Transcriptomic changes in donor soybean, dodder bridge, and the connected recipient soybean induced by cadmium addition.

Abstract

Background: Cuscuta spp. (dodders) are parasitic plants that belong to the Convolvulaceae family. In nature, dodder often forms a bridge-like connection between two or more host plants like, which is known as a dodder bridge. Cadmium (Cd²⁺) is an important heavy metal ion that affects plant growth. However, it remains unclear whether Cd²⁺ treatment can directly or indirectly induce transcriptomic changes in plants through dodder bridge.

Results: In this study, a pot experiment was conducted to investigate the effects of Cd²⁺ treatment on donor plant and neighboring recipient plant connected by dodder bridge. Transcriptome analysis revealed that Cd²⁺ treatment significantly affected the expression of genes involved in the 'Plant-pathogen interaction', 'phenylpropanoid biosynthesis', and 'isoflavonoid biosynthesis' pathways in both donor and recipient plants at 2, 12, 24, and 48 h. Cd²⁺ indirectly induced changes in the dodder bridge, which included processes related to oxidation-reduction ('oxidation-reduction process', 'oxidoreductase activity', and 'regulation of transcription') and Ca²⁺ signaling pathways ('Plant-pathogen interaction', 'MAPK signaling pathway', 'AMPK signaling pathway', 'mTOR signaling pathway'). Additionally, mRNA transfer was observed from soybean to dodder. mRNA, Ca²⁺ and ROS might play crucial roles in the signal transduction process induced by Cd²⁺ stress.

Conclusion: Cd²⁺ treatment could directly and indirectly induce transcriptomic changes in the donor plant and neighboring recipient plant connected by dodder bridge. These results contribute to a better understanding of how plants connected by dodder bridges respond to environmental stresses.