Maize leaf epiphytic bacteria diversity patterns are genetically correlated with resistance to fungal pathogen infection

Plant leaves host a specific set of microbial epiphytes. Plant genetic and solar UV-B radiation effects on the diversity of the phyllosphere were examined by measuring epiphytic bacterial ribosomal DNA diversity in a maize recombinant inbred (RI) mapping population. Several chromosomal quantitative trait loci (QTL) with significant effects on bacterial diversity were identified, some of which had effects only in the presence of UV-B radiation and others that had effects both with and without UV-B. Candidate genes with allele-specific effects were mapped to the bacterial diversity chromosomal regions. A glutamate decarboxylase candidate gene was located at a UV-B–specific chromosomal locus, and in a comparison between two RI lines with contrasting bacterial diversity phenotypes, high bacterial diversity was associated with high levels of glutamate decarboxylase enzyme activity, a component of the gamma-aminobutyric acid (GABA) pathway. The bacterial diversity loci exhibited a significant...

植物叶片定殖有一类特有的附生微生物。本研究以玉米重组自交系（recombinant inbred, RI）作图群体为材料，通过测定其附生细菌核糖体DNA多样性，探究了植物遗传因子与太阳紫外线-B（UV-B）辐射对叶围（phyllosphere）微生物多样性的调控效应。研究鉴定出多个对细菌多样性具有显著影响的染色体数量性状位点（quantitative trait loci, QTL）：其中部分位点仅在UV-B辐射存在时发挥调控作用，其余位点则在有无UV-B辐射的条件下均能产生效应。具有等位基因特异性效应的候选基因被定位至与细菌多样性相关的染色体区域内。一个谷氨酸脱羧酶候选基因被定位在UV-B特异性染色体位点上；在两个细菌多样性表型存在显著差异的RI系的对比实验中，高细菌多样性与高水平的谷氨酸脱羧酶活性呈显著正相关，而该酶是γ-氨基丁酸（gamma-aminobutyric acid, GABA）代谢通路的关键组成成分。细菌多样性相关位点表现出显著的……