Overexpression of -Like Lectin Genes from Confers Tolerance toward Infection, Aphid Infestation and Salt Stress in Transgenic Plants.

Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL) groups all proteins with homology to the tobacco () lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (), referred to as NLL1 and NLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the NLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, infection and infestation trigger the expression of particular genes. Stress experiments with lines overexpressing the from soybean yielded an enhanced tolerance of the plant toward bacterial infection (), insect infestation () and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.