Fig. 6: A 20-bp deletion is associated with a decrease of ZmSnRK2.10 transcription and an increase of shoot Na⁺ content.

a The association of 42 natural variants in ZmSnRK2.10 (including the promoter region and 3′-UTR) with the expression of ZmSnRK2.10 among 105 maize inbred lines. The lower panel showed the pattern of the pairwise linkage disequilibrium (LD) of the variants. The red dots highlight the complete LD between the two significant SNPs (SNP-467, SNP-357) and Del-356. The association was determined using a mixed linear model in Tassel 5.0. b Haplotypes of ZmSnRK2.10 among maize natural inbred lines grouped according to the significant variants. c Comparison of the transcript levels of ZmSnRK2.10 between Hap1 and Hap2 inbred lines under control and salt conditions. d Comparison of the shoot Na⁺ content between Hap1 and Hap2 inbred lines under 100 mM NaCl treatment. The center lines represent the medians, the box limits denote the 25th and 75th percentiles, the whiskers extend from the 5th percentile to the 95th percentile values, and the dots represented the outliers. (Hap1, n = 31; Hap2, n = 74). e The transcript levels of GFP with the indicated promoters (see Methods). Different letters indicate a significant difference (P < 0.05) based on the one-way ANOVA. f In-gel kinase assay of ZmSnRK2.9 and ZmSnRK2.10 using maize inbred lines Zheng58 (without Del-356) and E588 (with Del-356). Total proteins were extracted from 7-day-old plants with the indicated treatment. Recombinant GST-ZmHAK4^N served as the substrate. Kinase activity was detected by autoradiography. Coomassie Brilliant Blue (CBB) staining provided a loading control. The red arrow indicates the target bands. Similar results were observed in three independent experiments. g The PCR confirmation of the development of a molecular marker for the ZmSnRK2.10 locus depends on the presence of a 20-bp deletion. h The Na⁺ content in the shoot of 2-week-old Zheng58 and E588 plants with the indicated treatments (h). Data are mean ± s.d. of three independent replicates. Statistical significance was determined via a two-sided t-test. i Shoot Na⁺ content of the F2 plants carrying alleles ZmSnRK2.10^Zheng58, ZmSnRK2.10^E588, and ZmSnRK2.10^Zheng58/E588. The centre lines represent the medians, the box limits denote the 25^th and 75^th percentiles, the whiskers extend from the 5th percentile to the 95th percentile values, and the dots represented the outliers. Data presented in e, h are mean values ± SD of three independent replicates. Statistical significance was determined using a one-way ANOVA test. Different letters represented a significant difference at P < 0.05. Statistical significance shown in (c, d, i) was determined by a two-sided t-test. Source data are provided as a Source Data file.