Discovery of protein interactors of SUGARWINs in Saccharum officinarum using cDNA library screening.

Sugarcane holds considerable commercial significance due to its role as the primary source of sugar and its potential as a global biofuel resource. Fungal pathogens and insect pests present significant challenges to the cultivation of this crop, leading to substantial reductions in crop yield and sugar recovery. In response to pathogen infection, plants initiate their defense mechanisms, which involve the upregulation of pathogenesis-related proteins such as chitinase, glucanase, and chitosanase. SUGARWINs refer to a group of PR-4 proteins that are associated with the defense mechanisms of sugarcane against phytopathogens. Their gene expression is induced in response to wounds caused by Diatraea saccharalis larvae and diseases caused by fungal pathogens such Colletothricum falcatum and Fusarium verticillioides. We report the finding of some other proteins that interact with SUGARWINs and may also have a role in the defense against fungal diseases. The sugarcane cDNA library was screened against SUGARWIN1 and SUGARWIN2 proteins to find possible interactors. A strong interaction of both SUGARWIN1 and SUGARWIN2 was observed with oxygen evolving enhancer protein 1 and synaptotagmin 1. These interactions were further validated by BiFC (biomolecular fluorescence complementation) assay. For further molecular characterization, subcellular localization studies of SUGARWINs and interactor proteins were conducted by translational fusion with green fluorescent protein. Sugarcane yield is threatened by fungal pathogens, prompting plants to activate defense proteins such as SUGARWINs. This study identified two SUGARWIN interactors – oxygen evolving enhancer protein 1 and synaptotagmin 1 – through cDNA library screening, with interactions confirmed by biomolecular fluorescence complementation assay. These proteins may contribute to fungal resistance, offering insights into sugarcane's defense mechanisms and potential strategies for enhancing crop protection. This article belongs to the collection: Functional Genomics for Developing Climate Resilient Crops - Volume II. [ABSTRACT FROM AUTHOR]