Y Xu, F Liu, S Zhu, and X Li

Frontier in Plant Science; 17 July 2018 | https://doi.org/10.3389/fpls.2018.01033

Nucleotide-binding site-leucine-rich repeat (NBS-LRR) domain proteins are immune sensors and play critical roles in plant disease resistance. In this study, we cloned and characterized a novel NBS-LRR gene ZmNBS25 in maize. We found that ZmNBS25 could response to pathogen inoculation and salicylic acid (SA) treatment in maize, and transient overexpression of ZmNBS25 induced a hypersensitive response in tobacco. High-performance liquid chromatography (HPLC) analysis showed that, compared to control plants, ZmNBS25 overexpression (ZmNBS25-OE) in Arabidopsis and rice resulted in higher SA levels. By triggering the expression of certain defense-responsive genes, ZmNBS25-OE enhanced the resistance of Arabidopsis and rice to Pseudomonas syringae pv. tomato DC3000 and sheath blight disease, respectively. Moreover, we found little change of grain size and 1000-grain weight between ZmNBS25-OE rice lines and controls. Together, our results suggest that ZmNBS25 can function as a disease resistance gene across different species, being a valuable candidate for engineering resistance in breeding programs.

See: https://www.frontiersin.org/articles/10.3389/fpls.2018.01033/full

Figure 1: Comparison of ZmNBS25 with other disease resistance proteins. (A) Phylogenetic analysis of ZmNBS25 and other plant resistance proteins. Bootstrap values (1,000 replicates) are shown as percentages at the branch nodes. Bar = 0.2. GenBank accession numbers and plant sources are: AtRPM1 (CAA61131.1) from Arabidopsis thaliana, HvSL8 (AJ507098) and HvMla1 (AAG37356.1) from Hordeum vulgare, OsXA1 (BAA25068.1), OsRGA5 (AGM61351.1), and OsYR5 (AF456245.1) from Oryza sativa, SbPc-A (ACB72454.1) from Sorghum bicolor, SiRPM1-like (XM_004978992.1) from Setaria italica, TaLr10 (ADM65840.1) from Triticum dicoccoides, ZmMRPR1 (NM_001112339.1), ZmRp1 (AAP81261.1), ZmRXO1 (AAX31149.1), and ZmRGA4 (NP_001147651.1) from Zea mays. (B) Conserved domain comparisons between the amino acid sequences of ZmNBS25 and other resistance proteins. Black, red, and blue shading represent 100%, ≥75%, and ≥50% amino acid sequence similarity, respectively.