistic upstream open reading frames (uORF1 and uORF2) within the 5′ untranslated region of the gene encoding GDP‐L‐galactose phosphorylase (GGP). By leveraging a natural translation‐enhancing haplotype of uORF1 (Hap2) and performing CRISPR/Cas9‐mediated targeted mutagenesis of the highly conserved uORF2, we successfully engineered an elite dual‐uORFs variant. This variant significantly increased vitamin C (Vc) content and concurrently improved key silage quality traits, including crude protein and phosphorus levels, without inducing growth penalties. Transcriptomic profiling further elucidated the molecular mechanisms by which the dual‐uORFs variation coordinately regulates Vc biosynthesis and the improvement of silage quality. Our findings deepen the understanding of the conventional paradigm of single‐uORF regulation and provide a novel strategy and superior germplasm resources for the precision breeding of high‐Vc, high‐quality silage maize.
Jing Zhou, Xi Wang, Yajing Zhang et al.· Plant Biotechnology Journal· 0 citations
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