Secreted Peptide SpPIP1 Modulates Disease Resistance and Salt Tolerance in Tomato

Tomato is a globally important horticultural and economic
crop,
but its productivity is severely affected by various stresses. Plant
small secretory peptides have been identified as crucial mediators
in plant resistance. Here, we conducted a comparative transcriptome
analysis and identified the prePIP1 gene from Solanum pimpinellifolium (SpprePIP1), as an ortholog of Arabidopsis prePIP1 encoding the precursor protein of PAMP-induced SSP
1. The expression level of SpprePIP1 is transcriptionally
induced in tomato upon infection with Phytophthora
infestans (P. infestans), the pathogen responsible for late blight. Overexpression of SpprePIP1 resulted in enhanced tomato resistance to P. infestans. In addition, exogenous application
of SpPIP1, whether through spraying or irrigation, improved tomato
resistance by enhancing the transcript accumulations of pathogenesis-related
proteins, as well as reactive oxygen species and the jasmonic acid
(JA) levels. Integrated analysis of transcriptomics and metabolomics
revealed the potential contributions of JA and phenylpropanoid biosynthesis
to SpPIP1-induced tomato immunity. Additionally, SpPIP1 may strengthen
tomato resistance to salt stress through the ABA signaling pathway.
Overall, our findings demonstrate that SpPIP1 positively regulates
tomato tolerance to P. infestans and
salt stress, making it a potential plant elicitor for crop protection
in an environmentally friendly way.