Molecular mechanism behind soybean adaptation to short-day, high-temperature environments cracked

A team led by Professor Nian Hai of the College of Agriculture at South China Agricultural University and Researcher Han Tianfu of the Institute of Crop Sciences at the Chinese Academy of Agricultural Sciences announced on the 22nd that important progress has been made in research on the molecular mechanism of soybean adaptation to short-day, high-temperature environments. They cloned the soybean long-juvenile gene J, which researchers had been searching for for nearly half a century, and revealed the distribution patterns of J in soybean varieties from China, the United States and Brazil. The related research results were published in the journal Molecular Plant.

Tropical regions were long considered unsuitable for soybean cultivation. In the 1960s and 1970s, scientists discovered "long-juvenile" germplasm resources that delay flowering under short-day, high-temperature conditions, have a longer vegetative growth period and accumulate more dry matter, and applied them in soybean breeding, enabling soybeans to expand rapidly in low-latitude regions. But until now, genetic and breeding scientists had been unable to confirm the specific gene and mechanism of action that determine this trait.

Han Tianfu and other researchers constructed a recombinant inbred line population using the conventional variety "Zhonghuang 24" and the long-juvenile variety "Huaxia 3" as parents, used RAD-Seq technology to construct a genetic map, carried out linkage analysis and combined it with whole-genome resequencing of the parents, and mapped the long-juvenile trait to the GmELF3 gene. They found that in "Huaxia 3", this gene is missing one base, causing a frameshift in the gene sequence and inactivation of the protein it encodes, thereby delaying flowering and producing the long-juvenile trait. Introducing the GmELF3 gene from "Zhonghuang 24", namely the J gene, into "Huaxia 3" achieved functional complementation and made "Huaxia 3" flower earlier, further proving that the GmELF3 mutation causes the long-juvenile trait.

It is reported that the cloning of the J gene provides a technical pathway for improving excellent soybean varieties in mid- and high-latitude regions, and is of great significance for developing soybean production in low-latitude regions, expanding the areas where soybean varieties are planted, and enhancing the capacity to ensure plant protein supply. (Reporter Li He)