Functional characterization of phosphorus deficiency-responsive GmNTLs in soybean roots

Objective  Low phosphorus (P) availability and aluminum (Al) toxicity constrain crop production in acid soils. NTL transcription factors play an important role in the mechanisms of plant response to various abiotic stresses, including Al toxicity. This study focused on analyzing the function of GmNTLs in soybean roots responding to P deficiency.

Method  Expression pattern were performed on 15 members of the GmNTL family in the soybean by RT-qPCR assays. We further investigated the function of some GmNTLs members in adaptation to low P by overexpressing the genes of GmNTL1/4/7/8/10/12 in Arabidopsis thaliana.

Result  The phylogenetic analysis and the tissue expression analysis of each subfamily members revealed that 15 GmNTLs were divided into three subgroups and different GmNTL family members had different tissue expression pattern in soybean. The RT-qPCR results showed that the expression levels of GmNTL1/4/7/8/10/12 in soybean roots significantly increased after 12 days of low P treatment. Overexpression of different GmNTLs in Arabidopsis showed different responses to low P. The fresh weight of transgenic Arabidopsis overexpressing GmNTL4/10/12 significantly increased compared to control lines under high P treatment. Overexpression of GmNTL4 significantly improved fresh weight of transgenic Arabidopsis plant under low P deficiency; Whereas, the plant fresh weight of transgene lines overexpressing GmNTL1/12 significantly decreased. Overexpression of GmNTL12 reduced the primary root length of transgenic plants; Whereas, overexpression of other GmNTLs had no significant effect on primary root length.

Conclusion  GmNTLs involve in the response of soybean roots to low P stress, and these results can provide a theoretical basis for cultivating soybean varieties with high P efficiency.