Plant-Fungi Mutualism, Alternative Splicing, and Defense Responses: Balancing Symbiosis and Immunity.

Alternative splicing (AS) is the process of RNA maturation in eukaryotes, which is essential for post-transcriptional regulation. The transcripts produced by AS can encode distinct protein isoforms and contribute to the regulation of eukaryotic growth and development in response to a changing environment, and they are crucial in plant-fungal interactions. Plant-fungal symbiosis is one of the most significant biotic interactions in the biosphere. The symbiotic association of fungi not only improves plant growth and resistance but has potential significance for endangered species conservation and reproduction. Alternative splicing is involved in regulating symbiotic responses to host immune signals, regulating the host-symbiont contact, and initiating signaling during symbiosis. In recent years, mRNAs research has been progressing rapidly, and AS is an important post-transcriptional regulator that requires further investigation. However, while AS has been widely studied in mammalian disease research, very limited studies are available on the regulation of AS in plant-fungal symbiosis and their role in benefiting the interacting partners. In this review, we provide an overview of our existing knowledge about AS in symbiotic plant-fungal relationships and discuss potential hotspots for future investigation to expand our understanding of plant-fungal interactions.