A naturally occurring SNP modulates thermotolerance divergence among grapevines.

Chen, Haiyang; Yu, Haibo; Yuan, Ling; Kong, Lingchao; Li, Shenchang; Cao, Xiongjun; Li, Yang; Wang, Yi et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

With the increasing challenges posed by global warming and climate change, heat stress has become a significant threat to the sustainable production of grapevines. However, the genetic basis of grapevine thermotolerance remains poorly understood. Here, we combine genome-wide association study with transcriptomic profiling to identify TTC4 (thermotolerance on chromosome 4), a gene encoding a WRKY transcription factor, as a key determinant of thermotolerance in grapevine. TTC4 directly activates two thermotolerance-related genes, HSP18.1 and APX3. We also identify a heat-suppressed repressor SPL13 (SQUAMOSA-promoter binding protein-like 13) that cannot bind to the GTAT element (TTC4<sup>T(7631)</sup>) in intron 2 of TTC4, but can bind to the natural variant, GTAC (TTC4<sup>C(7631)</sup>). Grapevine accessions with TTC4<sup>C/C(7631)</sup> genotype exhibit significantly lower thermotolerance compared to those with the TTC4<sup>T/T(7631)</sup> and TTC4<sup>C/T(7631)</sup> genotypes. This fine-tuned regulation contributes to thermotolerance divergence among grapevine populations. The TTC4<sup>T(7631)</sup> haplotype holds significant potential as a genetic resource for breeding thermotolerant grapevine varieties.

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