Purification, Characterization, and Expression Analysis of a Putative Lectin in Peanut ( Arachis hypogaea L.).

A lactose-specific lectin (named Arachis hypogaea L Lectin (AHL)) was purified from the seed of the peanut Arachis hypogaea L. by single-step affinity chromatography using lactose-coupled agarose. AHL showed strong hemagglutinating activity to human A/B/O erythrocytes (RBC) treated with neuraminidase. The results of matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry (MALDI-TOF-TOF MS) analysis indicated that the protein AHL shared high homology with the peanut lectin chain A protein (gi|1942899). The AHL has binding activity to some Gram-negative bacteria and fungi spores which caused disease in peanut. Transcripts of AHL were detected in different peanut tissues, and the expression profile of the AHL gene changed in different parts of the plants. The variation in the mRNA transcript level in seeds was quantitated by real-time polymerase chain reaction during different growth periods. The expression profile of the AHL gene changed greatly in samples collected in different days after pegging. We explored the variation in AHL mRNA expression in six cultivars of peanut; the expression level observed in Lu Hua 12 was the highest. The data we described can provide us with clues to know more properties about peanut seed lectins at the biology chemistry and molecular biology level. [ABSTRACT FROM AUTHOR]