, a Soybean Expansin-Like B Gene, Alters Root Architecture to Improve Phosphorus Acquisition in .

Expansins comprise four subfamilies, α-expansin (EXPA), β-expansin (EXPB), expansin-like A (EXLA), and expansin-like B (EXLB), which are involved in the regulation of root development and growth under abiotic stress. To date, few EXLB genes have been shown to respond to low phosphorus (P) in plants. In this study, we identified an EXLB gene, , by analyzing the transcription profiles of GmEXLBs in soybean. Quantitative analysis showed that was expressed and induced in the lateral roots of soybean under low P conditions. The observation of β-glucuronidase staining in transgenic suggested that might be associated with lateral root emergence. overexpression altered the root architecture of transgenic by increasing the number and length of lateral roots and the length of primary roots under low P conditions. Additionally, the length of the elongation zone and the average cell length in the elongation zone were increased in transgenic . Increases in biomass and P content suggested that overexpression enhanced P acquisition in . Overall, we conclude that expression is induced in soybean under low P conditions, and the overexpression of improves P acquisition by regulating root elongation and architecture in , which provides a possible direction for research of the function of this gene in soybean.