Fig. 1. Isolation and characterization of a thermosensitive ossgs3a mutant.

a The glumes of thermosensitive abnormal palea (tsp) mutant and 2537 (wild-type) in Shanghai in the summer with high field temperature (HT, ≥35 °C) frequently occurring at rice booting stage, or in Hainan in the winter with normal temperatures (NT) suitable for rice growth. Pa, palea; le, lemma. b The seed-setting rates, 1000-grain weight, and grain yield per plant of tsp and 2537 grown under high field temperature. Values are mean ± s.d. (n = number of biologically independent samples in the graph). Significant differences were determined by two-tailed Student’s t test for pairwise comparisons. c Map-based gene cloning of OsSGS3a. The locus responsible for the mutant phenotype was preliminarily mapped to a region between markers RM27667 and RM27792. Combining with the whole-genome sequencing-based MutMap method, a single nucleotide deletion at position 1697 in the last exon of OsSGS3a in tsp was identified. The chromosomal locations of markers and the numbers of recombinants are indicated by the numbers above and below the chromosome, respectively. d Western blotting analysis of OsSGS3a protein levels using anti-OsSGS3a antibody. OsSGS3a protein (69.4 kD) was detected in 2537 while the truncated OsSGS3a protein (64.6 kD) was produced in tsp. Equal protein loading was confirmed with the anti-OsActin antibody. The star indicates unspecific bands. Experiments were repeated three times with similar results (b, d). e T₁ transgenic plants expressing the Flag-tagged coding sequence of LOC_Os12g09580 (OsSGS3a) developed glumes that were morphologically identical to 2537 under high field temperature. Scale bars, 1 mm (a, e). Source data are provided as a Source Data file (b, d).