Extended Data Fig. 3: Effects of DRESH8 on sRNA and local gene expression, and ZmMYBR38 on plant drought tolerance.

a, Mapping of 21-, 22-, and 24-nt sRNA reads to DRESH8 and mRNA reads to DRESH8, ZmPP2C16, and ZmWRKY51. DRESH8 interrupts ZmPP2C16. mRNA and sRNA reads both map to the DRESH8 locus, but only mRNA reads map to ZmPP2C16 and ZmWRKY51. DT2-DT4 indicate various drought stress levels, as reported previously⁵¹. b, Genomic structures of the ZmPP2C16 and ZmWRKY51 loci. Lines ending with arrows indicate the direction of transcription. Arrowheads indicate the positions of the primers used to detect ZmPP2C16 (in red) and ZmWRKY51 (in blue) in PCR analyses. c, d, PCR results using genomic DNA and cDNA templates for ZmPP2C16 (c) and ZmWRKY51 (d). Primer annealing sites are indicated in (b). e, f, DRESH8 does not affect the expression of ZmPP2C16 (e) or ZmWRKY51 (f) under either WW or DS conditions. Values (dots) indicate qRT-PCR data for maize inbred accessions with (+, N = 28) and without (-, N = 63) DRESH8 grown under WW and DS conditions. n.s., not significant, as determined by two-sided Student’s t-test. g,h, Overexpression of ZmMYBR38 in transgenic maize (g) and Arabidopsis (h) plants. WT, maize KN5585 used for transformation; Col-0, Arabidopsis WT accession used for transformation. i, Transgenic Arabidopsis plants overexpressing ZmMYBR38 (OX1 and OX4) are more drought tolerant. Values shown on the right represent means ± SD from three replicates (N = 292 plants for OX1 per replicate, 192 plants for OX4 per replicate) of the percentage of plants that survived. The P values were calculated by two-sided Student’s t-test. For c, d, g, h, the experiments were repeated independently for three times and similar results were obtained each time.