A natural variation in SlSCaBP8 promoter contributes to the loss of saline-alkaline tolerance during tomato improvement

Jian Liu; Chi Zhang; Heyao Sun; Yinqiang Zang; Xianwen Meng; Huawei Zhai; Qian Chen; Chuanyou Li

doi:10.1093/hr/uhae055

A natural variation in SlSCaBP8 promoter contributes to the loss of saline-alkaline tolerance during tomato improvement

Hortic Res. 2024 Feb 23;11(4):uhae055. doi: 10.1093/hr/uhae055. eCollection 2024 Apr.

Authors

Jian Liu¹, Chi Zhang¹, Heyao Sun¹, Yinqiang Zang², Xianwen Meng², Huawei Zhai², Qian Chen³, Chuanyou Li⁴

Affiliations

¹ College of Agronomy, Shandong Agricultural University, Tai'an, Shandong 271018, China.
² College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, China.
³ Beijing Key Laboratory for Agricultural Applications and New Techniques, Plant Science and Technology College, Beijing University of Agriculture, Beijing, 102206, China.
⁴ College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, China.

Abstract

Saline-alkaline stress is a worldwide problem that threatens the growth and yield of crops. However, how crops adapt to saline-alkaline stress remains less studied. Here we show that saline-alkaline tolerance was compromised during tomato domestication and improvement, and a natural variation in the promoter of SlSCaBP8, an EF-hand Ca²⁺ binding protein, contributed to the loss of saline-alkaline tolerance during tomato improvement. The biochemical and genetic data showed that SlSCaBP8 is a positive regulator of saline-alkaline tolerance in tomato. The introgression line Pi-75, derived from a cross between wild Solanum pimpinellifolium LA1589 and cultivar E6203, containing the SlSCaBP8^LA1589 locus, showed stronger saline-alkaline tolerance than E6203. Pi-75 and LA1589 also showed enhanced saline-alkaline-induced SlSCaBP8 expression than that of E6203. By sequence analysis, a natural variation was found in the promoter of SlSCaBP8 and the accessions with the wild haplotype showed enhanced saline-alkaline tolerance compared with the cultivar haplotype. Our studies clarify the mechanism of saline-alkaline tolerance conferred by SlSCaBP8 and provide an important natural variation in the promoter of SlSCaBP8 for tomato breeding.