[Screening of target protein interacting with lipid transfer protein AsE246 of Astragalus sinicus and expression...

AsE246 was a novel nodule-specific expressed nodulin gene encoding non-specific lipid transfer protein 1 (nsLTP1) of A. sinicus. We screened and identified host plant target protein interacting with AsE246, and characterized the expression patterns of target gene under symbiotic and stress conditions.

Yeast two-hybrid system, small-scale yeast hybridization test and real-time PCR technique were used to capture the host target protein that interacts with the bait protein AsE246, and to quantitatively analyze the temporal and spatial expression characteristics of target gene during root nodule development and nitrogen fixation process.

One positive clone was obtained, its cDNA insert sequence and Blast analysis showed that: the target protein was a DnaJ-like protein, thus the corresponding encoding gene was named as AsDJL1. AsDJL1 was specifically-enhancing expressed in nitrogen-fixing root nodules, and significantly increased under NaCl stress while significantly decreased under (NH4) 2SO4 stress.

This work was the first report on the isolation of proteins interacting with LTP. The work obtained some direct and convincing evidences to show the interacting gene demonstrated high similarity as AsE246 in expression patterns and functions involved. The present progress provided a basic foundation and theoretical basis to undertake any further investigation into their interaction, and regulation mechanism associated with symbiotic nitrogen fixation or response to environmental stress.